Sizewell to forum, calling Sizewell..........................................

 

Just catching up on this thread now. I'll see if I can contribute anything once I I have read the whole thread.

 

Does the P0016 error clear when the engine is hot, and stay off?

 

No. If I reset it comes back on after a couple of starts and stays on.

 

From limited experience on a volvo VVT system and some theory (only): higher oil temperature means less pressure, and so does lower (idle) speed. This suggests that higher oil pressure is locking either a VVT actuator or its solenoid. Could you swap solenoids around and see if the fault follows a solenoid – P0017/8/9?

 

Good observation. So it could be that the locking pin in one (or more) variator is remaining locked after startup. It's only supposed to lock the cam position during no oil pressure as the engine starts then it's designed to release. So it could be one variator's pin is needing too much pressure to release it. This was my best guess. I wonder how easy it is to replace variators?? To do the cam chains on this engine its a full engine out job, was trying to see what I could do without replacing everything related and doing the full job. :evil:

 

Nice to swap sensors as well first.
Otherwise 3 chains, 3 tensioners, 6 saddles, some sprockets, pack of different gaskets, etc. My goodness...
Sure parts budget is about 2k in GM pricelist. Alfa one could be hardly imagined. And labour cost add on of course. Please accept my condolence...

 

The dreaded P0016...
At least it is on the 4 cylinder engine where it always means the cam chain.

 

Why is oil pressure at start up is high ???... Just because of increase from zero pressure to conventional idling one. No. There exist much higher pressure engine working regimes to engage solenoids.
Moreover solenoid is el.+mech. devise means that particular failure code would be triggered directly for each from four solenoids.

 

Just because the oil is cold; but it could be a pressure and temperature effect.

.Temperature will have a direct effect on the solenoids, expanding the casing and freeing off the piston

Temperature could also be affecting 'your' sensor(s) of course....

The ecu will know if the solenoid coil is faulty and set a code. It's theoretically possible for it to work out whether the piston has actually moved, from the inductance of the coil, but this would require extra hardware in the ecu and I doubt that they do it; so you won't get a 'stuck piston' code.

This is all theory though. If you want to get technical about it you need to set up a two channel oscilloscope to display the crank and affected cam sensor. You can then see the phase relationship between the two and, hopefully, work out what is going wrong. It might be easier to swap solenoids/sensors though, as a starting point.

 

Oil is cold of course at first start but how really far. I could hardly believe temperature oil impact from sump down to up at solenoids.
And it is Australia. Sure it is 25"C++ now. Anyway it is clear what to do now. Let us hope for miracle.
What bloody stuff are chains made of now ???...

 

I know - it is strange... That's why I am looking for help from the fine people on this forum :blabla:

 

Thanks everyone, all comments are very welcome. It's a weird one. Just the fact that under certain conditions it works fine and not at others makes me think it's less likely a chain.

Oh and the code that is triggered is a "result" (or symptom) of the problem not the actual problem. So the code is saying that one cam is out of phase - meaning it has noticed that one cam is not varying it's timing the way the ECU is expecting. So it's the symptom or result that it is reporting not the specific item that is causing it...

I've attached a printout of the fault code for my vehicle.

Happy New Year :-D

 

Useful attachments.

The ECU cannot wait for ever for the camshafts to set. Once the ECU has issued the instruction to "Unlock" a camshaft: a continuous sequential process, it expects a "tell - back" from the camshaft position sensor, attached to the actual camshaft via the rotor which is the advance/retard mechanism, within "X" time frame. Otherwise, the "wait" will "Time Out" and the ECU will see this as a fault - hence the code. But this can occur due to low oil pressure; The voids are substantial and the orifice for the oil feed to them is restrictive; and pressure is too low to work properly.

What is more alarming about this "Alfa Design" is, when the Solenoid Valve opens to drain either the advance; or retard cavities of either the inlet or exhaust camshafts, their operating times are unequal.

Fundamentally this is because, the inlet camshaft retard time is faster than it's advance. Conversely, the exhaust camshaft advance time is faster than it's retard. Why? because of the internal spring in the Phaser mechanism.

This spring biases the camshafts in the direction of their "Park Position" Inlet - fully retarded, Exhaust, Fully advanced.

When a solenoid valve opens to drain, it is open to "Cam Cover Pressure" - virtually atmosphere and it can quickly empty due to the large orifice on the snout of the V.V.T. solenoid device: too quickly for the oil feeding into the voids, which should be controlling the rotation of the camshaft to it's new "Preset Position. In the case of the inlet retarding, this is made worse by the bias of the internal spring. In the case of the exhaust advancing, made worse by the bias of it's internal spring. This can cause "Cavitation" and certainly does not result in the camshaft "Locking" when the ECU instructs the solenoid valve to close the voids. And these solenoid valves open and close, very fast; intentionally, to ensure that both sides of the vanes of the camshaft phasers are constantly full of oil.

Only when this condition is satisfied will the camshaft be held in position, when the thrust of the rocker arm loads the face of the camshaft. A principal reason for this engine never to achieve it's stated economy figures and probably low specific power output. The net effect is "The camshafts are never held in their set position - ever!"

Not only that, by "Filing to Flats" which bridge the two walls that separate the valve ports on the V.V.T. solenoids, the pressure will indeed equalize, but even when the ports are closed in the set position, the camshaft will continue to rotate under the influence of the internal spring. as it forces oil before it, across the "Bridge to the cavities; voids behind the direction the spring is naturally biased towards. Also, this is subject to the thrust on the camshaft face, exerted when it rotates and comes into contact with the valve rockers.

This phenomenon can be minimized with sufficient oil pressure, which this engine does not have. Fundamentally, the oil pressure should exceed the pressure on the thrust face of the cam shafts by a very large margin - which it does not. Alfa, I think realized this and that is why this engine is fitted with very broad dwell angle camshafts; to minimize the error, inherent in their V.V.T. System. And they should not have bridged the solenoid walls which separate the the ports. An obvious mistake.

These "Flats", not only fail in to do what they were intended to, but they also provide a continuous drain of oil, from supply input, across, one or the other "Bridge", to whatever drain happens to be open, when the ECU instructs the camshafts to "Unlock", "Continuously" reducing the oil pressure across the block galleries.

An otherwise very good engine; no, a very very good, very strong engine is reduced to ridicule. "Pride goeth before destruction and Haughtiness before a fall". On the basis of what I believed Alfa did with this engine, I'm not surprised they got someone from Ferrari to design the Giulia's engine. I hope for their sake, there was absolutely no involvement in it's design by Alfa. :rage::rage::rage::rage::rage::rage::rage:

Intermittently jammed open Spray Jets, after the engine has been switched off, will cause the block to drain down and your bearings will suffer until your oil pressure is sufficient to overcome the continuous bleed they are causing, when you start the engine up again. And if the engine is hot and one or more are jammed open/ leaking, they will reduce the oil pressure to the V.V.T.'s.

 

Someone correct me if I'm wrong, but my understanding is that there are three chains in the 3.2l V6 engine. 1 chain for each bank of the V and a balance shaft chain. So lets say the timing chain for the rear bank is a little bit more stretched than the front one - to the point where it is throwing up the error. Temperature affects tolerances and oil viscosity... I wouldn't discount a chain, especially when the error code points at it. It's tempting to overthink a symptom when the cure is an injection of money!
One bit of information missing from your description is how many kms/miles since the chains and slippers were replaced.

 

Correct - 3 chains.
As I mentioned - 130,000kms / 85,000m - never touched the cams/chains etc.

Sure it's fair enough to throw money at it and just replace everything - chains, variators, solenoids, sensors etc. But it if is just one particular item, then I'd rather do that.

It doesn't make a lot of sense that one of the three chains is stretched. Wouldn't they pretty much wear together. The main thing is that it works "on and off" meaning sometimes it will just stop working, and if the oil is hot, I can simply put it in neutral for more than 6 seconds, then it will work. This is unlikely to be a chain - it's more likely a variator, solenoid or sensor from what I can gather.

Regardless all the suggestions and ideas are very helpful.
Thank you.

 

This was more to do with the 2.2 engine, but may be helpful:
http://www.alfaowner.com/Forum/alfa...ider/363215-brera-2-2-jts-electromagnet-solinoids-timing-chain.html#post5116109

 

Thanks sizewell, that is very interesting. Sounds like is less likely to be the chains and possibly one or more components of the internal workings of the VVT.

From the limited information I have provided here do you have any educated guess as to which components are causing my issues?

Would replacing any of: solenoids, variators, sensors etc solve my issue? Could it be a faulty spring in a solenoid or something like that?

What oil would you recommend given your knowledge with these issues? I am currently running 0w40 and am in Australia where average temps are 20-35degrees C. I was running 5w-40 up until this issue started some 6 months ago.

Would it be an option to put a higher flow oil pump???

Many thanks for your knowledgeable input!

 

Ok so this is proving to stump a lot of Alfa specialists... Maybe someone can shed some light.

I have a 159 with the 3.2 JTS engine and have an issue with the variable valve timing (VVT) not working.

When the engine is cold the VVT does not work, meaning under load the valve timing does not change and the engine lacks power. Once the engine oil temp gets up to operating temp it works fine and engine has full power across the rev/load range.

This happens 100% of the time - doesn't work cold, works hot.

The ECU shows a P0016 error (Phaser exhaust sync error bank 1/sensor A). It is always this code that comes up. I have had occasionally a P0105 error but I think that is a result of the camshafts not working properly. I no longer am getting the P0105 though, just the P0016.

Something very interesting is that when the car is almost at full operating temperature and the VVT is working it will sometimes stop working. When this happens, while I am driving, I put the car in neutral and let the engine idle for 6 or more seconds and then put it in gear and continue driving - the VVT will then start working again – every time.

The problem started 6 months ago and it does it 100% of the time when cold – VVT does not work. In the beginning it would start working when the oil reached 70degrees C but now the oil temp pretty much has to be full operating temp (around 100 degrees) before it works consistently. Currently car has 130,000 kms / 80,000 miles.

In the beginning I thought it was an oil issue as one oil change I left the oil in for 15k miles instead of the normal 6k miles. So I had all the four solenoids removed and cleaned. The mechanic said they looked clean and seemed in good working order. Although it still may be a possibility one is faulty. I was using a 5w-40 fully synthetic oil, now I am using 0w40 fully synthetic (and I stick with the proper PAO/Esther oils). Since this issue I have also been doing an oil flush with the oil changes, but the problem has not abated.

Another thing I read is that there is a locking pin that stops the VVT working on start up. This is because there is no oil pressure and the locking pins stop the cams from moving uncontrollably at start-up. Once the oil pressure is up the pins release and the VVT works. It almost feels like this pin is getting stuck (at least on one or more cams) – but that is my layman’s guess.

I have contacted a number of Alfa specialists here in Australia and even quite a few in the UK - none have heard of this kind of issue. Some suspected a stretched chain but realized that it likely would be an issue at all temps not just cold. Edward at Edward labinjoh has been quite helpful and has seemed the most knowledgeable on the subject but he's still looking into it.

Apologies for attaching your original post, but it makes it easy to refer back to it when trying to answer your last.

V.V.T Solenoids - they are easy to check. Take them out individually and remove the retaining spring which is over each V.V.T. Port mesh. The mesh can be gently "Uncurled" from the port sections to expose the Solenoid Piston.

In their rest state, one should be able to see the opening around the edge going to the Drain, which is the snout of the device body - where the oil exhausts out into the head. The central port ( input ) in the un - powered state will be open to the rear port, nearest the Solenoid power socket. You should be able to blow through that to ensure it is not fouled in any way.

Others on this site will be able to tell you the solenoid operating voltage; 5 volts or possibly 12 volts. Otherwise, connect it to a variable power supply and slowly turn up the volts until it operates - then stop. depending upon which way you have connected your Power Supply to the pins, the V.V.T. will either, if it is working correctly, move to close off the input port to both the advance and retard ports either side. Reversing the polarity of the power to the pins and the rear port should now connect to the drain and the input port to the front port. It may be that the reverse is true, but no matter, you should be able to determine that the solenoid valves are functioning correctly.

Should there be a problem you should see it straight away. whilst doing this, you can give the V.V.T. meshes a good clean as these meshes are very fine and in themselves cause a pressure drop. It would be good however if someone could actually provide the correct detail, w.r.t. the working voltage. These tests will eliminate, or otherwise, the V.V.T.'s from the equation.

Personally, I am tempted to take the meshes off the Advance and Retard Ports as nothing is going to get through the one on the input - of any size that is. And there should be nothing in the V.V.T. Voids in any case. But that is me just speaking off the top of my head.

Rather than working on the basis of speculation, or indeed opinion; including mine, "IT REALLY IS A GOOD IDEA TO FIND OUT EXACTLY WHAT YOU ARE DEALING WITH".

Personally, my first port of call would be to determine exactly what your oil pressure actually is.

To do this, it would not be a bad Idea to buy a 100 PSI transducer to screw into where your Oil Pressure switch is. This connected into the Oil Cooler/Filter assemble, at the front of the block, just to the left of the front bank exhaust manifold. They are available on the internet/e-bay for under £20 and are powered by 5 volts DC. The output is scaled 0.5 volts = 0 PSI, 4.5 volts = 100 PSI, I.E. 2.5 VOLTS = 50 PSI They are Three wire devices" and the output can be referenced using a digital volt meter - across output wire and zero volt rail.

Or you could use a conventional capillary gauge.

As the position of the Oil Pressure Switch is in the gallery feeding from the Oil Cooler/Filter into the block, this will give you absolute evidence on what pressure your engine is working at and all speculation on about this will be resolved. This alone will eliminate, or otherwise, a fundamental factor; not necessarily the sole one but non the less an important one, "YOUR ENGINES WORKING OIL PRESSURE".

If you are not comfortable with this, your garage/mechanic can do this for you. "Just tell them/him what you want done. I understand how some "Mechanical Pre-Madonnas" like to do things their own way, but never come up with anything concrete. It's a simple check and it will help you hugely in getting to the bottom of your problems.

I am conscious of running the engine, if indeed it is being bled dry, but you are going to have to bite the bullet at some point. Just stay off the throttle. However, once the oil pressure is determined and oil is circulating around the engine, one can quickly determine how well that pressure holds at tick over and indeed if the engine is switched off and then re-started. If the galleries are being drained down by for instance, those spray jets, it should be quick to spot it.
Just kicking what you have said around in my head and not intended as definitive, however, Bank 1, sensor A P0016 - is that the rear bank exhaust sensor? If it is, it is furthest from the furthest oil pump and fed from a convoluted junction at the centre of the V where the take off for the crank, journals and spray jets are fed. Also from the rear main gallery, the lower timing chain tensioner is fed.

Also, you went 15 k instead of your usual 6 k. Is it possible your oil filter bypass valve operated because the filter was blocked and allowed some detritus into the block? The camshafts have individual Check/Non return Valves in their feed from the block galleries, into the heads, where these N.V.R.'s are fitted. Their orifices, when the ball is open is possibly less than 2.mm. There may be some "Crap" on the underside of the check valve; or even in it, causing a blockage, or partial blockage, sufficient to cause it to fail when the engine oil is cold/too thick, yet sufficient flow can get through when the oil is hot.

Either way, the actual intended design of "Mad Dog Alfa" allows a substantial amount of oil to flow across the V.V.T. Bridge to drain and yet they get away with it - just.

So if there is any chance there is detritus around the/those check valves, but notably the one with the P0016 code, it will do no harm if the V.V.T. is withdrawn when the engine is running: but leave it electrically connected, and inspect the oil flow coming up from the head - fitted N.V.R. below. On tick over, the cam shafts should be locked in any case - meaning oil pressure is below the spring pressure required to release the pin. A blip of the throttle should see the oil pressure spout up. If indeed there is detritus causing a restriction, that damned "Bridge" is making matters worse, to the extent the pin cannot release.

Also, If your oil is hot and the V.V.T. oil pressure is barely enabling it to work, thin oil will flow across the bridge more readily, allowing the cam shaft to return to it's locked position, under the influence of its internal spring: if the valve timing is set for what is light load characteristics - such as on a flat section of road on cruise control - for instance.
"The Phasor is rotated only a small distance from the Lock position and thus as oil flows across the Bridge, it returns to its preset position and the Lock - Pin engages.

Would consider an extra oil cooler myself - just a though for when you get this sorted.

 

Wow, thanks Sizewell, that's a lot of detailed information. I think I'll have to start with checking oil pressures, then get the solenoids re-checked. I read that you said best not to drive it, but I have to say I've been driving the car a lot. In fact this weekend I did a 700km country trip at highway speeds - 110-150km/h (or whatever I could get away with). After continuous driving the check engine light actually went off. I guess it was the long time operating at normal temperatures. Still the VVT would stop here and there while driving, but the 6 seconds+ coasting in neutral then re-engaging, got it working every time.

From your description of how things work I'm taking a guess its the solenoids, which was my guess from the very beginning. I think when I got them checked they (the mechanic) didn't look as carefully as you have outlined.

 

Good Luck, hope you get it sorted.

 

Hope you guys don't mind me jumping in here but I'm having an almost identical experience as crimson96 with my own Brera 3.2 V6. I have the dreaded P0016 Phase Synchronisation (exhaust)/revs but I noticed that it didn't always come back immediately if I cleared it with the engine hot and running. I too experienced the EML going out on a long drive. However having replaced the exhaust cam phase sensor on the rear bank of cylinders to no effect I had a closer look at the values using multiecuscan as described earlier in this thread. The odd thing is that when I take a look at the values for the rear bank exhaust sensor with the engine running it seems to work fine for a while then goes back to zero. I need to investigate this further as I haven't yet established the exact circumstances when the sensor stops working but the car drives like I'm getting intermittent performance. Sometimes it goes like a tortoise and other times all seems to be working fine and it will take off like the hare.

The desired values and actual values for the 3 other sensors appear normal although as this is all new to me I'm not 100% clear what I'm looking at! Intend to inspect the solenoids as the next port of call but very interested to hear how you get on with your inspection. Thanks

 

Hi. IMHO, Alfa made a real dogs dinner of the V.V.T. system which they just strapped on to the standard G.M. cast Block. You can see this when looking at the block as the gallery up to the head of the front bank is ~ 16 mm., whereas the rear gallery is ~ 9 mm. My Spare engine is away at the moment, having the work done on the V.V.T. system but these are; if I recall correctly, the figures I recorded earlier in a post. The difference between the two is; I believe, because the Insignia Turbo oil feed was taken from the front bank.

To add to this the oil ways of the block are extremely tortuous and result in considerable imbalance in oil flow/pressure. Plus, Alfa clearly were in trouble with the V.V.T. system and that IMO is evidenced by the fact they cut flats across the isolation separators of the V.V.T. Solenoids. So whenever the V.V.T. is instructed to set, oil pressure, needed to rotate the vanes of the V.V.T.'s is reduced because it is bled straight to whichever V.V.T. solenoid port is open to "Drain". In essence, this slows down the V.V.T response time even further, increasing the risk that the E.C.U. {E.M.S}; which is "Watching" for the positional sensor input pulse to "Set/Lock" the Camshaft in position, to "Time Out" and thus an error code. And this will be worse when the engine oil is hot.

That it happens to be the rear bank exhaust camshaft is to me obvious as this is furthest away from the oil pump at the end of these tortuous galleries.

To alleviate this problem, my modifications include a bypass pipe which takes oil from my modified Oil cooler/filter assembly into the rear bank plug which is behind the Alternator Mounting Plate. As this is taken directly from the Oil Cooler/filter assembly, it will be; less a little attenuation due to the length of the bypass pipe, substantially the same pressure as that which enters the block by the conventional galleries.

It will also benefit the lower timing chain tensioner, which is in close proximity to the rear block plug.

With the particular type of oil used; low viscosity, at higher temperatures, the flow rate across the V.V.T. "Bridge" to drain; IMHO, leaves insufficient oil pressure to sustain the rotation of the camshaft to the correct E.C.U. derived position. The Exhaust camshafts are naturally biased towards the "Maximum Advance Position of by the Internal Spring of the V.V.T. Solenoid". In other words, low oil pressure is increasing the time it takes for the camshaft to "Set", taking it outside the time when the E.C.U. is expecting the pulse from the positional sensor.
Alfa's insistence on such a low viscosity oil; the basis being to speed up the V.V.T. operating times is counter intuitive given the blasted bridge they cut into the V.V.T. Solenoids. And does little to protect the rest of the mechanicals.

Were I not to address these problems, knowing what I know now, I would be running a higher grade oil, probably going to the same grade as my 916 3.0 GTV. IMHO, it will do the engine a lot more good than the current oils recommended. Especially if I was running this engine in hot climates such as Australia. Just a thought! But worth a try - could be a simple solution to an expensive problem which will never be resolved by Alfa.

It is clear from the 159, 3.2 handbook when they state "No need to warm the engine up on start up, the engine can be driven straight away without warming the oil", the reason they say this is because, "On Tick-over/Idle, the inlet camshaft advance void is open to drain and the exhaust camshaft retard void is open to drain, so oil pressure is at it's lowest. So they know there is a problem.

 

I've had my Brera 3 weeks now (bought it with the error P0016) and have done alot of study on the issue. I'll admit my initial understanding (see above) was wrong. Mine has done 100,000km and I've ordered the chains, pads etc from GM in the US without bothering to get my oscilloscope out or disassemble the engine to inspect the parts.The Holden guys here say the chain stretch might only be 3-4mm over it's length to cause the issue.

This is what I think is happening:
- chain(s) stretch and pads wear with use. Consider how many revs the engine must have done in 100,000km! A metal chain running over a plastic pad - it's got to be worn by now.
- phasing relationship between cams change because of the wear of these parts.
- the phasing relationship is measured in 1000ths of a second. Worn parts mean a camshaft gets into position 'late'. When the computer detects timing exceeds preset limits via the camshaft sensors the computer throws up the P0016 error and lights the 'check engine' warning.
- to protect the engine from damage (valves and pistons kissing) the computer locks the solenoids and hence power output is limited. In the direct injection engines the clearance between valve and piston is tiny.

I'll let you know how I get on. I've put my money on the chains/pads being worn.

 

Fine! Although most of what you say is not true. The sampling rate is based fundamentally upon the ring on the crankshaft and there are not many "Teeth" - for want of a better word, to produce pulses of mere milliseconds. The E.C.U. functions on the basis of the analogue derived signals from the sensors. True, the E.C.U. has to work quickly, but it is predictive. The analogue inputs to this engine are crude and there is considerable margin for inaccuracy.

I have before me the camshaft and the V.V.T. sprocket. This is not speculation this is fact. It may well be unpalatable for those that have spent money on new chains - my engine has now got 108,000 on it - but the distances that the chain can stretch in the intervening space between inlet camshaft and exhaust is no where near as great as can be induced by, a) erroneous level detection from the positional sensors - G.M. did not change theirs on a whim, and b) given that detection times of the positional sensors will be extended due to low oil pressure, they amount to the most obvious failing. If the chain stretch is the fundamental cause, surely that will affect both camshafts on both banks.

I am not ignoring the chain tensioner wear but my spare engine has done less than sixty thousand. Two of the three spray jets were jammed open, permanently reducing block pressure. And looking more closely at the tensioners and guides, the wear is not that great.

I, for one am hoping that I can get those bolts out of the V.V.T. sprockets, without having to take the front cover off. and then I will be improving, firstly, the oil flow by turning the shank of the bolts down by about 1 mm. and then fitting Dowty washers between the face of the sprocket and the bolt head.

You can spend as much money as you like, changing your chains. But I am stating categorically, the lack of a copper or Dowty washer and the shank of the bolt, restricting the flow to the voids is not speculation. It's fact

 

A couple of questions Sizewell.
If the VVT works properly at high temperatures, then wouldn't that imply that oil pressure is sufficient? At cold temperatures pressure would naturally be higher than at hot temperatures - correct? So if it works fine at high temperatures and causes issues and colder temps, then wouldn't that mean it isn't oil pressure?

Also someone is suggesting to me to test another EMS/ECU and see if the problem is software related. Specifically they want change the "box" over from a similarly spec'd (correctly operating) car and see if the problem remains. Wouldn't the program be exactly the same and have the same tolerances?

From what I have gathered from all the posts here is that it's 1.) Oil pressure issue, and/or 2.) Solenoids
Sure I understand the oil galleries are issues but they are unlikely to change as a car gets older, its the moving parts like an oil pump or solenoid that would make an issue like this over time. So that's why I'm thinking oil pump (oil pressure) or the solenoids. But again, this is my layman's understanding of whats happening here.

Many thanks.

 

One can over analyze issues and if one is not careful, a lot of money can be spent without really resolving issues satisfactorily.

The oil feed ways to the V.V.T.'s should be the same diameter throughout. They are not. In my case, I am lucky as I have bought a spare engine and am able to study where I believe the problems lie.

Firstly, if designers go to the lengths of providing oil seals throughout the oil way system, it seems irrational to then allow oil to bleed through the front face of the V.V.T. sprocket and the bolt that fixes it to the camshaft proper.

Secondly, the oil ways; from leaving the bearing caps, throughout the camshaft and the V.V.T. void orifices are of uniform diameter. In the case of the inlet camshaft I have before me, this continues all the way through to the advance voids. No restrictions whatsoever.

In the case of the retard oil ways, the apertures to the voids are Identical to those drillings through the camshaft. However, to get the oil to the retard voids, the oil passes through the camshaft drillings (4 off, 90 deg. offset), into the drilling for the fixing bolt. However, the shank (un-threaded section) of the bolt "Pinches" the oil way which is formed between the bolt perimeter and the inside of the camshaft drilling.

In an engineering sense - because I am an engineer, this is nonsensical. It is probably one of many illustrations where there has been an absence of engineering support in production and someone ordered the wrong bolts.

The clear intention of any one designing these systems would be for uniformity throughout. If subsequently, there are problems, it makes it very easy for engineering/development to identify where they are.

I have repeatedly said, there never is a "Silver Bullet", it is alway an accumulation of little things that cause major problems. The trouble with software engineers is, they think they can fix physical problems by simply programing them out. That was never the intention in the early days. Equipment was properly designed and aligned and then software "Applied".

What I am endeavoring to do, is find all those little things; flaws, which Alfa have chosen to hide and get this engine performing as I believe it can. I firmly believe this is a 300 BHP engine.

Any engine, no matter what configuration, Straight, Flat or V, no matter how many cylinders can be greatly improved, by valve and ignition timing. Once you achieve the maximum, then one can think about turbo's, increased capacity or perhaps block architecture. But the simplest and least expensive method is to improve Valve Timing/Engine Breathing.

Now, the arguments about this engine have been going on for years and for the most part what I read is Bull - ****. It is as "Strong as an Ox" and; but for the galleries, which are not; as I understand it, a problem in "Turbo Form", this engine deserves to be recognized as a Alfa.

Non the less, this bolt and lack of copper washer is a clear failing. I am not saying it is going to resolve all the problems with this engine. But it is a failing and needs to be rectified. My problem is, I need to find a way of retaining the sprockets on the engine whilst I remove and replace the bolts with the four I am having machined. And Fit copper washers - dismissed Dowty washers.

This problem exists on all four cam shafts so when they are fitted I expect the V.V.T response time to quicken. It is not the end of the story however; as you know, given I am feeding oil to the bearing caps directly from the Oil Cooler/Filter assembly. But if this camshaft is typical of those on my engine proper, it clearly has to be rectified.

To do this I am shaving 1 mm. off the shank diameter, from 23 mm. to 30.5 mm. from the head end of the bolt. Then fitting a copper washer. Those distances need the thickness of the copper washer added.

Your problem revolves around your exhaust camshaft on the rear bank, furthest from the oil pump, with restricted oil feed when both filling and emptying the retard voids and oil bleeding from the front washer. I would be very interested to know how software could apply to these issues?

 

Don't leave us sizewell!

I'm sure plenty of us on here hold you in high esteem, I most certainly do.
Your understanding of the inner workings of the V6 come across as second to none.
Your posts are always very thorough and well written, and that's something of a novelty on here.
Lots of people will gain a better insight into the issues with this engine from your writings.
I can understand the frustration when you're going to all the effort and trouble to find intelligent solutions.

 

You've got to carry on now to see if your theories are correct

 

Thanks Sizewell, please don't misinterpret my questions and postings. I am not a mechanic and cannot do this work myself, plus this is my only car. So I have to give it to a mechanic to fix. I am trying to figure as best I can what I should focus on as the issue, then give them the car and tell them to do one or two specific things and then try something else another time until I get it sorted. So that is why I am asking stupid questions trying to figure what is the best way to start this process. If I had another car and had the skills I could take it apart and try lots of different things until its sorted, but I don't have that luxury.
Trust you understand and many, many thanks for your advice and posts here.

 

I think you've jumped a little hastily to the conclusion no-one is listening to you or taking any heed of what you are saying.

What I hadn't mentioned in earlier posts was I had a noisy engine particularly at idle although no specific rattle. After some enthusiastic driving yesterday the noise has developed into a very specific rattle which I feel now needs attention. As its a rattle there can't really be any other explanation for that other then chains and guides.

Believe it or not I have taken on board everything you have said in your extensive posts which have been very helpful in understanding why these problems occur. I will be investigating the sprung check valves on the three dual spray jets as that is a concern and I also intend to follow your advice on the rear bank and will be having the Phaser fixing bolt machined to allow easier flow of the oil past it along with a copper washer.

I'm in the same boat as crimson96 although I may rebuild the engine myself having fully stripped and successfully rebuilt a V6 Busso. However I'm no engineer and do need the car back on the road reasonably quickly. I thought these forums were to help each other rather than trading insults. I too seek a better performing engine for this car.

I look forward to your updates on overall progress with this engine and echo the sentiments of others on here encouraging you to continue to share.

Many thanks, your assistance is appreciated and kind regards.

Ross

 

I think you've jumped a little hastily to the conclusion no-one is listening to you or taking any heed of what you are saying.

What I hadn't mentioned in earlier posts was I had a noisy engine particularly at idle although no specific rattle. After some enthusiastic driving yesterday the noise has developed into a very specific rattle which I feel now needs attention. As its a rattle there can't really be any other explanation for that other then chains and guides.

Believe it or not I have taken on board everything you have said in your extensive posts which have been very helpful in understanding why these problems occur. I will be investigating the sprung check valves on the three dual spray jets as that is a concern and I also intend to follow your advice on the rear bank and will be having the Phaser fixing bolt machined to allow easier flow of the oil past it along with a copper washer.

I'm in the same boat as crimson96 although I may rebuild the engine myself having fully stripped and successfully rebuilt a V6 Busso. However I'm no engineer and do need the car back on the road reasonably quickly. I thought these forums were to help each other rather than trading insults. I too seek a better performing engine for this car.


I look forward to your updates on overall progress with this engine and echo the sentiments of others on here encouraging you to continue to share.

Many thanks, your assistance is appreciated and kind regards.

Ross

I acknowledge there are issues about timing chain stretch and guide/tensioner wear. I also understand crimson did not do himself - or more specifically his engine any favours, by going to 15k without changing his oil and filter.

Question: Can you reset the p codes and does the car run at tick over without P00016 re - occurring?

If the answer is yes, then as the camshafts are locked in the idle position, Inlet fully retarded, Exhaust fully advanced.

Then the relationship between the position sensor detection pulse - for want of a better description - is within the boundaries of what is considered error free detection by the E.C.U. The camshaft advance/retard rotor is "locked and it's position is fixed with regard to the timing mechanism - the chains.

What changes, when the throttle has been exercised is, the camshaft rotors are un - locked and free to advance/retard under the influence of oil pressure, driving the rotors in the direction the E.C.U. has demanded.

The physical profile of the rotor plate dictates when the "tell - back pulses" occur and if the camshaft rotors have moved within the specified time frame, dictated by the E.C.U then no error will occur and the E.C.U. will be free to set the next successive cylinders timing appropriately.

But what dictates when that occurs, is down to oil pressure/flow rate into the camshaft voids; in either direction depending upon which direction the E.C.U. has demanded the camshaft to rotate.

The "Slots" and "Tabs" on the rotor plate are the areas/time frames within the cycle, where the pulses should occur. Within those and there will be no P code failures. I acknowledge, they are relatively small areas and timing chain stretch/tensioner and guide wear will push the time those pulses should occur, towards failure - i.e. outside the E.C.U. "Wait Time".

But what dictates how well the camshaft advance/retard characteristics mimic those set by the E.C.U.'s predicted setting, is the oil flow into the camshaft voids.

The V.V.T. System is seriously low on oil pressure to achieve this. Which makes the situation worse when one considers how badly the timing chains , guides and tensioners are lubricated. So what I think is the case, is a chicken and egg situation. The lack of adequate lubrication for the chains and guides, lack of pressure to keep the chains taught and lack of pressure/oil flow for the V.V.T to function properly. And minimize wear.

Both inlet and exhaust camshafts can rotate 50 degrees, indicating serious potential performance. But It seems to me, it just isn't capable of responding fast enough to deliver it.

I have bought a set of "Cap bolts" to have machined. They have a range of 86 Nm as opposed to those fitted that is 76 Nm. The cam bolts have been torqued down to 66 Nm. So in shaving 1 mm. off the shank, there rating should still be adequate for the purpose. However, I need to have some Stainless Washers machined as the heads are hex and I need to spread the torque across the whole face of the fixing. Also, a copper washer is probably not appropriate as it could lead to loosening.

 

Mr. WellSize:weeping: Nice to read, learn and check next time... I would forgive your occasional Russophobia...:weeping:
Anyway similar car has been just released from service I used chain rebuild.
Here is a part list has bought from GM. They are the same to Cadillac/Buick cars with 3.6 engine.

12589011
12590920
12609262
12586959
12597417
12600461
12586961
12586960
12600462

 

BuonGiorno, Thanks for the list of part numbers - Much appreciated.:beer:

 

I have 22JTS which is different from 32JTS of course.
I had bought this car used ex Germany with a three years old ( by production date ) with only 48k kms mileage.
Service book shows only one maintenance at 27k kms which is OK for this bloody alfa schedule.
As soon as car arrives St.Pbrg I had made a complete inspection with new oil change.
I had saw some ELMs shows up later and finally I got hard repeating P0016 in two months from oil change.
Than engine was stripped my mechanic had found absolutely loosen tensioner and chain over- spin thereof.
He had compared main chain with new one and concluded no stratch. Just over- spin because of loosen tensioner and blocked oil nozzle. He had proposed to me to keep everything old and replace tensioner and nozzle only to confirm guess. I have some special relation with my service where we can discuss such issues. I was too happy with GM part prices to avoid any experiments with my car.
What is my message. Here in Russia we have absolutely no chain issues for the car sold new locally because greedy dealer had fixed 10k kms oil change interval. If you miss it you would be refused any warranty claims. As soon as car arrives used ex Europe with longer oil change interval all chains issues are welcome.
To apply same background I have explained hereinabove why don't you think about oil pressure to make chains tighten.
As I also have learned from 32JTS strip 2 camshaft chains are OK with no stretch. Only lower one creates a problem but friendly speaking it concerns single particular ( ex compressor btw ) car since we have no much 32JTS on the roads.

 

BuonGiorno,

Correct, because oil pressure is common to all elements of the engine's system. If the oil pressure is so low as to fail to unlock the camshaft and given the rear exhaust camshaft is closest to the "Lower Primary Chain Tensioner", this is a real issue. But I though everyone appreciated that!

My spare 3.2 was bought from a carpenter who was doing some work for me. It rattled like a tank with less than 60,000 miles. But he continued to drive it; error codes and all. Eventually the engine seized. Con rods bent, crank bent, bearing shells spun. When I finally got the engine apart, all was revealed, including two "jammed open" Piston/Bore spray Jets. The carpenter admitted he failed to keep on top of oil level and regular oil changes.

Now on the basis of pure hypothesis, this is my take on what happened:-

1 - low levels - insufficient oil to stop metal to metal contact.

2 - fine particles building up in the galleries.

3 - failure to change oil regularly - possible Oil Filter Bypass Valve opening due to blocked filter.

4 - debris blown under oil pressure into block galleries.

5 - Main gallery terminated behind water pump in a convoluted union which feeds the rear bank gallery and drops vertically down to feed the crankshaft, journals and "Spray Jets"

6 - because of the architecture of that union it acts like a "Catch - Pot" - a magnet for all detritus accruing in the block.

7 - "Crud" builds up at this point and eventually causes "Spray Jets" to seize open.

8 - Oil pressure seriously reduced and engine drains down oil when engine is stopped - hot oil ably assisting in this.

9 - Punter comes out to start engine and galleries have to re-fill before oil pressure is sufficient to run engine.

10 - "Supposition", but very familiar with hydraulic lock - drained Galleries and Voids have filled with air - allowing "H.L." to occur. Solenoid valves are below camshaft V.V.T.'s so this is a real problem - software could resolve it!

11 - engine switched off - V.V.T. voids are open to cam cover pressure - virtually atmosphere - Air fills voids - "Check valves are on the inlet side of the V.V.T. solenoid - the four voids on each camshaft, fed from the port at the snout of the V.V.T. solenoid bleed their oil into the cylinder heads" and fill with air.

12 - slow moving cold oil - on start up, not enough to overcome the trapped air in the voids and camshaft oil ways.

13 - until engine oil is warm and air can be evacuated cam shaft(s) do not rotate within the "Time frame" to satisfy the E.C.U. and thus "P - codes" are generated.

14. - what future for these engines if the problems remain un-addressed.

Just my take on things - probably completely wrong.

 

GM supplies two different part numbers for each bank chain

These are the numbers I used -only one for the secondary chains as both identical.

Item Description GM Part No
1 Pad Rear bank left hand chain slipper pad. 12623514
2 Pad Rear bank right hand chain slipper pad. 12600462
3 Pad Front bank cam chain pad (right side). 12600461
4 Pad Front bank left hand chain slipper pad. 12623513
5 Chain Primary cam belt chain. *12597307 (NOT 12633451)
6 Pad Primary chain top pad. 12597417
7 Chain Stretcher Rear bank cam chain tensioner. Not Reqd
8 Chain Stretcher Front bank chain tensioner. Not Reqd
9 Tensioner Primary cam chain tensioner with pad. ACDelco 12609263
10 Pad Primary chain slipper (right side) . ***WRONG PART SUPPLIED BY ALFA***. 12586959
11 Chain Cam shaft chain (x1 supplied) . 12589011 (NOT 12633452)

 

Cheers:beer:

 

dont know if it is of any help here, but ive changed (or in a process of changing) all sprockets and chains to the "upgraded one" from LLT engine. camaro 3,6.
ive searched for information around europian sites of the chevrolett cars owners and what i clearly can see that the new chains are somehow better then the old ones "bicycle chain" LLT uses it as standard. the biggest different is the type of pulley on the crank wich is moving freely alongside the crank to, probably, reduce the chain tensions. LLT has already an improved internal design (according to mace engineering)

mine car hade exactly the same issues, bought it with the stretched chain. the problem however was lying not in chains itself but in pads, wich were cracked. se pictures in my thread brera 3,2 bebuild.

camaro owners did not had the same issues as other GM cars before 2009 (or maybe 2010) as we discussed with sizewell in mine thread some improvments has been made and some of them probably did something good.

 

Radical, I have asked several engineering sources about the freedom of the bottom sprocket and the response has been universal - to allow "Float" to minimize any slight errors in the alignment with the intermediate idlers/sprockets for the upper chains: eliminates lateral pressure exerted upon the links of the Primary chain. That has to be a very big plus when one considers this is a mass produced engine.

Things are back to normal, my spare engine is sitting in a workshop with bypass pipe fitted, just trying to find the easiest way into the front bearing caps with the 8 mm. pipe.

Also, my spare V.V.T. solenoids are at another engineering shop being modified. I have long felt, the V.V.T. should not be allowed to drain down completely either when the engine is switched off, or at tick over. I also believe, if there is to be any restriction in the V.V.T. system, it should be where the oil leaves the drain port of the solenoid valve. So the exercise is to maintain oil way cross- sectional area throughout and control the out-flow at the snout of the V.V.T. - effectively "Slug" the system. The initial intention of this was to try to counter the rotors from moving under spring pressure as opposed to oil pressure. This was of course, before I took the camshafts and sprockets apart. But view hasn't changed on this issue.

It would look incredibly odd - although Americans could probably fashion some kind of cowl to mount on the Hood to disguise it, "And Make It Look Incredibly cool" - but the snout of the V.V.T would need to be connected to a hose to take it above the V.V.T. sprockets and then be returned into the cam cover to drench the chains from above.
However, that is just one of the more bizarre solutions I have considered. It is important; I believe, to get some lubrication to the chains and sprockets and this will come from my drilled an tapped front bearing caps.

As I say, things are back to normal - going backwards. It is particularly frustrating as the sub frame is off and the steering rack is coming out for renewal. Jeez, we're going to Germany in July and at this rate it won't be finished.

 

I've not read all these engine mod posts as I have a different opinion as to the problem and the fixes, and reservations on the hydraulic theories put forward, but the mileage I do means I have a different time/cost balance - and a K-series engined Caterham with the odd problem of it's own ;-) I've certainly not taken the 3.2 engine apart far enough to investigate myself, so I'm making no suggestions of my own - I've no information to do so.

However, before you drill those bearing caps, could I suggest you research roller chain lubrication, also including the later Morse type chains that are used. And I mean from chain manufacturers, not wiki-nearly-but-usually-not-quite-rightia ;-)

In my opinion, based on 20 odd years of industrial experience of all sorts of drive mechanisms, drenching from above is not the way to go, at least not directly onto the chains on the sprockets.

I'd be very nervous about a modification to the supply of lubricant to highly loaded hydrodostatic bearings. Tribology is a massive subject all on it's own but given there don't seem to be too many complaints about knocked out camshafts etc, someone somewhere got something right-ish.

Good luck!

 

Too late, I'm afraid , the camshaft front bearing have been drilled and an 1/8th BSPP to 8 mm. compression fitted. Nothing personal, but I could get dizzy chasing around at all the suggestions. I am open to them, but it does require a little more at this point to change direction. The suggestion of drenching the chains from above was largely tongue in cheek about creating a "Stand Pipe" to retain the oil in the V.V.T. system. In actual fact, oil is sprayed - orifice size yet to be determined - from the front of the bearing cap, directed just under the chain where it meets with the sprocket. the orifice does not need to be particularly large as it is - less a little attenuation - at outlet pressure of the Oil Cooler/cooler assembly.

The overriding intention is to get oil pressure/flow rates up across the block, particularly to maintain timing chain tensioner pressure and increase the V.V.T. response time. A by-product of this work is to improve lubrication of the timing chains, tensioners and guides. Also, if there is an element of temperature related problems attendant to the ubiquitous chain stretch, as this oil is being fed directly from the Oil Cooler/filter assembly, this may provide an element of cooling as well as reduced friction.

The car has 108.000 miles on the clock so it's true value is about zero and it did not cost much in any case. But I am determined to get to the bottom of these "Undefined Issues", where no one has fully investigated the veracity of them. I am confident the engine can be improved and have never known an Alfa not meet it's power and economy figures. Valve timing is crucial to that and this issue is indelibly linked to the working oil pressure of the engine - across the block.

If only I can get to the point where I am starting to see some results. Very - Very frustrating.

However, if there was anything obviously amiss, Alfa would have resolved it. That so many owners have been vociferous in their criticism - in the States customers were trying to get funds together to sue Alfa, there must be some thing which collectively result in a less than sparkling engine. I hope I can find some of the truth, or otherwise in this. Besides, I bored, so I need something to occupy my time.

 

I'm genuinely interested in this project - like some others i may have gone in a different direction and may be overly protective of Alfa engineering, but luckily we're all different. Best case we all benefit from a thorough analysis of known problems and find some real gains all round - worst case an engine only lasts another 100k miles with no significant gains. Either way we all benefit. Keep up the good work.