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Discussion Starter #141
Still progressing slowly. Engine now fully installed and at last we have oil pressure - 3.5 ~ bar at the oil pressure switch.

It has been a challenge and a worry. The pump had not been primed, the rotors (vvt) empty after rebuild as were the hydraulic tappets. So the oil pressure really did not want to rise. However, it did - eventually!

Problem now is she won't run, miss - firing. So a little mre work needed to understand why. I have an idea why, but won't know for certain till next week.

No clattering though - everything seems tight.

There probably was about 10 - 15 thousand left on the clutch so that was replaced in it's entirety, incuding hydraulic release bearing.

Last to go on will be the alloy cam covers, which have been sprayed, and likewise the sprayed inlet manifold.
 

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Still progressing slowly. Engine now fully installed and at last we have oil pressure - 3.5 ~ bar at the oil pressure switch.

It has been a challenge and a worry. The pump had not been primed, the rotors (vvt) empty after rebuild as were the hydraulic tappets. So the oil pressure really did not want to rise. However, it did - eventually!

Problem now is she won't run, miss - firing. So a little mre work needed to understand why. I have an idea why, but won't know for certain till next week.

No clattering though - everything seems tight.

There probably was about 10 - 15 thousand left on the clutch so that was replaced in it's entirety, incuding hydraulic release bearing.

Last to go on will be the alloy cam covers, which have been sprayed, and likewise the sprayed inlet manifold.
The best things in life are worth waiting for!

Happy the oil pressure is OK - what a worry that was.
Good luck with the mis-fire.

Will be nice to see some pics of covers and manifold ...
 

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Bit of an update on mine...

I purchased some alloy rocker covers from a camaro in the US, i then prepped and painted the rocker covers and intake manifold.

The rear bank alloy cover fitted perfectly, unfortunately when i went to fit the front bank rocker cover it was a few mm short on the front right. So unfortunately i had to refit the original alfa cover.

I then have had the secondary cats removed and lambda sensors refitted.

The results in preparation for silverstone on the 8th that went very well, with the attached photos.

No running issues at all, a lot of pull through all the gears and handles alot better than most cars there (may have been more driver skill vs the other drivers)

I did raise the suspension height by 10mm front and rear on the B16's and played around with the damping and now have very little understeer on long fast corners so I'm very pleased.

As a result I was able to take Abbey, Copse and the entry to Maggots & Becketts in excess of 90mph on a damp drying track, im sure if it was a warm sunny day the grip would have been even better.

I was very impressed with how it handled, especially with the back end stepping out abit under hard cornering and braking into the corners with it being corrected with ease and no fight :)
 

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Discussion Starter #146
Impressive! You have left the manifold cats on? Neat job under the car and cam covers look great. Still not had a chance to look at mine as the misfires are being investigated. Great relief with the oil pressure coming up though - 3 bar plus on the starter motor - that's at the output of oil filter/cooler, oil pressure switch removed and test gauge fitted.
 

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Bit of an update on mine...

I purchased some alloy rocker covers from a camaro in the US, i then prepped and painted the rocker covers and intake manifold.

The rear bank alloy cover fitted perfectly, unfortunately when i went to fit the front bank rocker cover it was a few mm short on the front right. So unfortunately i had to refit the original alfa cover.

I then have had the secondary cats removed and lambda sensors refitted.

The results in preparation for silverstone on the 8th that went very well, with the attached photos.

No running issues at all, a lot of pull through all the gears and handles alot better than most cars there (may have been more driver skill vs the other drivers)

I did raise the suspension height by 10mm front and rear on the B16's and played around with the damping and now have very little understeer on long fast corners so I'm very pleased.

As a result I was able to take Abbey, Copse and the entry to Maggots & Becketts in excess of 90mph on a damp drying track, im sure if it was a warm sunny day the grip would have been even better.

I was very impressed with how it handled, especially with the back end stepping out abit under hard cornering and braking into the corners with it being corrected with ease and no fight :)
Out of interest...why would one of the covers be too short?...thought they used the same lump in the Camaro.....obviously not exactly the same I guess!
 

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yep, ive left the manifold cats on as when i met up with a v6 owner earlier in the year who had the auto delta manifolds fitted with all cats removed and their performance cats fitted, the car was just a rasp machine at any revs

as i track mine i was very concerned with decibel level and not being allowed on track. Fortunately leaving the main cat manifolds in place has resulted in no rasp with a 3/4 rev 93db and max revs on the limited being 110db

At the moment i have no idea why the rocker cover was slightly short on the front right bank, i will be liaising with sizwell to resolve this (it may be that i have bought a different variant of cover that doesnt fit)
 

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yep, ive left the manifold cats on as when i met up with a v6 owner earlier in the year who had the auto delta manifolds fitted with all cats removed and their performance cats fitted, the car was just a rasp machine at any revs
That'll be the sports cats which are fitted causing it to be raspy, the original 400 cell (each) twin-cats would probably have gotten rid of that rasp. A few people on the GTA forum have gone through similar after fitting sports cats in place of the twin cats in conjunction with decat manifolds.

Ideal solution for a track car is remove all 4 cats and fit the biggest silencer possible in the space where the twin cats were fitted, then a good cat-back system after that.
 

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Discussion Starter #150
sizewell

That'll be the sports cats which are fitted causing it to be raspy, the original 400 cell (each) twin-cats would probably have gotten rid of that rasp. A few people on the GTA forum have gone through similar after fitting sports cats in place of the twin cats in conjunction with decat manifolds.


Ideal solution for a track car is remove all 4 cats and fit the biggest silencer possible in the space where the twin cats were fitted, then a good cat-back system after that.
Good to know the twin cat section is made up of 2 X 400 cell elements. The Autodelta one is apparently a single 800 cell element but the ECU needs to be re - worked to meet emissions. I have been tempted to consider that path, but now I shall limit my modifications to just the Cat - Less Manifolds. I really don't want to introduce another un - quantifiable element to the mix.

Just to keep things positive, I contacted C.B. to ask if they could provide more by way of identifying each cam as I still have an issue with misfires. Happily they obliged.

In keeping with an earlier comment about inlet camshafts, I studied the spare Brera ones, which the C.B.'s replace. The Inlets have a duration of 254 deg. whilst the exhausts have 250 deg., a mere 4 deg. difference.

But the difference can be seen clearly. I read an article; whilst researching, which talked about "Stratified Charges" and "Swirl Techniques" for direct injection engines. A technique of creating a slow to open profile on the inlets causes the intake air to stream in to the cylinder, which has a slight vacuum due to the NVO, and in conjunction with the pistons specially designed crown, generates a swirling charge which promotes stratified charges. Linked into all this is, it helps to keep the cylinder walls cool and can reduce pre - ignition when AFR are lean to ultra lean. All clever stuff, all for the sake of 4 deg. in this instance.

This again seems to re - enforce the earlier comment that the inlets have a more profound effect on an engines performance than the exhaust. Obviously, the two are designed hand in hand, but the onus seems to be more on the inlets.

Further to the oil pressure being 3.5 ish bar, I said it was measured at the oil pressure switch position on the Oil Filter/Cooler. Well it is essentially the same. Except that, the orifice that hitherto had the oil pressure switch is now where the "Horseshoe" pipe of the CLLS is located. And this Horseshoe bypasses the directly cast entry into the convoluted oil ways of the JTS engine. In fact it takes the output of the oil filter/cooler directly to the front bank main oil gallery leading to the central, restriction of the "V", where it then feeds the rear bank main gallery and also the crankshaft main bearings and "Oil Spray Jets".

The other side of the central restriction, being the rear bank main gallery, is of course now also fed by the bypass line which comes from the oil filter/cooler, around to the plug nearest the lower timing chain tensioner.

So I think it is fair to assume, the oil pressure reading we have recorded is virtually that which would be seen at the centre of the convoluted "V" restriction, given it is fed east and west.

The outlet of the oil pump into the block: corner of the block casting and immediately 90 deg. to the right and out to the oil filter/cooler, has now been relieved by scalloping. The result? A much smoother radius on the turn, with sharp residual machined edges removed.

Clearly, the radii is not ideal for oil flow. But at least the flow will suffer less turbulence and thus create less back pressure on the oil pump bypass valve, which again, one would expect will result in higher outlet pressure, by causing the oil pump relief valve to open less and when increased flow rates are experienced (when oil is hot), this can sustain high temperature oil pressure better.

Rather pleased with this aspect. Even the guys who have installed the engine are pretty impressed. Particularly, as the boss said, " This is on the Starter Motor! It will be great when the engine is running at X 1000 RPM!" VVT's should benefit greatly.

Now, all I need, Is to cure the timing issues.
 

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Yes!

Oil pressure cannot be sustained, if the flow rate is below demand! Restrictions create the problem.

To reiterate, the ECU is predictive. The speed at which the camshafts rotate dictates what angle the ECU sets for the next cylinder’s power stroke; and importantly, exhaust valve opening.

We know the rear bank exhaust camshaft position sender is always late and progressively fails, throwing a code.

The exhaust camshafts are heavily biased in the advance position, by both the internal spring AND the hydraulic configuration, dictated by the ECU [control of the solenoid valves].

However, the speed of operation of the front bank exhaust camshaft, given it is the first major device after the oil cooler/filter is; should we say, normal. So the tell - back from its position sensor, to the ECU is within the standard timing parameters embedded within the ECU.

The ECU will, as a function of this set a predicted angle for the rear bank exhaust camshaft, at an angle which the camshaft cannot assume in the time the ECU predicts.

The exhaust camshaft timing is such that at idle, it is fully advanced, causing hot exhaust gases to heat the cats to light - off temperature quickly and thus quickly cause the reduction of pollutants by catalytic conversion. This occurs on start up. But light off temperatures have to be maintained throughout its duty cycle.

So, if the rear bank exhaust sensor is late, the ECU will interpret this as being “lower revs”. Lower power and hence to maintain light - off, will set an angle for the front bank exhaust camshaft, which is too far advanced for the power the engine is making.

Camshaft too far advanced - exhaust valves open too soon in power stroke - elevated exhaust gases cook the cat and, as the exhaust valve has opened early, an extended period during which these gases are reflected; due to cat restriction and re - ingested at a much higher temperature than normal. Evidence being the difference between the two pictures of the cats.

Further evidence was given by poster on this forum which indicated, by inspection of front bank spark plug, lean to very lean burn. The poster was investigating misfires, a function of unstable flame front of very lean mixtures.

This, I believe is also connected to “Coil Pack” breakdown/melting, which is seen predominantly on the front bank.

Lean burn in this instance can only be a function of retained hot gases, restricting the intake of fresh air charge.

The relevance of the last paragraph is, as hot gases reduce the inflow of the fresh air charge, the M.A.F. will sense a lower flow rate and the ECU will adjust the fuel injected to achieve the appropriate fuel/air ratio for the air flow the M.A.F. has just sampled.

This can only result in an extremely lean mixture, which will cause unstable fuel combustion, extremely high upper cylinder temperatures and potential breakdown of coil packs and melting.

The current drawn by a coil pack, under normal operation, is not sufficient to generate the heat required to melt the coil pack. Were this to be the case, there would be evidence of ECU failures, of which none have been reported to date.
Hi Sizewell, I have been following this thread with interest. I have been trying to get more info on the lean burn process at low revs but without much success. My car has been misfiring with subsequent coil failure for some time and it always happens between 1500-2200 revs when accelerating with medium throttle. The OBDI reader has been indicating that the oil pressure switch is faulty but does not require serious attention' also no indication on the instrument display. I read a number of threads where this is the case. However, since replacing the oil pressure switch the misfires at low revs have disappeared completely. I could not find any information on the Bosch MED 7.62 setup to see how it would react with a fly oil pressure switch. What is your opinion on this?
Great thread this!!
 

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Discussion Starter #152 (Edited)
Hi Sizewell, I have been following this thread with interest. I have been trying to get more info on the lean burn process at low revs but without much success. My car has been misfiring with subsequent coil failure for some time and it always happens between 1500-2200 revs when accelerating with medium throttle. The OBDI reader has been indicating that the oil pressure switch is faulty but does not require serious attention' also no indication on the instrument display. I read a number of threads where this is the case. However, since replacing the oil pressure switch the misfires at low revs have disappeared completely. I could not find any information on the Bosch MED 7.62 setup to see how it would react with a fly oil pressure switch. What is your opinion on this?
Great thread this!!
Hi Rob!
Sorry to have missed this - been taken by the Brexit debate and also been staying away from my 159 as a project, given there is a problem with the hydraulic tappets. The garage will get to them, as and when, it is just they are a bit busy at the moment so trying not to get too impatient.

However, just came upon this as a result of looking in on what Jim is doing with his GTA cams. I just posted on his thread a few hours ago as I was interested in something he said about Lambdas being wired wrongly - which led me to the following;-

The kind of approach this guy does in the video rally chimes for me and it leads to another possibility for misfires. Jim's response was pretty timely too and it all helps fill in the gaps in my knowledge.

When my engine died on the track at Bruntingthorpe, it cut out immediately, stopping almost "Diesel - like" and could not be restarted. Getting her home however, several hours later and it was possible to start the engine. The guy who looks after her said, it is possible, the failure of oil pressure; being potentially fatal, could cause the ECU to prevent the engine being restarted. However, the intervening hours could well have caused the ECU to clear its fault logs and I am not sure whether the battery had been disconnected, which would also clear the faults log - I think.

Below are other attachments which you may find helpful. In Jim's reply to me, he pointed out, there are Lambda "Fakers on the market, but the problem comes with the need to modify the ignition timing in conjunction with them, which is pretty complicated.

Everything about this engines engine management system is complicated and as it had such a short production life, there is no after - market interest in understanding it better. It seems as though the attached video throws even more light on the interrelationship between the valve timing, ignition timing, Lambda performance and NVO. The attached document on NVO throws a lot of light on upper cylinder temperatures in conjunction with Hydrocarbons being retained within the cylinder and essentially re - burnt as a means of reducing them {The greatest concentrations of HC's occur around the piston ring/cylinder wall region and are usually the last components to be expelled through the exhaust valve - thus NVO, particularly at low revs can be tailored to trap them quite accurately}

As cylinder temperatures are elevated, to maintain "Light - off" temperatures for the manifold cats, the retained HC's, quickly expand and effectively reduce the inflow of fresh air into the cylinder. So the air flowing across the MAF is lower and thus the fuel metered by the ECU, based on that air flow, is also reduced. This creates a Lean to extra lean burn during low revs/light load conditions.

If the conditions that exist on the BMW in the video are similar to your 3.2 JTS, wrt to lambda probe out of spec/failure conditions, this too would add to the potential for misfires and burnt out coil packs.

It seems to me, for the NVO function of this engine to perform at its best, it is very important, not only that vvt function is very responsive, but the Lambdas must be tracking the exhaust gases accurately. The NVO only exists on this engine at tick - over/light load/low revs and it is intended to maintain light - off of the cats. But imbalance between the front bank and the rear bank timing would result in excessive temperatures, as evidenced in the pictures of my burnt front manifold cat.

I have read too, that in conjunction with NVO, piston design and slow to open camshaft profiles; just at the lower shoulder of the cam opening profile, and the slight negative pressure NVO creates, promotes the initiation of swirl and with it Charge Stratification. This assists cylinder wall cooling and lean burn whereby combustion is centred around the small indent in the centre of the piston crown, spreading out uniformly as the burn progresses. It can enable engines to operate on extremely lean mixtures as essentially, the centre of the stratified charge appears, for all intents and purposes to be like a small cylinder, where the ratio of fuel to air is correct for that small volume, the stratified nature of the fill has created.

Of course, the slow to open profile of the inlet camshaft, will only stimulate this Charge Stratification at low revs/light loads. Once the revs of the engine climb, that particular region of the camshaft profile becomes irrelevant and in the ECU will revert to conventional fuel metering. But it must be remembered, the ECU can only act upon the telemetry it receives from all the engines sensors. Not least of which are camshaft position sensors, the MAF and the Lambdas.

Hope that makes sense.
 

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Discussion Starter #153
Hi Rob!
Sorry to have missed this - been taken by the Brexit debate and also been staying away from my 159 as a project, given there is a problem with the hydraulic tappets. The garage will get to them, as and when, it is just they are a bit busy at the moment so trying not to get too impatient.

However, just came upon this as a result of looking in on what Jim is doing with his GTA cams. I just posted on his thread a few hours ago as I was interested in something he said about Lambdas being wired wrongly - which led me to the following;-

The kind of approach this guy does in the video rally chimes for me and it leads to another possibility for misfires. Jim's response was pretty timely too and it all helps fill in the gaps in my knowledge.

When my engine died on the track at Bruntingthorpe, it cut out immediately, stopping almost "Diesel - like" and could not be restarted. Getting her home however, several hours later and it was possible to start the engine. The guy who looks after her said, it is possible, the failure of oil pressure; being potentially fatal, could cause the ECU to prevent the engine being restarted. However, the intervening hours could well have caused the ECU to clear its fault logs and I am not sure whether the battery had been disconnected, which would also clear the faults log - I think.

Below are other attachments which you may find helpful. In Jim's reply to me, he pointed out, there are Lambda "Fakers on the market, but the problem comes with the need to modify the ignition timing in conjunction with them, which is pretty complicated.

Everything about this engines engine management system is complicated and as it had such a short production life, there is no after - market interest in understanding it better. It seems as though the attached video throws even more light on the interrelationship between the valve timing, ignition timing, Lambda performance and NVO. The attached document on NVO throws a lot of light on upper cylinder temperatures in conjunction with Hydrocarbons being retained within the cylinder and essentially re - burnt as a means of reducing them {The greatest concentrations of HC's occur around the piston ring/cylinder wall region and are usually the last components to be expelled through the exhaust valve - thus NVO, particularly at low revs can be tailored to trap them quite accurately}

As cylinder temperatures are elevated, to maintain "Light - off" temperatures for the manifold cats, the retained HC's, quickly expand and effectively reduce the inflow of fresh air into the cylinder. So the air flowing across the MAF is lower and thus the fuel metered by the ECU, based on that air flow, is also reduced. This creates a Lean to extra lean burn during low revs/light load conditions.

If the conditions that exist on the BMW in the video are similar to your 3.2 JTS, wrt to lambda probe out of spec/failure conditions, this too would add to the potential for misfires and burnt out coil packs.

It seems to me, for the NVO function of this engine to perform at its best, it is very important, not only that vvt function is very responsive, but the Lambdas must be tracking the exhaust gases accurately. The NVO only exists on this engine at tick - over/light load/low revs and it is intended to maintain light - off of the cats. But imbalance between the front bank and the rear bank timing would result in excessive temperatures, as evidenced in the pictures of my burnt front manifold cat.

I have read too, that in conjunction with NVO, piston design and slow to open camshaft profiles; just at the lower shoulder of the cam opening profile, and the slight negative pressure NVO creates, promotes the initiation of swirl and with it Charge Stratification. This assists cylinder wall cooling and lean burn whereby combustion is centred around the small indent in the centre of the piston crown, spreading out uniformly as the burn progresses. It can enable engines to operate on extremely lean mixtures as essentially, the centre of the stratified charge appears, for all intents and purposes to be like a small cylinder, where the ratio of fuel to air is correct for that small volume, the stratified nature of the fill has created.

Of course, the slow to open profile of the inlet camshaft, will only stimulate this Charge Stratification at low revs/light loads. Once the revs of the engine climb, that particular region of the camshaft profile becomes irrelevant and in the ECU will revert to conventional fuel metering. But it must be remembered, the ECU can only act upon the telemetry it receives from all the engines sensors. Not least of which are camshaft position sensors, the MAF and the Lambdas.

Hope that makes sense.

It seems the more analyze this engine and think I know what is going on, the more I realize it is just not that simple. In fact it is pretty sophisticated and pretty complex.

I return the issue of lean burn at low revs because I felt I have only painted half the picture, even though more will come out as I look further into it. But I reiterate, I write this down principally for my benefit. I took some pictures of the piston crowns whilst the engine was apart, but sadly I have erased them.

Anyway, there are sloping extrusions, shaped like wedges cast into the crown in the area around the inlet valves. The valve timing of the JTS is 9 deg. after TDC exhaust valve closes. 11.5 deg. after TDC inlet opens, 2.5 deg. NVO. This is before any intervention by the VVT's.

Therefore there is no cross - flow, inlet to exhaust. But the piston is 11.5 deg. into its induction stroke when the inlet valves open (0.010 inch/ 0.25 mm.).

At this point, the piston is actually 1.71845 mm. below TDC (85.6 mm. stroke). The cast wedges on the piston crown are in close proximity to the opening inlet valves. However, a slight depression has been created because the exhaust valves closed before the inlet valves opened. So, as the inducted air enters the cylinder, it is deflected by the cast wedges of the piston crown causing it to rotate around the cylinder wall. In doing so, heat is transferred from the wall to the fresh charge. The warmed air charge expands, mixes with the trapped HC's and slows the rate of flow through the inlet tracts, effectively reducing the density of the inducted air charge.

I think it important to say here, the inlet tract also plays an important role in getting the flow started. So the slight ram - air effect of the inlet manifold/pipework/air filter box assists in a way a BMC cone filter cannot.

After the initial rotation of the air charge has been established, it becomes self - sustaining, not unlike water going down the plughole. The piston travels beyond bottom dead centre - and the ram effect of the inlet tract increases the volumetric efficiency as it continues; due to inertia, to push air into the cylinder against the rising piston. The rotational motion of the air charge causes stratification with cooler air; and thus more dense air, being concentrated towards the centre of the cylinder in a vertical fashion {warmed air around the cylinder walls, forming a barrier against the in-rushing cooler air causing it to focus around the centre in a vertical cylindrical fashion. Thus the density of the charge air is greater at the centre of the cylinder, progressively getting less dense towards the cylinder walls}.

"Jet Thrust Stoichiometric"

The spark plugs in the JTS engine are central to the Stratified Air Charge, the greatest density of which is also central.

The Jet relates to the high pressure "Jet Injectors", where the high pressure stream is directed towards the centre of the cylinder, closes to the spark plug and directly into the stratified air charge where its density is greatest.

The injection occurs at or around Top Dead Centre and causes it to mix with the denser element of the air charge which is concentrated around the spark plug region, within the area of the small indentation in the cylinder crown that forms what can only be described as a "Secondary Cylinder".

The amount of fuel injected into the Central High Density Air Charge is calibrated to achieve an "Air Fuel Ratio of 14.7:1 - Stoichiometric Ideal".

Although the central charge area is "Stoichiometric", for the "Whole of the Swept Volume" it is "Lean Burn".

The Density and Volume of that Central Charge has been determined by Design Modelling. And thus it is correct for Alfa Romeo to include the term "Stoichiometric" along with "Jet", which "Thrusts"; at high pressure, the fuel into the centre of the "Stratified Charge Air."

The ECU controls the metering of fuel under these circumstances and once the engine is under load conditions, it reverts to conventional injection techniques.
 

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Discussion Starter #154 (Edited)
The best things in life are worth waiting for!

Happy the oil pressure is OK - what a worry that was.
Good luck with the mis-fire.

Will be nice to see some pics of covers and manifold ...

Well, a little more eventful day, today. In the Bank in Bury St Eds and Adam phones to say they are about to remove one of the camshafts to investigate the hydraulic tappets, which we previously suspected. What I know from the e-disc and other sources was the exhaust tappet was 37 mm. But I was unable to find the inlet tappet height. However, as the tools I designed, but my mate Nigel fabricated; (The guy is Brilliantly Meticulous), had not actually been tested on an engine, Adam wanted me there to oversee it and discuss a few issues at the same time.

So, I bombed back along the A14 for 1600hrs, by which time he had the front bank exhaust, front bearing cap removed and the tool fitted. So with a spanner locking the camshaft and another undoing the sprocket mounting bolt, it took all of twenty seconds to undo the bolt. The remaining bearing caps came off in no time at all and there was the C.B. Cam sitting comfortably, waiting to be lifted out. Boom - Boom. What a triumph, and it was only to get better.

Four of the six hydraulic tappets, were incorrect!!!!! Two were correct!!!! being 37 mm. But the other four - clearly inlet valve tappets - were 34 mm. !!!!!!!!!!!!!.

Disappointing given I had supplied the engine builders with the e-disc and more importantly had said on more than one occasion - be careful with the hydraulic lifter as they are location specific - the 37 mm. for the exhausts.

But relieved, we have found the problem and grateful the engine had not been run up as my concern would be for valves hitting piston crowns.

I had been looking to buy some replacement tappets but as with all things for this engine, they cost a fortune and are difficult to source anyway. So Adam suggested we take the tappets from my defunct 159 engine and that is exactly what we are doing. This way, each camshaft can be removed and the correct ones fitted, without faffing about having to chop and change and risking the timing chains being disturbed.

So, I went and had a Pint. We aren't out of the wood yet. But it is one step closer. - Cheers!

Foot note:-

A 37 mm. hydraulic tappet fitted in place of a 34 mm. tappet; with these Colombo Bariani camshafts fitted, would create an Inlet Valve/Valve-seat gap at the "Inlet Valve Closing Angle".

This gap; at an angle of 82.5 deg. before TDC on the compression stroke, would be 4.71428 mm. (4.8 mm.).

Nominal Cam/Rocker Arm Ratio. 1.6.
 

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Discussion Starter #155 (Edited)
Well, a little more eventful day, today. In the Bank in Bury St Eds and Adam phones to say they are about to remove one of the camshafts to investigate the hydraulic tappets, which we previously suspected. What I know from the e-disc and other sources was the exhaust tappet was 37 mm. But I was unable to find the inlet tappet height. However, as the tools I designed, but my mate Nigel fabricated; (The guy is Brilliantly Meticulous), had not actually been tested on an engine, Adam wanted me there to oversee it and discuss a few issues at the same time.

So, I bombed back along the A14 for 1600hrs, by which time he had the front bank exhaust, front bearing cap removed and the tool fitted. So with a spanner locking the camshaft and another undoing the sprocket mounting bolt, it took all of twenty seconds to undo the bolt. The remaining bearing caps came off in no time at all and there was the C.B. Cam sitting comfortably, waiting to be lifted out. Boom - Boom. What a triumph, and it was only to get better.

Four of the six hydraulic tappets, were incorrect!!!!! Two were correct!!!! being 37 mm. But the other four - clearly inlet valve tappets - were 34 mm. !!!!!!!!!!!!!.

Disappointing given I had supplied the engine builders with the e-disc and more importantly had said on more than one occasion - be careful with the hydraulic lifter as they are location specific - the 37 mm. for the exhausts.

But relieved, we have found the problem and grateful the engine had not been run up as my concern would be for valves hitting piston crowns.

I had been looking to buy some replacement tappets but as with all things for this engine, they cost a fortune and are difficult to source anyway. So Adam suggested we take the tappets from my defunct 159 engine and that is exactly what we are doing. This way, each camshaft can be removed and the correct ones fitted, without faffing about having to chop and change and risking the timing chains being disturbed.

So, I went and had a Pint. We aren't out of the wood yet. But it is one step closer. - Cheers!

Foot note:-

A 37 mm. hydraulic tappet fitted in place of a 34 mm. tappet; with these Colombo Bariani camshafts fitted, would create an Inlet Valve/Valve-seat gap at the "Inlet Valve Closing Angle".

This gap; at an angle of 82.5 deg. before TDC on the compression stroke, would be 4.71428 mm. (4.8 mm.).

Nominal Cam/Rocker Arm Ratio. 1.6.
Sat in front of PC with a cup of extremely strong black coffee, wondering if there has been any progress with my toy (Q4 3.2 JTS). Adam hasn't phoned - were my calculations wrong - had a valve or two been stuffed into the piston crowns? If so, at what point do I abandon this expensive project? It has been great fun/extremely frustrating. But I needed it. I have been at a loose end since I retired at 68; still wish I hadn't, and I needed a project.

A previous project was finished some three years + ago. My son persuaded me, I should go digital with my camera. So I bought a Lumix G3 Micro 4/3rds specifically because, with an adapter plate I could use my OM 35 mm. lenses on the G3 body.

The thing was, everyone said using them on a micro 4/3rds camera, one doubled the focal length, whilst the aperture stayed the same. And folks said "You can get some incredible "Boken Effects" on wide apertures, particularly as I had a 50 mm. F 1.4 Olympus lens.

But I soon became disgruntled as the colours were saturated and in spite of the metering, they all seemed overexposed. The micro 4/3 rds to 35 mm. adapter was cavernous and it seemed to me the light was just bouncing around in there.

So I wrecked a perfectly good Sigma zoom lens as it appeared to have an internal baffle which might just fit inside the Panasonic adapter. It did! so that was fitted and the matt surface of it, steps down from just outside the rear element of the OM.1.4 to just in front of the G3 sensor. It progressively steps and the light absorbing surface ensures that there are no reflections, no stray light from inside the G3 adapter, getting onto the sensor.

But still the metering seemed to be lying. Further tests and I realized, the experts got it wrong. 35 mm. lenses on Micro 4/3 camera bodies do not double the focal length. Specifically, they maintain the aspect of the lens but double the focal length.

But what they also missed was, while a 4/3 rds camera has a sensor half the size of the focal plane of a 35 mm. camera, a Micro 4/3rds sensor is 1/4 the size of a 35 mm. focal plane. So it does not just pseudo - double the focal length of 35 mm. lenses, it doubles the aperture. My F1.4 50 mm. lens becomes Pseudo 100 mm. F0.7.

And my 250 mm. F4.5 becomes Pseudo 500 mm. F 2.25. But to keep the F stop of the G3 accurate, between the Baffle and the G3 Sensor, I fitted a Neutral Density Filter. I took the ND Element from an expensive filters and it fitted perfectly. It is only in almost pitch darkness that I need to take it out as these lenses now give incredible resolution in low light conditions. And I can point the camera almost directly towards intense light sources without causing the Boken Effect and the light meter going off scale.

OM lenses were always up there with the best and for purely nostalgic reasons I kept my OM2 Spot Program body as well as my lenses. And with my Macro Zoom lens can get some magical detail from some of the smallest objects.

However, That exercise ended and it was after a little while, the 159 3.2 JTS Q4 came into my possession. I did not realize at the time, this was to be my next project. And so it all began again! Fascinating! And still there is more to know.

Still, at what point do I stop - how much more can I plough into the 159, just to satisfy my ego. My need to understand everything? Is it the emptiness that projects generate in me - drug like, when they come to an end - that incredible "High " that I get; and have always got when I resolved problems with systems, sometimes left unfinished for months, sometimes years, even. Who was it that saw this in me, all those years ago? And then that feeling of emptiness that quickly overtakes the elation and almost becomes a depression, a need for another challenge.

I still have not resolved that. But sitting here, if I have to abandon the 159, what takes its place?

1026 am. Phone rings - it is Adam! Bad news/good news?

"16 of the 24 hydraulic tappets were fitted incorrectly! Oil Pressure in excess of 8 bar engine ticking over - sounds sweet." I cannot describe what those words meant!

For now, the "Drug" is still the same as it always was. Better than any Opiate. No words to describe it!
 

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Congrats, I've been following this topic for quite a while. Any ETA when it will be assembled and on the road? It will be interesting to see how it works and performs... the joys that project car brings:)
 

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Discussion Starter #157
Hi Sizewell, I have been following this thread with interest. I have been trying to get more info on the lean burn process at low revs but without much success. My car has been misfiring with subsequent coil failure for some time and it always happens between 1500-2200 revs when accelerating with medium throttle. The OBDI reader has been indicating that the oil pressure switch is faulty but does not require serious attention' also no indication on the instrument display. I read a number of threads where this is the case. However, since replacing the oil pressure switch the misfires at low revs have disappeared completely. I could not find any information on the Bosch MED 7.62 setup to see how it would react with a fly oil pressure switch. What is your opinion on this?
Great thread this!!
Hi RobV
Still puzzling over your problem. I detailed how I believe Lean Burn and Stratified Charges appear to be a function of this JTS engine. But actually, I believe it to be a function of all direct injection petrol engines.

Quote:- "
The spark plugs in the JTS engine are central to the Stratified Air Charge, the greatest density of which is also central.

The Jet relates to the high pressure "Jet Injectors", where the high pressure stream is directed towards the centre of the cylinder, closes to the spark plug and directly into the stratified air charge where its density is greatest.

The injection occurs at or around Top Dead Centre and causes it to mix with the denser element of the air charge which is concentrated around the spark plug region, within the area of the small indentation in the cylinder crown that forms what can only be described as a "Secondary Cylinder".

The amount of fuel injected into the Central High Density Air Charge is calibrated to achieve an "Air Fuel Ratio of 14.7:1 - Stoichiometric Ideal".

Although the central charge area is "Stoichiometric", for the "Whole of the Swept Volume" it is "Lean Burn"." Unquote.

If you look at my attached Dyno plot, it can be seen the AFR below 3000 RPM is running slightly leaner than above.

The link below is well worth watching as it gives some great detail about AFR figures.


AFR:-

However, back to the dyno plot. In the region up to 3000 rpm the AFR is less rich than above. From the video it was demonstrated that a figure of 0.92 Lambda is good for Torque output and being slightly richer than stoic, helps upper cylinder cooling. My 159 plot seems to demonstrate Alfa knew exactly what target AFR they wanted for this engine up to 5000/5200 RPM. Above this, things start to get very busy mechanically and the time taken to ingest air becomes increasingly shorter (Function of camshaft lift and duration being major issues). Consequently the AFR becomes increasingly rich, But this is the region the engine is starting to make serious power. It is also the region where upper cylinder temperatures climb dramatically. So the enrichment of the charge becomes crucial to keeping temperatures down to a safe operating value (what ever that is and can only be measured by "in - cylinder temperature probes".

However, as I said in earlier text, the injectors squirt fuel into the cylinder at very high pressure, directed towards the centrally placed spark plug, which sits above the indentation on the piston crown, which appears to be a secondary cylinder, within the actual cylinder.

The air within the cylinder has become stratified by the piston design and is least dense around the cylinder wall - most dense in the region of the central indentation of the piston crown and the spark plug. The fuel injected during light load/low revs is rich enough to create a ~stoichiometric AFR for that central indentation, which is ignited by the spark plug, directly above it. There is literally no power being made in this region because as the piston moves down and the flame front progresses outwards, the charge density decreases, therefore the motive force falls off dramatically. The lowering of the density also has the advantage of reducing the potential for "Knock". Thus achieving good low rev characteristics with an engine with a 11.2:1 compression ratio., a compression ratio that is most beneficial at higher revs, when the engine is no longer in lean burn.

However, if there are issues with valve timing on the front bank, given the angles are determined by the rear bank, then because the rear camshaft position sensor is late, the front cam has been set for an angle which is not appropriate for the engine load or speed. But a factor I had not considered before is, the Lambda probe reading on the rear bank manifold is also providing an erroneous reading - also as a function of late timing. It is therefore possible that the rear bank lambda reading is causing the ECU to select a lean fuel injection into the front bank cylinder - notably number 4.

Under these circumstances, the fuel injected into the secondary cylinder region, around the spark plug could causing the fuel air mix in the region of the spark plug to be extremely lean. This will elevate upper cylinder temperatures very quickly and central to this excess heat is the spark plug and "Coil Pack".

It is no more than a theory and difficult to prove without extensive and expensive testing. But the symptoms suggest there is a link. It has only just dawned on me, that there has to be a connection with the lambdas given the ECU is predictive and only acts on what has gone before. If the valve timing is wrong - evidenced by progressively failing cam sensor codes on the rear bank, then the gas discharge timing is also wrong and thus potentially the lambda reading also erroneous.

That "YouTube" clip is well worth watching a few times, to allow one to get one's head around the subject.

Sorry I can't be more helpful.

let me know how you get on Rob.
 

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Discussion Starter #158
Congrats, I've been following this topic for quite a while. Any ETA when it will be assembled and on the road? It will be interesting to see how it works and performs... the joys that project car brings:)
Thank you scamandeg.
I have been busy with some other stuff, which leaves Adam to get on and finish off. The conversation yesterday finished with, "Do you want us to do the MOT?". My response being, yes and can you charge the Air com - new pump fitted.

Only "OFF - Throttle" starts have been done so far, just to enable the oil to get nicely around the galleries, into the tensioners, the VVT Phasors and the Hydraulic Tappets. However, will pop down later today to see and hear her running - almost too afraid to really, it has been so long in coming together, it is difficult to grasp we may be almost there.
 

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Discussion Starter #159 (Edited)
Thank you scamandeg.
I have been busy with some other stuff, which leaves Adam to get on and finish off. The conversation yesterday finished with, "Do you want us to do the MOT?". My response being, yes and can you charge the Air com - new pump fitted.

Only "OFF - Throttle" starts have been done so far, just to enable the oil to get nicely around the galleries, into the tensioners, the VVT Phasors and the Hydraulic Tappets. However, will pop down later today to see and hear her running - almost too afraid to really, it has been so long in coming together, it is difficult to grasp we may be almost there.
Went down to see the garage. They were just finishing off with the A/C charging and all fluid levels. Everything was on full blast to get coolant around the system properly, whilst the engine was running - getting temperature up. All fault logs were checked and none reported. Throttle exercised to try to provoke any fault codes - none. Oil Pressure - 9 Bar on cold oil!

Car was reversed out to be cleaned/hosed as it was going to be MOT -ed. It would be a pity if it fails for a boot which does not seem to want to lock!!!!

However, engine revved a little and the sound from the exhaust was delicious. Deeper than I was expecting and no hesitation when throttle was pressed. The crankshaft is the original, which had been bent; 23 - 24 thou out, but straightened by Ivor Searle of Soham. It was then re - ground by Brian Randal of Hepworth and balanced by Scholar engines on the A140 towards Diss, the engine builders. One new con rod was fitted and the pistons and con rods were checked for balance/weight. Both the mains and the journal bearings are first oversize, + 0.25 mm.

The problem with the low compression was found to be the hydraulic tappets had been incorrectly installed. The exhausts are 37 mm., whilst the inlets are 34 mm. Hey! these things happen but I am happy that there was no piston/valve collisions. This was clearly the reason for the lack of compression. But unfortunately all four cam shafts had to be removed, in turn and the 159 tappets fitted - tool only allows one camshaft to be removed at a time.

I was a little in awe of the way the engine sounded, although I have poor hearing. It wasn't raspy and in truth sounded nothing like the Busso. But I think the combination of the camshafts and the cat less manifolds gave it a more of a "Blat" sound on hitting the throttle and a "Ttizz" on lifting, almost like a Turbo waste gate opening. Either way, it is very different from what it was hitherto. It sounded powerful, more Baritone than Tenor. Sounded more like my 2.5 GTV6 Alfetta after it was balanced and rebuilt with Colombo Bariani cams. But that was a while ago and maybe I just want it to sound like it - nostalgia kicking in!

Anyway, with any luck it may have passed MOT and be ready for the road tomorrow. Here's hoping for no more hiccups. Then 500 miles at 2500 rpm max, before another oil and filter change.

Looking forward to seeing how much the cams and Manifolds have changed the performance. Compression ratio will be a little higher as well as both the heads and the top of the block were re - dressed/skimmed. Hoping for over 300 horses. !0 percent should do that. But I am suspicious that the valve timing, going from 2.5 deg. NVO to 23.5 deg. PVO will also contribute to increased horses, along with the cams and the manifolds.
 

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Discussion Starter #160 (Edited)
Where do I find these brembos?

Sweet Irony! Phoned the garage and yes, the car failed MOT for the want of a boot that locks Ha! Ha! Essentially Adam must have just gone through the MOT, having previously ordered a boot catch. Can do no more but wait for that to arrive. Then it will be time to settle in and just enjoy the moment.

But I do like those front discs and calipers.
 
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