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(Post Link) post #1 of 127 Old 27-07-13 Thread Starter
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Ts camshaft gurus. A question of timing...

Hey all.
A while ago I fitted 2.0 cams in the 147 1.6 and rejoiced at a power increase.
Then the front cats fell out, mysteriously ending up in the bin, and a 2.0 variable length manifold fairy waved her wand and did her one job in life....

All is well until I remembered a comment on a thread about timing up the cams on the 1.6 block. There was a statement about advancing the cams after being set up with the timing blocks. Ala:
"I think that the best way to do this is to use the 2.0 locking tools and then attach an angle measurement tool (not sure about its english name) to the crankshaft pulley and measure 9 degrees of crankshaft advance for the inlet cam.

If you choose to measure the advance degrees on the cam instead of the crankshaft you have to measure 4.5 degrees."

Now, I've not timed cams before, is that going to be worth getting my hands dirty?

Tia. Ian.
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I've never tried this on the 16v, but I got very good results playing with the exhaust cam on my 155 8v.... for the life of me I can't remember if I retarded or advanced the exhaust timing... there's an easy 10 bhp there anyway
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(Post Link) post #3 of 127 Old 29-07-13 Thread Starter
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Cheers boss.

Oooh, just noticed your location....home of the best beers in the world.
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which is why I can't remember what I did on the 8v... i "think" i created more valve overlap
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LOL..
Ok, so have done lots of research and read up on cam timing, and havve formulated a plan.

Now bear in mind that i have never "timed" cams up before and this is still new to me!!

Ok, find absolute TDC on #1 and attach the timing disc to the crank pulley and bolt up a pointer to show it at 0'.
Now clamp the inlet cam using the timing clamp and slacken the taperlock bolts on the inlet cam.
Now retard the engine by 9' and tighten up the taperlock on the cam.

In my head this makes sense......
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it does, but it's very hard to get it right if you're going to retard the crank. otherwise use the TDC gauge and mathemathically calculate how far from TDC you need to be to get 9... saves you a crank timing disc.

or fit a vernier pulleys to the cams and adjust there, with double the resolution...
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The cam tapers allow a bit of movement so vernier pulleys are almost oem!
I have an 8" timing disc now, might just see if I can advance the inlet on its own....
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I think that, there is no need to touch the inlet cam, it already has cams phase variator which advances the cam and by thurow advancing, you risk valve to piston contact. In my point of view, it is better to retard the exhaust valve do widden the lobe separatuion angle thus increasing the overlap without ( not sure about it.. ) valve to piston contact.
Please correct me if I am wrong.
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My head is starting to hurt with all he reading i'm doing. Angles,overlap,advance,retard,duration,lift,durati on at .050.....,.aaaaaaaaaaaargh......(pop).....

So, retarding the exhaust timing creates more overlap which helps infill of incoming charge and exfill of burned up, fast moving nasties?
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Cuore_Sportivo_155

Yes, overlap helps the high rpm filling, but the engine might not idle normally. My idea is not to touch the inlet cam because it has a system which changes its position, but the exhaust because it doesnt have such a system.

P.S. Cuore_Sportivo_155 also said, he made changes to the exhaust cam position.
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What happened, did you retime the cams ?
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(Post Link) post #12 of 127 Old 12-08-13 Thread Starter
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I did a silly thing.....i picked up a book by some bloke called Vizard*, and i have absolutely no idea what i'm doing now!!!!
My main interest now is the statement in the first post, as to WHY it needs advancing by 4.5 cam degrees....? The duration is longer, the lift higher, my brain then started melting at the fifth cam event, the overlap that draws the intake charge in by the exhaust charge having inertia on its way out of the cylinder.......
So how much overlap does the 2.0 have as oem? And the 1.6?

Camshafts=voodoo i tells ya......

*-david 'tuning god' vizard. There aint a lot he doesnt know!
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I've still got David Vizards book on tuning BL A series engines - the bloke really knows his stuff and its all backed up by flow data and rolling road results.
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If wikipedia is correct then the timing is:

Intake: open 0/25 BTDC, close 55/30 ABDC, intake total angle: 235 degrees
Exhaust: open 50 BBDC, close 8 ATDC, exhaust duration: 238 degrees
Overlap: 8/33 degrees.
That's for the 2.0 16v engine.

Technical Specs & Information
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(Post Link) post #15 of 127 Old 13-08-13 Thread Starter
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Quote:
Originally Posted by Rockhopper View Post
I've still got David Vizards book on tuning BL A series engines - the bloke really knows his stuff and its all backed up by flow data and rolling road results.
Oddly enough, that's where I got into it. My mad cousin has a badass 1380gt. Only just ticked over, the cams were so mental!

I love the fact he flow tests with a vacuum cleaner

Last edited by Egon; 13-08-13 at 15:45.
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Quote:
Originally Posted by Egon View Post
I did a silly thing.....i picked up a book by some bloke called Vizard*, and i have absolutely no idea what i'm doing now!!!!
My main interest now is the statement in the first post, as to WHY it needs advancing by 4.5 cam degrees....? The duration is longer, the lift higher, my brain then started melting at the fifth cam event, the overlap that draws the intake charge in by the exhaust charge having inertia on its way out of the cylinder.......
So how much overlap does the 2.0 have as oem? And the 1.6?

Camshafts=voodoo i tells ya......

*-david 'tuning god' vizard. There aint a lot he doesnt know!
the 1.6 has less overlap, but I don't know how much exactly. And that will be the problem, too much overlap for a 1.6, which will cause bad mileage (unburnt fuel and air entering the exhaust and being wasted). reduce the valve overlap area (when drawn on a piece of paper) by 20% and you'll probably have to advance the intake cam by 4.5 degrees.
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I found all the info I needed, but I have a ream of data I need to rationalise before I post up.
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be prepared to spend some weekends finetuning your cams, whatever you do... Maybe leave the top timing covers off for a while so you can adjust quickly?
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And after you finish tuning the cams, DON'T forget to turn the engine by hand, to make sure the valves don't hit the pistons.
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Very good advice, that.
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I've already done this.

My mpg dropped by four. Mainly to doing town driving and the idle and anything below 3K was lumpy.
But when it got past 4.5K it felt much like a two stroke engine (Although not as feirce). I am in no doubt it made more power by increasing the overlap. (I did this on the inlet side).

But the 9 degrees is just to harsh.

If I was on the motorway alot i'd have kept. Given that the engine spends most of its time pottling around below 3k. I swapped it back to the original timing.

I also retarded 10 degrees. But it ran like a dog (effectively closing the overlap more) but it felt like the throttle was flooding the car with air.

Bear in mind the variator advances by 29 degrees at certain rpm.


It basically scavenges the fuel during the cam over lap. The greater the overlap the better for high rpm but rubbish for low rpm.
Closing the gap great for a lazy engine but no good for high rev's and power.


leaving the gap the same but advancing the crank moves power curves higher up, retarding crank moves the power curve down. (Al within a certain limit).


Problem is camshafts are fixed. Fixed lobes / shape (duration) / overlap / Lift
So whatever you you'll only find a balance.

Which is the point of the multi air systems (Fiat) or Toyotas VVTI or Hondas incredible VTEC system which both give you the best of both worlds (agressive cam and a soft cam in one).

Much more advanced vs the TS engine which is a bit draconionan compared to other engines.

Regards
Scott
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Thanks scottyf, that's worth it's weight in gold, info like that.
I have been trying to find someone whose done it before to compare ideas with but you just saved me a huge amount of spanner waving and time!!

Right, that's solved that one, where's that supercharger gone....
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Its a good idea to get a bit more peak figures from the engine. But unfortunatly unless you drive round at redline it just doesn't seem worth it.

Rather have a bit more midrange from 2k up to 4k which is where i drive most of the time.
Peak figures are all well and good on paper but in real world use. In traffic, round the city it was a complete dog.

the best performance increase without breaking the bank has been the 2.0L cams, air induction and a remap.

The other restriction is then the exhaust where the two pre cat's are.
Then maybe fitting the 2.0L throttle body would help improve things.

All those can be done without breaking the bank.


The 1.6 head has the same valve size as the 2.0L so the flow of air into the cylinders is more than enough on the 1.6. So porting will do very little for the 1.6.
Freeing up the air flow in via the throttle body and more so getting out will have a better overal affect.


changing the overlap on the camshafts is good if you are going to do a track day.


I still think you could easily get 150hp from the 1.6 unit.
Induction
2.0L Throttle body
4-2-1 manifold
5w 40 oil
2.0L cams
Remap
and a higher rev limit (maybe close to 8K anything more and you'll get valuve float with hydro lifters) would see the 1.6 hitting 150hp I believe.

But even the above you are talking 500.
In which case could you have bought the 2.0L and had the additional power in standard form and the additional torque and the insurance etc...

But the 1.6 is a little sweeter and rev's a bit happier with the above it would be quite a quick car with the lower ratio gearbox.
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(Post Link) post #24 of 127 Old 26-08-13 Thread Starter
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Heh, you're not a million miles away from where my head was at.
Is the 2.0 t/body bigger then? I have no precats,2.0 cams,2.0 inlet (although not wired in and functional) and it does feel quicker.
I love the fact that I can wring the life out of it and it goes like a 2.0!
I need a remap, and to activate the variable length manifold, but the throttle body idea sounds good....
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I believe it is actually bigger. I am not sure the complete specs. But I am sure from reading this forum it tends to have a slightly larger diameter.

As the valves are the same size in both 1.6 1.8 and 2.0 heads the 1.6 gets far more air than its standard power dictates. So the head should have more than enough flow to hit a 2.0L power output. But it has to do so with more Rev's rather than anything else.

The problem is though the 1.6 will never have the same torque due to the smaller throw crank.
Also as the lifters are hydro you can't get them to rev out higher than 8'000 due to valve float.

Mechanical lifters are the only way forward really. As thats where your ceiling limit is.
The only other issue then is if the crank is balanced enough to hit over 8000rpm. Which i doubt it is.
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