Kent Cams - timing up

Al Mac

New Member
Chaps,

Kent Cams on standard pulleys - should the mating marks on the chain still match up with the ones on the sprockets as per standard?

Cheers
Alex
 

williams

New Member
Ideally, you need adjustable pullies to set the cams to kents specs. If your just using standard pullies then you'l have to set them to standard marks but you wont be seeing the full potential of the cams.
 

Al Mac

New Member
Reason I ask is that when we took the cams out to retorque the head, the marks on the pulleys don't seem to be anywhere near the ones on the chain.

We marked up the teeth on the pulleys with tippex so that they went back in the same place, and the engine seems to turn over by hand with no issues, but seems odd that the factory spec marks are waaaaay out from the normal position as per the workshop manual. Does that make sense?:?


Ta

Alex
 

williams

New Member
When you start turning it over the marks on the chain wont line up with pulleys every single relvolution. If you marked chain and pulleys and put them back in without moving the crank it should be fine. I wouldve marked the head aswell and marked the crank up aswell.
 

Empty Pockets

New Member
Ideally, you need adjustable pullies to set the cams to kents specs. If your just using standard pullies then you'l have to set them to standard marks but you wont be seeing the full potential of the cams.

Kent specs won't be any good if he's changed gasket thickness etc, only way to do it properly for maximum gain is on the dyno and keep taking the rocker off and adjusting, lot of fucking about.
 

Al Mac

New Member
Another thought: when we removed the camshafts, we cabletied the chain to the top of the engine to stop it falling down towards the crank; would having slack on the chain at the top have allowed it to fall off the crank pulley at the bottom, or is there sufficient contact down there to hold it on regardless?
 

williams

New Member
Kent specs won't be any good if he's changed gasket thickness etc, only way to do it properly for maximum gain is on the dyno and keep taking the rocker off and adjusting, lot of fucking about.
its alot easier to time them up to the specs 1st, gets you closer than setting to standard timing marks.
gasket thickness wont affect valve lift though.may need timed very slightly different because of larger combustion chamber volume, but a better starting point when fitting them would be to fit and time them to kents specs.
 

williams

New Member
Another thought: when we removed the camshafts, we cabletied the chain to the top of the engine to stop it falling down towards the crank; would having slack on the chain at the top have allowed it to fall off the crank pulley at the bottom, or is there sufficient contact down there to hold it on regardless?
it could have happend, depends how much slack you've had. ive never had a problem doing that, but i've always marked up all the pulleys.
 

Empty Pockets

New Member
its alot easier to time them up to the specs 1st, gets you closer than setting to standard timing marks.
gasket thickness wont affect valve lift though.may need timed very slightly different because of larger combustion chamber volume, but a better starting point when fitting them would be to fit and time them to kents specs.
Sounded like you were using kent specs as the maximum gains, it's easier but you'll never get the full potential without messing about with it on a dyno, too many variables to just expect generic settings to be the same on every car. If you want to do it properly it's on a dyno with lots of adjusting, no other way.
 

Al Mac

New Member
it could have happend, depends how much slack you've had. ive never had a problem doing that, but i've always marked up all the pulleys.

I've had another look, and I don't think it will have dropped - it looks like the chain is in contact with pretty much 2/3 to 3/4 of the bottom pulley anyway, so the teeth wouldn't let the chain drop unless I'm reeeaaaally unlucky.Which I have been known to be of course, lol.

I can turn the engine over by hand all the way round in any case, so if I haven't got it totally perfect I shouldn't be more than a tooth out in any case I'd think?
 

williams

New Member
Sounded like you were using kent specs as the maximum gains, it's easier but you'll never get the full potential without messing about with it on a dyno, too many variables to just expect generic settings to be the same on every car. If you want to do it properly it's on a dyno with lots of adjusting, no other way.
i said to use kents specs as it sounds as though he's fitting them at home. so it would be best to set them to kent specs rather than standard timing. then the car will be as good as it can be untill he gets the car on the rollers.
 

williams

New Member
I've had another look, and I don't think it will have dropped - it looks like the chain is in contact with pretty much 2/3 to 3/4 of the bottom pulley anyway, so the teeth wouldn't let the chain drop unless I'm reeeaaaally unlucky.Which I have been known to be of course, lol.

I can turn the engine over by hand all the way round in any case, so if I haven't got it totally perfect I shouldn't be more than a tooth out in any case I'd think?
personally, i would turn the crank to tdc and check the cams are in the correct place.
 

Empty Pockets

New Member
i said to use kents specs as it sounds as though he's fitting them at home. so it would be best to set them to kent specs rather than standard timing. then the car will be as good as it can be untill he gets the car on the rollers.
The way i read it is he's using standard verniers anyway so it's not aplicable, all i'm trying to say is the kent specs are a guide, not the ultimate settings as it's spec and user dependant, it sounded like you were saying they were the ultimate setting that's all, no worries, i'm not trying to teach you to suck eggs mate and i agree with you that kent specs are probably better than zero'ing them untill you can get it done properly on the rollers with verniers .:thumbsup:
 

skiddusmarkus

Active Member
Exactly how much messing is setting up vernier pulleys with aftermarket cams.Car is going to Fusion soon for mapping and I have hks pulleys set to zero and Tome 260 cams.Wanting to have the cams set to spool the gt2876 up a little faster rather than have them set for topend.Are we talking hours here?
 

williams

New Member
If you've got a fairly common engine set then your mapper will prob have an idea of where they need to be which will speed the process up a bit. Its worth doing properly though imo for the extra time it takes.
 

Al Mac

New Member
So on a standard, non-adjustable pulley set, should I position the cams as per standard ones (ie: crank at TDC, keyways at 10 and 12, 20 chain pins between pulley markers), or will it be so different that the timing will be more than a tooth out from this?

I've got them in the standard way at present, the engine turns over by hand with no issues, but once I put it all back together and fired it up it ran really lumpy, almost like it was on 3 cylinders (I haven't totally ruled out plugs/leads yet but a cursory examination hasn't turned up any problems so far).

Apologies if this sounds thick - first time I've had to do this, lol
 

Al Mac

New Member
Ignore the above - Cam timing is spot on so far as the chain is concerned. It just turns out that engines don't start so well when ignition leads 2 and 3 are the wrong way round...

Serves me right for working on it in the dark, lol


Anyway, all back together, went out to get some fuel in it and then for a little spin - so far seems to be holding together OK, and doesn't seem to be pressurising the coolant or blowing steam out the back. Will give it a proper run on the weekend and set the dizzy timing up properly, but pleased so far :)
 
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