Thread: Cams + Crank Timing Chain Question..Mating Marks..

Its definatly not the ECU, do you know how shitty it would run with the timing that advanced? The thing would be knocking like crazy if the base timing was at like 27 degrees or whatever? It HAS to be something mechanical , as thats what the base timing is, simply mechanical timing, and the ECU digitaly changes the ignition timing. I'm thinking maybe the camshaft may be ground wrong or something...either that or maybe the timing chain is streched that far? Thats a possibility as well...lets work on figuring out what it IS not what its NOT, the mechanical timing orientation of the cams to the crank.

Remember that this timing issue was going on before we did the s4 swap so it's probably not the cams.

Could be a tensioner problem. If you have the old style tensioner I would recommend replacing it very soon.

hmmm, ordering one now.

A tensioner would only affect the slack side of the chain, keeping it from jumping time on the intake cam; the distance between the exhaust cam sprocket dot and the crank sproket dot is where the stretch would affect the physical timing, the only real solution is to replace the timing chain, if it is in-fact

The updated tensioner only disallows the oil from draining back when the engine is off making the tensioner not rattle on a cold startup. Lucas does your tensioner rattle on a cold morning when starting? If bot, then it's a waste of money IMHO.

I wouldn't go so far as to say it is a waste of money, maybe not a necessity, but it is easy to change, reduces valvetrain noises, and has finer teeth for more finite adjustments.

I still do not understand why you are asking about this. What is the problem, again?

You have said general things but not asked a question or I have not discovered what your problem was, yet.

It's already ordered.

I didn't notice any rattling. I remember when we did the S4 cams we heard some rattling of the chain like it was hitting the valve cover or something but that seems to have corrected itself over time.

Agreed, it's not a waste of money, but it's fixing what ain't broke.

The problem is the distibutor is almost all the way advanced to get a base timing of 15°.

GOMBA did you order it from gregv? If not you'll need the updated gasket to replace at the same time, as I think Greg sells then as a 'kit', although you might check anyway.

Whoever installed the cams had some slack between the exhaust cam and the crank gear. This moves the 15* base timing forward.

I had the same, exact thing happen to me when I installed Briawn Crower Stage 2 cams. I popped the valve cover off, took off the exhaust cam and put it back on making no slack in the chain between the exhaust cam gear and the crank gear.

Just like that, the base timing of 15* was close to where it was originally. On my car, 15* appears slightly retarded (towards the firewall with a larger gap in the top slot of the dizzy groove). My JWT ECU requires base timing of the dizzy to be at 25* so I had to advance it a lot and I could only get 15* by damn near completely advancing it fully.

Weird, it happens, I remedied it after 5 weeks of dicking around.

yes, GregV



You checked your cam timing and it was fine before you took the exhaust cam off? Wouldn't your suggestion move the dimple marks on the cam gear relative to the # of links in the chain? I think you'd essentially be moving the chain a tooth or two. Also, I've had this issue prior to S4 cam install, although we zip tied the chain and such so if it was a problem before, it would have still been a problem after S4 cam install.

My cam timing, using all the methods, is perfect.

-G