Timing chain adjustment...

[Skullzaflare]

Tim I understand what you are saying. I appreciate your sincerity. But I will say that I DO have proof of the links being off. The comparison is the link at the end. One problem with degreeing the cam is that no one really can give a good description of how to without using the links. Everyone says it has to be just a little before twelve o'clock. The problem is that the human eye can only be but so good. It's hard to tell when cam is off only 4* (one tooth on the crank). Therefore i was looking for guidance on how to set it using the plated links that were on the original chain I had on there. The reference to PQ's dizzy link is only for the one picture that shows the difference between various chains. He shows that some have off count, off colored, or even no plated links. Hence the problem with my previous chain. But it's now in the past as the chain has been replaced and degreed correctly and I am now in the process of rebuilding the dizzy. Thank you again for being so kind Tim. Always known you to be very helpful.

 

The chain on the right is the previous...the one on the left is the new Cloyes chain...

http://www.flickr.co...N07/6328909635/

 

Thanks,

Charles C. Palka

i recall somewhere saying if you have trouble seeing the offset, hold a string in the middle of the crank bolt, and hold it up and over the center of the cam bolt

you will either be slightly before 12, or slightly after

[nightwalkerancestery]

Tim_C: That was exactly my argument. But no one believed me. Pictures speak a thousand words But yeah I've gotten that sorted out now. Timing is dead on. Now I'm looking at getting a New Vac Advance. Old one's diaphram is gone.

 

Skulz: I was wondering how to degree everything. That's a good idea. The only thing that gets me is that it's a matter of guessing. Just a little after or before isn't much of a measurement. You could be one link off on the crank but to the eye it looks about right while the whole time you're a half a link off on the cam. That's my only concern is the estimation factor.

 

Thanks,

Charles C. Palka

[Indiana]

There's no way to be off "half" of a link. You know how many times I've seen where someone will move the chain at the crank instead of the cam? I just laugh inside. It doesn't make any friggin difference. I said how you can check it and you can lay a straight edge on top the head and it lines up at the cam gear and if you can't tell which low spot between two teeth that dowel is at you are blind. If its off one entire tooth is EASY to see. You have to make certain that the chain is tight on the right side, rotate counterclockwise a little then back clockwise to make sure. You said you could see your links but you thought it was off ONE tooth you never said the link was off like 15 and it was so screwed up but I was still trying to tell you how to check it even if you had no links to check. You can't see that ground out place in the crank timing gear with the guide on, the chain on and the drive gear for the oil pump/balance shafts anyway. You can remove one guide and see it though. You didn't have the pan off making it more difficult.

 

How far off is it when its off one link? Its off about 18 degrees. There's 38 roller links that can fit around that cam gear, there's 720 degrees of one ignition even so that's about 19 degrees for one tooth. This is why it runs like crap if its off one tooth. We have to make some assumptions when people start asking for answer like your block and head haven't been milled down more then the stock limit spec of only a mere .008". If you have a built motor with forged pistons and had the deck cut to zero, you removed about .040" and if your head was milled well hell that's about the thickness of the headgasket and that's about one tooth on the chain. Next thing happens someone uses a reground cam. They don't correct the dowel pin hole on those so its random how far its off they can grind it either side of the lobe and that can either add to how much the cam would be retarded from milled surfaces or have the effect of correcting it and some that have used the degree wheel have found that to be true, they said oh it was off only a little bit its not even worth it to degree your cam. B S Cam degree is everything and just as important as ignition timing. Roller rockers used on a non roller cam also screw it up.

 

What are stock cam degrees?

 

intake open 25 btdc, close 59 abdc

exhaust open 64 bbdc, close 20 atdc

 

What's the effect of being off one tooth? Your exhaust valve was closed, meaning it is seated and closed just about at TDC so it didn't even get to mash out everything it needed to so there's burnt crap left in there to mix with the air/fuel for the next event. You have the intake valve closed now also delayed at 78 abdc AND you are igniting this mix under full igntion advance at 34 btdc so you only got to compress this mix for 68 degrees of the 189 degrees of duration it takes for the piston to go from the bottom to the top on the compression stroke. That chain off one tooth lost you at least 10% of your compression ability. WOW, what a dog of a motor but some still think its fine because their forged pistons cause the compression ratio to change and it now runs when before it didn't so what do they know, they have nothing to compare it to. Retarded cam timing also has the effect of making boost earlier but you loose the top end. You see dyno runs with the torque curve FALLING OFF, you wonder why? Motors are built to make them better and many think the MOST IMPORTANT part isn't worth checking because you can't buy some "kit" to do it and have to read a little and learn something.

 

I appologize for the assumptions that I and others on here make when we attempt to answer questions and help people but we can't first send out 30 page questionaires so we can make a better quess. This isn't your fault its just the way it works and it will happen again and again.

[Indiana]

You think that screwed up cam timing effects your air/fuel ratio? How about EGTs and coolant temperatures?