Timing chain slack

[MikeW]

Perhaps tension is the wrong word then. I'm guess thinking of it in static terms. If there is slack on the straight side due to stretch then changing the locator hole eliminates that slack which in my mind is the same as pulling on the chain a bit which is why I called it tension. I agree that it's different than the tension on the chain while it's moving. On the straight side the tension is caused by the crankshaft sprocket pulling down against the resistance on the camshaft sprocket. On the other side the tension comes from the tensioner.

In any case I'm not disagreeing with what you're saying; I suppose I'm more trying to get it clear in my mind how it all works.

[montoya_fan01]

In any case I'm not disagreeing with what you're saying; I suppose I'm more trying to get it clear in my mind how it all works.

me too.

I guess what I was trying to say was that (in my mind) there cannot be any "slack" (lesser tension) on the driven (straight) side of the chain. However, there can be increased "distance" between the timing marks of the two sprockets, but that distance would be filled with a "longer" (stretched) chain which (via the crankshaft sprocket) will pull the camshaft sprocket with the same amount of force (tension) applied to the chain.

[jmortensen]

You want NO slack? Take a look at the Kameari tensioner. That's about as close as you're going to get, but even there you have some amount of chain stretch to deal with.

The sad fact is that the L series doesn't keep EXACT time, and the tensioner doesn't take up ALL the slack, especially when you rev up the engine and then abruptly let off the gas.

Here's a good thread about the Kameari tensioner setup from hybridz: http://forums.hybridz.org/showthread.php?t=102066

[ZSaint]

A stretched chain will always be a stretched chain regardless of which hole (#1, 2 or 3) you put the cam sprocket. All changing these holes does is change the can timing. A stretched chain will give you more cam retardation. You begin to lose your bottom end power. Changing to the #2 or #3 hole will advance the can back to where the factory specs were/are. The chain will remain stretched, however. Wild cams usually take 5` to 6` of advance to help out the bottom end. Mild cams tend to be 2` to 4` advanced. This is what my experience shows. (I have never timed a stock camshaft.) You really need to time the cam by the cam grinder specifications to maximize the power. Whe spend all of that money and time to just stick the cam in and run it not knowing what the timing is?

[a7dz]

I do not know how you got into the tension of the chain. The original question has never been answered. Great info I guess but, not what the question ever asked. As I understand the question he is asking about slack. Now where is the slack on the chain. On the slack (tensioned side) or on timed side? And is it normal in a non running completely functional engine?

[jmortensen]

I do not know how you got into the tension of the chain. The original question has never been answered.

You've got two forces resisting you when you turn the engine by hand. The compression and the valvetrain. It seems pretty clear to me that you a point in the valvetrain where it wants to move forward, and the crank doesn't. No big mystery.

That's not the answer? I was feeling pretty sure...

[ZSaint]

In terms of "slack", I believe Jon M. answered the question beautifully. We have all turned our engine over by hand and once in a while when the cam is just right with spring tension just right, the cam will kick ahead. Without oil pressure to take out the slack, the chain is loose and the valve springs are strong enough to catch the cam and kick it forward. Not to worry. This will not happen when running.