Timing Chain Noise

I have some timing chain noise. Not bad, but there. I have the tool for tensioning the top chain. Is there any chance that a car sitting for a month or two might have some corrosion on the gears and chain that may cause this noise? When my car restoration was complete, the mechanic was concerned about a slight bearing squeal coming from the gearbox. The gearbox has sat idle for almost 15 years. He added some STP and the squeal was gone. I drove the car for 500 miles and then changed out the gear lube. In 38 years, the squeal has NEVER returned and the gearbox has run strong. Any ideas about adding STP over the chain for a few hundred miles?

Since you can check chain tension by just removing one cam cover I’d certainly want to examine that as a first step. Hopefully you have some idea of how tight it should be as it is a hard thing to describe.

Not unless the oil was suffused with water.

As for STP…NO. That crap should only ever be used on an engine you don’t care about!

In gearboxes, it can have beneficial uses, but not in engines.

1 Like

It would only run for 100 miles or so and then change the oil out. I will check chain tension first. As I understand it, not too tight when cold .

The only car I religeously used STP was my 72 Firebird, it also is the only car I had to replace a worn out cam, had the car since new.

OK, I bit the bullet and removed one cam cover. Chain and gears look pristine where contact is made. I used my finger at the side of the top chain to check for play. The chain moved ‘easily’ 1/4" to the side. This, in my humble opinion is excessive. Now for a consensus of opinion on how much slack is sufficient. I would think that as long as I could push the chain and get some motion that this would be acceptable. I also understand that as I do this procedure, it is important to rotate the crank shaft to equalize the tension. I have enclosed a pic of the top cam gear and chain. Thanks for all of your input.
Ron Brook

Just rotate the adjuster till the slop is barely perceptible, around 1/2 millimeter.

What I did (read on here I think) was to tighten it completely tight, then backed off one tooth. Probably gets it to the same place Paul describes.

I found it helpful to take a digital photo of the adjuster, then count and label (on the photo) the position:

The when done the results can be examined with a 2nd photo:

So in that example, it has moved 2 teeth.

Alternately, a couple of paint marks can at least note your starting point:

Then I saw this when it was dead tight:

Either way, it may be worthwhile to have someway of knowing where you started and where you have gone.

1 Like

Just finished it up. Gear moved two teeth and the play went from over 1/4 inch to a couple of millimeters. Run tomorrow.

Complete. The ratchet moved two clicks CCW. Checked the chain slack and is more on the order of a couple of millimeters. Tomorrow we run.

1 Like