Tourney3p0

How much slack would be required on a stock timing chain in an 88 to hear it make noise?

I posted awhile back about trying to find a metal on metal noise. Not a knock, not a tick.. I've pulled the valve covers and pulled the oil pan. I'm 99% sure now that it's the timing chain, and I've had a couple of good mechanic friends agree with me.

I've heard of people getting slack in them (I'm at 110k miles) but was wondering how much slack would need to be in there to get to the point I'm at.

69vetteracer

Normally a worn timing chain will cause the car to run like hell before it starts to make noise. How does yours run. As a chain wears out the timing retards. I have seen only one that actually made noise. Good luck. :chevy

Tourney3p0

When it's cold it doesn't make a noise.
But when it's cold I have to pump the gas a couple of times on startup or it'll idle down and die.

When the car is warm it makes the "clack" sound but the car starts and runs great. It doesn't have a rough idle, but it will gradually fluctuate between 600-800. I put a screw driver up toward the timing cover and could hear it much more distinctly.

JAKE

Check the ignition timing to see if it has changed. The timing will not hold steady if the chain has really stretched from wear.

The ony time I've actually HEARD a timing chain was when it was hitting the timing chain cover. Examining the inside of the cover will confirm this, but if you go so far as to inspect the chain, might at well install a new one while you're in there.

Jake

Tourney3p0

I can tell when it's warm (and when I can hear the sound) that the timing is a bit off. I always assumed that it was because the knock sensor was picking up the "clack" sound and retarding the timing, but this makes sense too.

Exactly. :D
Oh well. I'm confident that it's my timing chain now. It'll be awhile before I tackle it, but when I get it off I'll try to get some pictures so we'll all know exactly how much slack is needed for it to hit the timing chain cover.

geezel

I'll throw my 2 cents in... I just installed a new cam & timing chain in my '86 with 65k miles. The stock chain had a lot of slop but never made any noise. The new chain is as tight as a piano wire.

JAKE

Try this, remove the serpentine belt. Start the engine and put your hand on the timing chain cover.

You should be able to feel if the chain's hitting.

Just be careful that your hand doesn't touch the crank pulley and don't let the engine run for long since you won't have any coolant circulation with the belt off. Best to do it with a stone cold engine.

Jake

mike 1985

i think you can also check it by the crank timing tab and the dist. rotor. Basically turn the motor over by hand and watch the rotor. Bring the timing marks to 0 then turn the motor the opposit direction while having someone watch the rotor. As soon as it moves stop and look at how many degrees the the balancer has moved. Divide that number by 2...if it's more than 4 you need a new one.