Timing Chain Slack?
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 1,117
Likes: 0
From: DFW TX
Timing Chain Slack?
Im in the middle of a cam change on the 92 LT1 and have a new GM timing chain.
I expected the chain to be somewhat stiff and have vitually no slack when installed.
Instead I find that when installed, it has some slack, almost as much as the old chain I took off.
How tight should a new timing chain be when first installed.
Experienced answers and no opinions please. Thanks.
Dan
I expected the chain to be somewhat stiff and have vitually no slack when installed.
Instead I find that when installed, it has some slack, almost as much as the old chain I took off.
How tight should a new timing chain be when first installed.
Experienced answers and no opinions please. Thanks.
Dan
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 1,117
Likes: 0
From: DFW TX
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Ive seen s bunvh of posts about the GM chains having a little slack. Cant see how it would create a big problem. Get a super tight one and run it for a bit. Bet if you pull the cover you have some slack, they do stretch like anything else.
Has the motor ever been line bored?
Has the motor ever been line bored?
Racer
Joined: Feb 2006
Posts: 269
Likes: 0
From: Vancouver B.C.
My LT1 Cloyes double roller set was 'loose'. (and no line bore)
Doesn't factory offer double roller? LT4? Double roller chains are looser than OEM, IMHO.
Why won't you answer '86 and '93? DO you have new sprockets?
Doesn't factory offer double roller? LT4? Double roller chains are looser than OEM, IMHO.
Why won't you answer '86 and '93? DO you have new sprockets?
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Racer
Joined: Feb 2006
Posts: 269
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From: Vancouver B.C.
By loose, I mean after install. The chain ("leeward" side) had 'play'. Not tight at all. Installing it was tight though. The only tight chains I've ever seen have been stock non-roller ones. And only most of them, not all.
I've never ever replaced just a chain. I ALWAYS replace both gears.
I've never ever replaced just a chain. I ALWAYS replace both gears.
Le Mans Master
Joined: Oct 2004
Posts: 5,841
Likes: 19
From: CLT, North Carolina
I pulled mine down to replace front cover seals and while I was in there elected to do the chain and gears too because the chain was pretty loose. I was surprised to discover the new one was also a lttle loose but I let it go and buttoned it back up. About all you could do is take two gears and a pile of new chains and go through them to find the tightest one which is not very practical. This is what occurs when you stack up production tolerances: cam bore center to c/shaft center and chain to chain. Wouldn't be worth worrying about on a stocker because a tight chain would loosen up after a few miles anyway.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
I just installed a new Cloyes timing chain set on the 388 LT1 I just built. Chain was tight with no slack.
If the gears aren't correctly indexed with each other the chain can still go on, but there will be slack on one side or the other.
Jake
If the gears aren't correctly indexed with each other the chain can still go on, but there will be slack on one side or the other.
Jake
Instructor
Joined: Mar 2007
Posts: 170
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From: PORT JEFFERSON LONG ISLAND
ive done a few lt1s,double rollor tend to have a bit more slack but nothing extreme either way.You need to install new gears along with the chain to mimimize the extensive slack your complaining about.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
After I've indexed the chain with the cam gear and the crank gear and the camshaft dowel pin, I push UP on the cam gear very hard. This may cause the camshaft to rotate counter-clockwise just a tad.
This has helped me take out any small amount of slack that may exist. Just have to be sure that the alignment dots haven't moved. A straight edge is the way I make sure of that. I use 6 o'clock on the cam gear and 12 o'clock on the crank gear so the dots are as close together as possible - minimizes error that way.
Just remember that with the dots in that position, you won't be on the TDC compression stroke for #1. That's important to remember when installing the opti.
Jake
This has helped me take out any small amount of slack that may exist. Just have to be sure that the alignment dots haven't moved. A straight edge is the way I make sure of that. I use 6 o'clock on the cam gear and 12 o'clock on the crank gear so the dots are as close together as possible - minimizes error that way.
Just remember that with the dots in that position, you won't be on the TDC compression stroke for #1. That's important to remember when installing the opti.
Jake
Pro
Joined: Nov 2005
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From: Bardstown Kentucky
Safety Car
Joined: May 2006
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From: Salem NH
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
If the chain isn't tight it'll cause flucuation in both the valve and ignition timing.
Give me an update on the build when you have a chance.
Jake
