Timing chain questions
Thread Starter
Safety Car
Joined: Jan 2001
Posts: 4,989
Likes: 500
From: Hilton NY
Timing chain questions
How sloppy can an LS engine timing chain get before it needs to be replaced and is there an easy way to check how loose it is? The second chain was installed about 60,000 miles ago and it had some slop when new. Can a too loose chain cause recurring long cranking before starting as if the cam and crankshaft position sensors go in and out of sync?
Melting Slicks
Joined: Sep 2008
Posts: 3,127
Likes: 799
From: Espanola New Mexico
There is no easy way to check how loose a timing chain is other then pulling the front cover off. Recurring long cranking could or could not be caused by a loose timing chain. The real problem of a loose timing chain is that it may eventually skip a tooth or two of the cam shaft sprocket.
Instructor
Joined: May 2008
Posts: 174
Likes: 45
From: Pahrump NV.
You could pull a valve cover and then turn crank back and forth watching rocker arms to get a good idea of slop but it is no way accurate.
Just an FYI don't get too excited about a little slop in a chain I have seen brand new motors tore down and the chains really stretched and I have seen some with 80k miles and look brand new 60,000 miles on any chain is fine wouldn't worry about it till its over a 100k miles or more unless your racing the heck out it.
I recently completely rebuilt my engine with all new parts and all new sensors and it refuses to fire no matter how long I crank on it the first time! hot or cold! So I hit the key let engine make a couple rotations STOP hit the key again and she fires off every time.
I believe the problem may be with a stuck fuel check valve in the system or the pump its self allowing fuel pressure to bleed down when engine is shut down.
Cranking her twice doesn't bother me so I live with it its just an Old Chevy after all.
Just an FYI don't get too excited about a little slop in a chain I have seen brand new motors tore down and the chains really stretched and I have seen some with 80k miles and look brand new 60,000 miles on any chain is fine wouldn't worry about it till its over a 100k miles or more unless your racing the heck out it.
I recently completely rebuilt my engine with all new parts and all new sensors and it refuses to fire no matter how long I crank on it the first time! hot or cold! So I hit the key let engine make a couple rotations STOP hit the key again and she fires off every time.
I believe the problem may be with a stuck fuel check valve in the system or the pump its self allowing fuel pressure to bleed down when engine is shut down.
Cranking her twice doesn't bother me so I live with it its just an Old Chevy after all.
Last edited by Dudly Doright; Sep 25, 2022 at 06:05 PM.
Running Guns & Moonshine
Joined: Aug 2001
Posts: 12,497
Likes: 7,178
From: CT
Have both of you attempted a relearn for the crank position?
I have nothing to offer on the loose chain factor other than if you replaced it recently it doesn't make sense that it could have stretched quickly.
I have nothing to offer on the loose chain factor other than if you replaced it recently it doesn't make sense that it could have stretched quickly.
Burning Brakes
Joined: Feb 2019
Posts: 1,028
Likes: 377
From: SW Ohio
LS timing chains are loose when new, and would remind you of what we would consider too loose back in the small block chevy and mopar days. Installing a chain tensioner / damper helps avoid any excess chain "whipping" and is a good investment when you replace your timing set.
My car also has the fuel pressure bleed down thing - seems to be more common as they get older. I replaced both my fuel pump and siphon pump two years ago and it did nothing to help the issue, and its as easy as turning the key to accessory once, then off, and back on to prime the fuel system. It will fire right up once the fuel rails are primed.
My car also has the fuel pressure bleed down thing - seems to be more common as they get older. I replaced both my fuel pump and siphon pump two years ago and it did nothing to help the issue, and its as easy as turning the key to accessory once, then off, and back on to prime the fuel system. It will fire right up once the fuel rails are primed.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,430
Likes: 3,981
From: Cape Coral, Florida
How sloppy can an LS engine timing chain get before it needs to be replaced and is there an easy way to check how loose it is? The second chain was installed about 60,000 miles ago and it had some slop when new. Can a too loose chain cause recurring long cranking before starting as if the cam and crankshaft position sensors go in and out of sync?
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,430
Likes: 3,981
From: Cape Coral, Florida
LS timing chains are loose when new, and would remind you of what we would consider too loose back in the small block chevy and mopar days. Installing a chain tensioner / damper helps avoid any excess chain "whipping" and is a good investment when you replace your timing set.
My car also has the fuel pressure bleed down thing - seems to be more common as they get older. I replaced both my fuel pump and siphon pump two years ago and it did nothing to help the issue, and its as easy as turning the key to accessory once, then off, and back on to prime the fuel system. It will fire right up once the fuel rails are primed.
My car also has the fuel pressure bleed down thing - seems to be more common as they get older. I replaced both my fuel pump and siphon pump two years ago and it did nothing to help the issue, and its as easy as turning the key to accessory once, then off, and back on to prime the fuel system. It will fire right up once the fuel rails are primed.
Burning Brakes
Joined: Feb 2019
Posts: 1,028
Likes: 377
From: SW Ohio
***Edit - it is in fact in the fuel pump***
Last edited by CinciZ06; Sep 26, 2022 at 03:05 PM.
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