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Does this front cam/cam bearing look strange or broken to you?
We put in a Cloyes double true roller.
Chain was rubbing the block at the middle oil gallery plug/casting area.
Motor ran perfect,no noises before this chain install.
Removed the chain and put in a brand new bone stock chain set.
The noise is still there.
Thanks for looking.
Inspected all the rod and main bearings...look like new.
Possible the valves were adjusted too tight? piston hitting a valve?
As soon as new timing chain arrives,I will re install the pushrods and adjust the valves.
This time with the intake off so I can see in there.
Looks like a sloppy cam bearing or cam install. It is ugly but fine. Put it together and pull one injector off at a time to see if it is one cylinder related. A valve only hits a piston once and would think if stock it is about impossible for valves and pistons to hit.
Looks like a sloppy cam bearing or cam install. It is ugly but fine. Put it together and pull one injector off at a time to see if it is one cylinder related. A valve only hits a piston once and would think if stock it is about impossible for valves and pistons to hit.
Its a 100% original L98. Never been touched or modified.(50k Original Miles.Mobil 1 Since new)
The cam and cam bearings are 100% original.
The reason for taking this apart was to install a new timing chain.
The Cloyes Double True Roller rubs the center oil gallery casting.
So we took it out and installed a Cloyes Single Roller Chain.
After hearing a knocking noise again,after the 2nd chain was installed.....I removed the oil pan and timing cover.
Trying to rotate the engine with a crank socket,the engine would hit a spot where it would not rotate anymore.
Removed all bearings (rod and crank) just to be sure it wasnt a bearing.
They all look great.
Then removed all pushrods and spark plugs...engine rotates very smoothly now with no stop.
So thats why I think a valve(s) was too tight.
Cam and lifters rotate very smoothly and all lifters are going up and down smoothly.
This is the 3rd time the engine has been ripped down so thats why I wanted to check everything very carefully.
The motor ran like a brand new engine before the timing chain fiasco.
So whats different thats causing a knocking sound?
Only thing different is the chain/gears and the valve adjustment.
I am putting it all back together and will adjust the valves with the intake off so I can tell exactly when each valve is in the correct spot.
After its back together,I will run a compression test.
So you did a valve adjustment at the same time you replaced the timing chain? You probably didnt need to do that. Lets assume you timed the chain correctly but if you didnt, you could have had a piston hit a valve. If you adjusted a valve to tight it could hit as well
Hopefully you did not have piston to valve contact, maybe you had coil bind on one of the springs if you had the adjustment too tight. It should have run poorly with some of the valves that far out of adjustment.
Its a 100% original L98. Never been touched or modified.(50k Original Miles.Mobil 1 Since new)
The cam and cam bearings are 100% original.
The reason for taking this apart was to install a new timing chain.
The Cloyes Double True Roller rubs the center oil gallery casting.
So we took it out and installed a Cloyes Single Roller Chain.
After hearing a knocking noise again,after the 2nd chain was installed.....I removed the oil pan and timing cover.
Trying to rotate the engine with a crank socket,the engine would hit a spot where it would not rotate anymore.
Removed all bearings (rod and crank) just to be sure it wasnt a bearing.
They all look great.
Then removed all pushrods and spark plugs...engine rotates very smoothly now with no stop.
So thats why I think a valve(s) was too tight.
Cam and lifters rotate very smoothly and all lifters are going up and down smoothly.
This is the 3rd time the engine has been ripped down so thats why I wanted to check everything very carefully.
The motor ran like a brand new engine before the timing chain fiasco.
So whats different thats causing a knocking sound?
Only thing different is the chain/gears and the valve adjustment.
I am putting it all back together and will adjust the valves with the intake off so I can tell exactly when each valve is in the correct spot.
After its back together,I will run a compression test.
L98 1991 5.7 Engine Noise
