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Has anyone here heard of eliminating timing chain stretch via this method: Mix a little moly lube in a pan with some oil,put timing chain in it,heat to 200 deg F for an hour or so? I read this in one of my big block Chevy books,apparently Gary Grimes of Grimes Automotive Machine does this,strange but true!!
 

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302/Z28 said:
Never heard of it. I always used true roller double roller chains and never were bothered with stretch.

Vince

I don't know how you would measure stretch, but wear will cause up to 4* retarded timing.

Just set your engine on the timing mark and rock the crank back and forth to see how much slack is in the timing set by watching the rotor for movement. I have seen 4* lots of times. Stock silent chains have had 6*.

I always time an engine with 2* more cam advance than specified because it is only going to get slower.
 

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gear drives have the best timing accuracy but they do transfer some of the crank harmonics to the valvetrain instead of absorbing them liek a chain or belt drive would.......but i know a guy that has ran a gear drive on a 400 small block for 165,000 miles not a single problem so idk i say go gear!!!!
 

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xntrik said:
I don't know how you would measure stretch, but wear will cause up to 4* retarded timing.

Just set your engine on the timing mark and rock the crank back and forth to see how much slack is in the timing set by watching the rotor for movement. I have seen 4* lots of times. Stock silent chains have had 6*.
Your example is most likely the best to determine. Also spark scatter on the light may be a major result and measuring the chain deflection while the front cover is off.

Quality parts and double chains will also keep it tight. You also have to consider cam/crank CL's being off (as a result of initial machining (built-up tolerances) and squaring the deck/saddle. CLOYES can make custom length chains.

Actually, in gear drive, the outer gears have the ability to float somewhat as opposed to direct gear drive (upper-lower gears) (reverse valve train rotation)
 
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