Differences between Cloyes timing chains
Drifting
Joined: Nov 2003
Posts: 1,637
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From: Honeoye Ny
Originally Posted by Zix
The hex-adjust won't work on an LT block though because the cam pin needs to be free to spin the Opti, but the hex-adjust sets have the adjuster covering the pin so it won't fit into the optispark.
Le Mans Master
Joined: Jul 1999
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From: Phoenix AZ
Originally Posted by Baldturbofreak
Yes it will, it protrudes for the adjuster by a few hundred thou. All you need to do is mill/grind a little relief into the pocket for the pin. Works great
Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by sothpaw2
This is what Cloyes told me to use so I hope it works.
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by 500hp
I believe the 3157 is a new offering for an LT1 retrofit. I think it is a single roller chain (to fit the thicker LT1 alum. timing cover) with hardened gears and NO waterpump gear.
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,692
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From: Hayward CA
Originally Posted by 500hp
I believe the 3157 is a new offering for an LT1 retrofit. I think it is a single roller chain (to fit the thicker LT1 alum. timing cover) with hardened gears and NO waterpump gear.
I got the chain yesterday, and you are correct, it is a single roller chain. But.....this sucker is really THICK.
Race Director
Joined: Jan 2002
Posts: 12,264
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From: O'Fallon Missouri
Originally Posted by TM-96CE
I got the chain yesterday, and you are correct, it is a single roller chain. But.....this sucker is really THICK.
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Racer
Joined: Jul 2004
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From: San Diego CA
Originally Posted by TM-96CE
Hmm - if that's the case.... 9-3157 should work for me - since it's supposed to be designed for the LTx motor.
Safety Car
Joined: Sep 2002
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From: Maryland
Originally Posted by STL94LT1
I've heard it is the same design as the GM Extreme Duty timing set, without the provision for the water pump drive.
Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by TM-96CE
I got the chain yesterday, and you are correct, it is a single roller chain.
Pro
Joined: Jan 2004
Posts: 707
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From: Syracuse Utah
I'm guessing here, but I believe the 3145 is not shown as a fit for the lt1 is because the early optis required the nose driven shaft. The stock cam gear is splined for this shaft, while the 3145 just has a large hole in the center. The 94/96 optis used the cam pin to drive the optis. I have a 94 with the early style opti and I modded the 3145 by putting a plug into the center hole and splined it. Has run perfectly all summer that way.
Burning Brakes
Joined: Nov 2001
Posts: 1,241
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From: Houston TX
the 3157 is actually the same as the GMPP #12371043. that's the identical crank sprocket and chain as the LT4 ED set, with a different cam sprocket. the GMPP part number, though, comes with new cam bolts, retainer bolts, and retainer. it's also a lot cheaper than the 3157 is from summit.
-michael
-michael
Drifting
Joined: Nov 2003
Posts: 1,637
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From: Honeoye Ny
Originally Posted by Zix
I know it won't work for the 9-3145A double roller hex adjust, unless you also want to mill down the cam gear as well because it pushed the Opti out too far. I just went through this during my last engine build.
just remember to add/subtract whatever you adjust cam timng to to match your igniton offset in the programming, otherwise your timing will be off.
Last edited by Baldturbofreak; Nov 15, 2005 at 12:47 PM.
Burning Brakes
Joined: Nov 2001
Posts: 1,241
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From: Houston TX
i wanted to follow up since what i said above turns out to be incorrect.
the 3157 is the same as the GM #12371043, but with a different crank sprocket. the cloyes crank sprocket is a standard sbc size, and has +4 and -4 keyways in addition to 0.
the sets cloyes makes for GM all have the undersize crank sprocket. this is presumably to allow easier/faster assembly by robots, since the crank sprocket can be fully seated before installing the chain and cam sprocket. with the regular size crank sprocket, often you have to push both sprockets on together since the chain doesn't have enough slack.
the 3157 is the same as the GM #12371043, but with a different crank sprocket. the cloyes crank sprocket is a standard sbc size, and has +4 and -4 keyways in addition to 0.
the sets cloyes makes for GM all have the undersize crank sprocket. this is presumably to allow easier/faster assembly by robots, since the crank sprocket can be fully seated before installing the chain and cam sprocket. with the regular size crank sprocket, often you have to push both sprockets on together since the chain doesn't have enough slack.
Le Mans Master
Joined: Feb 2005
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From: The Motor City
Originally Posted by MSR
the 3157 is actually the same as the GMPP #12371043. that's the identical crank sprocket and chain as the LT4 ED set, with a different cam sprocket. the GMPP part number, though, comes with new cam bolts, retainer bolts, and retainer. it's also a lot cheaper than the 3157 is from summit.
-michael
-michael
Safety Car
Joined: Sep 2002
Posts: 4,030
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From: Maryland
Originally Posted by Zix
The GM Extreme Duty set is also heat treated 
No, it isn't. I have a $2,000 short block bill to prove it, and that's just the short block work at the machine shop. Shards of metal are not good for a motor.
I measured the ED gear (the cam gear) at only 28 RC in teeth region. That's like 130 ksi tensile strength, which I think is how you get the plate stock from the mill.
Le Mans Master
Joined: Feb 2005
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From: The Motor City
All the cloyes crank sprockets are only hardened just below the teeth, and is visible as a 'flame' looking ring under the teeth the rest is not hardened. Thats why I never liked all the additional keyways for timing especially the house shape, can be a place suspect to breaking even if it is softer.
Just curious here southpaw, was the center section intact or was there anything left that was in one piece to determine the week area?
Just curious here southpaw, was the center section intact or was there anything left that was in one piece to determine the week area?
Safety Car
Joined: Sep 2002
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From: Maryland
Originally Posted by mseven
All the cloyes crank sprockets are only hardened just below the teeth, and is visible as a 'flame' looking ring under the teeth the rest is not hardened. Thats why I never liked all the additional keyways for timing especially the house shape, can be a place suspect to breaking even if it is softer.
Just curious here southpaw, was the center section intact or was there anything left that was in one piece to determine the week area?
Just curious here southpaw, was the center section intact or was there anything left that was in one piece to determine the week area?
You just don't mesh a gear which is 41 RC with a gear that is 28 RC. In contact, the soft gear will wear. In my case, I think had something that acclerated the wear, but I bet that every gear will wear way faster then it should.