LT4 timing chain options?
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Team Owner
Joined: Feb 2006
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From: San Antonio Texas
LT4 timing chain options?
Last time I was into the front of my LT4, I put on a new Opti and installed an electric water pump. I removed all the drive mechanism for the old cam driven pump. The timing chain didn't look too worn so I didn't change it but I noticed that it was only a single roller thickness. Is there anything different, that sets it apart from other small blocks after you get rid of the water-pump drive, that would prevent the installation of a regular double roller & sprocket set? Special part#, or regular small block set, or are LT4's stuck with that single row thing they came with?
Race Director
Joined: Jan 2002
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From: O'Fallon Missouri
Yes you can run a double roller timing set, just make sure it is for a roller block. I'm running a Cloyes 9-3145 double roller timing set.
FYI: You may need to do a small amount of clearancing on the timing cover.
FYI: You may need to do a small amount of clearancing on the timing cover.
Last edited by STL94LT1; Jul 27, 2009 at 01:05 PM. Reason: Wrong info
Thread Starter
Team Owner
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From: San Antonio Texas
Melting Slicks
Joined: Nov 2004
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From: Cape Coral FL
Yes you can run a double roller timing set, just make sure it is for a roller block. I'm running a Cloyes 9-3145 double roller timing set.
FYI: You may need to do a small amount of clearancing on the timing cover, and you'll also have to eliminate your CPS reluctor ring.
FYI: You may need to do a small amount of clearancing on the timing cover, and you'll also have to eliminate your CPS reluctor ring.
Le Mans Master
Joined: Aug 2004
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From: Metairie Louisiana
I went with the same timing chain. I dont know why but I had to do a huge amount of clearancing on my 95 timing cover. I even went through on one spot.
Last edited by rickneworleansla; Jul 27, 2009 at 03:31 PM.
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Team Owner
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From: San Antonio Texas
Wow! Where was the clearancing problem mostly located? At the top side or down near the crank, or just all around? Did it affect the opti mounting?
Melting Slicks
Joined: Jan 2009
Posts: 3,482
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From: folsom california
I replaced the stock single roller timing chain in my lt4 with a gm extreme duty chain. It is also a single roller design , but is noticeably larger than the stock chain. It is a definite upgrade.
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Thread Starter
Team Owner
Joined: Feb 2006
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From: San Antonio Texas
Shows you what I don't know! I thought the LT4 came with that chain in it. Do you know if the chain that Summit Racing offers is the Extreme duty GM chain, or just a stock LT4 replacement single row?
Safety Car
Joined: Sep 2000
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From: Hinckley Ohio
I have Cloyes double roller, electric water pump, removed reluctor ring, reprogrammed to compensate for removal of reluctor ring..
Le Mans Master
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From: Metairie Louisiana
Last edited by rickneworleansla; Jul 28, 2009 at 01:41 PM.
Thread Starter
Team Owner
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From: San Antonio Texas
Yeah, I pulled the front off mine to put on an electric water pump, when the stock Opti got hosed and I removed all that water pump drive stuff while I was in there. I figured the performance engine would have a big whopper chain on it and was surprised to find such a thin chain! I'd read about people buying a new replacement for their LT4's only to find it had just as much slack in it as the chain they were replacing. Mine didn't look too bad so, being a typical tight azz, I left it in there. The cheap photo cells in my MSD Opti can't respond fast enough above 5500rpm (man, it took me forever to figure that out) so I'll be going back in there some day and want to be ready with the right stuff next time.
Melting Slicks
Joined: Jan 2009
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From: folsom california
I bought my gm extreme duty timing chain set from summit; summit part number NAL-12370835, $249.95 (at the time I bought it) plus $11.95 shipping and handling.
I also replaced the water pump drive assembly, gm part number 12551727; in a stock water pump drive the bearing on the after end of this assembly essentially supports the entire water pump drive and any play will allow the water pump drive shaft to wobble and damage the water pump drive shaft seal on the front of the timing chain cover. Mine was definetely shot at 145,000 miles; your experience may differ.
good luck.
I also replaced the water pump drive assembly, gm part number 12551727; in a stock water pump drive the bearing on the after end of this assembly essentially supports the entire water pump drive and any play will allow the water pump drive shaft to wobble and damage the water pump drive shaft seal on the front of the timing chain cover. Mine was definetely shot at 145,000 miles; your experience may differ.
good luck.
Melting Slicks
Joined: Feb 2008
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From: Palm Beach
It must be programmed out.
The LT4 extreme duty chain is pricey but is plenty strong.
7th Gear
Joined: Aug 2010
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From: Downers Grove Il
I swapped out my optispark, and re checked my sequence for the plugs to it 4x. I then, try to crank it over and nothing. I swapped out my fuel filter, and ignition control module, and still nothing. I pulled plug 4 and checked for spark it is white not really blue. I was wondering if my timing chain might be off a little preventing it from firing and starting well? Any ideas?
Melting Slicks
Joined: Jan 2009
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From: folsom california
regardless of where you installed the timing chain, assuming you have fuel and spark, the engine will fire, it might not run, but something will happen. If it doesn't fire at all, pull a plug wire and see if you've got spark; then go from there
7th Gear
Joined: Aug 2010
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From: Downers Grove Il
timing chain?
I have spark, yes the engine tries to run. but, it does not. it sounds like it is not getting gas. I've changed my fuel filter, the fuel pump sounds like it is going, I changed out the ignition control module, new starter. Someone told me that the optispark could be bad? How do I check that?
Le Mans Master
Joined: Feb 2000
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From: Kempner Texas
I would have MUCH PREFERRED the GM LT4 timing chain set but immediate availability was an issue back in 2006 and I needed to finish the engine in order to beat-up on my nephew's GTO. LOL
Jake
Le Mans Master
Joined: Feb 2000
Posts: 9,715
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From: Kempner Texas
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
[QUOTE=forrestwa;1575139134]I have spark, yes the engine tries to run. but, it does not. it sounds like it is not getting gas. I've changed my fuel filter, the fuel pump sounds like it is going, I changed out the ignition control module, new starter. Someone told me that the optispark could be bad? How do I check that?[/QUOTE]
Go to SHBOX.COM he's got a Opti test procedure among all the other excellent testing procedures.
Jake
Go to SHBOX.COM he's got a Opti test procedure among all the other excellent testing procedures.
Jake