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LT-4 timing chain

Posted: Wed Sep 16, 2020 8:57 am
by rebelrouser
Doing a rebuild on a 1996 corvette grand sport with a manual transmission. Had a rod bearing noise, motor in good shape otherwise, hone marks still in the cylinders. Ordering engine kit and it seems the LT-4 has several differences to a normal Lt-1 engine and they only made the LT-4 one year. Got around everything but one issue. If it has a manual transmission the LT-4 has a different timing chain. GM part number 14088783 GM does not make it anymore and I could not find one anywhere. Can't really find good info on what the difference is between the regular timing sets and the LT-4 is. Do any of you guys have some info or experience on this issue?
I was looking at the GM performance 12370835 timing set, but the reluctor wheel is made on the gear, and I can't seem to find anybody that knows if this is the difference.

Re: LT-4 timing chain

Posted: Wed Sep 16, 2020 11:27 am
by lewy-d
I am not certain, I think the LT4 got a single roller chain set and the non-LT4 received a link type.
Google search shows a few of the 14088783 avail. I've had good luck calling both pace and scogin and asking if the part in question is in stock.
Alternately, Cloyes has a 9-3651x3 and a C-3039.

Re: LT-4 timing chain

Posted: Wed Sep 16, 2020 11:53 am
by BLstangin
https://www.rockauto.com/en/parts/acdel ... chain,5724

rock auto appears to have it in stock

Re: LT-4 timing chain

Posted: Wed Sep 16, 2020 6:30 pm
by rebelrouser
BLstangin wrote: Wed Sep 16, 2020 11:53 am https://www.rockauto.com/en/parts/acdel ... chain,5724

rock auto appears to have it in stock
I guess I am getting old, I know I looked yesterday at Rockauto, and all I saw was VIN P engines, but you are right they do have one VIN5 engine timing chain, which should be mine. Thanks for looking.

Re: LT-4 timing chain

Posted: Thu Sep 17, 2020 12:53 am
by jred
did a 1996 lt4 for a corvette a couple of years ago,, I kept calling a LT1 instead of a lt4 I reused the stock cam with new roller lifters and did a standard rebuild customer had some problems with the opti spark and the car would set a code,, they thought that we had installed the timing chain set wrong,, this one has the reluctor wheel between the lower gear and damper hub,, I call the warehouse to get in touch with manufacture which happens to SA Gear I called and talked to tech,, He pulled the prints on the gear set and said that they SA Gear bought that gear from G.M. In doing some research it seem that the LT4 has slightly more compression and some different gaskets ,,

Re: LT-4 timing chain

Posted: Thu Sep 17, 2020 10:14 am
by rebelrouser
jred wrote: Thu Sep 17, 2020 12:53 am did a 1996 lt4 for a corvette a couple of years ago,, I kept calling a LT1 instead of a lt4 I reused the stock cam with new roller lifters and did a standard rebuild customer had some problems with the opti spark and the car would set a code,, they thought that we had installed the timing chain set wrong,, this one has the reluctor wheel between the lower gear and damper hub,, I call the warehouse to get in touch with manufacture which happens to SA Gear I called and talked to tech,, He pulled the prints on the gear set and said that they SA Gear bought that gear from G.M. In doing some research it seem that the LT4 has slightly more compression and some different gaskets ,,
I will have to admit, I had no idea there was a LT-4 until I took this job. In doing my research, it has numerous small differences with an LT-1, and the timing chain deal, if it has a manual transmission, is different than an automatic transmission model. Nobody could tell me the difference in the timing set, but I think it has to do with the number of teeth on the reluctor wheel. It has a high resolution, lots of teeth. Most engines only need one pulse from a cam sensor just to tell the computer when the cam is on TDC. This one has resolution only usually used in a crank sensor.