LT1/4 engine help needed
05-28-2011, 11:28 AM
#1
Le Mans Master
Thread Starter
LT1/4 engine help needed
OK, so I put a 383 in the 92 in January.
It was starting to leak oil, and looks like at least the timing chain is gone.
Option 1: put a new timing chain on the 383 and hope the oil leaks are easy to fix. Does the engine need to come out to replace it?
Option 2: have the original 350 gone thru and freshened up. Probably will not need bored.
OK, opinions, options, engine guy reccomendations within 30 miles of ATL???
It was starting to leak oil, and looks like at least the timing chain is gone.
Option 1: put a new timing chain on the 383 and hope the oil leaks are easy to fix. Does the engine need to come out to replace it?
Option 2: have the original 350 gone thru and freshened up. Probably will not need bored.
OK, opinions, options, engine guy reccomendations within 30 miles of ATL???
05-28-2011, 11:57 AM
#2
Race Director
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I just buttoned my LT4 up a few months ago and stopped all leaks. The 2 main areas are the rear of the intake manifold and the front corners of the oil pan. Silicone is required in these areas. If I were you, I would remove water pump, opti spark, timing cover and oil pan to do it right. Actually, may be the only way to stop leak and, of course, only way to install chain. I am sending a PM to you, James.
05-28-2011, 12:14 PM
#3
Racer
Thomas Racing Engines
1970 Dahlonega Highway
Cumming, GA 30040-4540
(770) 887-1050
05-28-2011, 02:12 PM
#4
Safety Car
Unfortunately I spent 100's of hours working on lt1 motors with my camaro.
Southern son is right about the intake leaking, very common and hard to put the intake on without messing up the silicone. The rear main seal will also leak, along with the timing cover seals.
Why do you think you need a new timing chain?
If replacing the chain, you should get an lt4 extreme duty chain and sprockets.
Southern son is right about the intake leaking, very common and hard to put the intake on without messing up the silicone. The rear main seal will also leak, along with the timing cover seals.
Why do you think you need a new timing chain?
If replacing the chain, you should get an lt4 extreme duty chain and sprockets.
05-30-2011, 01:01 PM
#7
Safety Car
First of all, LT1's ALWAYS leak oil So I can only assume that it's leaking a LOT of oil or you wouldn't have posted
Same advice - check the corners of the oil pan. However, contrary to typical forum wisdom, I did NOT put silicone on my corners (Fel-Pro gasket) for specific reasons and it does not leak. So while I'd still recommend it, I don't think it's a mandatory thing. Of course I have a Canton pan, can't remember what is on your 383 but I assume the equivilant?
I have also had leaks at the dipstick tube, and if it happens when the car is running it is often the back of the valve covers. It's tough to get them to seat properly to the head sometimes, mostly on the rear of the passenger side.
One more question - did it only start when you put in the 383? Once in awhile the rear holes leak on the passenger side that attach the oil pan. They are blind holes and sometimes a 383 bore job knicks them so they are no longer isolated from the oil. This is what happened to me and it took 18 months to find it. All it takes is some thread sealer and you are good to go.
Timing chain - I'd go double roller. You can change it without pulling the motor but it's more work. If you don't have room to pull it, it can still be done. If you do, pull it and save a lot of headache. You may have to machine the timing cover (this seems to be random, I had to machine mine but others have not). But this is not hard. You could probably do it yourself with a grinder, but might as well pay a pro to do it more cleanly. Take it off, put playdo on it, then put it on to see where it's interfering.
Same advice - check the corners of the oil pan. However, contrary to typical forum wisdom, I did NOT put silicone on my corners (Fel-Pro gasket) for specific reasons and it does not leak. So while I'd still recommend it, I don't think it's a mandatory thing. Of course I have a Canton pan, can't remember what is on your 383 but I assume the equivilant?
I have also had leaks at the dipstick tube, and if it happens when the car is running it is often the back of the valve covers. It's tough to get them to seat properly to the head sometimes, mostly on the rear of the passenger side.
One more question - did it only start when you put in the 383? Once in awhile the rear holes leak on the passenger side that attach the oil pan. They are blind holes and sometimes a 383 bore job knicks them so they are no longer isolated from the oil. This is what happened to me and it took 18 months to find it. All it takes is some thread sealer and you are good to go.
Timing chain - I'd go double roller. You can change it without pulling the motor but it's more work. If you don't have room to pull it, it can still be done. If you do, pull it and save a lot of headache. You may have to machine the timing cover (this seems to be random, I had to machine mine but others have not). But this is not hard. You could probably do it yourself with a grinder, but might as well pay a pro to do it more cleanly. Take it off, put playdo on it, then put it on to see where it's interfering.
05-30-2011, 01:04 PM
#8
Safety Car
05-30-2011, 03:14 PM
#9
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Almost 130K (bottom end) on my LT4 and getting close to 370RWHP with ongoing tuning. As far as chain, I checked my LT4 extreme duty chain after 60K+ miles and found only 1/8" play on slack side and uniform through entire travel. Of course, upon original installation, I was very careful to pull it through a vat of oil in order to lube it up really, really well.
05-30-2011, 04:21 PM
#10
Team Owner
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some people just like C4's
others need to get over it
If the timing chain when, it could have worn a hole in the cover
any metal in the pan?
others need to get over it
If the timing chain when, it could have worn a hole in the cover
any metal in the pan?
05-31-2011, 01:53 AM
#11
Former Vendor
I once blew up my 383 LT4 engine so bad it broke the block thru the front, between 2 & 4, 4 & 6, and out the side. In other words, it nearly broke the block in half! My "LT4 extreme duty" timing chain was still good though! That is one bad a#* timing chain.
I raced mine for 10 years, had it out many times. Never did get it to not leak somewhere.
Robert
I raced mine for 10 years, had it out many times. Never did get it to not leak somewhere.
Robert
05-31-2011, 08:41 AM
#12
Race Director
strange.. I had my LT1 for 12 years and almost 200k miles and didnt have an oil leak problems.. However, at about 150k miles or so I made it a stroker 383.. at that time I replaced every gasket/seal in the engine.. including the ring seals in teh timing chain cover and the gaskets for the valve cover bolts.. I mean everything. damn good engine that was..
05-31-2011, 10:23 AM
#13
Safety Car
