Lt1 spun bearing
Thread Starter
Melting Slicks
Joined: Jul 2000
Posts: 2,107
Likes: 14
From: Lancaster PA
Lt1 spun bearing
While running at Summit Point raceway with my 94 auto I had an overheating and loss of power issue. I limped it back to the pits with decent oil pressure and when I removed my helmet I heard the sound. Today I confirmed my suspicion that I have a spun rod bearing. I just had the tranny rebuilt in March and now I have to take it out again and remove the engine and rebuild. Does anyone know of a good source for a crank kit? I just want to take it apart and thoroughly clean everything, install a new crank kit and reassemble. I am not interested in upgrading the motor because I will probably sell this car and look for a manual trans Vette. Any advice that your guys can give me to help with this job would be greatly appreciated.
Large Impressive Member
Joined: Jul 2003
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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
Any parts store should be able to order you a crank kit. They used to be pretty reasonable but I haven't bought one in years. I've got a couple of good, standard LT1 cranks laying around. Let me know if you'd like one and we'll work something out. I wouldn't be looking for much out of one due to shipping costs.
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Originally Posted by Slalom4me
Sorry to read about the misfortune.
I'd like to ask if you can mention what kind of oil pan
was on the engine.
.
I'd like to ask if you can mention what kind of oil pan
was on the engine.
.
Was this a stock motor or heads/cam set-up, and what was the max rpm?
For the rebuild, since you are selling, I would get the used LT1 crank offered here and a bearing kit (rod&mains), clevite 77 standard size (not oversize). Plus of course, all the seals. Not sure if the rods themselves will be ok or not, should inspect.
Thread Starter
Melting Slicks
Joined: Jul 2000
Posts: 2,107
Likes: 14
From: Lancaster PA
Stock pan, Stock engine, I always overfilled by a quart of oil. Never lost oil pressure that I know of.
80,000 miles are on the car
Will the motor have to be totally disassembled to clean and flush out residue?
80,000 miles are on the car
Will the motor have to be totally disassembled to clean and flush out residue?
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Safety Car
Joined: May 2002
Posts: 4,010
Likes: 26
From: Somewhere nowhere
If you were 1 qt over, I'm surprised you spun a bearing...
Although my LT4 now has much more start up knock than it did 3 years ago. over 5000 track miles now. So I may be seeing a spun bearing soon.
Although my LT4 now has much more start up knock than it did 3 years ago. over 5000 track miles now. So I may be seeing a spun bearing soon.
Drifting
Joined: Jun 2001
Posts: 1,997
Likes: 1
From: Lake Ozark MO
I have an odd knock on startup at the very front of the engine. Goes away when warmed up. Maybe 6800rpm shift points for the last 3 years are giving me an indication that it's time for an all forged 396?
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Originally Posted by CF6873
Stock pan, Stock engine, I always overfilled by a quart of oil. Never lost oil pressure that I know of.
80,000 miles are on the car
Will the motor have to be totally disassembled to clean and flush out residue?
80,000 miles are on the car
Will the motor have to be totally disassembled to clean and flush out residue?
However, if the crank has to come out, then the engine has to come out and I would totally disassemble it at that point.
Racer
Joined: Feb 2001
Posts: 381
Likes: 8
From: NORTH WEST PA
Originally Posted by Dan Parker '96
I have an odd knock on startup at the very front of the engine. Goes away when warmed up. Maybe 6800rpm shift points for the last 3 years are giving me an indication that it's time for an all forged 396?
Most likely piston slap ... and from what I hear a common problem. I'd go easy until the engine warms up and quiets down before you give it a normal workout.
Safety Car
Joined: Jul 2001
Posts: 4,871
Likes: 15
From: Detroit's West Side MI
Go start your car and rev it in Neutral.
If you get the knock / rattle sound under DECELERATION it's most likely a rod bearing. You can R&R that with the motor in the car. However, if the crank is scarred badly then you need to pull it out and machine it, anyway.
If it's under ACCELLERATION then it could be a main bearing (although I've seen this with rod bearings, too). You have to pull the motor. You can't get the end caps off with the motor in the car.
What is your target for the rebuild? If you want to go cheap there are several options. When I spun a rod bearing last fall I bought a stock 40K mile LT1 motor from a local builder (he had about 30 of them, B-body motors), cleaned it up, slapped my heads and cam on, and was back in business. Cost me $650 for the motor and some more for gaskets and such. I did all the labor and paid my buddies with beer.
It's really not that bad to pull the motor from a C4, I can do it now in a few hours. Of course I don't know how much time having an auto trans would add, if any.
If you get the knock / rattle sound under DECELERATION it's most likely a rod bearing. You can R&R that with the motor in the car. However, if the crank is scarred badly then you need to pull it out and machine it, anyway.
If it's under ACCELLERATION then it could be a main bearing (although I've seen this with rod bearings, too). You have to pull the motor. You can't get the end caps off with the motor in the car.
What is your target for the rebuild? If you want to go cheap there are several options. When I spun a rod bearing last fall I bought a stock 40K mile LT1 motor from a local builder (he had about 30 of them, B-body motors), cleaned it up, slapped my heads and cam on, and was back in business. Cost me $650 for the motor and some more for gaskets and such. I did all the labor and paid my buddies with beer.
It's really not that bad to pull the motor from a C4, I can do it now in a few hours. Of course I don't know how much time having an auto trans would add, if any.
Thread Starter
Melting Slicks
Joined: Jul 2000
Posts: 2,107
Likes: 14
From: Lancaster PA
I just had the tranny out in March and I still have the borrowed trans jack in my garage. It won't be bad to get out the second time now that I know the ropes. After that is out I'll just have to disconnect the other stuff holding the motor in and pull it out. I have an engine crane lined up to borrow and I will need an engine stand. I just priced a crank kit so it should not be too bad in cost. I will just chip away at the project as I have alot of other things to do right now. This car probably won't see the road for a few months. I'll have to drive the C3's for the summer.
Drifting
Joined: Jun 2001
Posts: 1,997
Likes: 1
From: Lake Ozark MO
Originally Posted by RED92LT1
Most likely piston slap ... and from what I hear a common problem. I'd go easy until the engine warms up and quiets down before you give it a normal workout.
