Crank Replacement
Thread Starter
Navigator
Joined: Apr 2012
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Crank Replacement
'96 LT1 175,000 miles. Spun the #8 connecting rod bearing and gouged the crank journal. Definitely a new crank, but is it possible to drop the crank without having to pull the block? Anyone ever done this before? Thanks. - Carl
Melting Slicks
Joined: Sep 2010
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Even harder is the trans.. but if I could change a crank in a F body.. the C4 has much more pan clearance..
The opti & balancer are a pain
With that mileage I would really consider a low milage swap.. or a complete re-build
The opti & balancer are a pain
With that mileage I would really consider a low milage swap.. or a complete re-build
Last edited by THE 383 admiral; Sep 14, 2012 at 01:40 PM.
Drifting
Joined: Sep 2012
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From: Murphy NC
At 175k miles, you really should do a complete rebuild or low mileage swap like Admiral said. When you spin bearing, there is no way to know where all the damaged bearing pieces go. IMHO, if you just throw a new crank in without a rebuild, you'll be throwing good money away.
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
yes you can
Converter/clutch, that pita balancer timing cover (chain has to come off opi etc
You could pull the whole motor in that time.
Can only hope for the best but if your bearing is spun your rod is probably history,pretty much every metal surface has the potential to be fubarred from all the metal being forced through it.
Converter/clutch, that pita balancer timing cover (chain has to come off opi etc
You could pull the whole motor in that time.
Can only hope for the best but if your bearing is spun your rod is probably history,pretty much every metal surface has the potential to be fubarred from all the metal being forced through it.
Last edited by cv67; Sep 14, 2012 at 02:14 PM.
Race Director
Joined: May 2006
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From: Phoenix Arizona
It can be pulled without pulling the engine but it is a LOT more work. First, the transmission must be removed , or at least pushed back about a foot, which is a LOT more work than removing it. Than you need to remove the flywheel, front engine accessories and timing cover, remove the suspension cross braces, and remove the oil pan. You will also need to remove the drivers side cylinderhead to remove the piston and rod in order to re-size the rod. Probably need to remove the passenger side cylinderhead to remove the #7 rod which shares the same throw on the crank. This is a VERY abreviated discription. All this and you have a 50/50 chance that contamination will immediately take out the new crank. In sumnation, you will have spent three to four times the work and energy to just F**k up the job. Does that answer the original question?
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It can be pulled without pulling the engine but it is a LOT more work. First, the transmission must be removed , or at least pushed back about a foot, which is a LOT more work than removing it. Than you need to remove the flywheel, front engine accessories and timing cover, remove the suspension cross braces, and remove the oil pan. You will also need to remove the drivers side cylinderhead to remove the piston and rod in order to re-size the rod. Probably need to remove the passenger side cylinderhead to remove the #7 rod which shares the same throw on the crank. This is a VERY abreviated discription. All this and you have a 50/50 chance that contamination will immediately take out the new crank. In sumnation, you will have spent three to four times the work and energy to just F**k up the job. Does that answer the original question?
Thread Starter
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So you did this on an F-body without pulling the block?
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Thread Starter
Navigator
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Could very well be, and if I have to pull that head to pull the piston and replace the rod I can live with that. Pulling the block is what I'm trying to avoid. I have plenty of time but I don't have a real shop and hoist.
Melting Slicks
Joined: Sep 2010
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YES.. its very tight on a f body.. I also have years of experience.. to help me out..
PS it was a high milaege motor I wanted to pull any way.. this bearing spun about 120mph
I only removed the crank.. it was wasted.. and rod 5.. I already had my built 357 waiting.. to go in.. when I had a f body 2 years ago.
Let us stress the fact.. its very easy to pull the crank.. but putting back in while the block is in the bay.. is completely different.. the crank is about 55 pounds.. you need to be perfect installing. In tight quarters..without hitting the journals.. passing each rod.. this is assuming.. you have no internal damage or debris..
PS it was a high milaege motor I wanted to pull any way.. this bearing spun about 120mph
I only removed the crank.. it was wasted.. and rod 5.. I already had my built 357 waiting.. to go in.. when I had a f body 2 years ago.
Let us stress the fact.. its very easy to pull the crank.. but putting back in while the block is in the bay.. is completely different.. the crank is about 55 pounds.. you need to be perfect installing. In tight quarters..without hitting the journals.. passing each rod.. this is assuming.. you have no internal damage or debris..
Last edited by THE 383 admiral; Sep 14, 2012 at 03:52 PM.
Team Owner
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St. Jude Donor '09 thru '20
Engine is toast. Pull the whole thing and get it re-done properly. Time to inspect those cylinders for a proper 4.030 bore, and now that you need a new one, buy a 400 crank (3.75) for a 383 SBC stroker.
Le Mans Master
Joined: Oct 2004
Posts: 6,314
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From: South-central Missouri
Having gone that same cheap way before ... and suffering the consequences a couple months later, AND since it is a high mileage motor, I can't agree more with the recommendations to pull the motor and overhaul it!
However, you may not need a new crank, necessarily. Depending on how bad it is, turning it 0.010 or so might clean it up. Then using over-size bearings on the rods connected to that crank journal may suffice. You will want to replace all the bearings tho. And, then why not have the bores checked and bored if needed - start over with a fresh motor, rather than a bandaide fix??
Hate to see you go through the trouble - thinking you're saving some time or effort to avoid pulling the motor. For little more effort, rent the cherry picker and motor stand and have a lot of fun while your refreshing your toy!
P.
However, you may not need a new crank, necessarily. Depending on how bad it is, turning it 0.010 or so might clean it up. Then using over-size bearings on the rods connected to that crank journal may suffice. You will want to replace all the bearings tho. And, then why not have the bores checked and bored if needed - start over with a fresh motor, rather than a bandaide fix??
Hate to see you go through the trouble - thinking you're saving some time or effort to avoid pulling the motor. For little more effort, rent the cherry picker and motor stand and have a lot of fun while your refreshing your toy!
P.
Race Director
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Having gone that same cheap way before ... and suffering the consequences a couple months later, AND since it is a high mileage motor, I can't agree more with the recommendations to pull the motor and overhaul it!
However, you may not need a new crank, necessarily. Depending on how bad it is, turning it 0.010 or so might clean it up. Then using over-size bearings on the rods connected to that crank journal may suffice. You will want to replace all the bearings tho. And, then why not have the bores checked and bored if needed - start over with a fresh motor, rather than a bandaide fix??
Hate to see you go through the trouble - thinking you're saving some time or effort to avoid pulling the motor. For little more effort, rent the cherry picker and motor stand and have a lot of fun while your refreshing your toy!
P.
However, you may not need a new crank, necessarily. Depending on how bad it is, turning it 0.010 or so might clean it up. Then using over-size bearings on the rods connected to that crank journal may suffice. You will want to replace all the bearings tho. And, then why not have the bores checked and bored if needed - start over with a fresh motor, rather than a bandaide fix??
Hate to see you go through the trouble - thinking you're saving some time or effort to avoid pulling the motor. For little more effort, rent the cherry picker and motor stand and have a lot of fun while your refreshing your toy!
P.
Then he will dump to POS on the next guy.
Thread Starter
Navigator
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OK, lighten up guys. Since it's never burned oil the rings are obviously good. The tranny and everything else about the car is AOK so with a new crank/bearings, oil pump, timing chain, and Opti I would say it's far from a lemon. We have other reasons for needing to sell it that have nothing to do with its current state of repair.
But there is one question remaining: The #8 connecting rod. Some say since the bearing spun the rod is automatically toast which means pulling the head and either replacing the rod or having it machined to spec. Others say to reassemble the rods & caps without any bearings, mike them all, and if there's no difference between #8 and the others just go with 8 new connecting rod bearings on a new crank. What's your experience?
But there is one question remaining: The #8 connecting rod. Some say since the bearing spun the rod is automatically toast which means pulling the head and either replacing the rod or having it machined to spec. Others say to reassemble the rods & caps without any bearings, mike them all, and if there's no difference between #8 and the others just go with 8 new connecting rod bearings on a new crank. What's your experience?
Race Director
Joined: May 2006
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From: Phoenix Arizona
OK, lighten up guys. Since it's never burned oil the rings are obviously good. The tranny and everything else about the car is AOK so with a new crank/bearings, oil pump, timing chain, and Opti I would say it's far from a lemon. We have other reasons for needing to sell it that have nothing to do with its current state of repair.
But there is one question remaining: The #8 connecting rod. Some say since the bearing spun the rod is automatically toast which means pulling the head and either replacing the rod or having it machined to spec. Others say to reassemble the rods & caps without any bearings, mike them all, and if there's no difference between #8 and the others just go with 8 new connecting rod bearings on a new crank. What's your experience?
But there is one question remaining: The #8 connecting rod. Some say since the bearing spun the rod is automatically toast which means pulling the head and either replacing the rod or having it machined to spec. Others say to reassemble the rods & caps without any bearings, mike them all, and if there's no difference between #8 and the others just go with 8 new connecting rod bearings on a new crank. What's your experience?
Last edited by zr1fred; Sep 20, 2012 at 02:07 PM.
Le Mans Master
Joined: Dec 2006
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From: H-Town Texas
If you have to sell the car anyway, just sell it as is. This way the new owner, knowing full well the issue, can repair it, mod it, upgrade as they see fit. You won't really be losing any money as you would have to buy the parts anyway.
There might be someone right around the corner looking for just a project like this. Just a thought
There might be someone right around the corner looking for just a project like this. Just a thought
