Okay,
I recently pulled my forged built LT1 motor after finding my crank was bent. It has only 6k on the entire assembly, and I wonder what all I can save?

I am thinking that I could replace the crank,bearings, and re-use the rest if I keep the pistons and rings in the same cylinders they came out of. Anybody have some experience in this area? Thanks!

 

Cranks are straightened all the time, it's no big deal. Replace the bearings and the rings. If you really want to replace the crank, send it to me

 

Not to high jack the thread.. But how would you go about straighting a crank.. Never seen it done..

 

it is very common.most machine shops can handle this task.id say leave the rings, but if you do replace them then make sure to scuff up the walls with a hone so the new rings will seat properly.use a new medium or used coarse stones to do this.read up on cross hatch,it shoud be 35-45 deg.youll have to spinn the hone kindof slow and move the hone up and down the bore pretty fast to get this right.you might want to have your machine shop do this as well, but id say your old rings should be fine.if you replace your bearings, have the machine shop polish the crank and tell you what size bearings youll need.youl brob end up ordering .001 oversize bearings, but have them mic it out after polishing to make sure.
cranks are strightened buy placing the crank in v blocks,then with a dial indicator the machinest will deturman where the bend is.after that hell put it in a huge 30+ ton press and bend it back stright.the crank will go from the v-blocks to the press and back again about 15 times before he gets it stright.ive had this done and it does work very well.

 

Very good info guys. The old crank is not going back in my car. I am buying a new one for piece of mind. The inside of the snout would need to be drilled and tapped for a bigger bolt due to threads being ripped up. I am going to replace the bearings for sure, and keep the rings. I'll have the machine shop take care of the block for me. Here is my big question:
Would sending 1 rod/piston/and the new crank to have it re-balanced be sufficient for the entire re-build? Thx again.

 

What brand is the old crank?

 

Why did the crank bend? Won't make much sense to install a new one and have the same thing happen. Whenever an engine is apart, install new rings. To balance the crank, only 1 rod, piston, wrist pin, and ring stack is needed. They weigh them and then assemble a bob weight to match.

Rich

 

Thx for the good info. The crank bent because my old SFI balancer that was keyed split along the keyway and came off the motor. It bent the snout of my crank in the process. So new rings for sure even after only having 6k on them? If so, I have total seal right now. Should I get the same brand or something different?

 

Eagle Forged with a slight bend!!!

 

If it was something else, I would take it from you - I stay away from eagle stuff though.

 

I never offered it up. I would not even give it away and still feel good about myself. No need to give my broken parts to somebody else so they can "fix" them and sell for a profit. It will make a great bar-stool base for my garage.

 

What made you think I would do that? If it had been a bent callies I would have made you an offer so I could use it in something of my own - I never sell "fixed" parts.

 

Nothing personal to you, just my way of saying I want to make sure I do the right thing. I understand your point of view though.

 

I would do the rings, for sure. It's a lot of work getting a motor out of a 4th gen and then back in. But it's not unreasonable to re-use them if you are careful about getting them in the right hole.

Rich

 

The block and saddles need to checked and probably need an align bore/hone.