1996LT1Z28

I need to replace the crank in my 96 Z....don't ask, but it's slightly bent at the balancer.

I have a crank from another LT1, which is in great shape....bearings look great, all mic'd out well within spec.

Now....do I need to worry about rebalancing the rotating assembly?

Should I use the bearings out of the donor engine that are "matched" to the replacement crank, or just buy new bearings (I think I know the answer to that one). Just need an opinion...

Thanks!!

green.Z

If you're re-using the same pistons and connecting rods, I'd say you're probably OK to skip balancing. Especially if you just want to repair the car.

I would definitely buy new main and rod bearings, sized to the replacement crank. I would also make sure to check the resulting bearing clearance with some Plastigage during assembly. That's cheap insurance.

You may want to consider getting the replacement crank Magnafluxed, just to make sure there are no cracks.

1996LT1Z28

green.Z -

Yep, keeping the same rods and pistons. I'll take your suggestion and get std size bearings and check with plastigage.

Thanks for your time

shoebox

I'd have the new crank checked, polished, then mic'd. Then, you can get bearings to fit.

1996LT1Z28

Shoebox...will do. Thanks!

8cylinders>4

Ridge Reamer? you've obviously never had a LT1 or any relatively current 350 SBC a part. The last ring ridge I saw was from a late 70's early 80's "lightweight" 305

Here's a pic of a 150,000 miles lt1 cylinder

MachinistOne

Must have been a unique situation - most modern engines come apart at 150K+ with barely a perceivable lip, I haven't seen a bore worn enough to even consider using a ridge reamer in over a decade. Ridge reamers were used to keep from potentially damaging the ring lands so that pistons could be knurled and reused, but nobody reuses pistons these days so it's a pointless and time wasting labor operation.

MachinistOne

Boy, I can just imagine the vein in your forehead throbbing while you typed out that grammatical disaster.


Let's go about this point by point.

First off, I quoted you specifically and said it must have been under special circumstances that you needed a ridge reamer (in your opinion). Like I said, of the hundreds and hundreds of late model engines that I have built, I have never come across one that has had an actual lip worn into the top of the cylinder.

Second, I never said anything specific about the OP not needing one...you put those words into my mouth. On that point though, if the OP ends up finding a ridge that necessitates a ridge reamer he absolutely should not be reusing the pistons anyways so it's a moot point, this is not the 70's where labor is cheaper than parts, that is the reason why pistons were saved, knurled and reused with a light hone on the cylinder. That process is simply not done anymore so ridge reamers have gone the way of the dodo.

Third, if your statement about your pistons being unremovable without a ridge reamer wasn't a complete exaggeration or fabrication, that had to of been the most abused and poorly running LT1 in history.

Remember to take your blood pressure medicine.


Edit: I thought your username was familiar...you're the guy who created a big fuss over line honing in another thread and was subsequently told that you and your limited and ancient knowledge should get packing.

https://www.camaroz28.com/forums/lt1...-868738/page2/