My engine is apart getting a new block and pistons. Took everything in yesterday and they told me that my K1 crank that had 5 passes on it is cracked in 20 places with the biggest being over a inch long and the crank is bent.

My question is what could have caused this? I had Reher-Morrison perform the balance on it when it was new so they should have known if it was bent, right? I pulled the motor out because the oil pressure was getting low and it kept lugging down and stalling to find the center three main bearings with what looked to be overheated. The block had the center three caps were splayed and I had replaced the outer allen head holts with grade 8 bolts because I couldn't torque the allen heads.

So what came first? Was the line hone distorted from the now fully torqued main caps, or was the crank bent to begin with? The crank is junk and will need to be replaced but I am curious as to why this happened. It's my first bent crank and it's almost brand new. Here is a pic of the main bearings.

Ya got some pics of the piston tops and close ups of 3,5,2,4 plugs, looks like heavy detonation to me

Those bearings look really bad.
Did everything have 5 passes on it since machined? (block, rods, pistons, bearings, etc?)
It would be good to see the assembly blue print sheets with all the measurements taken (checked). But detonation can kill things too.

I think he had water in his oil, from a cracked block IIRC.

What is really wild is that the two main bearings on the ends looked fine. There was no detonation with 34* total timing with 11.5to1 compression with 110 octane race fuel. No water in the oil either, at least not visible. I'm having a hard time with this. Everything was new except the block. I took a assembly out of the block, and put this assembly in. Kept the main studs the same and changed the outer bolts on the splayed caps. Had .0024 main bearing clearance.

You can drive yourself nuts trying to analyse motor autopsy's. Some are real apparent, some drive U crazy. We've all been broke and U just plan the next one.

I'd lok REAL hard at that block before I put anything else in it.

It would be hard to pin it on the block, crank or assembly, but the crank is dead, assembly will be new, so that block better look perfect before reuse...

Whatwas the max rpm and was it a 4" crank?

From the looks of those brgs. I'd say that those journals got real hot. That kind of heat will bend the crank. I have a 427 crank on the bench at work that wasn't hurt as bad as those brgs. and it pulled 0.050" on the center and 0.046" on #4

Randy

it's very unlikely that the crank was bent. had it been, they would have never been able to balance it. it appears that a number of things could have gone worng with the engine after seeing the pictures of the bearings. what do the rod bearings look like front and back?
severe detonation, oiling issues, bearing clearances and many more things come to mind. as mentioned, changing fasteners (and torque loads) on the mains could also be a likely suspect. what condition is the block in now?

The rod bearings looked good as well. They were a little messed up from the junk from the main bearings. I suspected that the three center main caps were the culprit once I pulled it down. I assume the outer bolts never were torqued to begin with on the original build. This block is not being reused. I have a tall deck R3 at the machine shop right now. It was a 4.00 crank and it saw 7000rpm two times.
Dan I'll be calling you.

I have dealt with a four bolt converted block some, and in that block if not torqued properly the center three caps do change every dimension in the short block. Until you torque them all down, the crank usually won't even turn. so, that makes me think that the linehone should have performed with the maincaps tprqued the same as in actual use. When things heat up, that kind of things happen, incuding the cracks in the crank. I don't think the crank caused it.

I agree with JRYKI. This is especially true on stock block small blocks. You'd be amazed at how much those lower ends move around based on torque. They are really not great candidates for 4 bolt conversion. My own opinion is its better to use a good ProGram 2 bolt cap and studs than a 4 bolt conversion on the stock block stuff.

I am sorry to hear of the damage. It sucks to go thru so much to have it live only a few passes. It does seem to be something other thn the crank failing however. My guess is the center of the crank was not supported by the three changed center caps and it was flexing severley.

Good luck with your new build and just chalk it up to experience and move on to a bigger better engine.

Thanks for all the info guys. I'm trying to be the best engine builder I can be, but being young without any real engine building mentors around I have to learn by doing. I usually learn the most when something gets messed up. I never had a good feeling about the block in question and should have replaced it but when it is your own money you tend to believe in parts you shouldn't. The new motor will be much better I'm sure.

Could a cracked block (possibly weakened by the splayed bolt machine work) cause the same scenario?

First off, you are making good power to run that fast at 3300 lbs. That said, I hope you either have an aftermarket block, or are working with a low deck B motor based around the 400 block. To me, it is all about keeping the rotating weight down to the minimum, and keep a good eye on clearances during assembly. I started off just like you did, not much mentorship. But guys on the board here helped tremendously.
If you don't have mikes and gauges to measure every last part you are going to put together, get them. They are a lot cheaper in the long run than situations like this.
I have a full set of outside mikes, a GOOD dial bore gauge, dial indicators, etc and use them all. Even the best shops can have something slip by.
That said, Reher Morrison is someone I do business with when ever I can. They are great to deal with, and I trust their work and reputation. So that leads me to believe the cause of all this is not with their work. Also, I own their engine assembly books. I suggest you read all their tech articles on line as well.
You have suffered the pain and expense of a motor gone sour, now it is time to reap the rewards of a very well done build! A new plan for a shortblock is in order, so ask what the guys are running.
My personal favorite is like 440jims 512 lowdeck combo, a 512 cube 4.25 stroke 4.375 bore lowdeck motor with a very light bobweight. An aluminum rod motor set up this way with aluminum caps, and a girdle will handle about anything you can throw at it and live due to a bobweight of about 2000 grams. A RB motor like mine comes in at 2432 and is steel rod, and flexes the megablock I have bad enough to cause me grief. It lives, makes great power, but I would be better off with a lowdeck 4.5 bore deal!
Last, but not least, is oil control and flow. Did you ever have even a small dip in oil pressure during braking? all oil passages the proper size, at least 10 psi per 1,000 rpm? minimum 15w40 or preffered 20w50 race oil? A good pan with a side bucket? All this is important, and I paid money in the form of hurt parts to learn it.