Reuse crank?

Hi all

I had a piston pin break this weekend, this of course resulted in most of my short block being destroyed. But after tearing it down the crank looks fine.

What is the general feeling about this would you guys consider reusing it or is it just junk ??

from the teardown:

 

Holy crap, you did all of that on a burn out, see you lifted the blower too, take the crank to a crank shop and have it checked out. get yourself a throttle stop, for your bunouts.

 

Yeh it was on burnout for the second run of the day, we found out afterwards in pit that the ignition had come loose. So it must have been spraking at all the wrong times. rpm on the brunout was normal.

About the crank shops ... my problem is that i live in Denmark = back water country in regard to racing engines and shops that have the expertise and know how.

So what exactly are the procedures for checking a crank like mine out?? except the obvious in regard to journals etc

 

Corn Husker Method

Stand your crank on end on a good solid surface like a heavy bench. Take a small hammer and tap on the crank in differant places { not Journal faces } it should make a real sharp ring. If you get a real flat sound its probably cracked around where you sounded it. A company called Crown in Woodstock Ill. 800 766 7655 sells a 3 part cleaner-penetrant-developer that also brings out cracks real good if used right. The best way is Magnaflux but we dont have that in our corn field either

Best of luck.

 

Im not sure how you usually do it in Denmark but in the US we've found its best to remove the piston thru the top of the bore after the heads have been taken off. Speaking from experience, I find its a much better method than taking it out thru the side of the block. I didnt get a cool photo of mine.

 

hehe, yeh i usualy do that too flyingpig ... but not this time tho, but you can bet i'll be double checking the ignition clamp from now on

 

Did that happen at Mosten?

 

With that much damage, I would definately send the crank out to have it checked. I'm sure you dont want to put a new motor together, only to have the crank break due to a crack, and have to start all over again.

BTW. I would send the block out and have it checked too, looks like it may have a crack or two. hehe.

Jason.

 

Hmm sounds like another dane is lurking here ..

 

I thought I was the only redneck that did this But we hang our crank off the snout bolt.

We've done this for years with 100% success, until last spring Accidently, yes accidently, we had a crank magnufluxed. It had a 1.25" long crack in it But yet the hammer sound test said it was good
I'm not sure what I'll do with cranks this winter.

Sune
You could put the crank in the block with only the front and rear bearings and check to see if its crooked. If its bad that might help your decision.

 

I like that crank bolt idea, never thought of that.

 

Assuming it checks out for cracks you can also use a degree wheel to make sure it has not twisted.

A friend of mine was over in Japan years ago, and was in a garage and evidently over there it was standard procedure to tap all of the parts of the cars suspension, frame, rear housing, axles flanges etc. He said the guy had 4-5 hammers of different sizes and did this stuff religiously like a musician before a concert any time they had a car on the rack.

 

The way my kid launches sometimes I think about maybe taping him on the head to see if he is all there

 

When i tore the engine down, all the bearings looked worn but ok even the one on number 1 cyl. after i took all the rods and pistons out, the crank turned like normal with all the mains still bolted down. there is nothing to see on any of the journals.

But yeah i'll get it flux'ed (i found a place in sweden that can do it) if im going to reuse it, but i got to admit that im thinking hard about hemis at the moment.

 

Sune,

Sit the block in V-blocks or in the block with only front and rear bearings in and check the run out with a dial indicator on the middle journal. It will tell you if its bent, better to check this first before spending money having it magnafluxed

 

Crank check

If you live in Denmark, you could send it to MMR(Malmö Motor Renoveringar) Sweden.

 

You need to check all 3 journals with a dial indicator, & not just the center. The crank can be bent on one side, depending were the damage was.

 

There is a good stock BAE stage 6 PM engine down south in Sweden that might be up for sale...it's been runing 4.08 1/8 tuned by two blown engine rookies.. on a real mild tune up.

 

the lindbergs bros engine... yeah i have seen it, way too expensive i think tho.

Nah if i decide to go hemi, im gonna get a top fuel racer i know to help me out. he used to run alcohol... has lots of good alcohol stuff laying around.