I will never trust a repaired crank again

[geno]

http://www.netsnapshot.com/pcw/b?KEY=20&ACCOUNT=2412
This was repaired by Crankshaft Specailty and chromed back to STD

 

[bruce]

Originally posted by geno
http://www.netsnapshot.com/pcw/b?KEY=20&ACCOUNT=2412
This was repaired by Crankshaft Specailty and chromed back to STD

Mind sharing what all happened?.

 

[Otto J]

Thanks Geno, Now in the back of my mind the wheels are turning.

 

[Scott231]

Wow, those bearings took a hot ride. Classic weak spot on a even-fire crank - the offset throws between adjacent cylinders.

 

[geno]

The crank is out of a friends car and had seen black death on the rod throws twice Welded back to std once and chromed to std the last time. I knew it was a matter of time at the power level we were looking to get. The car went 9.6 on 20# boost with a 1.67 60ft the run before. It also went 146 mph getting in and out of it twice with another bad 1.6 60 ft on a 9.88. The mains bearings got hurt after the crank broke im sure..

 

[S2V6RACER]

So that crank broke once and was welded up and "restored". It broke in the area of repair?

 

[geno]

I dont know the exact history of the crank other than it was repaired twice after seeing black death and spinning rod bearings It sure broke off clean right at the fillet

 

[750H.P.V6]

Gene,

I heard about Dennis' mishap from Len this morning. That sucks. I guess this is why Billy Anderson is so adamant about not using repaired cranks. How come with all the $$ Dennis has he was using that crank? Is this a back up motor or something?

Neal

 

[turbodave231]

Whitey at Moldex once told me that he would never recommend welding on a Buick crank to repair. He didn't say why........I Guess I have my answer.

Dave

 

[Ron Tarabori]

Think I would start looking for an oiling problem. I have a few Busch and ASA motors in here that had broken cranks in them and when the crank breaks and the motor is shut down it very seldom hurts the other bearings in the engine. When you cook every main and rod bearing in the engine you've got a problem in the oiling system someplace.

 

[geno]

Remeber the broke off ends were hitting each other as they passed each other at 7000 rpm. The rear main was the only thing supporting that end of the crank from #6 aft and the touque converter. So thats why the #4 main was hurt and the next forward main#3 took a beating from the counter weight missing off the end of the crank. I really dont think its a oiling problem because the bearings i took out when i refreshed the motor were perfect. All the rod bearings looked good considering the crank broke
Quote
When you cook every main and rod bearing in the engine you've got a problem in the oiling system someplace.


Did you look at the rod bearing pictures and see they looked fine
It did spin any bearings

 

[geno]

Quote
I have a few Busch and ASA motors in here that had broken cranks in them and when the crank breaks and the motor is shut down it very seldom hurts the other bearings in the engine.

This break let the forward 5 cylinders run and it hurt itself just before the finish line and then died after the run.
Also these were coated bearings so they look black.He said the shake was wild feeling along with the hammering when the broke off ends would bash each other. You can bet i will be looking close at the oiling system

 

[Ron Tarabori]

After I posted I was wondering if they might have been coated bearings as they look very dark thats why I thought the entire bottom end had been oil starved. These things will still put power to the rear when the crank breaks but they sure don't sound good doing it. What kind of oiling did this engine have? Dry sump?

 

[geno]

Its wet with a external Weaver pump and large capacity oil pan and windage screen with hindged trap door

 

[Otto J]

That was Dennis Hogan's crank wasnt it?

 

[geno]

That would be his to bad to because the car was starting to work

 

[750H.P.V6]

Gene,

I've always said "The light bulb burns brightest just before it goes out". BTW, did you find another crank yet? I noticed there was one on Ebay and they closed the auction early.

Neal