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Discussion Starter · #1 ·
Just got my 331 reassembled after the thrust bearing failed on initial break in. We still don't know why it failed. Here's the background.

331 stroker
Mcleod scattershield
G-Force T-5
SPEC flywheel and clutch.

Logic states that something pushed on the crank from the rear yet all items were in spec except that I did not index the bellhousing as I thought that Mcleod's didn't need to be indexed to the crank.

We measured and found it to be .012 out - accepted tolerance is .003-.005. We used offset dowels and now it's within accepted tolerance. So could this have trashed the thrust bearing?

We'll try to break it in tomorrow. Hopefully it'll go smoothly.

Any other thoughts would be appreciated.

Steve
 

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Are you using the motor plate between the bellhousing and the block to provide the proper distance? Sometimes people forget to put this on before the flywheel goes on.
It sounds like the tranny is being bolted in against the crank and it should not be. The tranny should stop before the input shaft 'seats' against the pilot. In other words the input shaft should be floating with no thrust on it.
 

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Discussion Starter · #3 ·
There is ample distance between the shaft collar and the flywheel/pilot bearing We also have installed the block plate.

When the thrust bearing trashed on break- in we had excessive play in the crank as you'd expect - but this play was also seen with the tranny bolted on. You wouldn't expect to see excessive play if the tranny was pushing forward.

Thank you for your input.
 

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So...now what? Just going to try it again and hope?
Sorry to hear about the probs.
 

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Discussion Starter · #5 ·
On 2006-07-04 15:50, allenman85 wrote:
So...now what? Just going to try it again and hope?
Sorry to hear about the probs.

Yes, we are breaking it in tomorrow. I will keep the board posted on this odd and expensive problem.
 

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If that doesnt fix it... what timing set are you using? I doubt yours is coming loose, but when my cam gear came loose it pulled the crank forward and wore the hell out of the thrust bearing.
 

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Discussion Starter · #7 ·
Good news, the engine survived the initial break-in. The oil and filter was clean. We'll change the oil a few more times and keep monitoring it. I hope this nightmare is finally over. The car was supposed to be on the road in May.

Thank you for all your input.

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<font size=-1>[ This Message was edited by: DrStang on 7/5/06 9:11pm ]</font>
 
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