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Discussion Starter #1
I have 5 minutes on a 454 and when I revved the motor a couple of times it kicked the alt belt and sparks flew from the dampner area.

the Pullies are lined up perfectly.

ON inspection, I found that the balancer had rubbed the tivia timing marker and wore a chunk off of the bottom allen bolt. I figured I would check the crank shaft end play.

A reputable machine shop had assymbled the motor.

I crawled under the front of the car and grabbed the front of the pulleys on the crank and yanked it back and forth. It clunked back and forth.

I don't have a dial indicator but figured it moved about a 64th of 1 inch when I measured it with a special steal ruler. ( I know, not very accurate).

My BB rebuild manual says there are no oversize bearings to take up excessive crankshaft end play. Is this true?? Any advice what the machine shop should offer as a fix if it is infact a problem??

Thanks


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Mr. D
72 454 El Camino
68 RS/SS Camaro
73 RS/LT/Z28 Camaro
99 Firebird TA WS-6 A4
 

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It sounds like you may have the wrong timing tab or mounting bolts. I can't imagine so much end play that the crank walks back 1/8" +, unless somthing is really wrong. If it turns out that there is excessive end play your engine builder should be responsible. In my book that is exactly what you are paying them for...MK

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hometown.aol.com/mkrauser/gmracing/gmracing.htm


70 Chevelle Fathom Blue
70 Malibu Convertible Midnight Regatta Blue

Chicago - Suburbs
 

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Discussion Starter #3
I have a roller cam and an after market aluminum timing cover and a Tivia timing marker.

It goudged (sp?) half of the bolt but only on the inside of it and apparently only when reved hard (3,000 - 4,000 rpms). that is when i noticed the sparks.

Should I be able to rock the crank back and forth by just yanking on it???
Thanks
 

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D,
The crankshaft end play spec on a big block is .003-.007" I have seen plenty of them at .010 with no problems. You should have to use a dial indicator to measure it. 1/64" is about .015... thats a bit much. There are a lot of things that can cause thrust failure on a new motor. Torque converter installation is on of the big ones. Was your converter tight against the flexplate when you installed the motor, or could you pull it away from the flex plate 1/8" or so ? Here is a link to a tech bulletin about possible causes:
www.aera.org/tech/tb1465r.htm
e-mail me any questions you might have.
P.S. I am pretty sure there are oversize thrust bearings available, but the crank will have to be reground to accommodate them.

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Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100



[This message has been edited by BillK (edited 12-15-99).]
 

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Are you sure its not just the dampner moving? to grab the timing marker sounds like the dampner may have sheared the Key? possible that when the pulleys were installed the dampner bolt wasn't torqed?
 
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Oversize bearings are available, 10 wide to 30 wide. If the end play is excessive, the crank will need to come out and be re-ground.



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Wally
Gold #67
67 Malibu "Small Block"
90 SS454
71 Malibu "Small Block"
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Discussion Starter #7
Bill K
I had not hooked up the converter yet. It is back about a 1/4 inch from the flex plate. I'll check out the link. Thanks

1bad67
I am pretty sure it isn't just the dampner. I personally torqued the center bolt on. They installed the dampner at their shop. I haven't noticed anything unusual about the dampner. It looks fine.

Wally,

So the bearing can't just be replaced? So If there is too much end play, then out comes the motor and they will have to tear it down again? I hate to complain but crap . . . I don't want to have to pull the motor again.
But gotta do what ya gotta do, right?
Thanks again for the replies.
MR. D
 
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