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I'm going to be building my motor in the next month or so. I will be using a Bugpack flanged crank and flywheel. My question is, what do I set the end play at? I have read .008-.010 but that seems way loose. What would happen if I used .003-.005 like a regular crank. I am aware that no shims will be used and the bearing will have to be grooved. Will the thrust bearing bind if I run it so tight? This is going in a "street" car if that matters.

This is how I understand it, if you don?t leave enough end play in it, when the bearing swells from heat, its going to grab the crank. Why will it heat up? Because the bearing is seeing the full speed of the rpm. speed=friction=heat
Standard crank, put one shim in, and each surface should only see half the speed, put 3 shim in like normal and you cut the speed down by 4 and there are 8 surfaces taking up the speed, friction, and able to disapate the heat that much faster and not transfer it into the bearing. Does that make sense? This is how it works in my mind. What do you think?


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Muffler Mike
www.MufflerMike.com

[This message has been edited by Muffler Mike (edited 04-26-2002).]

Explain what you mean by "the bearing will have to be grooved". I would set it a little tight as you are going to be using it on the street. .005 to .008. On a street car the thrust part of the bearing is going to waer every time you put in the clutch. Do not sit at stoplights with the clutch in. Do not start it in gear with the clutch in. If you are sitting and the motor is running, have it in neutral. The bearing will last much longer.

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Marty Staggs
www.staggsracing.com

[This message has been edited by Marty (edited 04-26-2002).]

If a person was to drive like that, how long would a flanged setup last on the street? Are we talking a thousand miles between new bearings or could it last up to 5K or 10K miles?

Steve

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Marty:
<B>Explain what you mean by "the bearing will have to be grooved". I would set it a little tight as you are going to be using it on the street. .005 to .008. On a street car the thrust part of the bearing is going to waer every time you put in the clutch. Do not sit at stoplights with the clutch in. Do not start it in gear with the clutch in. If you are sitting and the motor is running, have it in neutral. The bearing will last much longer.

</B><HR></BLOCKQUOTE>

I am not sure Steve.

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Marty Staggs
www.staggsracing.com

How do Chevy's get away with it?

John

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Marty:
<B>Explain what you mean by "the bearing will have to be grooved". I would set it a little tight as you are going to be using it on the street. .005 to .008. On a street car the thrust part of the bearing is going to waer every time you put in the clutch. Do not sit at stoplights with the clutch in. Do not start it in gear with the clutch in. If you are sitting and the motor is running, have it in neutral. The bearing will last much longer.

</B><HR></BLOCKQUOTE>

I meant to say notched. Last year in hotVWs, they did an article on installing a flanged crank. Jack Sachette notched the flywheel side of the rear thrust bearing to improve oiling.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JohnConnolly:
<B>How do Chevy's get away with it?

John</B><HR></BLOCKQUOTE>

I do not know.
I am more than happy to admit that.
It has boggled my mind for years.

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Marty Staggs
www.staggsracing.com

[This message has been edited by Marty (edited 04-26-2002).]

I think V8's get away with it because the thrust surface area of the bearing is greater (greater area = less contact stress per unit area) Aftermarket VW flanged cranks only have a .15" annular ring as a contact area. I believe a Chevy's is much wider. Anyone one got a BS Chevy apart to measure it?

I will have my dads 468 Big Block apart next week and will take some pics and measurements.

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Marty Staggs
www.staggsracing.com

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JohnConnolly:
<B>How do Chevy's get away with it?

John</B><HR></BLOCKQUOTE>

thats a damn good question. Marty might have a point on the size of surface.
i wonder if clutch slip in the flywheel transfers some heat as well, when a v8 set up thust is buried deep in the block. im not really sure. Ok marty, where is the thust in a v8 block

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Muffler Mike
www.MufflerMike.com