HELP! I-5 crankshaft end-play problem

[Ameer Antar]

Well, I talked it over w/ the race shop where I got the block machined and they told me I could have the crank ground down or just sand the bearings. They said they always sand the thrust surfaces of the thrust bearings when building a race motor to take any inconsistancies out of the surfaces. Grinding the crank would probly cost another $50 and maybe 3-4 wks as there's only one crank grinder here in CT. With all that I took my chances and sanded down the bearing shells on the thrust surfaces. I used the bearing cap to support the shell and wet sanded w/ 600 grit paper. After putting it all back together, I'm right on the money w/ .006" end play. Even though the silvery surface was removed and copper showing underneath, I think I did the right thing, b/c a bearing set is much cheaper than a replacement crank. I'd rather take my chances w/ the bearings than the crank. Who knows, the next set of bearings might be much smaller and a ground crank would then have too much play. I guess I'll find out soon enough. I'm surprised that no one else has had a similar problem... I guess maybe not many people bother to grind their crank and use oversize bearings... Thanks for the input though.

-Ameer

---Original Message---
From: Jim Green <jeg1976 at yahoo.com>
Date: 2/3/04 10:49:23 AM
Subject: Re: HELP! I-5 crankshaft end-play problem


--- Ameer Antar <antar at comcast.net> wrote:
> Yes, the shell fits OK, but it's got zero end float.
> I measured about .001" difference between the shell
> and the space for the bearing in the crank. No
> feeler gauge will fit in there, and I'm sure that
> will destroy the bearings in a running motor. The
> bearings are oversize as the crank main journals
> were ground to .25mm oversize. But I thought that
> only affects the journal diameter, not the thrust
> clearance. I'm thinking of sanding down the bearing
> shells for the #4 bearing, but I'm worried about
> removing the coating or just too much. Thanks for
> any other ideas.

Yea, it sounds like you need to bring the crank in and
have it ground to the right size on the thrust bearing
area.  I wouldn't sand the bearing down because like
you say, you'll remove the other coating, plus you'll
be driving around this car with a home brew crank
bearing.  Not something that sits well in my mind.


===== 
Jim Green
'89 90tq
'89 80q
http://www.mswanson.com/~jgreen/car_home.html

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