HELP! I-5 crankshaft end-play problem

[Joshua Van Tol]

You really need to find a better machine shop.

Sanding bearing to the point where the backing is visible is NOT a good 
idea, and will probably result in rapid failure. Granted, this is a 
thrust bearing, but still, it probably won't last. It might, but 
toasting a block and a crank would be a bad way to find out that it 
didn't.
On Feb 4, 2004, at 12:19 AM, Ameer Antar wrote:

> 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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