Martin :
I'm pretty sure the "0.254mm" indicates these are .010" undersize
bearings, meaning the crank has been ground to the first undersize.
If things look as good as you describe, I wouldn't grind the crank
again, but just put in new bearings. However, be sure to check the
clearances with Plastigage when reassembling.
Randall
"Martin C. Libhart" wrote:
>
> I finally had time this week to open up the bottom end of my '70
> Spitfire motor (1296cc) so I will know what to expect come rebuild
> time. I've had the motor on an engine stand since starting my frame-off
> restoration project last year. When I acquired this project car, the
> motor ran, but was a real dog. Good compression readings on cylinders 3
> & 4, but very low on 1 & 2; lots of blue smoke.
>
> To make a long story short, I was pleasantly surprised with my first
> look at the crank and rods, not to mention the fact that both thrust
> washers were still in place, with very little end float. In fact, this
> motor must have had a bearing job in it's recent past - the shells look
> like new, and the crank journals have no scoring. I expected much
> worse!!
>
> Here's my question....the main bearings are Clevite shells, and have the
> following on the back of each shell:
>
> Clevite CL 77
> MB-2359P
> 0.254mm
>
> Can anyone tell me if these are standard size bearings, or are they
> oversized due to the crank having been ground previously?
>
> Martin Libhart
> 1970 Spitfire
> 1972 TR6
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