Big 6 compression

[Robert Rose <rarose@xxxxxx>]

Jim,
  I don't know specifics of that model, but they sound good. The engine
is probably a 10.5:1 compression, which means 10.5 times 14.7psi (one
atmosphere)=154psi will be the perfect ideal number. Your values are I
dare say within the accuracy limits of your compression gauge. And more
importantly all of the cylinders are even.
- --Rob
  2001 330i
  (just traded in my 2000 M roadster)

> Date: Tue, 23 Jan 2001 00:20:07 -0500
> From: flatthead@domain.elided
> Subject: Big 6 compression
> 
> I just came back from looking at a 1988 535iS.  Everything looked good: 
> interior, no rust, it drives great, all records, no leaks, etc.   
> 
> Here's my question:  I did a compression check and came up with 150, 150,
> 151 150 149 150   psi front to back.   How does that sound?  Low? High? 
> I'm not sure.  The current owner says it burns no oil and has
> documentation to show that the oil is changed every 3000 miles with
> Castrol 20w-50 oil.  The car has 134,000 miles on it.  I've always
> thought the uniformity of the readings (no wild swings, especially
> between the #5 and #6 cylinders)  is the most important thing, but I'd
> like to know if 150 psi is a good reading.  
> 
> 
> It drives great, stops great (no shimmy)  and everything works except the
> right rear door lock.  
> 
> Anybody got any advice?
> 
> Thanks very much
> 
> Jim

- -- 
Robert A. Rose          web: http://www.rarose.com
Hillsboro, OR         email: rob@domain.elided

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