Subject: I Need Technical Information For Opel 4 Cylinder Motor built in 1944

From: [email-masked] (herschel.h.mayo)
Date: Fri, 12 Aug 1994 12:51:09 GMT

I'm overhauling a 1944 1.5 litre Opel Olympia engine.  This engine was
manufactured until the mid 1950s. I have not been able to find any
workshop manuals or other information about this motor. I need to 
know what the the outside diameter of the main bearings is so that
I can have the mains rebored. I also need torque specifications for
all of the bolts. 

                                       Larry Mayo

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From: [email-masked] (Bob Wilson)
Date: Fri, 12 Aug 1994 16:38:08 GMT

[email-masked] (herschel.h.mayo) writes:
: I'm overhauling a 1944 1.5 litre Opel Olympia engine.  This engine was
: manufactured until the mid 1950s. I have not been able to find any
: workshop manuals or other information about this motor. I need to 
: know what the the outside diameter of the main bearings is so that
: I can have the mains rebored. I also need torque specifications for
: all of the bolts. 
: 
: 
:                                        Larry Mayo

In the event that you cannot come up with the factory data, neither of the
two items you refer to above should pose any kind of problem. Torque specs
can easily be found for the particular thread size, class, and bolt/nut
hardness in almost any mechanical reference book; this is not by any means
a high performance motor (at least by current standards) so there should be
nothing unusual about the torque specs. As for the bearings, I assume you
are really interested in finding the nominal running clearances for them
(probably in the range of 0.0005" to 0.002" or about 0,01mm to 0,05mm)
so you can have the main bearing journals ground slightly undersize to fit
suitably undersized bearing shells. Any firm experienced in doing this work
should be able to suggest a bearing clearance typical for an engine of this
vintage and (likely) relatively low output. Chances are the clearance required
is somewhat larger than engines today use, and the manufacturing tolerances
were much wider then; both these points mean the your final selection of
a bearing clearance is relatively uncritical, at least by comparison with
the requirements of cars today.

Regards,

Bob