Re: stag-digest V3 #23

[ASMaughan@domain.elided]

In a message dated 29/11/97 13:26:35 GMT, you write:

<< It is true that the SAAB oil pump is different, higher rated I believe, >>

I have heard many bar room stories with regard to the fitting of SAAB oil
pumps, as has my father who before finally accepting that he needed a regrind
fitted one. The effect was that the engine then ran ( ie over 1500rpm ) at
approx 55psi but still dropped to 10 - 15psi at hot tickover. After the
rebuild the engine runs at 60 - 70 psi and idles ( 700rpm) at 45 - 50psi.
Inspection of the pumps reveals them to be identical in every dimension, the
only difference is the relief spring.

My engine has an uprated relief spring in it from Moss which causes it to run
at 75 - 85 psi and idle at 45 to 50psi. I have considered possible
detrimental effects on the chains but feel that as the 1850 SAAB used the
same single chain this is unlikely. Anyway chains are cheaper than rebuilds.

There is another reason why SAAB's don't suffer from oil pressure like
Stag's, this is to do with the idle speed. The SAAB engine with the "same"
pump idles at 800 - 900 rpm thus spinning it twice as fast ! and thereby
having a higher idle pressure with half as much engine to feed!

Sure this will spark loads of comment/controversy

Look forward to the flames ! ( to warm my soggy cold garage )

Andy Maughan