Bob,
I wouldn't do that. While there's great debate on oil, everything I've
read says DON'T mix viscosities. Mixing brands is OK, but you don't
want to do a science project on your freshly rebuilt engine. The oil
companies do a lot of research, I doubt you can do any better.
15psi on a hot BJ8 at idle is not bad at all (unless you're idling at 1,500rpm
;).
My BJ8 sometimes almost pegs the needle on a hot day, slow idling in traffic,
yet I've got over 60K miles and it still runs strong (even with nominal low
compression). With our main bearing clearances, you won't get 40psi at hot
idle, even if you used molasses ;)
BJ8s use a gear oil pump which is less effective at idle. You can install the
earlier rotor type for better oil pressure at idle, with the loss of some HP at
high revs due to the resistance of the rotor. If, when you rebuilt your engine
you didn't rebuild the rocker shaft I'd try that first; might be good for
2-3psi
at idle (max pressure is/should be limited by the relief valve).
I've followed this topic (oil) for years, both for my cars and for airplanes.
I've
experimented with different brands and viscosities for both, and have come to
the following conclusion: buy a decent, name brand dino oil, and change
it and the filter often (I was quite happy with Chevron Supreme 20W-50 at
about $1.20/qt, but my local Costco quit carrying it :(
I met John Schwaner the other day. John is a renowned expert on aircraft
engines and, of course, I asked his recommendation for oil. He said of all
the engines his shop gets the ones that look the best at overhaul used Phillips
66 dino oil. This is after Mobil, Shell and Exxon have spent millions
developing
and marketing various synthetics and blends that supposedly do everything but
wash your windows ;)
I will say, however, that any car I own with a manual transmission gets Redline
MT-90.
Oh, and drive your cars--and airplanes--often and hard. They like it ;)
bs
--
***************************************************************
Bob Spidell San Jose, CA bspidell@comcast.net
'67 Austin-Healey 3000 '56 Austin-Healey 100M
***************************************************************
-------------- Original message ----------------------
From: Bob Westenberg <srgrebnetsew@yahoo.com>
> Bob,
> I read this oil debate with great interest.
> Even after an engine rebuild, I still have pretty low pressure, when idling
>in
> the summer. ~ 15 psig at times.
>
> What is wrong with providing our own blend? That is, if you have a 7 quart
> system, provide 4 qt. straight 30W, 2 qt. 15W30 for covering initial cold
>start,
> and 1 qt of "motor honey" the old term for very high viscosity oils for old
> engines. The oils are certainly miscible between grades, but provide unique
> viscosities where required.
>
> Regards,
> Bob - BJ8
> Milford, MI
From: Bob Westenberg <srgrebnetsew@yahoo.com>
To: Bob Spidell <bspidell@comcast.net>
Cc: Healeys <healeys@autox.team.net>
Subject: Re: Oil question
Date: Wed, 7 Feb 2007 17:01:00 +0000
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