Date: Sun, 14 May 1995 23:27:02 -0700 (PDT)
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: David Schwarze <schwarze@superc.nosc.mil>
Subject: Re: Add-on Oil Coolers
ATVenture@aol.com writes:
>
> Did you use a new case? A pounded case will transfer 20% of engine output
> into heating the engine.
> A 'line bore' will not make a pounded case good.
Ack!
I should have pointed out that this is a type IV case, which is
aluminum, not magnesium, and does not fatigue. The bearings fit tightly
in their bores, just like they are supposed to. I wouldn't have assembled
the engine otherwise.
> Most line bore tools are the bar type and just make begger holes in the case.
> If the case was so whooped on to start with you have an incorect starting
> point for the machine work. If the axis of rotation of the crankshaft is not
> in line and angled up correctly to the piston cylinders then that engine will
> never have the output and will always overheat.
I had my machine shop check the bore and they said it didn't need an align
bore. I trust them, but who knows? I suppose it's possible they were
wrong...
> That melling while a fine peice of machine work is no good. The iron
> casting's rate of thermal expansion does not match the Mag-Al alloy of the
> case, so when your engine is warm oil leaks back into the sump from the high
> pressure side.
I wonder if this is a problem with aluminum cases as well as magnesium?
> It could also suck bubbles of air in on the intake side.
> also the pressure can go way too high with a melling, too much is too much.
> You could have so much pressure that the stock relief valve will bypass the
> cooler even with a hot engine.
Good point. But the only reason I went to the melling was because of low
oil pressure before the rebuild (yeah, I was mighty suprised that the
rebuild didn't fix the low oil pressure. Turns out the pressure dropped
because the motor was overheating!)
> The stock pumps work fine, if you must get one from berg, they are stock but
> the alluminum has been treated (anodized) to make the surface harder/wear
> better.
I'll do that next time around. Thanks for all of the feedback, everyone! :)
-David
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David Schwarze '73 VW Safare Custom Camper (Da Boat)
SAIC Comsystems, San Diego Calif. '73 Capri GT 2800 (Da Beast)
e-mail: schwarze@nosc.mil '87 Mustang Lx 5.0 (Da Sleeper)
http://papaya.nosc.mil/~schwarze '93 Weber WG-50 (Da Piano)
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