Subject: [Spridgets] Oil Pressure vs Quantity

From: "rrengineer.mike" <[email-masked]>
Date: Wed, 13 Aug 2014 02:56:02 -0700

My first Bugeye with the original 948 motor that I owned back in 1971 was kind of strange when it came to oil pressure. B While driving, the oil pressure would drop from 60 psi to 40 psi after a week or two. B Upon checking the oil, it was down a quart. B I would add a quart of oil and the pressure went back up to 60 psi! B I have always wondered about this. Oil pressure should have nothing to do with oil quantity. B Any ideas of the mechanics of this? B 
Mike MacLean
60 Sprite
56 BN2

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From: "Bud Osbourne" <[email-masked]>
Date: Wed, 13 Aug 2014 06:51:21 -0400

It's a function of the "lifting" capacity of the pump.  The lower the level
of oil, in relation to the location of the oil pump, the  greater the "lift"
the pump has to make, to draw the oil into it.  This translates to less
pressure on the discharge side of the pump.
Although I had to learn all about this in my day job, years ago, I never
equated it to automotive oil pumps until the late 356 engine guru, Harry
Pellow, called it to my attention.  It's real and it happens, for sure.
Some pumps are more prone to pressure drop due to lower oil levels than
others, but, nonetheless it happens.

Bud

-----Original Message-----
From: Spridgets [mailto:[email-masked]] On Behalf Of
rrengineer.mike
Sent: Wednesday, August 13, 2014 5:56 AM
To: [email-masked]
Subject: [Spridgets] Oil Pressure vs Quantity

My first Bugeye with the original 948 motor that I owned back in 1971 was
kind of strange when it came to oil pressure. B While driving, the oil
pressure would drop from 60 psi to 40 psi after a week or two. B Upon
checking the oil, it was down a quart. B I would add a quart of oil and the
pressure went back up to 60 psi! B I have always wondered about this. Oil
pressure should have nothing to do with oil quantity. B Any ideas of the
mechanics of this? B Mike MacLean
60 Sprite
56 BN2

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From: Michael MacLean <[email-masked]>
Date: Wed, 13 Aug 2014 12:38:39 -0700

Bud's reply makes sense and maybe if I had replaced the pump this "symptom"
would have gone away.  The pressure was rock steady through any kind of
driving, so I think the pickup was in the right spot.  At the time I 
knew
nothing of cars.  I just used the low pressure as an indicator and 
never had
to remove the dipstick.  It ran fine until I lent it to a 
friend that wanted
to visit his girlfriend in the Marines in Twenty Nine Palms.  He had to drive
from Hermosa Beach and I told him to just watch the oil pressure gauge and
stop when the pressure got down to forty.  I even supplied the oil.  I guess
he was only thinking of one thing while driving out there.  He got as far as
Needles, California and the engine seized.  He had to buy me a used engine
from the junk yard to replace the one he killed.  Yes, there 
were Bugeyes in
junkyards back then.  After that I had to use the 
dipstick like everyone
else.Mike
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From: Mike MacLean <[email-masked]>
Date: Wed, 13 Aug 2014 13:41:44 -0700

I didn't even ask. We were both surprised when the service station owner that had given him permission to leave it parked in his parking lot wanted $200 for a storage fee.B  A princely sum in 1971. Heck, the car only cost me $150 with a factory hardtop.
Mike

On Aug 13, 2014 1:36 PM, Rick Fisk <[email-masked]> wrote:
>
> What the heck was he doing in Needles if he was going to Twentynine Palms from Hermosa Beach?B  That's some serious getting lost!B  :-)B  
>
> Sent from my keyboard 
>
> > On Aug 13, 2014, at 3:38 PM, Michael MacLean <[email-masked]> wrote: 
> > 
> > would have gone away.B  The pressure was rock steady through any kind of 
> > driving, so I think the pickup was in the right spot.B  At the time I 
> > knew 
> > nothing of cars.B  I just used the low pressure as an indicator and 
> > never had 
> > to remove the dipstick.B  It ran fine until I lent it to a 
> > friend that wanted 
> > to visit his girlfriend in the Marines in Twenty Nine Palms.B  He had to drive 
> > stop when the pressure got down to forty.B  I even supplied the oil.B  I guess 
> > he was only thinking of one thing while driving out there.B  He got as far as 
> > Needles, California and the engine seized.B  He had to buy me a used engine 
> > from the junk yard to replace the one he killed.B  Yes, there 
> > were Bugeyes in 
> > junkyards back then.B  After that I had to use the 
> > dipstick like everyone 
> > else.Mike 
> > ------------------------ 
> > 
> > [email-masked] 
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