| Re: [GMCnet] High volume oil pumps [message #246392 is a reply to message #246357] |
Fri, 04 April 2014 15:39   |
GMC.LES
Messages: 505
Registered: April 2014
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Not to question Dick's abilities as a quality engine builder, but I wonder if one of his reasons for using the HV pump is to keep the oil press gauge stable? Most of his motorhome engine customers are likely less knowledgeable on engine internals and might be concerned if they saw fluctuating hot oil pressure at idle on a fresh engine. The HV pump certainly won't hurt our low revving engines and is a convenient way to keep the hot idle oil pressure up.
Since Dick has no control over oil quality, coach operating conditions, or the accuracy and type of pressure gauge used, hot oil pressure at idle could be all over the map. Using a HV pump would help reduce the variations one might see.
I agree with Bob on the idle oil pressure telling us about the condition on our engine. That info is only good to those of us who understand what is actually going on. To the rest of us it might raise false red flags.
Les Burt
Montreal
1975 Eleganza 26ft
A work in Progress
On Apr 4, 2014, at 8:35 AM, Ken Henderson <hend4800@bellsouth.net> wrote:
OK, now it's somebody else's turn to rattle Bob's chain just a tad -- We
always get such great information when we wake him up!
Ken H.
> On Fri, Apr 4, 2014 at 2:25 AM, Bob Dunahugh <yenko108@hotmail.com> wrote:
>
> The main, and rod bearings will pass the same amount of oil at 700 RPM as
> at 3000 RPM. As the bearing clearance remain constant as long as the oil
> pressure remains the same. The output of the oil pump goes up as the RPM's
> increases. At idle. The relief valve is generally closed. ( Except at start
> up with a cold engine. ) This can be observed on the oil pressure gauge.
> You can also observe when the relief valve opens as the RPMs increase..
> The oil pressure gauge will also increase. There will be a point that the
> gauge will stop climbing. Even though the RPMs continue to increase. That
> is the point that the relief valve starts to send the excess oil back to
> the pan. With the OEM pump in place. And if you pay attention to what your
> dash gauge is doing. You can get indications of the condition of your
> bearings, and pump. If you have a high volume pump. The relief valve is
> bypassing oil most of the time.This will decrease the movement of the
> dash guage. Some guys get upset bec
> ause of the gauge moves to much. When it moves. It's telling you a store
> on the health of your engine. A static gauge due to a high volume pump is
> saying nothing . And can mask issues that are building up internally.
> Personally. I like it that my dash gauge is communicating to me. As rorthe splash oiling systems. Yes. Way back in time. A splash system worked in
> car, and truck engines. But that wasn't the kind of splash that we have
> been discussing. There was more to that system then oil just flying
> around the crank case. And that oiling system worked well until
> compression ratios got above 5.2 to 1. As for the Briggs. Low compression
> with very little weight in the reciprocating mass. That's what made that
> work. Anyway. That's my input.Bob Dunahugh
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