Re:

[Clive Sherriff]

Rick is quite righ - high oil pressure is not necessarily good.news If you restrict oil paths to get high oil pressure, the result may be that not enough oil reaches the bearing surfaces. Sometimes a lower oil pressure is a sign of massive volumes of oil getting where it needs to. Be careful - Dont forget the resrtictor valve, ball and spring, the ball seating of which can wear quite a lot! Rehgards Clive =========================================================

----- Original Message ----- From: "Rick Waters" rwmgtc@yahoo.ca> To: "Mark Stolzenburg" stolzy40@sbcglobal.net>; grunau.garage@sympatico.ca>; "John Patterson" jwp_mgtc@chartermi.net>; "T-ABCs Forever" mg-tabc@yahoogroups.com> Sent: Tuesday, August 16, 2005 5:08 AM Subject: Re: [mg-tabc] > Oil pressure is an interesting topic. Too many variables to draw simple conclusions. I had John Marks rebuild and calibrate all my gauges. Interestingly enough, my oil pressure showed a lower reading after the gauge reading. > > I have a known good engine, complete with new rocker shaft and rocker bushings. The oil pressure, using 20W 50 when hot, is not constant. If I drive the car at 3000 to 3500 rpm, the gauge shows around 55psi. Drive it at 4000, and for a while, the reading goes to 60psi, but then drops down as the increased heat apparently makes the viscosity of the oil lower. > > What I think we need in these engines is the maximum flow of oil to the bearings on the crank. I get the impression that this is a small volume, high pressure oiling system, sort of the opposite of the old American V8 engine philosophy of high volume, relatively low pressure. High volume ensures that there is sufficient oil to form the hydrostatic wedge that keeps the rotating journals from actually touching the bearing material in the big ends and the main caps. It works like a waterski. > > Having blathered on, I think various efforts to increase the gauge reading by fitting restrictor pins to the rocker gear oil feed are not helpful. Neither is running 20W 50 in the winter, as the time for the thick oil to flow through the oil galleries and reach the bearing areas is increased, thus increasing wear. > > In short, it's not just about the pressure you see on your gauge. > > -Rick TC 7881 > > Mark Stolzenburg stolzy40@sbcglobal.net> wrote: > Bob, At what RPM are you suggesting 50 to 60 psi hot? I take it you are > suggesting the minimum 40 psi at idle? > Mark Stolzenburg > St. Louis, Missouri > TC 7812 > ----- Original Message ----- > From: "Bob Grunau" > To: "John Patterson" ; "T-ABCs Forever" > > Sent: Monday, August 15, 2005 5:03 PM > Subject: RE: [mg-tabc] > > > > John, > > I'd suggest using 20W-50 oil, 10W-30 is really too light for our XPAG > > engines. Cold oil pressure should be about 70 psi. I like to see 50 to 60 > > psi hot. My minimum hot pressure to run is 40 psi, but I hate to see it > that > > low. > > Regards, Bob Grunau > > > > > > > > Yahoo! Groups Links > > > > > > > > > -Rick Waters > > --------------------------------- > Find your next car at Yahoo! Canada Autos > > [Non-text portions of this message have been removed] > > > > > Yahoo! Groups Links > > > > > >