1977 MGB Oil Pressure

1977 MG MGB

55,348 MILES • 4 CYL • 2WD • MANUAL

CANTJO

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My 77B has high oil pressure. High being about 60psi at 1000rpm and 85 to 90psi at 3000rpm. I have checked the screen in the sump an it was fine. I replaced the relief valve and spring. I tried an engine flush. The thing that really bothers me is when i take the oil filler cap off I do not get any blow by or see any oil flowing. The older cars that I have owned when you take off the oil filler cap oil will blow out it. I have started and ran it several times for 10 to 20 minutes and it has not blown up yet. Does anyone have any suggestions?

Jun 2, 2009 at 4:25 PM

DOCFIXIT

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According to the boys that built car
idle pressure 10-25 psi
Running 50-80 psi Did you replace relief valve spring? was free length 3 in.? Normal opening of relief is 70psi.
Have you checked with mechanical gague. Lucas the Prince of Darkness can't be relied on.

Jun 3, 2009 at 3:01 PM

CANTJO

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Yes I replaced the spring and valve that I purchased from MOSS. I also checked with a mechanical unit also and no difference.

Jun 3, 2009 at 3:45 PM

DOCFIXIT

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If no rocker arm clatter i go with it was engine recently rebuilt. You have solid lifters and oil comes up into rocker shaft not alot of flying oil. what viscosity oil and filter needs relief spring.

Jun 3, 2009 at 4:13 PM

CANTJO

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No it has not been rebuilt. The odometer only shows 55149 and I'm guessing that's correct. I have 20w50 in it and a Purlator L14670. It does have a little lifter noise until the oil warms a little but then it is quiet.

Jun 3, 2009 at 9:14 PM

DOCFIXIT

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Pull the rocker cover and remove rocker assembly. Clean it out slug can build up inside. And give it a valve adjustment. Couldn't hurt
Also recomend a Robert Bentley service manual pretty sure MOSS has

Jun 4, 2009 at 1:43 PM