High Oil Pressure

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SuperV8
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Re: High Oil Pressure

Post by SuperV8 »

richardpope50 wrote:
Tue Jul 12, 2022 11:41 am
Normally my RV8 (from TVR Griffiths 500) runs circa 30psi. Water temp runs 85 - 90 and rarely exceeds that as fan brings temp back very quickly.

Yesterday as a birthday treat for my son he had an IAM Skills Day at Thruxton. It was hot (obviously) and when on the track he once thought the water temp hit 120c. OK, my car was the fastest there! He did not really notoce the gauges anyway as concentrating! On the last lap we think there was a small splat of water from the header tank that hit the windscreen. (Did do once many years ago when I had a blocked rad.) I thus assume water pressure caused this but not no signs of any escape of water anywhere. Oil temp was showing 90c which is hotter than normal which is circa 80c

At the end of the last session I drove home but on starting I immediately noticed oil pressure was 60psi. All else seemed fine but drove slowly. Oil pressure stayed around 60psi for a few miles and then on A303 at 50mph it came down a bit then fluctuated between 30psi (normal) and 60psi. Kept going as all seemed OK and within 20 mins psi stayed more often at 30 but short periods at 50. After about 45 minutes psi was normal at 30. the rest of the journey the psi stayed at 30. water temp was normal all the way home at 85 - 90c.

Any ideas why pressure so high?
Just found this oil pressure spec in the workshop manual for pre 99 (GEMS) and post 99 (Thor) engines.
gems thor oil pressure spec.JPG
How does your oil pressure compare?
Interesting the Thor has a higher pressure - at a lower rpm. Checked early and later service manuals and both quote a 60mm pressure relief spring length! so I wonder how else they are controlling the oil pressures?


Dax Rush 4.6 supercharged V8 MSII

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