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MG MGB Technical - Duhscovery?

Over the years numerous threads have asked the age old question "Why does my oil guage needle shake?"

The reply usually makes reference to an oil relief spring and other such stuff of which I have little or no knowledge.

Recently, someone recommended a Volvo oil filter, a Mann W917 - same one that fits on 240 and 960 (and apparently other Sweedishbricks). Because I have a 1989 245 sitting around and at least a dozen W917 filters sitting on the workbench, I gave it a try on the MGB engine.

Guess what? The needle shaking stopped. I have previously used K&N and other high grade filters and the needle shaked at hot idle - no more. I held a K&N next to a Mann filter, the Mann filter is shorter...could this be a clue?

Perhaps it's just a coincidence or just a fluke, but, what if the shaking was caused by a taller filter?

Well, I leave it to the gurus and MG sages. What do ya'll think?

rn
RN Lipow

By needle shake do you mean jumping about or vibration? My needle has always jumped around a bit at idle but holds solid at revs over 2k. I assume the jumping is accurate and the oil pressure is indeed changing that much at such low rpms.
Steve Simmons

almost a harmonic vibration - large sweeps from 60-80 psi while idling were previously the norm. It's pretty steady at 60psi at hot idle now.

when normally hot it jumps from a steady 60 to a steady 85 psi when the engine speed increases.

rn
RN Lipow

RN,

I'm assuming that the Mann W917 filter is a spin-on! I still have the old cannister on my '65 -B but plan to change over to the spin-on adaptor at the next oil change.

Cheers - Dennis
Dennis Rainey

yup, it's an inverted spin on for a 18V engine.

rn
RN Lipow

I'm sure the gauge is telling the truth , the implication is that this filter offers a different restriction to oil flow , this may or may not matter . Let us know how long the bearings last.
S Best

This thread was discussed between 25/04/2004 and 27/04/2004

MG MGB Technical index

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