Fluctuating Oil Reading

[AlanBartlett]

Fluctuating Oil Reading

Good Evening all,

I've recently rebuilt the engine for the weasel. All in the car (Well saloon at the moment to run in) Running nicely. however the oil gauge reading never seems to settle and is constantly flickering up and down the gauge even when warm.

Could it be any of the following

Too much wear in the pump? Although I didn't have any trouble with the original engine.
The gauge? I was happy when it was used with the other engine, a constant reading
Worn Oil Pressure relief piston or poor spring? Or even sticky?
Flow from the oil filter?
Perhaps the oil pump drive itself?


Thats my list of things to check, any other thoughts?

[Jeremy]

After rebuilding the Bradford Special engine the oil pressure was as you describe. So I took a look at the relief valve. I tried increasing the pressure on the spring but this didn't really make much difference so I took the relief valve apart and noticed a lot of pitting on the plunger itself. When fully pushed home the pits allowed the oil past particularly when warm with the resulting low pressure. The pits were bad and I think it was also sticking in the brass body of the valve leading to the flicking of the gauge needle.

So I re-made the plunger to the original size, although I thought I might need to make it oversize and ream the brass housing, but this wasn't necessary in the end. The new plunger sorted the low pressure and the flicking gauge and on SAE30 grade at cold I get 60 psi and warm around 40 psi at 30-40mph and at idle nicely in the idle range on the gauge.

[Tony Fearn]

Hello, Alan, and Jeremy.
Especially Alan.
What did you do after Jeremy's post?
Has it been sorted? If so how, (for future reference).
Tony

[AlanBartlett]

Evening Tony, Jeremy and all.

In the end I replaced both the spring and the plunger. There seemed to be a bit of pitting around the top of plunger, since then It does over read at cold, but settles to around 25/30 when warm. but isn't jumping around like it was. I haven't got out to road test too far yet, I shall keep you posted.

Cheers

Alan