High oil pressure

[Si Richards]

Evening all,

I ran the car up again last night and am starting to think I have an oil pressure issue. Initially we thought it may be down to the fact of a full rebuild but it's been run up to temperature a few times now and the oil gauge is reading max still. Yesterday I noticed there was a lot of oil coming from the top of the oil filter which hasn't happened before but it now makes me worry its more than just a new engine thing. I changed the oil pressure relief valve from a plug to a ball bearing and fitted a new spring as part of the rebuild. From what I have read online high oil pressure caused by too strong a relief spring seems to be a common issue (remedy cut down spring)

Before I get the side cutters out any comments greatly received.

Cheers
Si

[erictharg]

If it is an OE spec spring it cannot be "too strong". If it is an aftermarket spring (supplied with the ball ilo the original item) it may be, but I'd think unlikely. What is the gauge reading when hot and at what revs? Pressure relief valve should blow at 60 to 70 psi, which the engine should hold when hot at 2500rpm+ using 50 weight oil. If it is off the scale try re-installing the original plunger and spring (if you still have them). As long as the bore is not scored badly there's no reason for the original plunger not to do its job.

[Westfield 129]

In your run up, how hot did you get the oil? My car's psi on start up is pretty high, but is reduced as the engine and oil warm. Hot pressure should max at 60 psi around 3000 RPM. 60 PSI (I think that is Vizard's number), no more, no less (but I usually end up with a couple of psi more... ). You need to drive the thing to get the oil hot before checking for proper (normal running) oil pressure.

[adamwilkinson]

What is 'max' on your gauge in psi or bar?

Ours runs at ~90psi when first started, it then drops as the oil heats up to ~60-65psi and on idle ~40psi. This is only after cutting down the relief spring due to the pressure being 80+psi when hot. We didn't take a lot off, we used our prototype workbench pressure gauge to calculate how much to remove.

[jonclancy]

Have a look here, Si. And the posts that follow.

Jon

http://westfield-eleven.org/forum/viewt ... t=70#p3033

PS "Up the road I could make out a "swith, swith, swith" noise like a brake disc, but it seemed to be from the front (as I stopped to turn round)."

That'll be the oil pump being, er, reground then!

[Si Richards]

Thanks for the replies chaps, in answer to your questions I have only got the car running with wheels in the air so under no load and the max on the gauge is 100psi. I moved house (ish) today so haven't had a chance to play but I am going to remove the valve spring and ball tomorrow and check for marks etc so will let you know my findings.

Cheers
Si

[Westfield 129]

I'm sure that Mini Spares, Swiftne or MED Engineering have an externally adjustable relief valve for tHe A Series. Mini Mania has one in their catalog here in the US.

This makes adjusting the oil pressure a simple thumb screw adjustment. It might be easier than fiddling with the spring and spacers.

It will take a long time to warm the engine oil, maybe 15~20 mins to get a proper oil pressure reading. This is not the best thing to do with a fresh engine. Since there are no seals to blow, drive the thing for a while to see if the pressure drops as the oil warms to 80C or so.

[Westfield 129]

Slightly incomplete thought. What I meant was that idling a fresh engine until it gets hot to check hot oil pressure is not the best way to get a good break in.
Driving the car is always better, and gets the job done sooner.

I am a little pre occupied. Wife Pregnant, wants new sporty car with manual transmission. Driving lots of press vehicles, going to many used car lots, checking many internet ads... Exhausted...
BTW, LOVE the Ford Fiesta ST.

[Si Richards]

Its only taken a month to get into the garage but after some fettling I have replaced the relief valve with a new original spring and hey presto sensible oil pressure

Simple fix but this is a whole new world for me and I am one happy camper!!!!!

Cheers
Si

[erictharg]

If in doubt go back to stock! Glad you sorted it. A lot of aftermarket bits try to address problems that never existed in the first place on a well maintained halfway healthy engine. Carry on...