Thread: Head off/New Head Gasket Coming/Anything Else?

So, I got the head back from the machine shop. They put in new guides, seals and valves and I put a new head gasket on, torqued things up and fired it up. It runs really well, climbs hills in 3rd I used to have to slow down into 2nd gear and I'm quite happy with the result.

While I had the sump off, I replaced the bearing shells as I could see minor wear on a couple of them. There was certainly no ridges or pitting on the shells or the cam.

SO, now I have an oil pressure problem. I've always had an oil pressure gauge (electrical type) and it's always had pretty low oil pressure. As it ran fine, I just monitored things to make sure there weren't any fluctuations.

I just put on a Smiths dual gauge while I had the vehicle off the road and the oil pressure is dismal. I would be ok with looking for variations, but the green light is coming on as well which confirms the oil gauge(s) I've used are telling the truth.

At cold idle and running temp, the pressure is around 20 psi. However, when I run it for a few kilometres and then stop, the oil pressure drops to near 0 and the green light comes on. As long as I have the RPM's up then the light doesn't seem to come on....but the pressure is still lower than it should be.

When I had the sump off I didn't fiddle with the oil pump other than moving the screen around to facilitate putting the pistons and bearing shells on.

I'm not getting any bearing knocking, but then I'm also not driving it much at the moment.

Should I get a new pump and put it on, rebuild the existing one?

I'm not in the market for a new rebuild and can't imagine this is what's required as it doesn't have any knocking and runs great.

When I put the sump back on recently, I filled it with 6L of HPR 30 (Penrite - Penrite Oil - A Better Class Of Oil)

Any thoughts?

Cheers,
Neo

[QUOTE=neophyteguy;2050848]


G'day Neo,
Congratulations on getting the engine to run so well!

The oil you have used is suitable, so it seems that there is either excessive bearing clearance somewhere; which seems unlikely given that the engine doesn't rattle or knock; or it is something else.

My manual doesn't show the location of the oil pressure relief-valve very well, but it appears to be on the pump. It is worth checking, because if the ball or seat are damaged or dirty, the oil pressure will be lower than it should be. If you have to take the pump out to get to the valve, measure the pump and then decide if you need a new one.

Other places where oil might be leaking excessively and causing lower pressure could be the rocker gear and the camshaft bearings.

Anyway, check the relief valve first; the manual has very good instructions on how to recondition it and how to measure the pump,

Cheers Charlie