oil pump queery

[TOPTON]

On the way back on sunday when nearly home, I gave it some heavy right foot to get past 3 cars and 2 wagons. 3rd gear and loads of umph and I noticed the oil pressure had gone up to 80-90lb pressure. Not good so decided to look at the relief valve as the problem.

What is this part sticking out of the side of the oil pump because I'm almost sure the relief valve is just behind the pump housing



Picture isn't perfect but it is a bolt with a lock nut on it

[keatsie]

That looks like an adjustable oil pressure relief modification?

[wild rover]

I had a similar problem on the way to the fest. When the ignition is switched on before turning the engine does the gauge show higher than zero. When the wire is disconnected the gauge rises off the gauge.

[TOPTON]

When ignition is switched on, the needle moves just above the zero white mark on the dial. Disconnect the wire and it doesn't move at all when ignition is switched on.

When running it earlier, it was ticking over as usual at around 30-35, giving it some revs 2.5-3k it rose to 55-60psi and came back down as the revs dropped off.

[Number 7]

It's quite a bit different to this one:


But yes, it's an adjuster for the pressure on the relief valve spring, and therefore the oil pressure. Has an extension been welded to the original boss, because it does look to be a long arrangement? As for the pressure, how sure are you that the gauge is accurate? Idle pressure of 30-35 (hot I assume) is very high - would normally be maybe 15-20. And the revved up pressure is also very high - I would expect to see around 40 hot for these engines in reasonable nick.

[TOPTON]

It has had an extension welded on, not by me though. On my photo you can see the brazing marks about an inch from the pump body.

The oil pressure has always been the same since I got the car, rather higher than what everyone says it should be for a low pressure/high volume engine but it has never gone up as high as it did on sunday. Maybe its time for a new oil pump if this one has been butchered.

Maybe the same person who bodged my suspension did this mod also.

[Number 7]

Could you not borrow / buy a separate gauge to just hook into the system and verify what your own gauge is reading? It is a rather elaborate mod I have to say. The trouble is with those sort of hot pressures, cold pressures will be higher, and you risk unduly loading up the drive gear and pumping up the lifters.

[adam quantrill]

Part of the problem might be that if the plunger is occasionally sticking in the long tube (hopefully machined smooth inside but who knows?) then it could get stuck so as to give no relief. You'll then get a very high reading.

I would change the oil pump cover to a standard one.

[TVRleigh_BBWR]

You can get manual gauges that will fit and are quite cheap, should be the most cost effective solution.

[Number 7]

adam quantrill said:

I would change the oil pump cover to a standard one.

Agree - but can you still get them? I think the gears are still available, so worth changing them anyway.

[TVRleigh_BBWR]

Number 7 said:

Agree - but can you still get them? I think the gears are still available, so worth changing them anyway.

RPI do a re-con one but they are very expensive about £150.00, and they won't last as long as they are not anodised.

[TOPTON]

I have taken out the long bolt and spring. The piston at the pump end will not come right out as its catching on something in the stupidly modified extension. But it is moving freely in and out about 15mm when poked with a screwdriver.
I put the bolt and spring back in but put less pressure on it this time, on start up it went to +25ish psi on the gauge. Gonna let it warm up and try a run out.

[Number 7]

TOPTON said:

I have taken out the long bolt and spring. The piston at the pump end will not come right out as its catching on something in the stupidly modified extension. But it is moving freely in and out about 15mm when poked with a screwdriver.
I put the bolt and spring back in but put less pressure on it this time, on start up it went to +25ish psi on the gauge. Gonna let it warm up and try a run out.

25 is better for a cold idle. What sort of clown bodged that in the first place though, if you can't even get the valve out without taking the cover off?

[TOPTON]

Number 7 said:

25 is better for a cold idle. What sort of clown bodged that in the first place though, if you can't even get the valve out without taking the cover off?

The same person I guess, that bodged the front coilover setup. The coilovers were bolted underneath the lower arms using 2 10mm bolts. Started rattling loose not long after I bought it

Been out to give it some umpty. Only on the far side of 4.5k revs does the gauge read more than 50psi. 3k revs in 5th gear so it sitting at around 45. Assuming the gauge is correct of course.
I think I may buy a capillary guage and fit that in its place, keeping the original fittings in place in case I revert back