oil pressure

[phil3uh]

Hi All,

Now I suppose it's not usual for people to complain of too much oil pressure but I am.

Driving home from work last night I glanced across the gauges ,all was well apart from the oil pressure. I was alarmed to see it at 90psi!As the miles went by and the engine warmed and the oil thinned it gradually dropped to around 70psi and 50psi on tickover.I have read somewhere that there is a pressure relief valve in the filter head assy.I wondered if anyone out ther has had the same experiance and if so what did you do to remedy the problem.

Regards

phil3uh

[Don Elliott]

My TR is a 1958 TR3A, but I assume that the oil filter body on your TR4A must be similar to mine. On the side of the aluminium base for the oil filter, there is a large nut that can be loosened about one half a turn. Then you can reduce the setting for the relief valve by screwing the central threaded rod. There is a spring and a ball valve inside. The details are more clearly explained in the manuals.

 

The way it works when the engine is cold and the oil is also cold, the oil pressure relieves itself to whatever setting where it has been set. Yours has been set too high. You want it to be down to 70 psi on your gauge when it's cold. As you engine and the oil get hotter, the oil pressure will stay about 50-70 psi as you are motoring along at 3000 RPM depending on the condition of your engine. If the engine and oil are hot and you come to a stop and you are waiting there a few seconds at idle speed, the oil pressure will drop to 20-30 psi which is also OK. Sometimes is an older engine, the oil pressure may drop to 10-20 psi. That's not a problem either for an idle condition.

[Nick Webster]

Assuming that the car is not new to you and you know the oil pressure has been OK in the past then although as Don says, it could be the relief valve, it is a bit odd that it has suddenly made a jump in pressure. Could be the gauge of course. Another thing worth considering is that water might be getting into the sump. Being heavier than oil, water takes more energy to pump and gives wonderful pressure readings (but is a **** lubricant). Check that the sump level is not going up and other signs such as emulsion or steam from the oil filler cap. In which case either the figure of eight joints may be suspect, a porous liner or plain old head gasket. Hope it is the relief valve!

 

Nick

[phil3uh]

Hi Guys,

Thanks for the info.The oil pressure has been ok up to now giving 70 ish psi under load dropping to 20-30 psi when hot at tickover,so now I'm worried that it may be more than just the relief valve.I'll check the relief valve this weekend when I change the oil,first checking the filler cap and dipstick!

Thanks

Phil3uh

[Allan Westbury]

Hi Guys,

Thanks for the info.The oil pressure has been ok up to now giving 70 ish psi under load dropping to 20-30 psi when hot at tickover,so now I'm worried that it may be more than just the relief valve.I'll check the relief valve this weekend when I change the oil,first checking the filler cap and dipstick!

Thanks

Phil3uh

 

I too would be very suspicious of just adjusting the pressure relief valve if everything has been OK up to now. You need to find out what has caused the change, before you try & compensate for it.

Don't know which side of the oil filter the pressure gauge is fed, but could a partly blocked filter be the problem, or maybe some sh*t in the pipe to the gauge or in the pressure relief valve itself. Try to find the cause before coming up with a solution!

[Dick]

Hi All,

Now I suppose it's not usual for people to complain of too much oil pressure but I am.

Driving home from work last night I glanced across the gauges ,all was well apart from the oil pressure. I was alarmed to see it at 90psi!As the miles went by and the engine warmed and the oil thinned it gradually dropped to around 70psi and 50psi on tickover.I have read somewhere that there is a pressure relief valve in the filter head assy.I wondered if anyone out ther has had the same experiance and if so what did you do to remedy the problem.

Regards

phil3uh

 

May be it's just that the relief valve stuck and now has freed itself off......I'd take it out and make sure that it is clean and that the spring shows no signs of binding.

Dick.

[MikeF]

Hi All,

Now I suppose it's not usual for people to complain of too much oil pressure but I am.

Driving home from work last night I glanced across the gauges ,all was well apart from the oil pressure. I was alarmed to see it at 90psi!As the miles went by and the engine warmed and the oil thinned it gradually dropped to around 70psi and 50psi on tickover.I have read somewhere that there is a pressure relief valve in the filter head assy.I wondered if anyone out ther has had the same experiance and if so what did you do to remedy the problem.

Regards

phil3uh

Cosmic coincidence! Mine is high on my 4 too but has been since I got it, So a helpful thread and reminder. its been on my to do list for a while. I took every thing off at the oil filter, including the oil pressure gauge and pipe. The oil pressure gauge capillary pipe was full of black tar sludge and around the relief valve was not really oil, So I cleaned it all out and then 'bled' the pipe on re-assembly. Although I change the oil and filter often enough, on consideration I think this sludge probably reflects that up till I got the car it had done about 3000 miles in the previous 16 years and what with one thing and another only about 1000 in the 2 years or so I have had it. This stuff probably has been there since then and probably some since the car left Coventry. I adjusted the valve and the peak pressure is now 70 at 3,500 with the hot idle 40. I was surprised by the amount of adjustment it took to get it down though - about 5 half turns.

 

 

Mike