TR2/3/3A TR3 pressure relief valve setting

[tdskip]

Hi folks - how should I be adjusting, if at all, the pressure relief valve setting on a TR3/TR4 motor.

My oil pressure is a bit low at idle and I'm wondering if this is a point of correction. The PO also put in 15w50.

Thanks

 

[SCguy]

Tom,

My TR4 engine has lowish pressure at idle (once warm)as well. At least compared to my TR6. I'm also using 15-50.

 

[tdskip]

Hi Larry - have you ever played with the valve setting Larry?

 

[martx-5]

The factory manual says 70 psi at 2000 rpm. At idle, it will be considerably less. Probably 20-30 psi.

 

[SCguy]

My TR4 is between 20 and 30 at idle when warm. No I've never adjusted the valve.

 

[TR3driver]

The pressure relief valve only opens when the pressure is above the valve's setting. Thus it only regulates the maximum pressure, when the oil pump is supplying more oil than will pass through the bearings.

Since the pump's output goes up with engine rpm, but the gaps in the bearings remain roughly the same, the PRV is normally closed at idle and it's normal for the pressure to drop.

The usual rule of thumb is that 10 psi per 1000 rpm is adequate when the engine is under load. But even that is more than strictly necessary when the engine is just idling. I've driven engines that showed no pressure at all at hot idle, and they ran a long time.

 

[tdskip]

The usual rule of thumb is that 10 psi per 1000 rpm is adequate when the engine is under load. But even that is more than strictly necessary when the engine is just idling. I've driven engines that showed no pressure at all at hot idle, and they ran a long time.

Phew....