TR2/3/3A Oil pressure running high - TR3

[newmexTR3]

Hey guys,

For some reason last week I noticed that my oil pressure was running high. Instead of 20-30 at idle, I'm at about 50 and the pushing 75 at speed.

Gauge internals are new and I had adjusted the oil pressure relief valve a few months back so that it was at the correct setting.

Only things that have changed recently are rack & pinion steering installation and new timing cover gasket, neither of which should have any effect on this.

Ideas of what it could be? I run a 10-40 Castrol in it, with the spin on adapter.

Thanks!
Gavin

 

[newmexTR3]

Anyone have any ideas? Bueller? Bueller?

 

[Moseso]

The reason no one is answering is that they just think you're bragging. "Oh, help me! The oil pressure in my TR3 is getting too high!" Not the usual problem.

Are these fully warmed up figures?
Is this a reasonably fresh engine?
What was your "at speed" figure before?

Cold, mine (fresh engine: only 2500 miles) idles at 50. Hot, it may drop to 30.
At speed, the max pressure actually climbs a bit in mine. 70 cold. When it gets hot, it goes 75-80. All with 20/50 Valvoline Racing. In a fresh engine, I don't think the at-speed reading should drop below max, even when hot. That only happens (the more common complaint) as your bearings and/or oil pump start to near the limits of wear.

Surely, the recent things you did have no bearing on oil pressure.

The only WAG I can come up with would involve the spin-on oil filter. Don't some of these have some kind of pressure operated bypass in 'em? I don't really understand the function of these, but if it malfunctioned, could it lead to higher oil pressure?

 

[trfourtune]

I'd check the guage.
If your oil passages were plugged, off of the main oil gallery, you could get higher pressure, but this is unlikely (but possible).
Spin on oil filters have an oil by-pass in them that operates around 25 psi, it varies with different filters. That means that most of the time your oil is not being filtered. That is why race cars use different filters/screens that filter 100% of the time, no by-pass. You can't just use a racing filter though. Race cars change filters after every race or more(practices).
Rob

 

[trfourtune]

OOPS! sorry all,
didn't mean to scare you. Let me clarify, it's the differential oil pressure across the filter that causes it to by-pass. Many filters have a by-pass as low as 8 psi. So if the filter causes a 8 psi pressure drop or more due to flow restriction then the filter starts to by-pass. This happens at higher rpms all the time. That is why it is very important to change your filter. If you run synthetic with long change intervals, you still change the filter frequently. Heavier oils tend to open the by-pass sooner.
Rob

 

[TR3driver]

Taken by itself, I see nothing wrong with those pressures. So the concern is why did it go up. Is there any chance you changed oil at the same time? Back when I ran Castrol, I did have trouble with it losing viscosity (getting thinner) over time.

Note that the original filter head also has a bypass as Rob described. This bypass remains functional even with a spin-on adapter installed. I don't know what pressure it is supposed to open at; but even without the bypass, a clogged filter can cause the gauge reading to go up. Wouldn't hurt to change the filter & oil, see what happens.

 

[newmexTR3]

Good ideas guys, thank you.