Low Oil Pressure

[Vince]

I have noticed lately that it seems like the oil pressure at idle on my 1961 TR3A looks awfully low - about 10psi under a hot idle. I checked it today with another gauge, it's accurate. It will be as high as 50 even hot if RPM's are high enough, more like about 40 when running down the road. I am running Valvoline Max 10W40 oil. No abnormal sounds from engine (rods, lifters). Is this normal? Should I go to 20W50 oil? My XKE's idle oil pressure went up nicely with 20W50.

This engine sat without running for over 30 years, I have put about 300 miles on it since restoring the car. I did no major work on the engine, just changed oil three times. Compression is fine.

 

[tdskip]

Hi Vince, you should be using a 20w50 conventional (non-synthetic) oil, 10 weight is too thin.

Change the oil and let us know how you get on.

 

[TR3driver]

Definitely bump up the oil viscosity.

And start saving your nickels & dimes for a set of rod bearings.

 

[Foura]

Just out of interest, what is the lists recommendation for idle oil pressure? My 4A pulls 70 psi when cold and keeps at least 60 in normal running, but drops to around 20 psi at idle. Any thoughts?

Foura

 

[TR3driver]

Kind of low, but not really enough to worry about. If it drops much lower (10 psi at hot idle), I'd start thinking about some new rod bearings.

Changing rod bearings with the engine in the car is relatively easy, and a good periodic maintenance item IMO. ISTR the Haynes recommends doing it every 30,000 miles (which is perhaps a bit often). But they are relatively cheap, and doing so may extend the life of the crankshaft journals.

I'm assuming you are already running 20W50 oil, and it doesn't show any big improvement after an oil change. Also no other symptoms of advanced wear, like blue smoke from the exhaust or bad noises.