[TR] Oil Pressure 102

[Jerry Van Vlack]

Maintaining Oil Pressure

I'll relay my experience for what it's worth.

I have a TR4A that has perhaps 90,000 miles on it. Probably more as I've 
owned it since 1969 when it had 18,000 miles. It was my only car for 2 years 
and I drove it a lot. The speedo cable and speedo have been broken numerious 
times.  The engine was rebuilt 20+ years ago but the crankshaft was not cut 
undersize as it was in good shape and had good journals with very minor 
scratches. We can debate if I should have cut the crank when I had the 
opportunity but I didn't. Standard new bearings were used.

Fast forward to a few years ago when I was retuning from an approximate 7 
hour drive and stopped at the PA / OH line to pay my Turnpike toll. I 
glanced at my oil pressure and at idle it was 5 pounds. O' my gosh or 
something more poetic went thru my mind. Revving the engine brought it up to 
35/40 pounds and I drove the last 75 miles with my eyes glued on the gauge.

Memorial Day weekend was a few weeks away so I decided to drop the pan and 
look at the bearings. I did and they were worn but not badly worn. The Crank 
still looked good, at least on the rods. The next thing I looked at was the 
oil pump and the bottom plate was very badly scored. Out it came.

I spent the next several hours with a flat glass and oil soaked emery cloth 
working the scratches out of the bottom plate of the pump. I had previously 
sent away for new oil pump internals (doubt very much that the shaft is 
pinned unfortunately but since the engine is out of the car I'll tend to 
that this winter). I replaced the rod bearings and installed the 
reconditioned oil pump with the bottom plate clearances on the tight side.

Fired it up and now I have 50 pounds at hot idle and run down the road at 
65/70 pounds. I use 20W / 50 oil. The crank is still uncut, my pressure may 
be better if I'd cut the crank.

Moral of the story is having an oil pump with the proper clearances with a 
bottom plate that is scratch free does wonders for good oil pressure.Those 
tolerances are important.

All the normal disclaimers apply.

JVV