HERCULES RXC oil pressure

[42 chevy]

All;

 

According to my manual, "Once the engine is up to operating temperature and road speed ( I am assuming 1800 to 2100 rpm,s) the oil pressure should be 25 to 30 lbs and can drop back to zero at idle." "this is acceptable as long as the oil pressure rises with engine rpm"

What I am experiencing is 40 lbs on start up (1800 rpm's) and then after warm up, zero pounds at idle, 10 pounds at 1000 rpm's and 25 to 30 lbs at 1800 to 2100 rpms. The viscosity meter sits right at "Thin and Ideal" at all times. A new viscosity meter sending unit is on the engine and all gauges have been rebuilt. There are no strange noises coming from the engine. Oil is Shell Rotella 30W.

 

I have played around with adjusting the oil pressure regulator, the plunger moved freely. The only differance in oil pressure readings is a higher reading at at higher rpm's , with no differance at idle. The manual cautions about excessive oil pressure as it could "squeeze" out oil from the main bearings. I suspect that there might be some wear in the main bearings, but I am not going to pull the oil pan and play around adjusting shims and/or pressurize the system with the pan off and see where oil leaks or drips from.

 

Can anybody chime in and tell me what their oil pressure readings are on an RXC.

 

Thanks

 

John G

[Gordon_M]

I think the manual has it, though I've never run that particular engine.

 

It is common for all engines of that generation to wear and produce zero oil pressure on hot idle. As long as the oil pressure appears when you rev it you should be fine.

[MICHAEL01]

Hi John

Just read your thread and to give you an idea, l have just re-shelled and gone through my RXC engine, readings which lm getting when cold is at 650-900rpm 45-55psi with viscosity reading just above thick line and when warmed up settled at 400-550rpm 25psi. As soon as l touch the throttle pedal it increases straight away. The TM9-811 manual read that when warmed up, at idle normal pressure should be between 5-10psi. Have you tried a different oil gauge just in case of the other one being faulty. Hope this helps?

[42 chevy]

Michael;

 

I have tried several differant gauges , all with the same results.

 

John G

[MICHAEL01]

Hi John

Worth a try hey. Just a word of advice, try every other option available in sorting this problem out before taking the sump off. I found out the hard way as the sump is held on by 3 gaskets, 2 either side running parallel with the block and then there's the back sump face one which marries up with half the flywheel casing (l had great fun with this one:embarrassed:). Naturally when we took mine off the rear flywheel gasket broke in half, in order to replace this one flywheel casing needs to come off. when taking flywheel casing of there is a big round seal which seals the end of the crank shaft. naturally again, when it come to engine test day on the cradle the seal started leaking, obviously l had upset something so out with the old and in with the new. Even now, with all brand new clean gaskets and some engine gasket sealant l still have a slight damp spot from the flywheel rear gasket. Ask you can see the sump has a row of bolts horizontal and vertically.

[42 chevy]

Michael;

I had previously removed the sump pan just to clean the pan out, and everything you said was true, I even replaced the flywheel seal, since the engine was running, I did not check bearing clearances.

 

 

John G

[MICHAEL01]

Woops! I had knock from a big end, so that's why l had to go through the engine. If worse case scenrio and u need to replace bearings, a product called plastigauge is a major help in getting bearing clearances right.(3 thou) manual states it all just a bit fiddley with shimming them up.