I’ve noticed on my 32 that when I drive it for 30 minutes or so and then stop for a few minutes when I start the engine again after stopping for a short time the oil pressure stays at 0. What is causing the pressure to not go up after the car is warm, bad pump? When cold starting there is no problem with pressure. Pressure reads 5-7 idle after warm and 10ish while driving after warm. When cool it will kick up to 15 or so. It’s only after running and then stopping and restarting do I see an issue. I attached a pic of recent oil level, pressure and the pump. Thanks for any help or suggestions.
None of the early engines need much flow or pressure as they don't have highly loaded bearings or bushings or need oil to help cool the engine.
The 4 cylinder engines have a solid part of the rod cap that passes through the trough to produce an oil mist that lubricates cylinder walls, wrist pins, rings and rod bearings, etc. The oil flow just fills the troughs and reservoirs that gravity feed oil to the main bearings. The valve train is lubricated manually by oil can.
In the early 6s rod dippers produce a little flow to the rod bearings but more important is the mist to lube pistons, rings etc. A little pressure is needed to lube the valve train.
99.44 % of the advise you get on oil pressure is from people with experience with more modern higher horsepower engines. Producing higher oil flow and pressure takes horsepower from engines that don't have excessive amounts.
the 1929 needs very little pressre as no parts get full pressre so all it needs is volumn. The 1932 gets full pressure to main bearings only. The gear type pump produces a more steady flow according to Chevrolet.
the one at TFS is the NEW Billy Possum (C&P Automotive Oil Pump) It is a NEW pump built for these cars, great flow and more pressure (think around 10psi @ idle then 25 psi @ cruising speed), even though it is NOT needed.
everyone says they are great pumps
i rebuilt the original single vane oil pump in my 1929 which is a 1 year application. I get around 5 psi cruising and tons of flow, which is what the older inline 6 needs @!! pressure is irrelevant flow is critical.
If it were mine I would replace te oil pump. The knocking is the main bearings not bearing filled with oil. I would try to find a genuine Chevrolet cast iron gear type pump for a 1930-1932 engine.
The replacement oil pump you have has a body made of aluminum or pot metal. I hve seen them craze and crack. Possible but a thought,
An easy test would be warm up the oii and remove the dash gauge oil line from the back of the gauge and see if oil is pumping out, (catch the oil in a container)
When you say you felt for number 1 TDC, do you mean you felt for compression with your thumb over the hole?
The valves on number 1 may APPEAR to be closed at TDC even on the wrong revolution as the exhaust will be NEARLY completely closed, and intake JUST starting to open. The best is to have the valve cover off and watch for valve movement. As you come up on number 1 TDC, the exhaust valve on number 6 will be closing and neither valve on number 1 wil be moving at all.
All that said, a fast and easy "try" is to just pull your wires out of the distributor cap and reinstall with number 1 wire where number 6 is now and working around from there. If you mistakenly timed to the wrong TDC (180 degrees out) that will correct it and the engine will start.
are you using a 6v timing light ? and solid source of power, as well as have the pick up close to the spark plug and facing the correct direction. I know the one i have is 6v and if it the pick up gets close to another plug wire it will pick that one up as well and make the light/mark JUMP around.
I pull plug wire for plug 1 out of hte loops, and ten put my pickup a few inches form plug 1, then use some string or zip ties to hold the pick and wire out and away from the rest of the wires. i pull the wire up and over the radiator support bars and tie them near the radiator. keep them from moving. I have also at times used my 12v mower battery for power on the timing light for a clear sharp light. and can run a ground from car frame to mower battery if needed.
