Hi. My 1927 Chevy has a 1928 engine with very low oil pressure, no indication on pressure gauge but obviously there is some pressure as when disconnecting the pressure line and starting the engine oil comes out of the connection. There is a distributor valve where the pressure gauge connects and also the oil line from the oil fiter - there is no oil filter on the engine, instead a line between the outlet to the filter and the inlet from the filter. Question: what does the distributor valve do? Also the top of the engine is well supplied with oil. The pressure gauge is overhauled and checked with low air pressure, working.

Olle

The oil distributor resists the oil pressure from the oil pump. Some oil goes up to the oil pressure gage, other oil is directed to the 4 troughs. The oil distributor also holds prime on the oil pump when the engine is not running.

Oil pressure is not the prime requirement in the 4-cylinder engine. The engine needs volume. That is why a vane pump is used rather than a gear pump.

My 28 runs 10lbs pressure at start up and it drops to 5lbs running. Ray has answered re the role of the distributor in the sump. The external union sends oil to the gauge and filter of course. NOW you say that there is plenty of oil in the top of the engine.This has nothing to do with the oil pump because oil is put in by oil can unless it has been modified to allow oil to be pumped up. In this case there would most probably be less pressure at the gauge.

Hi. Thanks for that. So it seems not too bad to be without or just have a very low oilpressure as long as there is up to full of oil on the oil stick.
Just ran the car today for a 100 km local rally, what fun!

Olle

Fill your sump approx 1/4" above the top line on the dip stick, it is far better to have a little more than a little less. I've been doing this on my Chev 4's for 30 years
Chris

Hi,
Just a thought.
With the original oil filter,it would have allowed the oil through slowley and I think from memory,there was a brass restrictor nipple on front of the filter.If your oil filter has been bypassed,the oil will be dumping out quickly via the oil filter pipes.Try restricting them.This may bring up the pressure a bit.

I just put a filter on mine. It had 12 lbs cold before the filter and now has 15lbs cold. I think the service book says 15 lbs cold is what they were supposed to carry. or maybe it was in the online 28 specs book.

Mine is about the same, 15 - 18 cold, 5 - 8 warm

Regards

Ray

Whilst on this subject on my Chev 4's I've had over the years, I don't use the oil filter as I have seen at least 3 occasions where the brass inlet line that goes between No.2 and No.3 cylinder has broken due to the copper hardening because of the heat between the cylinders. One of these occasions the engine ran the bearings. The driver didn't realise it was broken as the gauge still showed oil pressure because the oil goes to the gauge before going to the oil filter and had pumped all the oil out.
Chris