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JohnKeith

1927 Chevrolet Oil Pressure

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I'm the proud owner of a 1927 Chevrolet. Shipped it to the UK 2 years ago and due to time pressures we've not been able to try starting it until last week. Amazingly the battery still took a charge, the oil looked clean, and we started it.

Engine sounded healthy but we noticed very quickly there was no oil pressure on the gauge.

Also when we checked the dipstick there was no sign of the oil being disturbed as it would if being thrown around the sump.

Is there an oil pressure switch that might be stuck?

How do we get to it (sump off?)

Any other suggestions would be welcome.

Regards, John Keith, Cumbria on the Scottish/England Border, UK

Looking forward to Hershey.

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Johnkeith,

I am not sure about your 27 Chevrolet, but my 39 Chevrolet with the 216 cu in 6 cyl. engine had no oil pressure at idle it relied on dippers on the rod caps to scoope oil at idle and shop manual said oil pressure at 50 mph would be 13 psi. So I don't think these old engines had much oil pressure. my 39 was a mechanical gauge so you may want to try putting a temporay. gauge in it's place

Bill

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John, the 27 Chev's mains are flood fed from a reservoir and the big ends have a dip tray. Oil pressure is low at the best of times - 3-5psi at idle and 15-20psi at cruising. You would get splash if the dip trays were full.

The oil pump is driven off the bottom of the distributor and it feeds an oil distributor which is is external to the engine. I would take the distributor out and drive the oil pump with an electric drill. Loosen the pipe that goes to the oil filter and see if there is any flow.

Send me a PM and I will send you a diagram.

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John, the 27 Chev's mains are flood fed from a reservoir and the big ends have a dip tray. Oil pressure is low at the best of times - 3-5psi at idle and 15-20psi at cruising. You would get splash if the dip trays were full.

The oil pump is driven off the bottom of the distributor and it feeds an oil distributor which is is external to the engine. I would take the distributor out and drive the oil pump with an electric drill. Loosen the pipe that goes to the oil filter and see if there is any flow.

Send me a PM and I will send you a diagram.

Dave this advice is a real help. Can you send me the diagram to john@johnbkeith.plus.com?

Will you be at Fall Carlisle or Hershey? I'm in Chicago after these events,

Regards,

John Keith, Cumbria (on the English/Scottish Border, UK)

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The 1927 Chevrolet oil pump is a vane type pump with a small spring between the vanes. Sometimes the spring breaks and leads to loss of oil pressure. If it were mine, I would first check the oil distributor valve spring as shown here: 1927 Chevrolet Repair Manual - Capitol Cars - Series AA. If it checks out, I would remove the 18 screws and drop the oil pan for inspection of the oil pump and outlet tube shown on the previous and next pages respectively.

Best wishes,

Ron

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Thanks Ron. When we look at the engine configuration we see that it is not like your drawing. For example there is no external oil filter. We suspect this car to be a 1926 model that was registered in 1927. When we look at the 1925 manual on-line we also note it to be different again.

Is there any Chevrolet experts out there who can confirm that pre 1927 there was no external oil filter, and that this was introduced in 1927?

It looks as though draining the oil, dropping the pan, and checking out down under is the route to go, and if we still can't figure out what's wrong re-assembly and trying to get oil pressure through the the electric drill on the distributor assembly route described by one of the kind readers earlier.

The fact that the engine isn't knocking through the big ends when we start it suggests the crankshaft is scooping oil successfully.

Thanks again,

John Keith, Cumbria UK

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Hi John,

You are correct. The 26 Chevy would not have an oil filter. The 25 and earlier would have an external distributor and oil pump mounted to the rear of the generator. I would drop the pan and inspect the oil pump and copper line to the oil distribution block. You should be able to remove the bottom plate on the pump without having to remove the pump from the engine. Take care to re-install install the vanes according to the repair manual referenced earlier. Best wishes.

Ron

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