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Joined: Mar 2006
Posts: 244
Backyard Mechanic
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OP
Backyard Mechanic
Joined: Mar 2006
Posts: 244 |
I have a 1936 Chevrolet Standard with a motor that was rebuilt many years ago. I have been using 30 weight oil. This past year the oil pressure does not indicate on the gauge for a couple of minutes after starting then it will go to about 8 psig at idle and about 12 psig while driving. When restarting, while warm, the oil pressure will pop up as expected. Should I be concerned and if so what is the solution?
I just had the same occur on my 1928 4 cylinder this afternoon.
Dave Cufr #12505
1927 Capitol coupe
1928 National 4-door
1928 Speedster
1936 Standard Town Sedan
1975 Nova Custom Hatchback
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Joined: Dec 2001
Posts: 10,379 Likes: 1
Technical Advisor ChatMaster - 10,000
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Technical Advisor ChatMaster - 10,000
Joined: Dec 2001
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I would remove the 30 weight oil the next time the engine is warmed up and replace with detergent 10W-30. 30 single weight oil is just too thick.  
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
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Joined: Aug 2006
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ChatMaster - 1,500
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ChatMaster - 1,500
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I would remove the 30 weight oil the next time the engine is warmed up and replace with detergent 10W-30. 30 single weight oil is just too thick.  Also it is possible the oil pump screen is clogged, especially if it has had non detergent oil in it since the rebuild.
Ed
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Joined: Jan 2002
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ChatMaster - 25,000
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ChatMaster - 25,000
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Posts: 30,701 Likes: 141 |
My thoughts are the pmump may be loosing its prime or there is air in the oil gauge line.
#30 will flow readily in summer weather and a plugged screen would show a pressure drop after running and the pump pumps the oil out of the inside of the screen.
I would first determine if no oil is circulating during the time the gauge is not showing pressure. Removing the valve cover and checking if the rocker arms are getting oil would be one way to do this.
The pressures mentioned are normal for a 1936 with an originak vane type pump......and I would recommend 10W-30 also but that is not your problem. There could also be a problem with the oil distributor valve, left lower center of engine.
Gene Schneider
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Joined: Mar 2006
Posts: 244
Backyard Mechanic
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OP
Backyard Mechanic
Joined: Mar 2006
Posts: 244 |
Thank you for tips on where to look, I will follow up on those. I really don't want to pull the pan to check the screen but that does seems that it could be a problem. The oil that I am using is detergent.
But I am a bit confused because earlier this year I was told by a Chevrolet knowledgeable that I should be running straight 30 weight oil in my 4 cylinder and early 6 cylinder motors in the summer months.
Dave Cufr #12505
1927 Capitol coupe
1928 National 4-door
1928 Speedster
1936 Standard Town Sedan
1975 Nova Custom Hatchback
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Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
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ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
#30 is OK but 10W-30 is better. It is the viscosity of #10 when cold for faster circulation and the viscosity of #30 when hot.
If you have been using a detergent oil I would very much doubt if the oil pump screen is plugged.
Remove the oil gauge line from the left side of the engine. Up on starting or even cranking over the engine oil should shoot out hot or cold.
Gene Schneider
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Joined: Dec 2001
Posts: 10,379 Likes: 1
Technical Advisor ChatMaster - 10,000
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Technical Advisor ChatMaster - 10,000
Joined: Dec 2001
Posts: 10,379 Likes: 1 |
Tell your "Chevrolet knowledgeable" about Chevy Chat and invite him to join so he can get up to speed.
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
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