Reproduction Parts for 1916-1964 Chevrolet Passenger Cars & 1918-1987 Chevrolet & GMC Trucks



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#449654 10/30/20 08:46 PM
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Shade Tree Mechanic
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Shade Tree Mechanic
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Hi,
My 46 pickup had its engine restored by the previous owner and the mechanic who did the work has since passed. I'm not sure what the oil pressure should be and I couldn't find a specific reference in the manual. It seems low to me but I'm not that familiar with the 216. The gauge is only marked 0, 15, and 30. I am running 10W-30 oil and when I made my observation, the outside temp was about 72F. When cold, at idle it reads about 15. When fully warmed up, at idle it is close to zero and when I rev it up, I get a needle's width under 15 maximum. I connected an external gauge to the same location and confirmed the readings. If anything, the external gauge reads lower than the gauge on the cluster. There is an external oil filter plumbed in with hoses. I tried pinching off the hose but it did not affect the oil pressure readings. I would like to know if this pressure is too low and if so, what I should look for to fix it.

Thanks!

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Russell #38868
'48 4 door Fleetline
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Hello coachman28
Is this a long standing condition, or a recent development?


Ole S Olson
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The oil pressure should be about 13-14 pounds at 40 MPH and 5-7 pounds at idle speed. The only part that gets that full pressure is the main bearings. Every thing else gets low pressure.


Gene Schneider
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Shade Tree Mechanic
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Originally Posted by Chev Nut
The oil pressure should be about 13-14 pounds at 40 MPH and 5-7 pounds at idle speed. The only part that gets that full pressure is the main bearings. Every thing else gets low pressure.

With warm oil, 14 at speed is consistent with my observations. 5-7 at idle may be a stretch for my 216. Should I consider dropping the sump and replacing the oil pump?

Thanks for all the replies.

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The 1937-1939 mdels had a lower oil pressure. Larger pump with more volume and pressure new for 1940.
My 1939 had like 4 pounds at hot idle and 13 pounds at 50 MPH.


Gene Schneider
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Gene would know better than I, but in my experience Chev six oil pumps don't usually wear out or give trouble.
In fact, I just had the pan off my '46, so I had the pump apart while I was in there.
The factory machining marks were still there with almost no wear evident. Even on the end cover.
The only pump issue might be the possibility of a little something stuck in the bypass in the pump end cover that is allowing a little of the flow to bleed off.
OR... someone put a gasket under the oil pump end cover that is TOO THICK. I think the proper gasket is .012" thick. Be careful not to put in a gasket that is too thin.

Another possible cause of low pressure at low revs would be main bearing clearances being a little wide. Do you hear any bearing noise when you accelerate hard?

One other possibility, although unlikely, is a problem with the metering valve under the small cover on the left side of the block.
NEVER fool with the spring on the valve to try to increase pressure. If you think there is a problem with the valve, replace it. The valve is still available, even in NOS. If you want NOS and can't find one, I have several.

In the mean time... set your idle speed up a bit and don't let the engine run too slow. A slow slow idle is a little hard on an engine at the best of times.

Happy motoring!


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I agree with all of the above. And yes, 99% and 9 tenths of the pumps lasted longer than the engines.


Gene Schneider
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Coachman,

I, too, agree with the other whats been said.

If the mains are getting pressure fed and the valve train is getting gravity fed, with oil everywhere under the valve cover, then there is nothing much to worry about, Your pressure readings are in the normal rangel for a 216. I wouldn't start tearing into it just because the pressure seems a pound or two low, Just drive it.

I wouldn't mess with it until you decide that another overhaul or rebuild (of the engine ) is otherwise warranted.

Best,

Charlie computer



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Shade Tree Mechanic
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Thanks for all the good advice. I am inclined to continue driving it as is.

Regards.


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