Topic: no oil pressure at idle


james whitten    -- 05-29-2013 @ 4:40 PM
  can you put a 80 lb. oil pump in a 21 stud (1936) engine? are there any changes that have to be made? I need oil pressure at idle, I have none.This engine was completely rebuilt. The 50lb. pump gives me 24lb. at a fast acceleration. Jim w


supereal    -- 05-29-2013 @ 6:21 PM
  How are you measuring oil,pressure? The dash gauge is usually not very accurate. If you are certain, check the relief valve and spring in the front of the valve chamber to see if is present and correctly tensioned. The 50 pound pump is adequate. Installing an 80 will not fix it until you determine what the problem is.


kubes40    -- 05-29-2013 @ 6:35 PM
  One other thing... if the 50# pump has the relief valve built in, then the relief valve in the valve chamber must be loaded. If not, that valve will continue to open long before the pump can make 50#.
I have seen this over looked numerous times.


Old Henry    -- 05-29-2013 @ 9:13 PM
  Here's a way to get a more accurate reading of your oil pressure than what the stock dashboard gauge shows: http://www.fordbarn.com/forum/showthread.php?t=68156

Old Henry
(The older I get, the better old looks.)


james whitten    -- 05-30-2013 @ 10:20 AM
  Thanks for your suggestions. Ihave checked the pressure with a gauge scr*w*d to the block. Did the 1936 pumps have a relief valve build in it?





joe b    -- 05-30-2013 @ 2:22 PM
  James you said you checked the pressure with a gauge. Just curious. What did it read?


TomO    -- 06-01-2013 @ 7:34 AM
  The 36 long body oil pump did not have a pressure relief valve. The relief for excessive pressure was handled by the pressure relief valve under the intake manifold.

If all of the engine clearances are correct, you could have a worn out oil pump or a problem with the pressure relief valve seating. The 80# pump will correct the first problem but not the second.

What weight oil are you using? It will make a great difference in the oil pressure. Most of us use 20W-50 oil, due to the large clearances.

Tom


jim w    -- 06-10-2013 @ 1:51 PM
  To Joe B and Tom O, The oil pressure with a gauge in the biock was o @ idle and on a fast run up sitting still 22 lb. I am using 30 w oil. Thanks for your reply.


kubes40    -- 06-10-2013 @ 3:25 PM
  I'd like to know with 100% certainty what oil pump was put in there. The stock pump? A later 50# design?

If you don't know, I might suggest placing a stronger spring (or shim the existing spring) within the pressure relief valve.

As a side note: If there is a clearance issue in the bearings (first choice: cam)installing an 80# will only hasten the failure of the culprit bearings.


supereal    -- 06-10-2013 @ 3:31 PM
  Be sure the pickup tube is secure in the body of the pump. On the later style pump, we braze the connection, as they can come loose and admit air into the pump, causing,low or no pressure. are you using a stock mechanical fuel pump? We have seen installations of an electric pump where the push rod was removed, This allows oil pressure to drop or disappear because the rod keeps oil from escaping up thru the bushing.

This message was edited by supereal on 6-11-13 @ 2:07 PM


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