8BA really high oil pressure

[37coop]

Well guys,the pump is out and i have taken apart the pressure valve on both old and new ,surprised how simple the valve system is and came apart easily...sadly the new pump didnt have loads of rubbish in it and the spring pressure felt the same by hand,i was hoping somrething wrong would shout at me but it looks o.k . could something else cause the problem ?,i,m quite happy to swop the guts of the valve with the old one or even buy a new pump but dont want to put it all back together ,fire it up and got to come out again with the same problem ,scratching my head at the moment ,cheers Jim.

 

[37coop]

Yup ,i think I,v got it ........on close inspection the old pump has got a channel /hole behind the plunger in the pressure relief part that goes into the part the gauze filter is ,the new one hasn't a channel just the walls ,it still has the spring etc but nowhere for any overflow to go (high pressure pump or a manufacturing fault or neither ?), on the old pump I assume excess pressure the spring opens and excess oil goes up the channel and into the oil pan ,hope this is the answer as its taken over my thinking ,I wanna get back working on the 39 . thanks Jim.

 

[Ross F-1]

Can you drill a relief channel on the new pump? Or are you going to put in the old pump? At any rate it sounds like you've got it figured out!

 

[G.M.]

JWL you got my attention; maybe a pic of this fixture (I don't care about the valving)
I know about that. So I'm thinking machining this fixture from Alum. Do I need
"0" rings or not? This is a perfect shop tool we can really use.. My mind has a picture
of this, but I would like to see what you have...

thanks Sam

Hi Sam, here's a couple pictures of the first oil pump test unit we made in a hurry. The diameter of the pump at the pump end is larger then the diameter at the drive gear end. I machined the two ID's a few thousands smaller then the OD's of the pump so I had to tap it on as a snug fit. The out put for the flow and gauge can be anywhere between the ends, in the center is good. I didn't put a valve on this one just a pressure gauge. I bent the soft plastic hose to create the restriction as the oil is returned to the pan of oil. The first pump we tested pumped a full flow of oil with the pump pick/up submerged in oil with just 2 or 3 turns of the gear by HAND. This was for Skips 34 P/U, he said that looks like a good pump, I said we have the tester lets check it anyway. Took the drive gear off and put our 1/2" drill on the shaft. The drill rotating CW like drilling a hole is the correct rotation for the pump. Started the drill with the pump P/U in oil and it threw a big gusher of oil out the hose but as soon as we bent the hose slightly the gauge dropped to zero. Put another used pump on the tester and there was a full gusher and as we bent the hose the pressure went up near or over 100 lbs, this was a few years ago and I don't remember the exact pressure. I believe we looked at the bad pump some later and found excessive clearance between the bottom plate and the bottom of the gears, warn teeth would also cause low pressure. I used schedule 80 pipe for the second tester, it has a thicker wall you can also bore the center out of a coupler and glue it over the main pipe to make it thicker to thread for the gauge and output. We had a Lincoln V/12 that lost oil pressure over time as it heated up. We tried every thing and finally put the pump on the test unit. This was a pump with the bypass valve. We ran it a while and the pressure looked good but it started slowly dropping pressure from 45 and it took a while but got down to 6 or 8 lbs. Took the valve apart and tried several spacers on the spring and wound up with a piece of 1/8" pipe about 3/16" thick like a thick washer. We set it at about 55 lbs by the thickness of the spacer. The owner, a friend of mine drove it on long tours for a number of years and never had any more pressure problems. This was a fellow named Jack Armstrong from up in the N.E. part of the country. On a V/12 with hydraulic lifters when the oil pressure gets down to 12 or 15 the valves start clicking and the lower the pressure the louder they get. At 5 or 8 lbs they really talk to you. Like I keep saying the pumps are so easy to test and so important and hard to find the problem and fix I wouldn't install any pump new or used in an engine without testing it first. How many pumps do you think are replaced and didn't need to be. I would say 80 % or more. G.M.

 

[37coop]

Can you drill a relief channel on the new pump? Or are you going to put in the old pump? At any rate it sounds like you've got it figured out!

I thought about drilling but the angle is wrong ,the old one has got the bolt lug broken when being removed so I guess I will phone around and hopefully get a new one over here ,failing that its shipping from the good old U.SofA and pay the robbing Bs over here loads of tax on arrival .thanks for all the advice and fingers crossed its onwards and upwards , cheers Jim.

 

[37coop]

Just a last comment on this ,i went on to C&G catalogue on line to look at replacement oil pumps ,according to them the pump for my 51 truck is high volume ($289) the pump for trucks up to 47 is 80LB and $189,my original oil gauge in the dash goes up to 80LB, i guess i have the high volume pump that is causing the problem but the pump is correct judging by C&G ,cant work that one out ........the oil pressure wrecked the new mechanical gauge so i dunno , cheers Jim.

 

[Ross F-1]

That's not exactly correct. When Ford added oil squirt holes to the connecting rods in '50, they increased the capacity of the oil pump accordingly. But it's not the "high volume" Melling kind of pump meant for racers with sloppy clearances. I would just shop for a Melling M19 pump.

 

[rooboy]

To avoid any confusion about my post saying the relief valve could have been "stuck open"...
I was refering to the first 300 mls mentioned after startup, where it may have seemed to be working correctly ..or was being held open by some other fault, which also gave the impression it was working okay...The engine being a rebuild may have had particles in the oil system, that after some use, came loose and lodged in the valve area causing it to stick open.....Pressure from the latter startup may have removed the particles or any other related problems, allowing the valve to close,which then exposed the current problem.....
Before removing the sump, try isolating the oil filter from the engine totaly to see if it makes a change ......
Those old can type oil filters were not much better than nothing........Good luck

 

[Ol' Ron]

I made one of these pump testers, and was amazed at the amount of oil came out of the pump shaft bearings. Not a good design, but at least it lubricates the rear cam bearing.