I bought a 48 59ab off of CL. It was supposed to run yada yada. I pulled pan and cleaned the sludge. Spun oil pump by hand and it moved oil. Replace pan and started engine it runs and sounds good. No noises. BUT..... it has very little oil pressure. Won’t register on a wet gauge. Pulled line off and it pushes oil out about an 1 inch stream but does not spurt. Any help or suggestions?0
Oil pump pressure relief valve stuck open, weak spring ? Clogged oil passage, worn pump, after that it's not a quick cure. Sent from my moto e5 play using The H.A.M.B. mobile app
I once had an old chevy van with a worn out 283 that had no reading at idle, and might show 10 lbs at 2500. drove it for a looooong time. motor was so worn it had JC Whitney " plug anti foul " extenders. Looked kinda like a pipe nipple to keep the electrodes kinda out of the oil blast. Anyhoo.... if no weird sounds occur, drive it !
does it have an oil filter on it? the kind they use on flathead fords have to have a small orifice on the inlet so the filter doesn't bleed off all the oil pressure. there is a brass fitting that should have maybe an .060 size opening where the pressure hose screws to the filter housing. If someone put a standard fitting there it will have no pressure
My 394 Olds had .5 psi of oil pressure at warm idle. I put 3 quarts of Valvoline VR1 sae50 in with 2 quarts of lucas oil. Which bumped my pressure to 7 psi. Then I drove the car 5000 miles, including to Canada and back from NJ. The oil was like maple syrup, and was so thick it would collapse lifters on the highway. But it ran, and never quit on me. Sent from my iPhone using H.A.M.B.
follow Moriarity's post if you have a filter, that would be an easy place to start checking. flatheads dont need a lot of pressure, to survive, but they need more than you got. i would look at the oil pump next. pull the bottom cover off, and check to make sure the gears have not scored the side of the housing. if so, pump is shot. if the housing is ok, you can install the cover upside down if there is wear marks there, and while in there put new bushings on the shaft. many folks believe the original pump is better than the new junk if its not worn out. also, there is a long pump, early, and a short pump, post war, and the short pumps make more volume and pressure. they interchange with some mods to the pan baffle. next, there is a relief valve in the front left side of the valve chamber (under the intake man) check to see that the spring is not broken or stuck
You could consider replacing or rebuilding the pump. It could need nothing more that opening the bypass and replacing the spring. The pickup could also be clogged but I imagine that you have already cleaned that. next I would look at ha crank and clearances. if its loose fix it. If I just needed to get home I would dump some Casite Motor Honey in it. I have limped many an old car or bike home that way.
When I tore my Flathead down,,,( 49 Merc ),,,,,it looked great inside,,,,not a ton of sludge,,,but some . I bought it from Minnesota,,,,,,and never saw it run . I would guess the pressure was low on it after I disassembled it looking at the bearings . The bearings looked o.k.,,,,standard size,,,,,,I think the date on the bearings were around 1962,,,if I remember right ? The crank journals looked awesome,,,,I was planning on just a polish until I mic’ d them good . They measured over 3 thousandths wear,,,,,I couldn’t believe it,,,they looked perfect ! That much clearance on the mains and rods would have to bleed off a lot of pressure . I plan on grinding it .010-.010,,,,,and it should be good . That being said,,,too much clearance can easily bleed 15 pounds of pressure ,,,,,and bearings can be replaced without a complete rebuild. Tommy
Thanks for answers. I’m useing non detergent 40 wt oil. Will try the pressure relief valve clean out. It might be a while with work getting in the way but I will let you guys know what happen. Again thanks a lot
UPDATE. IFound a little time to tinker and the pressure relief valve seemed ok. Put intake back on and same low oil pressure. My son read where some people remove the oil clean out plug to the passage they run near the lifters and forget to reinstall it. The plug is in the block behind the time it gear. He tore into that an sure enough it was missing. Gaskets ordered. Does anyone know if we can order that plug or just have to find one? I will keep you updated on the out come
Recently there was a similar thread about a new engine.....Oh wait a minute, that was on a group page..... 1.Oil filter fitting as mentioned. 2. There is a gallery plug behind cam gear that often is forgot about. Without it, it will have little to no oil pressure. That was the culprit on that new/rebuilt engine
yeah, it comes up occasionally. i cant remember if its pipe, or straight thread. thats why i suggest calling mac
UPDATE The son was able to put the plug in and put the motor Back together. He fired it and had 60 lbs of oil pressure. He didn’t keep it running for more than a few seconds. But I think we found the issue. Thank you all for the help. Kris
The Jalopy Journal
