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New rebuild J5. No oil pressure

I

IMP

Member
Completly restored my J5. First time started it today and had to shut it right down because of no oil pressure? Did several 5 second starts. Removed electric pressure gauge and tried straight mechanical. No pressure. I heavily gooped all moving parts generously with assembly lube so i hope im ok yet but i need to find the problem before my next start and im not sure what my next move should be. Ideas anyone?
A machine shop bored out the Chrysler flathead engine and me and another guy installed all new engine internal parts including a new oil pump. Oil in my filter reservoir only dropped about an inch after all this and looks clear? I replaced my oil lines and all match my pre-restore photo? It seems to start and run good but this is the last problem I expected. I also submerged the new pump under oil and spun the shaft until all the bubbles quit coming out? The oil seemed to drain right back out of it during installation?
 

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I think I know what to try next.... Totally clean out a grease gun. Take the cap end off and turn it upside down screw the flex hose end into the T-fitting at the sender port, fill it with motor oil. Then pump up the system, leave the gauge in place. Remove the oil filter cover and oil should flow. If it does, its a bad pump. If pressure builds and no flow, it's a blockage. What do you think?
 
Sounds like a good plan to me.

Hope it works ! Let us know :flowers:

The engine looks beautiful.
 
you should never start a motor without fist primming the oil system to do this take the dist out and turn oil pump with a drill .what i have done in the past is go to the hardware store by a drill extension for a hole saw take oil pump drive out of dist put it in the drill extension put in oil pump turn with drill untill you get preasure
 
You can't do that with this motor. The oil pump is drive. Off the cam. The distributor is driven off the end of the pump with a key slot. So the cam has to spin for the pump to pump
 
an alternitive is to fill the oil pump cavity with lubraplate ,than pull the spark pluggs crank the motor till you show oil pressure. than reinstall the pluggs and re start the motor. also my suggestion would to use a test mechanical gauge to check your oil pressure
 
The ports in the pump go right into the block so i would be reluctant to pump grease directly into all the ports. And we did take the guage and pushed air into the back of the mechanical gauge and saw the gauge needle move freely up to 90 from 0 several times. Kind of a crude test but the gauge isn't stuck. Anyone know of a plug in the oil circuit, on the block anywhere that could be open? Or anyone have a diagram of the oil circuit path?
 
i take the oil pump cover off and pack lubraplate in to the gears to prime them it works well as for restriction it's been a while since i looked at a flat head dodge block. possability #1 main berings are up side down some manufatctors only drill the upper bering with an oil supply hole restriction 2 could be at the cam berings i have seen berings spin and cut off pressure to the the top end of the engine if cam berings were installed wong this could also be your problem a leaking pick up tube could also keep you from sucking oil check it for pin holes or a bad seal good luck.
 
I like the vacuume pump idea but I'm not sure what that would tell me. A mechanic at work told me today my grease pump idea sucked. I could never move enough oil to do what I want. Tonight ill check the easy stuff like the oil pressure relief valve. Maybe I'll take apart my old oil pump for a look then pull the end cap off the new pump to feel if the factory forgot to install the rotor or something like that. It's going to be tough to reach with the engine installed. I'm sure glad I've told myself over and over that track rig restoration is fun because now tough times don't seem as bad
 
Don, thanks for thinking about my J5 problem but we were very careful about the bearing installation and understood about the oil path in the journals. The oil pick up tube was solid. I screwed it in and out several times since I had oil pan problems too. I used thread sealant on the threads and got it screwed in fairly snug then center punch "peened" the edge of the block 3 places near the threads to make it firm. It's good. I don't like the grease idea yet. The pump should not need to be primed according to the machine shop and will not air lock. He flat out said the problem is not your pump. But I don't rule it out yet. I Still appreciate all the ideas anyone has. Thank You
 
It’s very important to prime the oil pump prior to installation. Before you start the engine, remove the oil pump and completely submerge oil pump in clean oil. Turn the shaft by hand until there are no more
air bubbles. Reinstall the pump with a new gasket. Fill the engine with fresh oil. Disconnect the coil wire and crank the engine until you have pressure on the gauge. Reinstall the coil wire and start the engine.
 
SOLVED! I just came in from my shop and read the latest messages... Thank You. You guys were right on. I found this:
http://www.imperialclub.com/Repair/Lit/Master/015/Page01.htm
On line and now I understand everything I need to know about Flathead oil pressure. I knew the problem was the pump after reading this excellent booklet
. So after removing 3 of 4 motor mount bolts and piviting the motor over an inch I was able get the pump out of the block for look. It looked dry. We pored oil in the rotor housing and reinstalled the pump and then cranked the engine over with the starter and got good pressure !!
I submerged that pump and spun it under oil just before I installed it. But I had it on the engine stand then and it sat for weeks and I may have even rotated the engine a time or two?? But that was it. Lost its prime. That simple. Thanks everyone for the help. Expect a thread from my Alaska J5 restoration in the near future as I will soon be in the engine break in phase and will run out of excuses to not post my photos. Well Good night all.... I will be dreaming about making new J5 trails tonight
 
the loss of prim on the pumps is why most builders will pack the pump wiyh lubraplate to ensure the pump is primed and ready for use.
 
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