# Ford 8n oil pressure after rebuild



## bigange5 (May 3, 2015)

Hello All,
I have been a member for a little while but have been lurking..... I recently rebuilt the motor on my Ford 8n. Prior to the rebuild I had great oil pressure until the pickup tube got smashed by the crankshaft and subsequently destroyed the main bearings......During the rebuild, I checked the oil pump gears and they looked fine. I put assembly lube on all the new motor bearings. I replaced the pickup tube and gasket, and packed the pump with vasoline to assist in priming. I keep cranking with distributor unplugged and am getting NO oil pressure or flow at the filter. I put gear oil through the relief valve hole. I also tried adding oil through the gauge line, but still get no flow. I have probably cranked it on the starter for a total of 60 to 90 seconds (over many different times) and am still showing no oil pressure. I don't want to start the engine running and "hope" that it will develop oil pressure.

My question is: how much time will it take to get oil pressure and flow when spinning off of the starter alone? Am I missing something? Should I just keep cranking off of the starter motor until oil starts flowing? Any help would be greatly appreciated.
Thanks,
Andrew


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## sixbales (May 18, 2011)

Howdy bigange5,

Glad you quit lurking and finally joined us here on the tractor forum!

I cannot answer your question as to how long it will take to get it pumping, as many guys have had this problem, and results vary.

I'm not sure this paragraph applies to your 8N. Is the oil pump driven thru the distributor? If so, some guys pull the distributor and use a drill and shaft to turn the pump to get it primed. I THINK your distributor turns counterclockwise - CHECK IT. If so, you will have to run the drill in reverse. Regarding the shaft to put on the drill, I really can't help you....check with your NH dealership. 

For the older model 8N's, there's a 15/16ths nut on the front timing gear cover, just under the water pump. Remove the nut, and pull the pressure relief valve and spring. Take care not to lose the spring. Use a pump-type oil can with a long flexible snout. Shoot 10 or more squirts of oil in the hole. Make sure you get it in the hole or it will just run down into the timing gear section.

To learn more, search the internet regarding priming an 8N oil pump.


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## film495 (Nov 1, 2013)

I googled this and some people say the oil should come out of the gague line when the machine has a prime. Turning the gas off is also another thing, not just disconnecting the electric, people do to avoid some carb issue. Also, it is a mechanical pump - so it appears will not show/read pressure until the machine is actually started and turning fast enough to move the mechanical parts to generate sufficient oil pressure. If it was an electric pump and gague, it would just show a reading like a modern car as soon as the key is turned.

Use a heavy oil or gear oil in the relief valve to prime, and I believe if you crank it, possibly add some oil into the cylinders as well for lube, if it primes, some oil will flow out of the gague line, if you have it disconnected to test. Clamp it off to maintain oil in the line, and reconnect, then remove clamp.

At this point, you should have a primed system and should be able to safely start motor. If it was my machine I would try this. I would let a significant amount of oil flow out of the gague line to make sure it is really flowing.

I am not an expert on this machine, so take this for what it is worth. I am also not a mechanic. In looking up other people with the same issue, they all say starting it without having a known prime, is both scary and likely does some wear damage to the machine, so if there is a way to better check for prime, I would go that route.


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