Hi All;
New to this forum. Have checked on the tractor forums. No one seems to know. My 1940 Ford 9nTractor has what I'm told is a "1/2 a Flat Head V8" 4cyl. My questions are when putting the engine back together do we bother with the rod nut cotter keys? Or just torque them and call it good like todays engines? Also, I don't know if the V8 is the same, but the oil pump is integral to the front main cap. I would like to use a new oil pump, not just a kit. I am not overhauling this engine, just rod shells and oil pump. It seems the I must align hone the engine to replace the front main cap. The is no caution from the supplier on this point. Has anyone installed a new oil pump/main cap assy on an existing engine?
Thanks, Frank.

 

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I can offer advice to only one of your questions, if the rod nuts originally came with cotter pins (keys?), definitely replace them with new ones. Don't take a chance without them and don't reuse the old ones. ...Terry

 

Anytime you replace a main bearing cap on any engine it needs to be line bored. Oil pump
housings generally do not wear unless the driven gear is out of alignmemt or very loose.
or sand is injested into the engine. It is the best lubricated part of an engine.

 

Thanks for the replies fella's. The oil pump housing seem real good. I guess I'll put a kit in it. Does anyone know if there's any special tool needed to r & r the driven gear assy?

 

I have a 9N from 1941 and have put a oil pump rebuild kit in the front main with no problems. Biggest problem was tearing the front end off to remove the oil pan.

 

Sounds good, Thanks 51

 

Frank, Don't know where you looked for Ford tractors sites but there are two extremely good ones out there with folks who know; old Ford mechanics who delight in straightening folks out. I, myself play with them and feel I know my way around them pretty well.

To set a common myth straight, the N engine is not one half of a flathead V8. Yes, I know there are a couple picture books written by so called experts that indicate it is. It is what I would expect an engineering group who designed one engine to come up with when they designed the other. If something works why change it. Dimensions are different but many parts appear to be similar. VERY FEW THINGS ARE THE SAME.
I use safety wire on the mains and like to put pal nuts on the rods. As mentioned, if you use another front main cap, oil pump, have it line bored. The N engine should be governed to 2200 rpm so issues that you have with the V8 you don't have with the N.
Have your friendly machine shop install the new bushings in your N oil pump.Even if you grind the crankshaft and install new inserts don't be disappointed if your oil pressure is not too high. 5lb at hot idle is not bad and the engine will live and be happy with that. The N engine has no cam bearings so you do loose OP there. The oil pressure relief valve is accesable through the timing gear cover, front of the engine and they do get crud in them and can cause lower pressure.
Good luck with the N.
ray

 

Thank you Ray;
I use this old girl to push snow in the winter.
This info is very enlightening! We Don't have an engine machine shop in town. The bushing in the oil pump is very good so I'm hoping the gears in the kit will make a difference. The safety wire on the mains was copper wire. I'm pretty sure thats not the best.
I'll have a look at the pressure relief.
Working on this old tractor is fun especially with input from guys like you that have "been there, done that".
This engine uses NO oil, and is a beautiful runner, except for the rod knock till the pressure comes up. Then there is no noises at all. Sometimes, after sitting a couple of weeks, the oil pressure does not come up at all on start up until I shut down and prime it thru the front [pressure relief?] hole with the big nut. I pulled the bottom apart to address this issue. Originally to replace the oil pump. I figured while I was in there I would slide in some rod shells as well. Preventative. Removed the rod caps to find std brgings with .005 brass shims behind the lower shells. I have located some .002 under shells and hope to be in the ball park with plastigauge when they get here.
Hows this plan sound so far?
Frank.

 

Frank, sound like you have a plan. Make sure that long oil pickup tube on the front main cap is not cracked thus allowing prime to be lost. I have successfully silver soldered them.

ray

 

Thanks Ray, The oil pump tube is in very good cond. I'll check and make sure the is no leakage at the joint where the "bell' pick-up attaches to the tube. Those bearings should be in next week.