Curiosity killed the oil pressure?

Forum members,
I was looking for more consistent oil pressure on an 8N front mount and did not get what I wanted! I got a new spring and replaced the old one which looked worn on the inside. The plunger had a flat spot about 3/16ths of an inch in area. Started her up and had less pressure than before. Is it possible to resurface the dome shaped plunger or should I just get the $21.00 new plunger? I have a metal lathe and/or drill press to resurface it. Are both surfaces made of the same metal or is the plunger softer? Any info is appreciated!!
Mr. T. Minnesota
 
plunger SHOULD have a flat spot.

is the new spring SHORTER than the old one? if so.. there's where some of the oil pressure went..

post back
 
SG,
The flat spot is on one side of the dome not at the end!! Shouldn't the dome be a complete dome except at the end/top? Am wondering why the dome is flattened on one side?? The guy that overhauled the engine had not replaced the spring and plunger. Hope I explained it a little better. Appreciate any more thoughts!!
Thanks,
Mr. T. Minnesota
 
On my sons 2n i removed the flat spot and it went from 20 at start up to 60! but still 3 lb at warm idel. so i went back to the orignal one . bob
 
and yet...my answer hasn't changed any....

at this point I'll assume you are answer shopping, waiting for one you want to hear.

so I'll leave it at that.

have a goodun'
 
Looked at the plunger on my 49N that is totally torn apart.

The plunger has a flat spot on only one side.

Had zero oil pressure when the engine was torn down.
 
OK ,if the plunger is supposed to have a flat spot what is the orientation in the hole?

The flat spot appears to be wear surface!
 
SG,
As to the spring length, it is the same. The tension seemed close to the same also. The spring said it was made in the USA too. The previous pressure was about 25 psi at a cold start and tapered off to about 10 psi. Now it does not get above 20 psi at a cold start and have not run it long enough to determine the hot reading. I do not plan to put in the old spring because the spring was worn where it contacted the plunger as it did on my 2N. A broken spring is not good news.
Thanks for the replies!
Mr. T. Minnesota
 
go rethink that one for a moment see if it comes to ua.

think about a seat and a free floating plunger with a flat on one side of the needle face. what do you expect happens in that gap.. no matter where it is? ?
 
The relief valve will set the high pressure at start up but has very little to do with amount the pressure drops when warmed up. That is more to do with bearing clearance and condition of the oil pump itself. If changing the spring lowered your cold start oil pressure the new spring doesn't have as much tension as the old one. I would expect your hot oil pressure to be about the same as it was with the old spring.

Mark
 
My theory is the plugs were fouled so badly, raw gas entered into the oil sump and thined out the oil so much the pump gears would not pick up the oil from the sump.
 
the flat spot discover happens almost as much as people asking if they can use a roto tiller on their 8n.

:)
 
YEa I have to go along with the other guys here on this one. If your pressure is dropping that much you have an oil pump issue or a bearing clearance problem.....or both.

If you haven't rebuilt one of these engines or for that matter any engine, they are easy. Cost really isn't bad. If you do the wrench bending and let a shop press out and in the sleeves, grind the valves, turn the crank, fit the wrist pins you can rebuild one for about 1200 or maybe a little less. I also think for a newby this is a great engine to learn on.

Rick
 
Found a used 42" wide rotor tiller, thinking about hooking it up once get the tractor
re assembled.

However, probably takes too much HP.
 
20 psi cold almost o hot,tried to fix it on the cheap.no luck,i have more tools than i need,sopulled engine and replaced liners,pistons,rings,rod and main brgs,had oil pump re built at a machine shop.also replacedvalve tappets and resufaced valves and seats.now have appox 70 psi cold and30 plus hot.just bite the bullet and fix it.Idid all thelabor,i work cheap. Hope this helps.Richard in Poulsbo, WA
 
Forum Members,
Appreciate all of the input on the oil pressure killing spring. This 8N has been completely overhauled with a questionable pump replacement. I will contact the PO. Tractor was a deal I could not refuse even with 8N oil pressure characteristics. I may bend a bit and return original spring but reverse it to let it wear in a different spot. Looking at the original spring and the new one they appear to made of different types of metal. The original seems to have been a better quality. Any other thoughts are welcome.
Mr. T. Minnesota
 
That flat spot on the relief valve plunger is there for a purpose which is to supply oil to the front gear train no matter what the oil pressure is. If it is too low to open the relief valve the gear train will still get it's needed oil.

This was figures out by some pretty smart engineers so don't try to outthink them.

Zane
 
laugh!


plenty of hp.

too high of ground speed.

just like we tell the other 3 million people that ask this every spring!

get a plow.

it will plow all day...
 
Seems like this pressure relief valve spring is problamatic.

Does any one know the pressure when this relief valve is designed to open at normal operating oil temperature?

A simple spring formula will indicate the correct free length of the spring before it is installed in the hole.
 


Wont't a disc harlow get the same result as the tiller, except it takes multiple passes??

Saw an 8N with a rotor tiller on You-Tube, recently.

U R correct, looked like drag racing.
 
i prefer a disc to a tiller.

you can find a reare howard or everett tranny for a older ford that lets them have a very low ground speed to use a rotovator or trencher.. etc.
 
Viewed to videos on You Tube, yesterday, one 9N and one 8N both using a tiller.

The 9N was going slow probably had a Sherman auxilary transmission

The 8N was going really fast, probably stock setup.

Found a 42" wide tiller with a hydraulic motor
connected to the gear box.

Suppose the total setup would have a hydraulic pump connected to the 8N PTO with hydraulic lines from the pump to the tiller hydraulic motor.

Would this set up work on an 8N?
 
(quoted from post at 08:10:22 11/11/12) Viewed to videos on You Tube, yesterday, one 9N and one 8N both using a tiller.

The 9N was going slow probably had a Sherman auxilary transmission

The 8N was going really fast, probably stock setup.

Found a 42" wide tiller with a hydraulic motor
connected to the gear box.

Suppose the total setup would have a hydraulic pump connected to the 8N PTO with hydraulic lines from the pump to the tiller hydraulic motor.

Would this set up work on an 8N?

You still have a ground speed issue and slowing down the tractor by clutching kills your PTO driven pump and with it the tiller. Put the pump on the front and it will work better. Combined with a step down Sherman to reduce ground speed probably quite well.

TOH
 
enjoy discussing tillers more than compression springs

this response could have gone under "soundguy" we got off the main subject and started another on tillers.

Read most of the archieves mating Ns and tillers.
Lots of guys want to use the N as a tiller puller, but no cigar.

Agree the best current solution isto mount a hydraulic pump to the nose pully and run line back to a hydraulic motor connected to the tiller right angle gear box with a Sherman to reduce wheel speed.

Someone needs to come to the plate design/build an aftermaket replacement for the Howard to reduce wheel speed and not reduce PTO speed for a direct PTO hook up to a tiller.
 
again.. with the N ground speed low.. that means you are idling... that means pto speed is slow.. that means your hyd output is low.. that means that hyd tiller is slow.

you've been told muktiple times now that N are not good tilelr machines. there are pretty much 2 trannies that make them a tiller machine. a howard and an everette.

a sherman DOES NOT make them a tiller machine. it slows down the trans AND the pto.

the howard and everette ONLY slow down the ground speed.. NOT the pto.

you seem intent of finding a 1200$ soloution to adding a tiller to an N when it's far cheaper to find a machine suited to use a tiller.. or simply get a plow and disc.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top