oil pressure at 18 does it still ok?

serge

Member
oil pressure at 18 does it still ok? does it mean I will have to replace the oil pump and could it damage something else?

thanks agin
 
18 at idle is pretty good for one of these old tractors. 18 at full RPM is not real good but not bad either since they are old. Running a thicker oil can help. Say your running a 5W-30 try maybe a 10W-40 or 20W-50 depending on where you are
 
the oil is 40 grade the temperature is around -25c may be I should replace the oil with some 5w30 instaed of non detergent 40?
 

it's sitting in my garage, the oil level is good and at idle it is 18 and half trotle come to 20
 
Non-detergent oil is a thing of the past and at that temp 40W is just flat out to thick to even be safe firing it up. I would try a 5W-30 or a 10W-40
 
Don't worry about it. As long as it Picks up oil and makes pressure and don't knock. These oil gauges today aren't a quality control item. Its low cost slam bam get it out the door and get paid type thing. I had an 8n and with 3 different gauges had 3 different pressures. Take ur pick.
 
(quoted from post at 22:38:38 02/09/15) Don't worry about it. As long as it Picks up oil and makes pressure and don't knock. These oil gauges today aren't a quality control item. Its low cost slam bam get it out the door and get paid type thing. I had an 8n and with 3 different gauges had 3 different pressures. Take ur pick.
Telling someone not to worry about oil pressure is quite possibly THEE worst tractor advice I have ever heard.
Anyone who wants to take care of their equipment would check the oil pressure.
Preferably with a known good and/or calibrated gauge, not three different TSC style cheapies.
 
Leave it alone. think about it. If they were so sensitive to every little hiccup, they wouldn't have lasted so long . If you want to listen to Gramma and Auntie who wet there pants over 18 versus 27 psi and say that is THEE worst advise you could hear. Go ahead and fix it and fix it right. There are 1000's of these out on the ranch or farm running 12-25 psi. They aint coming apart. What it says in the manual often times isn't golden and the little hobby farm life and suburbia is not reality.
 
"There are 1000's of these out on the ranch or farm running 12-25 psi."

This statement I would agree with, and, if that were hot oil pressure it would be acceptable. Great at hot idle.
But we don't know whether the tractor was hot or at idle or
cold and at full throttle. Big difference.
 
(quoted from post at 09:42:16 02/10/15) "There are 1000's of these out on the ranch or farm running 12-25 psi."

This statement I would agree with, and, if that were hot oil pressure it would be acceptable. Great at hot idle.
But we don't know whether the tractor was hot or at idle or
cold and at full throttle. Big difference.

And it matters. There are basically two reasons for putting an oil pressure gauge on an engine:
  • [*:5888baf192]Any number greater than zero tells you that there is oil in the sump and the pump is circulating it. That is essentially the same function as the oil pressure warning light on modern vehicles.

    [*:5888baf192]Lower than "normal" oil pressure is an indication that the bearings/journals are getting worn and oil clearances are approaching the recommended wear limit. When that happens the thickness of the oil film that protects the journals is reduced and journal wear is significantly accelerated. The [u:5888baf192]magnitude of the pressure loss[/u:5888baf192] is an excellent indirect measure of the increase in the internal oil clearances. It's not how much pressure you have - it's how much pressure you have lost from new that matters.[/list:eek::5888baf192]If you don't care about the second and are going to wait until it the bearings have eaten deep into the journals to fix it just ignore the gauge data. Since many (most??) people do not understand what that gauge data indicates they do just that. Consequently modern OEMs have pretty much eliminated the gauge in favor of the light. :twisted:

    TOH
 
Telling someone not to worry about oil pressure is quite possibly THEE worst tractor advice I have ever heard.

Well - I would say, IMO, telling someone to pull using the top link rather than a draw bar to be worse advice - but that is another matter. (grin)

To the question at hand - 18 psi at idle either hot or cold is darn good for this low RPM flathead 4 cylinder engine. I did a very complete engine rebuild 48 8N and palsti-gauged every bearing, rebuilt the oil pump (including new bushing), and replaced the oil gauge and I am getting about that reading now (was at about 5 psi before the rebuild). I completely agree with TOH, but my threshold on when to really worry is 5 psi at idle. Your mileage may vary.

Dan
 
(quoted from post at 10:35:55 02/10/15)
Telling someone not to worry about oil pressure is quite possibly THEE worst tractor advice I have ever heard.

Well - I would say, IMO, telling someone to pull using the top link rather than a draw bar to be worse advice - but that is another matter. (grin)

To the question at hand - 18 psi at idle either hot or cold is darn good for this low RPM flathead 4 cylinder engine. I did a very complete engine rebuild 48 8N and palsti-gauged every bearing, rebuilt the oil pump (including new bushing), and replaced the oil gauge and I am getting about that reading now (was at about 5 psi before the rebuild). I completely agree with TOH, but my threshold on when to really worry is 5 psi at idle. Your mileage may vary.

Dan

It's hard to get these engines back to that 25-30 PSI factory fresh pressure because the oil pumps are worn and you have a 70 year old camshaft that has been running directly in the block. Short of line boring the block. grinding the camshaft, installing undersize camshaft bearings and a new oil pump you are not going to get all of the oil clearances back to factory fresh. Your rebuild brought the pressure back up from 5 PSi to 20 PSI because you restored the crankshaft journal bearing oil clearances back to factory spec. That is your new baseline (e.g. normal) oil pressure. With regular oil changes and proper care it should stay in that range for another 2000+ hours. If it has to be rebuilt again after that it's likely the "next new normal" will be somewhat less than 20 PSI. Simple as that.

TOH
 
Try shimming the relief valve spring, could be your problem is
there. I installed new bearings in my 39 9N and installed a new
relief plunger and spring. The oil pressure only got to about 25 PSI
which was a disappointment to me. I removed the new plunger and
spring and re-installed the original. Pressure went to 45-50 on
start up and settles to 30-35 when fully warmed and stays there.

A flat washer added to the spring should bring it up some if that is
the issue.
 
(quoted from post at 10:35:55 02/10/15)
Telling someone not to worry about oil pressure is quite possibly THEE worst tractor advice I have ever heard.

Well - I would say, IMO, telling someone to pull using the top link rather than a draw bar to be worse advice
Dan
Possibly, but even though I've seen it done, I've never heard that
advice given as serious advice! LOL

You have some concrete numbers, not just a "don't worry" response.
Obviously you've checked that oil pressure because it was important.
Did you check it with a gauge other than the dash meter?
Maybe you just have a bad gauge. It happens.

I don't honestly know how many N's I've bought and sold, but
I have four here now. One of them, my 2N, will drop just
below 20 PSI at idle after plowing snow for 3 hours or more.
I bought it as a non-runner and put it to use when I got it running.
The other three never drop below 20 PSI.
None of the four have been rebuilt since I've owned them.

I have also seen N's run on 5 psi hot idle and not knock.
I wouldn't want mine there, but I know they will do it.

Back to the original topic - 18 PSI. Hot? Cold? Idle? Full throttle?
Hard to say if it is good or bad without knowing how its measured.
My 2N I would say is at 18 or so PSI hot idle. I call it good.
If it were 18 PSI cold at full throttle I would not.
 
(quoted from post at 06:42:16 02/10/15) "There are 1000's of these out on the ranch or farm running 12-25 psi."

This statement I would agree with, and, if that were hot oil pressure it would be acceptable. Great at hot idle.
But we don't know whether the tractor was hot or at idle or
cold and at full throttle. Big difference.

after 1hr of working it is around 18 to 20 this is a hot engine even a fast throttle still the same maybe 1 or2 more psi
 
(quoted from post at 08:27:41 02/11/15)
(quoted from post at 06:42:16 02/10/15) "There are 1000's of these out on the ranch or farm running 12-25 psi."

This statement I would agree with, and, if that were hot oil pressure it would be acceptable. Great at hot idle.
But we don't know whether the tractor was hot or at idle or
cold and at full throttle. Big difference.

after 1hr of working it is around 18 to 20 this is a hot engine even a fast throttle still the same maybe 1 or2 more psi
For hot oil pressure that would be acceptable.
Mine vary more than that from idle to full throttle though.
I would still test it with a known good gauge just to be sure the gauge is reading correctly.
 

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