B7100 cam plug - low oil pressure but no overheating

[Nelsonaragon]

Been reading a lot over the last couple of days regarding the dreaded cam plug. I recently purchased a new to me 79' B7100 and after adding both an oil pressure and temperature gauge, I noticed that my oil pressure appears to be low. I ran the tractor the other day at idle for about 20 minutes and the most it ever got to was about 10 PSI (maybe 15 at WOT). The odd thing however is that my water temperature never really got above 180 degrees or so; hence, my solicitation for advice from your knowledgable folks

1. If my water temps are okay, but my oil pressure is showing low, should I even worry much? I double checked with an IR thermometer near the neck of the radiator and my gauge temps were fairly close (+/- 5 degrees)

2. Is it even worth trying a new oil pressure gauge? The needle vibrates like crazy when I have it WOT but the needle seems to stay around the 15 psi mark. I did use a copper line but doubt that would affect anything. Using semi-synthetic 5w-30 oil from what I remember. Not sure if it would be worth trying plain old dino oil (or 15w-40) but then again, that's not really fixing the bigger issue if there is one. Also, the oil light has never worked...in fact the bulb is missing. The seller told me "not to worry about it" which does make me a little suspicious

Curious to see what others have experienced. I'll open her up if I have to, but would rather not since we're moving in a week or so and I really need her to help pull a small 5 x 8 foot trailer around our 2.5 acres to move things around.

I know I read on here about someone drilling an access hole (and later tapping it) in the front cover...not sure if anyone else has attempted it that way....

THanks!

Nelson

 

[85Hokie]

IN THE SHORT term.... and this is NOT a fix , rather a band-aid on a gash.

Place some straight 30 weight oil in it ..... this will ramp up the pressure for a bit, but once it gets hot, good and hot, it will still go back down.

I have seen tractors run damn near forever on 5 psi ......
15 is what I have hot at idle, 40 at wot on same machine.

It needs to be fixed - not a hard fix, just a PITA one.

The hole in cover would not be a hard fix - measure twice - cut once.

 

[bx tractorjoe]

My new to me b7100 also had a missing oil dummy light, and it was not hooked up..

After adding a auto meter oil gauge and copper line i have about 30 psi after running it for an hour and the oil filter about 170 degrees.

Water temps about 190 at the upper hose on the engine.

Dump the 10w30 and get some shell 15w40, or 30w is good too and see what happens.

Could possibly be a somewhat gloged oil pickup screen, but usually a flickering oil pressure gauge needle means your losing oil pressure between oil pump rotations, or at cam bearings or etc..

Hope its just the thinner oil causing it..

 

[85Hokie]

Nelson,

here is the hole drilling method info from 4 years ago - this guy did it with great success.

https://www.orangetractortalks.com/forums/threads/easier-cam-plug-fix.26583/#post-217857

 

[D2Cat]

85Hokie, thanks for digging that thread up. There's always more then one way to "skin a cat"!

 

[85Hokie]

85Hokie, thanks for digging that thread up. There's always more then one way to "skin a cat"!

I hope the cat can be ...... history!!! I hope I dont have to start drillin'

I thank goodness my B7100 are the later versions that seem not to have that problem!

I do like the method however - right damn ingenious!

 

[Nelsonaragon]

My new to me b7100 also had a missing oil dummy light, and it was not hooked up..

After adding a auto meter oil gauge and copper line i have about 30 psi after running it for an hour and the oil filter about 170 degrees.

Water temps about 190 at the upper hose on the engine.

Dump the 10w30 and get some shell 15w40, or 30w is good too and see what happens.

Could possibly be a somewhat gloged oil pickup screen, but usually a flickering oil pressure gauge needle means your losing oil pressure between oil pump rotations, or at cam bearings or etc..

Hope its just the thinner oil causing it..

Thank you both. The flickering needle really only happens at WOT when the whole darn thing is vibrating like mad. If I let her idle the overall vibration in the tractor calms down and the needle seems to stay in one place. I drained the oil I had in there and replaced it with 30w oil today and it improved but not much. At idle it was running about 10 psi and at WOT it was about 15-17. Quite honestly, I haven't actually used her hard enough yet to see what happens with the water temperature. I imagine as long as the water temps don't go too high (implying adequate lubrication) that the oil pressure won't really matter? I may try some 15w-40 and see what happens there too but I'm starting to think it's something other than just the oil type....

 

[85Hokie]

only problem with the 15w-40 ..... it is a thinner oil that the 30w that is in there now!

Find you a nail or bolt..... grind it down to that specification.... notch it....
and get someone to help you drill the hole.

Like I said before - the more viscous oil is a bandaid on a gash...... gonna help only so much.

10 psi is fine at idle - trust me .......when it drops below 5 psi .... then worry.

Your model is 1979 ... so I gonna say ...... plug be a missin'
If you decide to drill and find that PLUG is in there...... OOOOKKKK .... did I mention the rear plug? That my friend is a royal FPITA

 

[GeoHorn]

I ran my 9N Ford on SAE 50 oil for 19 years and it’s oil pressure when hot was 15 psi at ”working RPM” (no tach) and barely off the zero-needle at idle. It did not care one whit.

All any engine needs is “some” oil pressure..... 5 psi is as good as 50 if the engine is not ”lugged” but instead is operated at a good rpm. (The Ford has a pressure-control-plunger just in front of it’s governor and I replaced that when I first acquired that tractor in 2000, but it made no difference at all... I only recently sent it to it’s new owner who is working the “dog” out of it at 5 psi.

I first used aircraft SAE 50 oil because I had a bunch of it but switched to Valvoline “Racing” SAE 50 when I realized NAPA carried it. I only changed the oil every OTHER year.

Don’t lay awake at night over this,...or spend a fortune on what your tractor probably doesn’t care about. 5 psi is sufficient to keep bearings lubed and that’s the primary issue. If you have an engine with hydraulic lifters... and the oil pressure gets too low... the valve lifters will “clatter”... and that happens only when oil pressure virtually disappears.

 

[85Hokie]

" Don’t lay awake at night over this,...or spend a fortune on what your tractor probably doesn’t care about. "

Well said - well said!

 

[SidecarFlip]

Spend a few more bucks and get yourself a Glycerin filled pressure gauge. They don't flutter. All I use anymore. Not that much more expensive.

 

[Nelsonaragon]

Spend a few more bucks and get yourself a Glycerin filled pressure gauge. They don't flutter. All I use anymore. Not that much more expensive.

Awesome feedback from all of you, TY!!!! That was my original inclination - as long as the engine was getting SOME pressure and lubrication (and really, as long as it doesn't overhear) it was probably good enough. I can totally relate with not losing any sleep - what do they say, don't let perfect be the enemy of good?

Thank you all again for your help!!!!!

 

[bx tractorjoe]

I think you need 7 psi to float the bearings under normal conditions.. if you were pulling logs out of the woods with the wheels coming off the ground thats another story..

I would say the water temp will not tell you much about the oil, if the rod or crank get to hot and spin a bearing it won't raise the water temp before it happens.

 

[Nelsonaragon]

I think you need 7 psi to float the bearings under normal conditions.. if you were pulling logs out of the woods with the wheels coming off the ground thats another story..

I would say the water temp will not tell you much about the oil, if the rod or crank get to hot and spin a bearing it won't raise the water temp before it happens.

Yeah, luckily I don't plan on dogging this thing too much. I'll just be mowing our grass (likely with a 48 inch finish mower) and towing a fairly light utility trailer around our property.

I know it's just a band-aid for now, but what about upping the weight and trying a 40 weight diesel oil? I know the owners manual recommended 30 weight or 10w-30, but wasn't sure if bumping it up a little would help increase pressure?

 

[SidecarFlip]

Static pressure is kind of inconsequential, it's more about film thickness and boundary layer protection. The pressure only equates to flow for the most part.

I that vein, I'd stick with a high quality oil like Rotella in a straight grade versus a multi grade.

 

[torch]

I think any attempt to increase oil pressure by using thicker oil would be a foolish mistake.

The lubrication system is a network, with oil passages branching off in various directions. Engineers presumably did some friction loss calculations to balance the flow throughout the system.

Assuming the camshaft plug has fallen out, I think we all understand that the oil pressure throughout the system drops because there is insufficient back-pressure in the camshaft branch of the system. Put another way, there is less oil going to the crankshaft and camshaft bearings because of the excess going out the end of the camshaft.

Thicker oil could potentially raise the oil pressure seen at the sender (near the pump), by reducing the oil flow through the system. Everywhere. That means bearings already subject to reduced oil flow will get even less oil volume flowing through them.

In addition to the potential loss of lubrication in those critical points, there arises the problem of cooling those areas. We all tend to think of the radiator system as being responsible for engine cooling, but really, the water can only cool the castings. Internal components like bearings and pistons rely on the oil flow to remove heat from where the water can't reach.

But that's just my 2¢. And worth every penny. ;-)

 

[SidecarFlip]

Sounds good to me. I believe I'd bite the bullet and repair it.

 

[flynavy]

Been reading a lot over the last couple of days regarding the dreaded cam plug. I recently purchased a new to me 79' B7100 and after adding both an oil pressure and temperature gauge, I noticed that my oil pressure appears to be low. I ran the tractor the other day at idle for about 20 minutes and the most it ever got to was about 10 PSI (maybe 15 at WOT). The odd thing however is that my water temperature never really got above 180 degrees or so; hence, my solicitation for advice from your knowledgable folks

1. If my water temps are okay, but my oil pressure is showing low, should I even worry much? I double checked with an IR thermometer near the neck of the radiator and my gauge temps were fairly close (+/- 5 degrees)

2. Is it even worth trying a new oil pressure gauge? The needle vibrates like crazy when I have it WOT but the needle seems to stay around the 15 psi mark. I did use a copper line but doubt that would affect anything. Using semi-synthetic 5w-30 oil from what I remember. Not sure if it would be worth trying plain old dino oil (or 15w-40) but then again, that's not really fixing the bigger issue if there is one. Also, the oil light has never worked...in fact the bulb is missing. The seller told me "not to worry about it" which does make me a little suspicious

Curious to see what others have experienced. I'll open her up if I have to, but would rather not since we're moving in a week or so and I really need her to help pull a small 5 x 8 foot trailer around our 2.5 acres to move things around.

I know I read on here about someone drilling an access hole (and later tapping it) in the front cover...not sure if anyone else has attempted it that way....

THanks!

Nelson

Heres a link to a "youtube video" that this guy fixes his low oil pressure. Very clear and informative. He also explained about the fix from a Kubota service bulletin. You may want to try this Its pretty good.

I also had a problem with low pressure about 14psi, I know this sounds impossible BUT after i changed my oil 2 x (twice) within about 3 months, after the second change my pressure went up to 40psi. This was on Dec of 2020. no idea why but I'm glad and no complaints