Picked up another one

Tom Bond · Dec 18, 2020

Came across another 961 while out on a muzzleloader trip last weekend. Got to talking about it with the owner and now I own it. Everything is decent on it but the oil pressure drops to about 10-15# when hot and at idle. At PTO speed, it's about 35#. I changed the oil and filter and it's about the same. No smoke and runs smooth so I'm thinking it may need rod bearings and mains? The rod bearings don't look like anything too tough as I read through the service manual but the mains are what I'm wondering about. Do I do them both at once? Rods and mains? Just from looking at the manual, if I pull the main caps from the bottom, can you get a micrometer in there for an accurate measurement? When I pull the rod caps, do you just push the piston up to access the rod bearing and make room for the micrometer on the crank? This will be the first time on bearings for me so please bear with me. Manual says it can all be done from underneath. Any tricks I need to know before I attempt it? Kinda looking forward to this. Thanks! Tom

Bern · Dec 18, 2020

Those are completely acceptable oil pressure figures for today's engines. I myself would confirm the numbers with another gauge, and if you get the same values, run it. If it still bothers you, do some regular oil sampling.

Besides being a PITA to actually do, some people create more problems than they solve by rolling in new bearings.

BTW, 35 PSI is the factory specified oil pressure for first gen small block Chevys, along with many newer semi-truck diesel engines. The Ford tractor manual for your tractor calls for a minimum of 8 at hot idle.

showcrop · Dec 19, 2020

Do a little more evaluation with your compression tester and vacuum gauge.

Dean · Dec 19, 2020

If you decide to replace engine bearings (I wouldn't), do only the rods without removing the crankshaft.

Don't cause trouble for yourself.

Dean

JK-NY · Dec 19, 2020

What are you running for oil? How hard do you intend to use
this tractor? And does it use much oil ( I know you can’t really
answer this question yet.)That doesn’t sound that bad to me. I
would not worry about doing bearings yet. I would run it as is
for a while and get a better idea of what you are dealing with.
If it gets a lot worse on the oil pressure or starts knocking then
I would worry. If you feel the need to take something apart
drop the oil pan and clean any sludge and check the oil pump
intake screen. There is an updated oil pump, not sure which
one you may have.

JK-NY · Dec 19, 2020

Oh forgot to say- Congratulations on the new tractor!

Off Road SHO · Dec 19, 2020

(quoted from post at 04:26:27 12/19/20) Came across another 961 while out on a muzzleloader trip last weekend. Got to talking about it with the owner and now I own it. Everything is decent on it but the oil pressure drops to about 10-15# when hot and at idle. At PTO speed, it's about 35#. I changed the oil and filter and it's about the same. No smoke and runs smooth so I'm thinking it may need rod bearings and mains? The rod bearings don't look like anything too tough as I read through the service manual but the mains are what I'm wondering about. Do I do them both at once? Rods and mains? Just from looking at the manual, if I pull the main caps from the bottom, can you get a micrometer in there for an accurate measurement? When I pull the rod caps, do you just push the piston up to access the rod bearing and make room for the micrometer on the crank? This will be the first time on bearings for me so please bear with me. Manual says it can all be done from underneath. Any tricks I need to know before I attempt it? Kinda looking forward to this. Thanks! Tom

If you're going to push the rods up enough for a micrometer measurement, you have to take two measurements. One in-line with the throw, and one perpendicular to the throw. This is to check for out-of-roundness.

An easier way is to just remove the rod cap and use Plasti-Gage.

Another Tom

Dh2jr · Dec 20, 2020

I definitely would not want to just
change the bearings without having the
crank turned. I'm just thinking that you
could cause yourself just more headaches.
Just my 2 cents worth

Bern · Dec 20, 2020

People did that all the time back in the old days. It was called an "underhaul".

Husker 50 8n · Dec 20, 2020

I agree with keep an eye on the oil pressure and run it. Sounds like it may be within spec anyway. 961 is a very nice tractor. I like them on 12 volt. They just spin faster and make starting easier. The 172 has a nice sound when under a little bit of load. I have an 8n that was my Grandpa's and I do like using it. But if you were only keeping one tractor the 961/960 are so close in price to an 8n that the choice to move up would be easy for me. I have the early 4000 version, great tractor. Post a pic.

Picked up another one

Tom Bond

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Bern

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showcrop

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Dean

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JK-NY

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JK-NY

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Off Road SHO

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Dh2jr

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Bern

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Husker 50 8n

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