OC3 has weak power and looses oil pressure once it warms up.

[Cubert]

I am the the next owner in line of a Oliver OC3 crawler with a loader bucket and have little idea on how to trouble shoot my current issues. Maybe someone has seen this issue and can help point us in a good direction.

The machine starts up without issue and the throttle can somewhat power up the engine but after a few minutes of running the oil pressure gauge drops to 0 and I think I start hearing a little knock, this could be the engine running ruff at high throttle.

When cold it will move forward and backward ok, and will climb a small grade but once it warms up it starts stalling when trying to move it on flat land.

I have gotten a few good ideas to go check reading the following forum post

Oliver OC-3 crawler

My neighbor and I just bought an Oliver OC-3 crawler that has been sitting for a few years. It is equipped with backhoe and it runs from a Hercules four piston gas engine. We got it to start while cold, but when it warms up the engine dies and it refuses to restart until it completely cools...

forums.yesterdaystractors.com

But I dont' think its the same issues as oil pressure is also a part of the issue.

I did notice that the oil filter was missing the center oil tube that goes up into the oil filter, I have ordered one from olivercrawlers.com to repair this issue. I also read in service manual that oil pan should be dropped and cleaned out every 500 hours. Any one ever seen a oil screen or oil pan issue causing pressure issues?

 

[Cubert]

Also some extra information about current status of crawler

We tested piston pressure and each cylinder was between 48 and 55 psi (warm).
Oil is fresh and new, Filter is not new and missing center tube.
Gas is fresh, has new inline filter and new lines. Flow tested during line change shows good.

 

[Cubert]

Ok, we have solved half our problem, the no power issue was due to the third hydraulic valve, the unused valve in picture was extended out by 1 inch and engaging the pump and placed engine under load when no hydraulics are in use.

Still having the zero oil pressure after engine warms up.

 

[560Dennis]

Also some extra information about current status of crawler

We tested piston pressure and each cylinder was between 48 and 55 psi (warm).
Oil is fresh and new, Filter is not new and missing center tube.
Gas is fresh, has new inline filter and new lines. Flow tested during line change shows good.

48 55 is to low , warm up oil pressure drop to 0 is issue that I would do a correct action on with advice from your local machine shop.
also the front hydraulic pump driven off the crankshaft the crankshaft end play is a must correct while it’s a part. Do not over look this .

 

[TomA in CA]

I wonder if your suction screen is plugged. What kind of oil are you using? Have you tried changing it?

 

[Cubert]

I wonder if your suction screen is plugged. What kind of oil are you using? Have you tried changing it?

@TomA in CA That was my next step, Manual says it needs a cleaning every 500 hours, The machine was pretty dry when I got it. Looks as if it hadn't been greased in a while. So I suspect other maintenance is lacking. The oil was freshly changes when I got it so I do not know type of oil. Was going to replace with some SAE30 after dropping the pan and cleaning..

@560Dennis I have the service and parts manual for this machine but could not find where they provided cylinder pressure specs. Do you know what my target pressure should be on the Hercules engines?

 

[560Dennis]

@TomA in CA That was my next step, Manual says it needs a cleaning every 500 hours, The machine was pretty dry when I got it. Looks as if it hadn't been greased in a while. So I suspect other maintenance is lacking. The oil was freshly changes when I got it so I do not know type of oil. Was going to replace with some SAE30 after dropping the pan and cleaning..

@560Dennis I have the service and parts manual for this machine but could not find where they provided cylinder pressure specs. Do you know what my target pressure should be on the Hercules engines?

I have a hercules engine manual , will look. ( is that what you’re looking at ?) anyway. For now tractor data say the oc3 compression ratio is 6.67:1 about = bout 100 psi. 0ne atmosphere times 6.67
question when you did the compression test , did you have the throttle wide open ?

 

[560Dennis]

FYI
prior posting may help you see link

Oliver OC-3 information

Hello I believe I have a 1955 oliver OC3 crawler. I am looking for information as to what I should have for Compression in PSI. We have had trouble getting the crawler running, initially thought It was timing, have timed it to the best of our knowledge, machine will backfire every so often. it...

forums.yesterdaystractors.com

 

[rustred]

The oil pressure is the most important thing to get fixed. Starting and stopping it with no oil pressure is a big deal!! Soon u will have no engine left. Put a master guage on it at least so u know what’s happening. If it’s going to zero don’t keep starting it ! Pull the pan and start checking. Now you need to check the rod and main brgs. Don’t matter what oil is in it as that’s not the problem. Start at the heart of the thing the pump., surely it can’t be worn out that bad that the psi drops to zero. And yes that is very low compression. So u might be in for a complete engine job.

 

[Cubert]

Here is what the crawler is doing,

 

[Cubert]

This is my first experience with both an Oliver and a crawler, so I’m a bit out of my element. Please bear with me if I ask any obvious questions.

My next questions are:

1. If we’re considering a complete engine overhaul, would it be easier or more cost-effective to replace the engine entirely? Are these engines readily available for purchase, either new or used? Is there a diesel alternative that would be compatible with the current transmission?
   
   
2. Regarding rebuild kits, is there a comprehensive kit available that includes all the necessary parts in the correct sizes for a proper rebuild? Or would it be better to have a more experienced mechanic assess the current engine and order the parts individually?

3. What could I expect to pay for parts and what would be the expected cost of a barnyard mechanic to manage the job?

Trying to set my expectations..

 

[rustred]

You do not know what u need for parts till u get it all apart. Then u make your list. Due to pres. Dropping is usually worn out cam, Rod and main brgs. As for if it needs sleeves or a rebore and pistons or just rings a person does not know yet. Put a master gauge on this unit to get some actual psi numbers. Can’t go by that guage. Depending what’s all involved it can be 2k-5k to to redo the engine. And no don’t get a half azzed mechanic on it , it’s your money u want a good job , not so it fly apart after. I do know what will work and what will not work without everything being replaced new. You will get all kinds of answers here but it’s not their money they are spending.

 

[BarnyardEngineering]

This is my first experience with both an Oliver and a crawler, so I’m a bit out of my element. Please bear with me if I ask any obvious questions.

My next questions are:

1. If we’re considering a complete engine overhaul, would it be easier or more cost-effective to replace the engine entirely? Are these engines readily available for purchase, either new or used? Is there a diesel alternative that would be compatible with the current transmission?
   
   
2. Regarding rebuild kits, is there a comprehensive kit available that includes all the necessary parts in the correct sizes for a proper rebuild? Or would it be better to have a more experienced mechanic assess the current engine and order the parts individually?

3. What could I expect to pay for parts and what would be the expected cost of a barnyard mechanic to manage the job?

Trying to set my expectations..

The OC3 was produced from 1951 through 1957. That's an average of about 70 years ago. You're simply not going to find a new replacement engine for a machine this old. Used engines are a slim possibility, but keep in mind that the engines you have to pick from are from equally-old machines. You stand a better-than-average chance of ending up with an engine with similar or worse problems.

An engine swap is possible, but it's not something for someone with no mechanical experience to take on. There are no kits to make any engine swap a bolt-in process. You're on your own with figuring out how to mount the engine, how to make the clutch work, how to connect the throttle, how to drive pumps and accessories...

Can't help you on rebuild kits or cost. You might want to see if you can find a machine shop that still does "old school" work like this, and see what it would cost. They can give you a pretty accurate idea, but such machine shops are far and few between these days.

 

[Frank(Mi.)]

This is my first experience with both an Oliver and a crawler, so I’m a bit out of my element. Please bear with me if I ask any obvious questions.

My next questions are:

1. If we’re considering a complete engine overhaul, would it be easier or more cost-effective to replace the engine entirely? Are these engines readily available for purchase, either new or used? Is there a diesel alternative that would be compatible with the current transmission?
   
   
2. Regarding rebuild kits, is there a comprehensive kit available that includes all the necessary parts in the correct sizes for a proper rebuild? Or would it be better to have a more experienced mechanic assess the current engine and order the parts individually?

3. What could I expect to pay for parts and what would be the expected cost of a barnyard mechanic to manage the job?

Trying to set my expectations..

I think there is a Facebook group on these old crawlers. You might want to check that out. I have an old OC-3 and used to follow a group called cletrac.org but they aren't active any longer. You may have heard of Zimmerman's in Pa. They sell parts for these machines. My Oc-3 isn't running now because I have given up on keeping this old engine going. (fuel issues. magneto. etc.) I have seen a repowered cletrac with an isuzu diesel engine but I don't have any info on how it was done. I was also told that a Toyota 22r engine will drop in but I can't verify that. If you ever can confirm one will work like that please let me know as I will like to repower mine...