How to make the decision regarding pistons?

[lastcowboy32]

We have a Chinese-made tractor on the farm that we used up until a couple of summers ago.

At that time, we just had that and a Ford 2N... and we were baling something like 3000 bales a year. It started having mystery heating problems, losing coolant, etc. It also had an issue where the oil pressure would start out at 40-50PSI and then get down to 10PSI as soon as it warmed up. I took off the head and had it checked out at an engine shop, the head was fine. I replaced the head gasket and put the head back on. There were no leaks from the head gasket... but the problems persisted. So, I'm positive it's not a head issue.

At 28hp...that little tractor was overmatched. I can't blame it for puking out after running a 7 foot haybine and a NH 276 baler for a couple of summers... all it did before that was mow lawns and move a little snow. All of the bearings, sleeves, rings and such were probably just plain worn out...given how the oil pressure drops like a rock as it warms up.

At that point in time, I had enough money to either fix this tractor, or buy a used Ford 3000. Given that the Ford 3000 was bigger, more horsepower, etc, etc. I went with the Ford. We also now have a Ford 4000. We also did an in-frame rebuild of the Ford 2N, and that's been running like a champ.

So...now... I'm looking at this little 28hp Jinma sitting next to the garage and thinking... I should get it back up and running over the next month. Good project to get done before we start building fence in April.

I looked up parts. If I tear down the block and replace all of the sleeves, rings, bearings (main, connecting rod...etc) parts will run me about 600 bucks.

If I replace the pistons, connecting rods and all of that hardware as well... that's almost another 500 bucks.

Is there a way to inspect or test the pistons, once I have them out?

I mean, in my little Ford 2N...I kept all four original pistons... cleaned all the deposits... just replaced rings, bearings and such.

I don't want to replace the pistons just because I'm in there, but I'd like to think that I did my due diligence in inspecting them.

 

[buickanddeere]

purchase something with live hydraulics , live PTO, a real drawbar, working brakes , a slow reverse. a slow first gear and a modern 12V electrical system.

 

[centash]

He's already got that.....and yes, the pistosn can be checked to see if they are in
spec. An engine rebuild shop can do it if you do not have the specific micrometers.
Ben

 

[Steve@Advance]

There are several things to check when reusing pistons.

Skirt to bore clearance, ring land wear and taper, and wrist pin clearance are the most important wear items to check. Obviously there is a need for careful inspection for damage and cracks.

You really need the wear tolerances and engine specs for that particular engine, and the instruments to perform the measurements. If this is something you are not equipped to do, a good diesel engine shop can help you make the decision. They see them every day, know what to look for.

Diesels are a whole different animal than a low compression, low tech gas engine. They are very unforgiving of shortcuts. Approach with great caution, one mistake and it's all over!

 

[lastcowboy32]

(quoted from post at 14:27:08 03/07/19) There are several things to check when reusing pistons.

Skirt to bore clearance, ring land wear and taper, and wrist pin clearance are the most important wear items to check. Obviously there is a need for careful inspection for damage and cracks.

You really need the wear tolerances and engine specs for that particular engine, and the instruments to perform the measurements. If this is something you are not equipped to do, a good diesel engine shop can help you make the decision. They see them every day, know what to look for.

Diesels are a whole different animal than a low compression, low tech gas engine. They are very unforgiving of shortcuts. Approach with great caution, one mistake and it's all over!

OK. That's the gut feel type of information that I was looking for. I don't want to extrapolate my success with re-using the 2N pistons into a different situation.

Now that we have some bigger machines to handle the mowing and baling, I'm really missing how nimble this little Jinma was.

It has 12 forward gears, four reverse gears, four wheel drive, a loader (with down pressure) and a 1/2 remote.

It just needs a lot of TLC in the engine compartment right now.

 

[lastcowboy32]

One other option is, 1600 bucks gets me an entire reman block with sleeves, pistons, rings and all bearings replaced... but I think I would need gaskets on top of that.

Yet another option is to just go for the complete and utter rebuild kit...all rings, pistons, bearings, sleeves, gaskets... every wear item in the engine... for 1100 bucks.

 

[buickanddeere]

(quoted from post at 17:24:21 03/07/19) He's already got that.....and yes, the pistosn can be checked to see if they are in
spec. An engine rebuild shop can do it if you do not have the specific micrometers.
Ben

Talking about why to avoid a Ford N series .

 

[lastcowboy32]

I understood where you were going there.

Thing is, I love our little 2N. I bought it for 800 bucks, rebuilt the engine for another 600, and I get all sorts of use out of it raking, drawing wagons, tedding, running the finish mower.

I have no idea where I would get that much utility for 1400 dollars out of any other kind of tractor.

Can it do all of the things that a modern tractor can do? Not by a long shot, but that's why we got the other Fords and why I now want to fix the Jinma.

 

[lastcowboy32]

The 600 bucks for the rebuild even included a repainting of the hood and fenders to blue and white to make it look like a big Ford

 

[David G]

I would spend the money on a bigger tractor.

 

[ss55]

2X on a bigger tractor.

 

[lastcowboy32]

(quoted from post at 09:53:56 03/11/19) 2X on a bigger tractor.

You know, I was going to post a somewhat snarky remark here about how all of my machinery is paid for...etc, etc.

But, in the spirit of being open-minded, I noticed that one of our local Mahindra dealers was running a special.

So...what the heck, I contacted them to get a quote.