new/used/rebuilt engine needed for JD 4100

[coloradotrout]

Thank you! I'll be making that contact today. If I can find a known good condition engine in that price range, that's the solution.

Bruce had one. If this works out, that would be amazing. Thanks Darryl.

 

[Kernopelli]

Glad to assist:thumbsup: Keep us updated.

 

[coloradotrout]

Should there be noticeable compression when turning the crank by hand? I can feel one piston going to the top. There's a good bit of force applied and then released. On the other two it's not that noticeable. This is with the valve cover off, dipstick tube off, oil pan off.

 

[coloradotrout]

Sharing a bit about the project. To get the Yanmar 3TNE74 ready for the JD 4100 have to:
swap exhaust manifold
swap governor/shutoff (to add solenoid shutoff for JD)
move fuel pump
move a block plug from near the oil pressure sensor
swap oil pan, spacer block, crank cover
swap frame mounting plate, starter

 

[dfkrug]

Should there be noticeable compression when turning the crank by hand?

Yes, lots of compression, but you can not easily tell which piston is pushing and which one is pulling.

It has been 2 weeks. Does this mean you bought an engine from Bruce, and you have it already? Details, man!

 

[coloradotrout]

Got the engine from Bruce. Fast ship, but got them swapped with a guy in NE. NE guy brought mine to me on 8.22. That added 4 days. Pretty much have all the parts off the JD that need to go on the Yanmar. All parts off Yanmar. I'm ready to start installing. Thus the compression check. With the YM pan off I can see the rod action. I can feel when compression is most. Your point about a vacuum is interesting but I would think it's the tdc compression that would be very noticeable. It is for 1 cylinder. Right as it's going to top there is a big increase in torque needed to rotate the crank. That's once in 2 revolutions. I believe that should occur 3x in 2 revs. There are 2 other times but they are much less compression and I can hear air escaping. It's many hours to the end so I don't want to continue unless I'm more certain this engine is good.

The valve cover is missing and when I got it one of the push rods was out from under the rocker arm. I had to loosen the rocker to get it under. Im not sure how it's possible to come out without pretty substantial force. I need to pull the rocker off to see if there is any other damage.

 

[dfkrug]

Hmm. What did you have to pay for this motor, and do you know anything about hours or use? Warranty?

Since it is easy when the motor is out, I would pull the head and check the bores. Replace the head gasket and rings if bores look good. A compression check is also a good thing to do, but that takes a special adapter and removing the injectors is not easy.

As for the valve springs, they are so soft you can compress them with your thumbs. My guess is that the engine got bumped in handling, which knocked the rocker off the rod. I wonder what happened to the valve cover....

 

[coloradotrout]

Bruce said valve cover was damaged. But it's gone. $1475 w ship. Was told 500h. Probably from Japan so no history. I can pull head and replace rings, but now I am edging past where I expected I needed to be with this engine.

 

[dfkrug]

Bruce said valve cover was damaged. But it's gone. $1475 w ship.

That is not bad $ if it is in good shape. If you drop it off your forklift or truck and it lands on its valve cover, I will bet that
the impact can pop a rocker off its valve.

 

[coloradotrout]

Yes. Fair price for full block. Even with the parts I have to swap a fair price. But if compression is low whole new ball game.

 

[ericm979]

Pull the injectors and turn it over with nothing in it so you know what it's like. Then put in one at a time to see what each cylinder feels like. Better yet, buy a compression tester for diesels. If one tests low, put a few cc's of oil in and do it again. If compression goes up, the rings are worn. If it doesn't, the valves or head gasket is the problem.

 

[coloradotrout]

Would using the glow plug opening be the same? Looks like there is a 10x1.25 adapter in the harbor freight compression kit also.

 

[ericm979]

Yes that works too.

 

[dfkrug]

Would using the glow plug opening be the same? Looks like there is a 10x1.25 adapter in the harbor freight compression kit also.

Interesting that you have glow plugs. Many of those DI Yannies for JD tractors use a heated intake instead. Or does the replacement engine have a different head?

I have never done a Diesel compression test, as the injectors are often very hard to remove, and you can tell other ways when you have a "bad hole". Great if you can use GP hole for gauge.

 

[coloradotrout]

(PS.. via mobile, my posts keep getting deleted when I try to edit)

I used the glow plug holes. I'm getting no measurable compression. I can hear air coming out from the bottom of the pistons. There is some compression - I can feel it with my fingers, but not nearly enough to register on the gauge. The spec is 498 psi.

I pulled all 3 glow plugs. It does crank over easier with them out. I put one back at a time and tried to measure. Nothing.

But at 498 PSI, I cannot imagine being able to turn the crank.

There's no oil in the engine (obvious since I have the pan off!). There was some, maybe a cup or so that poured out when I took the pan off. Pan looks good. No metal particles.

Am I missing something obvious? Is oil and heat needed to make these "air tight". I cannot imagine all 3 have major compression loss.

I want to put it all back together and start it up, but that's probably 20 hours for me. A lot to lose if I have a compression loss.

 

[coloradotrout]

I repeated the glow plugs insert compression test with a drill spinning the crank. Until I twisted and broke off the socket adapter I was able to get about 50 psi. That was 3 or 4 rotations. Plan now is to clean up the old engine pan, pan spacer, oil tube, crank cover and bolt them loosely in place. Then tip up the engine, strap it down, put on the mounting plate, flywheel and original starter and give it a spin that way. If compression then checks out, I'll proceed with putting the newer engine in the JD. There's red RTV on the Yanmar engine oil pan, grey/black on the JD. Which RTV should I use? block to spacer block, crank cover, oil pan to spacer?

As a side note, I compared the fan/alt belts. Mine with 1800h is at least 2x more cracked than the replacement engine. No idea if that translates to the replacement engine being much newer.

 

[coloradotrout]

I did a leak down test. Cylinder nearest the fan was 59 of 60 psi, next two cylinders 23-27 of 60 psi. I applied 60 psi input and observed the cylinder pressure. It's all leaking from around the rings. That's a cold engine - obviously since I have never attempted to run it. It's still sitting on the bench. I did watch the pressure through the piston motion and it varied some, but at TDC that's what I observed.

 

[coloradotrout]

Bruce is confident it is fine. He's agreed to 7 weeks from delivery to warrant the engine of excess oil consumption or loss of power. On to assembly.

Suggestions on rtv for block spacer, oil pan, crank cover? Suggestions for anything on the other paper or metal gaskets?

 

[dfkrug]

Suggestions on rtv for block spacer, oil pan, crank cover? Suggestions for anything on the other paper or metal gaskets?

Most Permatex RTV silicone gasket material is fine. You can substitute it for a paper gasket if there are no clearance issues. No sealants on the head gasket.

A leak-down test is the gold standard, and that is what I do. Sounds like you have bad rings.

 

[coloradotrout]

A leak-down test is the gold standard, and that is what I do. Sounds like you have bad rings.

Yeah, I'm afraid of that. Bruce insists his engine is good. Odd that 2 are nearly identical but in the 25 of 60 psi range. Hate to spend hours buttoning this all up, but he's convinced his engines are good. I hope so too!

Head is on. I *just* need to swap/add fuel transfer pump, a bolt-in plug, solenoid shutoff, oil spacer, oil pan, crank cover, mounting plate, flywheel, and the other ones I'll remember (I hope) as I run into it!

Oil spacer, oil pan, need rtv. Most others are paper/metal gaskets that I have. Should I put any gascacinch or such on those? or just dry?