Diesel Compression Tester for Yanmar 3TNE88

[Mechanos]

I'm looking for a compression tester with an adapter to fit my Yanmar 3TNE88 engine. Not having much luck. Anyone know where I can get one without having to go through John deere or Yanmar dealers?

[ctlguy]

I am not aware of one otherwise. Was in a hurry so I got from Yanmar, $1,600. Good luck.

[dfkrug]

[QUOTE=ctlguy;3028770]Was in a hurry so I got from Yanmar, $1,600. QUOTE]

Holy crap! Why not just make one, or have a machinist do one up custom? I
understand the hurry, but $1600?!

[ctlguy]

Yes that is always an option, but machine work isn't exactly cheap either. OEM tools unfortunatly fall under a different catagory than over the counter tools especially when price is concerned, most of the time I find the quality to be there as well. It will get used again (it better !!), and make some money in the process, but yes to buy one, use it once and place on a shelf. Not worth it, you might find out what a repair shop with the acceptable tools to give you a quote for compression test. My situation was a little different as time was my most important issue, I had the kit in my hands the next day and out the door.

[Mechanos]

Well, it looks like I found an affordable tester, but it does not come with any adapters. I also located two different adapters for this tester... an 17mm and a 21mm. Now I just need to determine which of the two fits my 3TNE88. I'm pretty sure it's the 21mm, but I need to verify that. I do have a buddy with a lathe and a Bridgeport mill. If it comes to it, I'll have him turn one out for me. If one of these two adapters works, it will be far cheaper than having him jack with it.

[Mechanos]

Looks like the injectors are M17's afterall.

[ThomasH]

I have one of the Harbor Freight units with 13 different adapters. I am not sure what all of them are thread wise tho...

Diesel Compression Tester Set - 14 Piece

[kenmac]

If you haven't bought yet, Hoye tractor parts has them




Yanmar Tractor Parts: COMPRESSION TESTER KIT - READ NOTES!

[dfkrug]

If you haven't bought yet, Hoye tractor parts has them

I see he makes them on his lathe. Note that there isn't even any threading involved, as the
injector hole is smooth and a clamp holes it in.

I admit I have never performed a compression test on a diesel, tho I have many times on
gas engines and I have rebuilt several JD (Yanmar) direct-injection engines.

You may want to consider instead performing a leak-down test. That setup is not
expensive and only has to handle 100psi. Furthermore, it will help pinpoint the
failing component (rings or valves). That's what I prefer.

[Mechanos]

I see he makes them on his lathe. Note that there isn't even any threading involved, as the
injector hole is smooth and a clamp holes it in.

I admit I have never performed a compression test on a diesel, tho I have many times on
gas engines and I have rebuilt several JD (Yanmar) direct-injection engines.

You may want to consider instead performing a leak-down test. That setup is not
expensive and only has to handle 100psi. Furthermore, it will help pinpoint the
failing component (rings or valves). That's what I prefer.

Yes, I plan to do a leak down test too. I can use the same adapter for both compression and leak-down. I've also used the leak-down setup to hold the valves in place to install new valve seals with the head still bolted to the engine.