Perkins 4.236 Compression Test Adapter

[Benjamin85]

Does anyone happen to have any recommendations as to where I can get my hands on a compression test adapter for my Perkins 4.236M? I have thought about just getting a standard kit;however, there are of course no glow plugs for this engine and I’m not certain the injector size.

[Lepke]

If you have an old injector, a machine shop can make an adapter out of it.

[Benjamin85]

That’s a good idea. I didn’t think of that. Thank you! I just don’t have an old injector.

[Cheechako]

Where are you? Some mechanics have them. I had one made and split the cost with my mechanic as he wanted to keep it (Florida)

[NahanniV]

I bought a compression test kit that included several adapters including one that matched the injectors on the 4.236 from Amazon for less than $100.
I've never had anything made at a machine shop for less than that.

Biggest difficulty doing that test was removing the injectors.
They will inevitably be stuck in the head.
If you can, take your time and let your corrosion breaker of choice soak in for a few days before even attempting to pull them.

Cheers,
JM.

[Cheechako]

It may be that getting a mechanic to do the test is good thing. One that has the adaptor and an injector puller etc. He'll test it, lube things etc.

[Benjamin85]

Thanks all. I actually found the dummy injector (M21) on Amazon. With the adapter and gauge a total of a little under $100.

I actually had the upper head assembly rebuilt so the injectors were just removed so won’t be hard to get them off and on again.

Sort of a mixed set of answers when I ask this question, but I want to have minimum of 350psi in each cylinder with no more than 10% variance between them and ideally I want 450psi. Does this sound accurate?

[sailor_ed]

If those injectors are held in by two bolts thru a collar then this will help with removal: un thread each bolt ~1 to 1 1/2 turns. Do not remove! Then crank the engine. Compression will usually break them free.



A friend used this technique but removed the bolts. Wound up with injectors flying around the cabin.! Lucky no one was injured. Big pressures involved here!



Good luck,


Ed

[sailor_ed]

Lacking the specs for that engine, I would assume that if it starts well and there is 10% or less variation then all is good.


I'm surprised an expert hasn't jumped in.


Ed