YM336D - Started knocking loud while tilling

[90cummins]

If you didn't remove the nozzles make sure there are no machining particles hiding in the injector chambers.

 

[tcartwri]

What does concern me is the fact milling .011" from the head makes the pistons much closer to the head, even with the head gasket. Seeing as there are dents in the pistons where the injector nozzles have hit the pistons tops it appears the nozzles are a major concern, especially now.

Domush, You are going to have to source a thicker head gasket, or have one made from copper. You do not have enough running clearance now with your valves. Do not reassemble the motor with a factory head gasket.

 

[284 International]

According to an online calculator, milling the head 0.011" will take your compression ratio from 21:1 to 22.4:1. My 3 cylinder YM186 has a compression ratio of 23:1. While they are different engine families, by itself I don't think will damage anything to have a marginally higher compression ratio. Perhaps the injector pump timing would need to be retarded, but I really don't know. A service manual should address what to do after milling the head, but I have no knowledge of this.

 

[Car Doc]

I am not sure the gas engine calculator is accurate 284 in this instance since we dont know the actual cc of the chambers and the other pertinent info maybe you have all that dont know that either is why I say that?

I have my doubts it raised it a full point but I may well be wrong it may be raised even more but based on the specs needed I dont think we have enough data. jmho

My engine runs fine and I did the same exact mill if not a bit more I however added an extra copper seal under the pre-chambers like I mentioned and used stock gasket bla bla bla fwtw.

 

[Car Doc]

I hate having to remove those nozzles (never did remove them completely), but if that is what is needed, so be it. I was contemplating simply grinding a flat spot into the nozzles in order to make them flush with the head, as right now only one of the three sits below the head surface, and only about .005". That would not require much grinding. It seems every time i have to remove something else, something else breaks and requires another Hoye order.

Opinions on grinding the nozzle bottoms instead of shimming?

I have been scratching my head over the hesitation to knock the pre-chambers out Domush for a guy who can build pullers to remove liners this task seems like an ant hill to a mountain climber just saying...

Also once they are out (if you so decide the need) be very careful with the injectors there is s very sharp point on the end that is critical to the proper injection stream so knock the chambers out from the bottom with a deep socket over a bench is my advice so they dont damage the tips.

here is the Hoye link to whats under there fyi. (I cant cut and paste it why dont know?)

www.hoyetractor.com/DESIGNS/injector-parts.jpg

 

[California]

be very careful with the injectors there is s very sharp point on the end[/url]

??? do you mean the pre-chamber is pointed, the part he was talking about grinding down?

The injector itself is blunt on the end. Here is my photo that corresponds to that Hoye diagram.

FWIW - I haven't tried it but Aaron (Hoye) once commented it is very difficult to drive the chambers out after they have been in there many years, and this would be a project that is best left to a cylinder head shop. (or an experienced pro like Car Doc). I'm guessing this is because the injectors are mounted at an angle, requiring the head to be blocked at an angle before putting it in a press.

 

[clemsonfor]

??? do you mean the pre-chamber is pointed, the part he was talking about grinding down?

The injector itself is blunt on the end. Here is my photo that corresponds to that Hoye diagram.

FWIW - I haven't tried it but Aaron (Hoye) once commented it is very difficult to drive the chambers out after they have been in there many years, and this would be a project that is best left to a cylinder head shop. (or an experienced pro like Car Doc). I'm guessing this is because the injectors are mounted at an angle, requiring the head to be blocked at an angle before putting it in a press.

He said to whack them with a hammer and big socket, maybe they are tighter than that?

 

[winston1]

Hoye sells this tool, I believe they have it made or make it themselves. May be a little high for one time use but I doubt Hoye has much mark up on the item. Yanmar Tractor Parts: INJECTOR REMOVER KIT

 

[California]

That tool will pull out the injector, the component shown in my photo. The head doesn't need to be removed. This is similar to removing a spark plug (except a straight pull).

However the two 'chambers' below the injector (see Hoye's diagram) need to be driven out from below.

 

[winston1]

That tool will pull out the injector, the component shown in my photo. The head doesn't need to be removed. This is similar to removing a spark plug (except a straight pull).

However the two 'chambers' below the injector (see Hoye's diagram) need to be driven out from below.

Woops, my bad, I thought there tool pulled the whole works.