6.7 stick in a 5.9 hole

biggy238

biggy238

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So I'm searching this, and in regards to physical fit (not tuning, not electronics) there are two crowds: the guys who say it doesn't work, without a reason why, and the ones who say it does.

I'm gathering that the hold down has to be machined to allow the clamp force needed to secure the CRIN3.
How much? Is this the only machine work needed, or does this vary by cylinder head/year production? I'm going to be running an 03 head for the time being.

I'm also curious to hear who has this setup running cleanly with a CM849.




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A 6.7 injector won't fit in a 5.9 hole because the injector bore is too deep.
It's very close, something like ~ .100 needs to come off the top of the injector bore for the tip/sealing washer to seat correctly.

I don't think there is any issue with the retainer ring.

Mark.
 
So with no alteration, the quill tube would also misalign?

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If the injector bore is 0.100" too tall, that would position the port 0.100" higher also, would it not?


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Testing
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The only thing being changed is the top of the bore, where the retainer sits, the dimension from the nozzle to the transfer tube remains unchanged.
Measuring both injectors confirms this.

Mark.
 
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You are contradicting yourself now.

If the nozzle is too high in the head, the quill tube will be also.

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If you machine down the top of the bore, the distance between the nozzle and the feed inlet/quill bore does not change... The "takeoff" dimension is outside of that CL.
 
CL?


We can go on and on about this. I don't have both injectors and a loose head to demonstrate with.


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You're over thinking it.

The distance from the BOTTOM of the injector bore UP to the quill tube entry point is the same.
The change is ABOVE the quill tube entry point, ergo machining the bore ABOVE the quill tube will NOT affect the quill tube's positioning in any way.

The truth is that the 6.7 injector won't seat in the 5.9 head simply BECAUSE the bore is too tall ABOVE the quill tube.
If you were to try to install the 6.7 injector in the 5.9 head as it is now, the quill tube would probably tip UPWARD to meet the feed hole and I know for a fact that the tip would leak compression past the copper washer.
Machining the top of the bore will correct the problem.

OR you could machine the bottom of the locator ring on the 6.7 injector body, which has also been done to correct this.

You have the parts there, do some measuring and looking, then come back and tell me what you find.

Mark.
 
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I am currently running 6.7 injectors in a 5.9 head, the top of the Injector bore and also the area were the hold down bolts need to be machined down about .100-.120 for a completely unmodified 6.7 injector and holder to fit correctly in a 5.9 head.
If you only machine the bore then you have to modify the hold down. If you don't machine the bore the injector will not seat to the bottom of the bore and you will have a bunch of compression in your return line.
 
Mark Nixon said:
You're over thinking it.

The distance from the BOTTOM of the injector bore UP to the quill tube entry point is the same.
The change is ABOVE the quill tube entry point, ergo machining the bore ABOVE the quill tube will NOT affect the quill tube's positioning in any way.

The truth is that the 6.7 injector won't seat in the 5.9 head simply BECAUSE the bore is too tall ABOVE the quill tube.
If you were to try to install the 6.7 injector in the 5.9 head as it is now, the quill tube would probably tip UPWARD to meet the feed hole and I know for a fact that the tip would leak compression past the copper washer.
Machining the top of the bore will correct the problem.

OR you could machine the bottom of the locator ring on the 6.7 injector body, which has also been done to correct this.

You have the parts there, do some measuring and looking, then come back and tell me what you find.

Mark.
Click to expand...
The only part I was "thinking" about is where the quill tube would strike the body of the injector, if the head weren't machined and the injector were shimmed upward.
Obviously this would wreck timing and duration with the nozzle that much farther out of the combustion chamber.

That is a 6.7 body I posted isn't it?

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biggy238 said:
CL?

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Click to expand...

Sorry... Center line. The distance between two points. That will not change because your issue is "outside" of the area between the bore "floor" and the feed hole.
 
Agreed. What I'm talking about is how high the injector sits in the bore before and after machining, which in turn changes where the feed port on the body sits in the cylinder head.

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Take a measurement from the bottom of the bore cup, to the center of the feed hole... Then measure from the crush washer on the injector to the center of the inlet. That will show what you are looking for.
 
QMFB said:
Take a measurement from the bottom of the bore cup, to the center of the feed hole... Then measure from the crush washer on the injector to the center of the inlet. That will show what you are looking for.
Click to expand...
So, explain in your words, what is accomplished by machining the 0.100" from the bore.



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That allows the Injectors to seat into the bottom of the bore. So the crush washer can do its job.
 
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