Flame heater in exhaust pipe

[cattlerepairman]

I never saw a conclusive answer. It appears to be a straight NPT thread, called a "Boss" thread, used in hydraulics and oil drain plugs. A 7/8-18 was mentioned FWIW. I used the metric plugs with teflon tape and never had an issue. I know they are not the "right" thread, just "close enough".

 

[frank8003]

The only metric thread on a Deuce engine exists
Study

 

[davesgmc]

The only metric thread on a Deuce engine exists
Study

??????

 

[cattlerepairman]

The army seems to disagree, at least in the TM9-2815-210-34-2-1 Maintenance of the multifuel engine : "1-11. METRIC SYSTEM. The equipment/system described herein is nonmetric and does not require metric common or special tools. Therefore, metric units are not supplied. Tactical instructions, for sake of clarity, will also remain nonmetric."

I do not remember coming across a metric thread when I rebuilt my LDS, but that is not to say that there could not be one, maybe in the AMBAC systems of the injection pump. The engine follows a German M.A.N patent, after all.

 

[davesgmc]

well, the spark plug hole thread in the intake elbow is certainly metric.

 

[davesgmc]

The injector thread is 3/4 20. Odd ball crap. Can't find anything that will just bolt right in. Guess it's lathe time to make a plug and a couple bungs to weld into the exhaust.

 

[davesgmc]

thread for injector is 3/4 20, odd ball crap/ so the elbow will be drilled out to accept a 3/4 pipe plug for now. to screw the injector into the pipe, a spindle nut from an s10 is 3/4 20 thread, use that welded into the stack. spark plug is simply an 18mm thread, going to used a cut down non fouler and weld into the stack. ned to figure how to lengthen the spark plug wire though. Plans in future will put a sprinkler valve on that outlet, and plumb it into the exhaust. so when the flame thrower system is switched on, some fresh air and turbo boost will entire exhaust, also inject some propane in there, it will ight off with the diesel, spark, propane air=flame. now i am thinking i need to inject all this pretty high up on the stack actually. other wise i may end up with just a flame in the pipe and noting coming out. either way, there gonna be fire.

 

[frank8003]

as to Post #23........
....from a very old flame heater delete post here in SS. I leave it as I found it.

I do know what the plugs are supose to be that go in the elbow on the deuce. Both are METRIC BOLTS.....The larger one is a M20-1.5 get what ever length you can and cut it down to make it a plug length....the smaller one is a M18-1.5 which ironically is the same plug used on an O2 sensor of most any car....so those are pretty easy and cheap to find....you can get them from ebay, the 20mm you have to find at a mom and pop hardware store(ACE/True Value by us) or a bolt supply house.

Anyway I hope this does make it easier for everyone looking to just plug off the holes and not rig anything up......also I suggest a thread sealer on the the bolts.

OHH OOHH OHHH, I know this one! I did the same to the truck that I sold to bonedoc the one hole is the same thread as spark plugs or O2 sensors (same size and pitch) so I used a O2 sensor delete plug that I had. I might have 1 more in my tool box at home. I can't recall what the other was but I don't remember getting it anywhere special. You might message bonedoc and get him to look at his it's been a while since I did it.

I believe what your all looking for is a straight thread NPT . At least that's what I call them. They have a special name that I never remember. You can get them in all sizes at your local hydraulic shop. They usually come with an "O"ring , but you also can use a copper washer.

And from my notes I found
GOLD ANODIZED ALUMINUM MAGNETIC OIL DRAIN PLUG BOLT 20X1.5 20 X 1.5mm M20 X 1.5
Metric threads in a Deuce!
Is there anything else on a Deuce that is metric threads?
M20 + M18 plug!?

 

[davesgmc]

well, the one is definately a metric 18mm, i just used an oil dain plg, the other thread in mine is definately 3/4 20 thread. not metric 20 mm, it does screw in a bit, but is not the same,. i measued the hole and the injector, both 3/4 20 tpi thread for sure

 

[davesgmc]

not too worried about plugg in the intake elbow, as it is getting filled out and retapped for a pipe thread anyhow. and a bung will be made from an s10 spindle nut

 

[frank8003]

So do I gottah work hard and resolve this or is somebody gonnah tell ALL exactly what it is, what is needed? There IS metric threads in a Deuce

 

[davesgmc]

so far a 3/4 20 thread fits the intake elbow fine, but that project is on hold,,,busted balancer is now being replaced.
a m20 1.25 is also very close, both seem to screw in and tighten up, choose which ever off ball ya want, im drilling it out and putting a fitting in for other purposes actually.

 

[Karl kostman]

In the REAL WORLD if you see a diesel truck and the exhaust pipe is glowing RED and flames are coming out of the stack that means that the end of your engines life is represented by all the signs, it wont be long till your walking!