How come the engines are so dang loud?

[linesplice]

OK, so someone can get a laugh from this, but I'm a newbie to these trucks and I am wondering why the 6-cyl diesel engines are so dang loud? I've had a number of 6-cyl diesel's on various (farm) tractors over the years and none of them are anywhere near the 100db. I have heard people say these things emit.

 

[Westech]

22 to 1 compression ratio has alot to do with it. Most diesels are 17-18.5 to one . O yeah and no muffler helps too.

 

[ken]

So the enemy can hear you comming for 10 miles and have plenty of time to set up a ambush.

 

[linesplice]

You'd think with 22:1 compression, they could squeeze more than 140 horse power out of them. What's the torque rating on the multi-fuel engines. Seperately, how come there is almost no information on the R6602 gasser - some people say it has a load of torque?

 

[Westech]

Its the multi's combustion chamber that gives it the low hp. The fule is sprayed on the sides of the cylinder wall and just a little bit in the center. That way it can burn all different fuels with different flash points. ( it burns more even *this is what makes it multi fuel*) You ever hear a cummins knocking away? thats because the fuel is sprayed right in the center and it makes big HP. But do you hear a multi knocking away? you better not!! its a compromise between power and flexibility.

 

[Jones]

De-tuning give less power but longer engine life. Locomotives where I used to work have Detroit 20V645s and 710s that put out 3,200 to 3,600HP. The same engine, for marine applications, with changes in pump timing and minor cam differences but no other modifications is capable of producing 6,000HP.
At the 3,200HP settings the RR gets 1,000,000+ miles between major overhauls better than 95% of the time.

 

[linesplice]

Very interesting. Thanks for the info guys. Some people are or have discussed the benefits of swapping a Cat or Cummins for the white or hercules multi-fuel since the M32 "can't get out of its own way". Think it's worth it?

 

[Westech]

I tell you what.. I truned up the fuel a bit in my multi fuel and rebuilt the top end (gaskets) and it moves just fine. I can do 55-60 all day long and with me adding taller tires I can get 65 out of her or 55 at lower RPM'S.... And look at this point too... a good tuned up Multi in a deuce is capable of 10+ mpg!!you think you will get that with a cat?

 

[Jones]

Look into injection pump timing and maybe bigger injectors before you throw the multifueler away. Like I said, little changes make big differences with diesels.
They like lots of cool clean air so maybe an air cleaner off of a 5 ton and an intercooler are future mods to consider. They don't like lots of exhaust restriction. Large dia. pipe lets the exhaust gases expand and cool too. Noise is nothing more than audible range air at anything over atmospheric pressure. The more differential, the "louder" the sound. As far as the whistle from some of the turbos; the more gases you put through a small opening the more the turbo whistles. The loudest multifueler turbos always look way undersized to me. All those CFMs spin the turbine and compressor wheels up beyond supersonic tip speeds. Put the larger "clean air" turbo on it and that will quiet the deuce down some.

 

[2deuce]

I'm wondering why the multifueler doesn't seem to get more miles on it between rebuilds? Since it sounds likes its detuned. Seems like none make it past 70 or 80 K.
If the muiltifuel was converted to diesel only did it get new pistons and new injectors with a better spray pattern too?
I'm also curious what the torque rating was for the R6602 in a truck.
Thanks

 

[Jones]

A lot of the problems with multifuelers is having a bunch of green troops that don't have to pay for their own repairs or explain to daddy why the rigs come back in the shape they're in. A lot of different drivers, all bent on seeing just what the deuce will do and not owning the vehicle makes for people who don't care how they drive the truck. Most deuce/ 5 ton/ HMMWV/ CUCV owners have a lot better luck and longevity out of a rig they have personal time, effort and interest in.
When a deuce is converted to straight diesel, all the motor pool does is lock down the fuel density compensator and re-route a line or two.

 

[ken]

2d, with regular oil changes and driven sensibly they can easilt make it past 100k. Since they are geared soo low people run them very close to the redline. Any engine ran at it's max rpm or just under won't run forever.
When they were converted to diesel only they bypassed the Fuel Density Compensator. They had some trouble with the compensators leaking fuel into the motor oil. The conversion to diesel or mutlifuel doesen't take long so it can be put back easily in the field.
Sorry i don't have any info on the gasser #'s
LS, I'm with westech if you crank the fuel rate up it will fly. Just watch your exaust gas temps and you'll be fine.

 

[Katch1]

another point with the noise is that it is a 50's era engine. Noise levels weren't a major consideration. If you do turn up your pump, I would suggest a pyrometor, you may want to know whats going on

 

[Westech]

well the multi fuel engine is "constant/continuous duty" rated. its made to run at 2600 RPM for over 12 hours straight

 

[G744]

Having the exhaust dump out in front of the passenger door contributes to more noise levels in the cab as well.

dg

 

[cranetruck]

Continous duty means that it can run at rated power forever. On my trips it runs at 2,200 to 2,600 rpm for 10 to 12 hours straight and it just loves it purring along. The replacement Cat engines are not rated continous duty at full power.
In a cab that isn't sound insulated and with an exhaust system that doesn't have a muffler, one has to expect some noise.
Few tactical war machines are quiet. Actually, I'd hate sitting in a sound proofed air conditioned cab if somebody was trying to shoot at me....

 

[reblawyer]

Somewhat related but a little off topic, how can you tell if a multifueler has been converted to diesel only? The engine plate on my deuce reads White multifuel but someone has stenciled diesel only on the tank.

 

[rmgill]

Check the fuel compensator. If there is a length of fuel line that runs from the fuel compensator and then back to it (looks like the lobe of a highway cloverleaf) then it's been bypassed.

 

[Westech]

well i found the torque of the multi... ld (non turbo) 300fp @1400rpm. ldt 305 fp@1500 rpm and the 5 ton lds 425 fp @ 2000 rpm

 

[bones1]

Somewhat related but a little off topic, how can you tell if a multifueler has been converted to diesel only? The engine plate on my deuce reads White multifuel but someone has stenciled diesel only on the tank.

I know old post. Can someone elaborate on this or are there any pictures of this conversion?.