M135 Muffler

[m1010plowboy]

This M59? http://armedforcesmuseum.com/m59-personnel-carrier/
Oh ya, this M59........ http://en.wikipedia.org/wiki/M59_(APC)

Two GMC Model 302 six-cylinder inline petrol engines
146 hp at 3600 rpm ( per engine, combined 292 hp )

That's a lot of horses with a pile of RPM so carb size/type would be good to know. I'll keep digging. Our 302 was only spec'd at 3,350 +/-50 rpm and what's that horsey number 130?.
The M59 would go nice with your M135! You have a muffler already, just need the rest.

The G749 parts just need some encouragement to be found. My soft tops showed up in a sea-can and I'll give out contact info, as soon as I know of inventory and condition. Any day is a good day with an NOS save.

 

[cmpman]

If you go to TM9-8025-1,the GMC Model 302 engine manual, it covers the engine as configured for the truck and for the APC. The APC version uses a zenith updraft model 263AW14 carb. There are illustrations of each on page 11.

 

[m1010plowboy]

302 M59 Carb set-up

If you go to TM9-8025-1,the GMC Model 302 engine manual, it covers the engine as configured for the truck and for the APC. The APC version uses a zenith updraft model 263AW14 carb. There are illustrations of each on page 11.

I looked right at it and flipped the page. Thanks for pointing it out!

 

[Blake]

G749 mufflers are still out there!

 

[MWMULES]

Wow if you want to let loose of one of those, please let me know! Great find.

 

[hendersond]

I suggest you buy a second truck just so it has a good home.

 

[SturmTyger380]

Any more where those puppies came from?

 

[Blake]

Those (2) were it. They were in a odd lot, found when cleaning out a garage. The guy that had them didn't even have any army trucks but knew someone/somewhere was looking for them. The m221 is very happy!

 

[metal magnet 1963]

Hello, I don't mean to poke my nose into stuff, but just had a thought how you could easily and very cheaply make the pipe flanges. Just put a short length in a small lathe, and with a homemade flanging tool, flare the end to perfection! It would be a learning curve to be sure, but would work.

 

[USMC 00-08]

I like your thinking! Welcome to the forum!

 

[SturmTyger380]

I wend down to my local muffler shop that does custom stuff. He had a flange machine and made about 5 of them for $25. I took an old one for him to look at.

 

[metal magnet 1963]

I like your thinking! Welcome to the forum!

Thanks, I've been trying for some time to find the very same item, and have come to the conclusion that home built is my one and only remaining option, but I also want the closest resemblance to the real article. I know the flanges will be the hardest to duplicate.

 

[hendersond]

Welcome! nice avatar, is it your truck? good idea. Thank you.

 

[metal magnet 1963]

Welcome! nice avatar, is it your truck? good idea. Thank you.

Yes it is, but looks way too small. Will try to get a far better picture uploaded. As for the muffler I'm going to make the whole thing and try to post progress here later. Hope to help others solve the same issue. Thanks.

 

[m1010plowboy]

G749 Muffler

How many mufflers are we going to need over the next 20 years?

Trying to get a handle on the G749 current and future muffler needs so a 'one off' can be done more efficiently. It'll actually be a "seven off" because I'm going to need them.



In regards to "detonating mufflers", the muffler man suggests we drill a +/-3/16 hole in the down-pipe before the muffler. This may reduce any gas that has been known to slide in the muffler, contributing to the big bang.

I'd like to get some feedback on our absolute minimum...and maximum design needs...and just thinking outloud but if you want to throw ideas in, it's appreciated.

-Can we just build a can and put ends on it or do we have other concerns like back pressure, tuning, dba?
- Can we maintain the amazing throaty sound and still go cheap? Build 2 styles? Hollow and packed?
- If "Restoring to the highest possible prestigious and original standard", do we need to re-create the inside of a muffler...to get points with the purists...and make them proud of what we did?

Met a girl in the 80's who had a friend that met another guy and we all had kids together, well not together but at the same time, not together in the same room at the same time...we did it at different times, a few times we might have done it at the same time because we did go to a few parties together, the 80's were crazy. His kid, who we're all very proud of, rides a bike at the G749 farm and his new job has him building tuned exhaust and mufflers. He just wants to know if it's 20 or 200 that he needs to build for the old deuce.

 

[hambone]

Plowboy, I would be interested in a muffler. I see the kid rides a green machine, between my two sons, we spent over 20 yrs. in the motocross world. I wish I had all the $ back we spent on the sport, new bikes, maintenance, travel every weekend, injuries(many broken bones), I could have had a nice MV collection. Looking back on it, I wouldn't change a thing, built a great relationship with my kids, if you don't keep them interested in something, they will get interested in the WRONG things. Hambone

 

[USMC 00-08]

I may be interested in 2 or 3 mufflers if it is cost effective to have them built and shipped south of your border.

I have a good original muffler (currently on my truck) and a hollow shell without an end on it. Been meaning to get that end welded on the hollow one so I can test the two. Life happens and I have not gotten around to it.

A man that I know who drove these in the US Army in the 1950's said they used to hollow the mufflers out to get better performance on the then new G749's. That is what I was wanting to test out. He said the sound was not that much louder after doing the modification.

 

[m1010plowboy]

Muffler

This is going to be like a big green bike, back smashing muffler reunion. I remember when the muffler kid's Dad broke his back, while dirt biking ......so bikers should get a special gimp rate, me thinks. This was one of the kid's projects for his sled. He's got great support and the best boss he's ever had, next to his Dad or me.



Here's the muffler kid's shiny shop.
http://www.npowerperformance.com/


We're one step closer after dropping off a donor muffler to get cut in half so we can document and re-create a few original styles if we want.



The ends are recessed, convex and likely seamed. I asked if he could re-create the hamburger they used to bond the ends for historical value.....he was quiet for a second. From a production point of view it's easiest to punch out an oval and weld it in place. We're tossing around -- build expense vs. durability and longevity-- but I can't build junk so we agreed on a $300.00 budget for a prototype. He's going to toss some ideas around so if he had to punch out ten, or one more in 2025 that we can get quality for a decent price. Getting the price lower will only happen if we can find a way to punch out good quality pieces and pop'em together quicker. He'd rather have an open budget and do a complete stainless exhaust system on Goose so it's good to have that option available if someone's doing a show piece.

I asked if he's stay off the bike until I get my muffler.

 

[metal magnet 1963]

Once the pattern is made, (the hard part) production will show the short cuts you can make to faster, better production. The market is out there, it will sell.

 

[metal magnet 1963]

Muffler suicide

How many mufflers are we going to need over the next 20 years?

Trying to get a handle on the G749 current and future muffler needs so a 'one off' can be done more efficiently. It'll actually be a "seven off" because I'm going to need them.

View attachment 576850

In regards to "detonating mufflers", the muffler man suggests we drill a +/-3/16 hole in the down-pipe before the muffler. This may reduce any gas that has been known to slide in the muffler, contributing to the big bang.

I'd like to get some feedback on our absolute minimum...and maximum design needs...and just thinking outloud but if you want to throw ideas in, it's appreciated.

-Can we just build a can and put ends on it or do we have other concerns like back pressure, tuning, dba?
- Can we maintain the amazing throaty sound and still go cheap? Build 2 styles? Hollow and packed?
- If "Restoring to the highest possible prestigious and original standard", do we need to re-create the inside of a muffler...to get points with the purists...and make them proud of what we did?

Met a girl in the 80's who had a friend that met another guy and we all had kids together, well not together but at the same time, not together in the same room at the same time...we did it at different times, a few times we might have done it at the same time because we did go to a few parties together, the 80's were crazy. His kid, who we're all very proud of, rides a bike at the G749 farm and his new job has him building tuned exhaust and mufflers. He just wants to know if it's 20 or 200 that he needs to build for the old deuce.

View attachment 576851

Plowboy, I don't think that idea of drilling a (big?) hole will fix this problem. The problem is only when you rev the engine up mid to high rpm, and then quickly close the throttle, causing a rich, mostly or completely unburned mix to go out the exhaust. THEN, when it finds a little bit of air to burn, comes the BIG BANG! You can't have a cracked exhaust, burnt out exhaust gaskets, or any "air " leaks at all. If you look at the video of my M-135 engine in the stand, you will see me jump from "hot foot" when the engine flames from the exhaust. That manifold is cracked, and has gasket blown out, PLUS, the heat riser shaft is snapped and half gone. By the way, I made that piece of down pipe from a piece salvaged from a 2000 G.M.C. 1/2 ton , with a 4.3 engine. It fit the flange, and all I had to do was flare the end, fit right on. It's aluminized steel pipe. I want to make my exhaust from that type of material, but after I correct the other issues. I like the idea of some sort of "relief" device located near or on the muffler just in case. Only the muffler ever explodes, so I would be temped to put the relief there. Like a spring loaded trap door device.Would only work under a over pressurization situation, and then keep the peace, (and quiet!)...
I need to make at least three mufflers, so I'll be in the thick of this this winter.