67RModel

Ahhh makes sense with the jakes and overhead cams. Every time I hear one of his stories I wonder "how good could they really have been compared to the competition?" I wanna say their max factory hp rating was 300 but like you said probably had more torque than most other engines of the time due to their larger size. I also always wonder too about the Allis Chalmers 25000 "Big Al" truck engine. Supposedly they were complete animals. Factory rated at 450hp when everything else was 300 or 350 max. I even think they came with a guarantee to be able to maintain the speed limit on any US highway at legal weight. They were painted purple and an option in Kenworth and Peterbilt trucks. I think Mack also built some F model cabovers with them for power. They are super rare and not much information left on them anymore.

I had one with a steel nose for sale a while back along with a DM800. Had them both sold multiple times and the deal always fell through. Luckily the DM600 finally got saved by a collector willing to restore it. The DM800 sadly fell victim to the torch. Its probably Chinese made brake rotors by now.. 😪

I have a buddy who rants and raves about a 1693 Caterpillar and how back in the day they were "all that and then some". He was running them in the mid to late 1970s in A model Kenworths. It seems to me looking back in hindsight they were not really all that impressive other than its large size and ability to take as much fuel as your could pump into it (from what I'm told). From what I understand they were a precombustion chamber engine and not able to have jake brakes installed on them for whatever reason. I mean Mack had direct injection I think as far back as 1953 when the Thermodyne 673 was designed. Also Mack had the tip turbine air to air charge cooler in 1971. I dont think Cat had any charge air cooling until the 3406A and it was the water cooled deal. Cat didn't have air to air until the 3406B in the early 80s. Plus Mack engines could have Jakes installed and they even developed their own Dynatard in I think 1971 also. Also, I am told they were very delicate over 1800 rpm. The valves and rocker arms would get wiped out real easy at higher rpms. I think the 1693s are kind of unimpressive on paper compared to contemporary Mack engines. Most of what I typed about the 1693 is what I have been told so I could be wrong with some of it. Thoughts?

The intake ports on Macks with CMCAC are pointing straight up. the outlet of the CAC runs straight along the top of the engine and turns vertically down into the intake manifold. Even the E7s. And yes by 1978 - 1982 Mack had to have been developing a charge air cooler like we have today. In fact I think they were the first domestic company to offer one. On the E6 engine.

The XT signifies a particular ECM software programming. The engine is E7 Etec with a 460XT tune. 460 being the horsepower. There are many members on here who can elaborate on the specifics of the XT tune versus non XT tuning. And yea $60,000 for that truck is insanity on a whole new level. The bidders that kept bidding after $30k need their heads checked.

They did. They just never sold it to the public. The Mack Big Six. 885 cubic inch inline 6 and utilized E9 cylinder heads. There is one sitting on an engine stand at the Mack Museum.

I think mechanically you need different injector lines and an oil plug in the block. Maybe there is some other small things too. Electrically they are very different if you look at the wiring diagrams for both. All the gauges and warning lights/buzzers operate through the VMAC module and extra sensors I think. So while the engine will run since its mechanical only, your dash might be doing all types of funny stuff. I'm not 100% certain on this but this is how I understand it.

I agree with all of the above. The vast majority of CH613s were road tractors. This one was probably converted to dump service. It is interesting though that It has a double frame. Most road tractors do not, however, maybe this one was specd for heavy haul and the drop axle is left over from pulling a lowbed and someone threw a dump body on it much later in life. Does it have a red button on the dash for trailer air supply? If it does that is another indication it could have been a tractor originally. The air ride would be a complete deal breaker for me for steel body, off road, dirt work. The transmission is another deal breaker for me. A Fuller 9 speed does not offer enough low speed and creeper gears for off roading and getting started in soft ground. Since it has a Fuller the rears are most likely set up for Eaton ratios (0.71 OD). With that being said your options are 8LL, 9LL, or possibly an 18 speed Fuller if you wanted to change out the transmission. If you change it figure on having to shorten the driveshaft since 8LL, 9LL, and 18 are longer than a straight 9 speed. Switching to a Mack tranny (2 stick) would most likely require you to switch out the rear end gears too. Crossmembers and mounting locations are probably not the same to easily switch to a Mack tranny either. You will probably miss not having a Jake since you are used to having one. Although fairly weak on these engines they do help on big hills and save your wheel brakes. Just my thoughts on the subject.

It could be that the pressure gauge is sprung and won't read past 20psi. You could purchase a cheap 0-150 psi gauge and connect it to one of the ports on the air tank just to verify you really aren't getting more than 20psi before you start getting real into the weeds. Does it have spring brakes? After idling for 5 minutes or so if you can try to release the spring brakes. You need about 60 - 65 psi to release them.

I wonder if the fellow JT sold it to still owns it? He is the one that finished the restoration and uploaded all the progress to JTs original thread. It’s over in the other makes section of the forum here. I don’t think he had been active for some years….

Saw this on Marketplace. Don’t know anything about it or E9s in general. Thought somebody here looking for E9 parts may be interested. In Youngstown OH.

I think when I did mine I just disconnected that line from the compressor first and aimed it into a large catch pan and let it drain out that way until it stopped. Then disconnected the hose from the side of the block. It took a few minutes but this way I didn't have to drain out any more than I needed to. This was on a 94 RD. If I remember right the radiator drain / lower hose is still a good bit lower than where that hose runs into the block. Either way will work though.

Ok. That makes sense. Thanks for the info.

I stumbled upon an old 24 page thread in the "other truck makes" about a GMC General truck. Its a great read if you have time to sit down and follow the whole 24 page story. Anyway, I couldn't help but notice how many really active forum members there were then (2014-2017). I noticed there were a ton of "BMT Lifetime" members and "BMT Benefactor" members that just are not here anymore. If you look at their profiles it seems like most of them disappeared in 2019 or early 2020. I came on board in early to mid 2020. Any idea what happened to all these guys? Thanks.

If you scroll to the bottom of the article there are like almost 6,000 comments. A lot of them are pure gold. What a clown this Sam Brinton is. Biden put this deranged clown in charge of spent nuclear fuel for the whole country. 🤦‍♂️

A real wrist snapper if you ain't paying attention.

Quick question: Is a Dynatard the exact same mechanical principle as a Jacob's compression brake with Mack's name on it? I have heard from several guys that they aren't as "good" as a Jake? I never asked what they meant by this. Reliability? Cost? Braking Power? what are the differences if any? Thanks.

Aren't Miller 211s DVI? If so its nice to be able to run of 120 or 240 Volt power incase you have to pack it up and take somewhere there is only 120V outlets. I know it limits your amperage but its better than nothing I guess.

Another tip / hack I think most people know but if not is you can use aluminum foil to "mask" off large irregular objects or objects tape won't stick too like hoses, wires, or oil covered reservoirs. It works the best for hoses. Saves a ton of time too.

One thing to think about if you swap your green cab onto the tandem dump chassis is the brakes. Looks like you have BW type 20 brake chambers on your drives. I believe the part number is 227851. As you probably already know they are just service chambers with no provisions for spring / emergency brakes. I assume this truck has a hand brake lever in the cab and a brake drum assembly on the output yoke of the transmission for parking. The service chambers you have are long obsolete and finding rebuild parts / replacements for them is very hard. The other bad thing about this setup is the fact that you can't just stick a 30/30 chamber or similar on there with some additional air plumbing and call it good. The clearance to the wheel is too tight. The mounting hole center-to-center is the same but the overall diameter and length are issues. A 20/24 chamber won't even fit. I have the same setup on my B81. I pondered this a lot and tried several different types and sizes of brake chambers. Basically your only two options are to 1: fabricate brackets that offset the chamber toward the frame to gain clearance from the wheel and use an offset slack adjusters. Or 2: obtain a pull style spring brake only chamber and mount it 180 degrees of the service chamber to pull on the slack adjuster with a small chain. I have seen several old (mid sixties) DM800s with this setup from the factory although they used steel rods instead of chain. I guess it was before the compound chambers were perfected and/or common. Haldex still makes pull type spring brake chambers but they are insanely expensive (around $400 each). I don't think you necessarily have to change them over since I'm guessing it will be just for hobby use / antique vehicle but for me the thought of a 15,000 pound vehicle rolling down the road with no way to stop it if there is a sudden air loss is scary. The good news is for a hobby truck you probably only need to convert one axle to have emergency brakes since you won't be hauling any weight. Just something to think about if you use the tandem chassis.....

Also, the original Maxidyne trucks from say 1966-1972 have two as well. However, the lower one is open ended under the hood. I assume so the intake air stream is partially warm. These trucks didn't have charge air coolers so I don't know why they did that but they did......

Darn. I gave away a good FRO15210B a few months ago when I was cleaning out my garage. I had it in there for years and nobody wanted it. I think the guy just turned it in as a core. He had a deal with Weller I think that if he gave them two 9 or 10 speed cores they would sell him an overhauled 13 speed. ¯\_(ツ)_/¯

I did not see this until just now. I will check in a day or two and let you know. $2000 for everything.

I don’t know if it’s like this all over Pennsylvania but in my area/district there is a program if you get a DUI or something like that the local magistrate(s) will order you to serve community service with PennDOT. From what I have heard and seen it amounts to riding around in the back of a crew cab pickup all day and sleeping. I see people all the time sleeping in the back seat of these PennDOT rigs around me.

I put this up in Craig's other thread about if a 350 Cummins would fit under the hood of a B42. I have this R model with a super healthy 237, 6 speed lo hole trans and Mack rears if someone needs a powertrain. Truck is crusty but the powertrain components are great. And it has jakes on it. $2500 in Pittsburgh, PA.