Freightrain

I remember a video from way back showing a big power KW getting out run by a Mack up a hill in Australia . The KW driver was like WTH! I tried searching for it but never find it.

When I met Karen 20 yrs ago, they still used their rotary phone in the dining room as their main phone. I bought her a cordless phone so she could go sit on the couch and be comfortable talking on the phone instead of standing in the corner! 😆

Dang. Fixable but will take some Norm Abram skills. I have replaced the side door of my trailer once already and it is getting rotten again. I need to seal the wood(or use cedar) as water gets behind the aluminum sheeting. It is a day project once I get the wood cut(non std dimensional wood). If the builders would just use the right wood you wouldn't have rot issues.

It is, just fuel and timing is different. The "673" denotes a Thermodyne(multi gear trans) and the 675/676 was Maxidyne(5spd).

Yup, from what I have read.

I think the 285/300 were 676(maxidyne). The 300+ isn't the same.

Thanks Steve. What I need to know is the serial number after the Etaz673c, does that correlate with anything? 7S8762 ??

Ford had similar coding for clearances so they could put correct parts together without having assembler measure anything.

Not sure of year. Only thing I have is serial on motor. EtAZ673C 7S8762. If that means anything. I looked on Agkits and they want truck serial number. I hope we can work around that.

Shop I use can cut rings. No issue there. Using fingernail, I'm guessing +.020 deep currently. Pretty solid groove. I did get #6 piston out. Was able to wiggle past oiler. Rod bearing was 12-7 112 62GB33-P1 Crank and bearings look fine.

Was hesitant to pull injectors, but going to have heads cleaned up. Should I zip the two bolts out of clamp and do they pop out easily? Will there be a seal ring in hole?

They are at least that. The deck has 020 hand stamped at each cylinder? Protrusion is more then that? Fire ring may be that by feel?

They are there, #4 had some crud in the area where gasket was blown. It was going to get worse had I try to just install and run it.

Got the heads off. Yup, took a 5ft cheater to get them to SNAP loose. Looks like I had a head gasket on its way out on #4? Rest looks ok. Cylinders ok, no damage. Noticable wear on top of liner. Not huge ridge, but very detectable. Not a " fresh" rebuild.

I wondered what "low flow cooling" was. Terms passed around and never knew what it was about. Thanks for clarifying.

I got it up on legs and the pan dropped. Looks like someone has been in it before. Orange silicone on the back and the main bolts look like the paint is chipped off like it has been apart. Rolled new brgs? It has signs that things have been apart other places(orange silicone). When I looked at truck originally I tried to find the serial number on frame but severe mud and crap kept me from getting in too close. I wonder if this is a transplant? Truck had straight 5 spd, did it originally have a 285 and this was put in? Never know now. Has new air compressor and lots of other pieces that don't match paint. It was definitely tinkered with. No idea on mileage (or hours) either. One bigass pan. Noticable marks from previous fingers in the bottom end. Will work on getting heads off next.

I welded a 1/16" thick lip on my cab and bolted boot to it with thin aluminum backer on the rubber side. The new opening for the bunk I made a similar lip to bolt boot to. Sounds like the up fitter just kinda cobbled it and hoped it would last past any warranty. 🙄 My trailer has similar luan(thin 1/8" plywood)with vinyl covering. You could replace that yourself. I just painted mine white to match.

CH looking good. The Windfall Wimmen model really add to the class!!! 😉 Bummer about the GMC bunk. I've been fighting leakage on my trailer for years. Had to replace the ceiling in the front(bed area)along with the three walls and part of the plywood flooring. Went from "eh" to rotted and mold in short order. I have the leak fixed so it should be good for awhile. I forget what the bunk looks like? Alum ext. with luan panel inside?

I was going to try to add one to my 237, but got a whole motor. I hear they are quiet noisy at full song? Guess I will find out. Seeing they are 40+ yrs old, it is likely harder to find one? Mine does work, as I had motor running and if I jabbed the throttle it would send a touch of wind into it and it would spin easily. They were popular before CAC was mounted in front of radiator.

The difference is, the 237 and 285 were made for only 5 gears. The 300+ isn't, so I bet it was slow to recover on a shift.

That Mack 10 spd must have similar OD as my Triplex. I want more though. A quiet, get home gear. Even if I only used OD on level or downhill. Not sure a 12 spd would fit under the cab in a B model? I would love to have one.

That would be a cool set up. Seen a few for sale but a bit pricey and not sure about rebuilding cost? Availability?

My 300+ has the flip flop linkage going to the pump so it can push instead of pull. A new local FB friend pulls using a 285/300 and removes the intercooler in an R model. Apparently this pump is " the pump" to run . He turns it like 3000+ rpm, all stock bottom end. Says it is no problem.

The 300+ needs more gearing. Like a Thermodyne. The truck had a 5 spd, but I bet it was a real PITA around town. But it was a fleet truck, so I assume that is why they used a 5 spd.

I'm not overly worried about a deep low. Like my deep under 6041 just for the slow truck race. Beyond that I don't "need" it. I know I am dealing odd pieces and trying to get something that works well together. Decent splits and something like the double OD I have using my Triplex and 6041. Gets me 65 mph at 1500ish. Much quieter then 1800! I don't like lugging it much with that 6041 and the 300 will be harder on it. I wouldn't kick a 18 to the curb if I found one reasonable, even it it means paying full core for it? If there is a DO version that would be a plus. I have the Eaton chart saved, need to look around. I need at least a single OD, period. I will remove the 6041no matter. As for clutch housing, Geoff and I were already poking around at those before I rebuilt the Triplex. Using the Triplex? I could, but I don't want to have to "baby it". If I feel the need to let it rip, I want a transmission that will not flinch. Just a note, I purchased a new $10k transmission for my race car. It is the top of the line, badass, never have to worry kind of transmission. I have no problem with doing that for the Mack. I only want to do this once. Thanks for all the input guys. It will come together somehow.