vanscottbuilders

Hi Chuck,

You'll like it here.

We have trucks and parts, discussions and services available.

Advice and opinions, whether you need them or not.

And, mostly, we have a really good group of people who are into

the same thing you are - prerserving our old Mack trucks.

Welcome aboard.

What part of the country are yor from?

Paul Van Scott

I think Thaddeus is correct at 23,000 lbs. and the stamped brake shoes make it fairly new.

Probably post 1970.

Send the info and a donation to the Mack Museum, and I'm sure they will confirm it.

Paul Van Scott

Good for you!

Looks like a nice project. I love it when they run and drive before you start with the restoration.

Paul Van Scott

Spanky & Morgan,

I was pretty surprised to see this latest post. I really thought that these two vehicles had come home long ago.

It's gotten pretty tough to run around the country and pick up these antiques at low rates, as much as someone might want to.

We have made an effort to help whenever possible, but at $3.50 plus per gallon and add in the cost of insurance, permits, truck depreciation and maintenance, trucks need to be paid both ways for a load like this.

And at the going rate of around 1.75 to 2.00/mile, you can do the math.

I would suggest that you contact a freight broker or flat bed trucking company in Oregon to see if they have anything that might cover your trucking costs one way. Or perhaps a broker might put the load together one way, albeit at a slightly rate.

There are numerous internet services that advertise loads for different types of trucks. Check them out.

As for the load itself, if Morgan's Peterbilt is still a part of this load, then with both trucks loaded on the trailer, you will fill a 48-53 ft. step deck. And the trucker will need ramps.

Just some things you might want to pass on to the broker.

It will be less expensive if both trucks can be loaded at the same yard. And if they can be unloaded at one yard, also.

That's my two cents.

Paul Van Scott

Sounds like a good candidate for a truck project - Good Idea!

Sure is big torque at 630 ft.lbs. - more than our old Mack diesels, and at a pretty low

RPM for a gas engine.

275 bhp is no slouch either.

And I'm surprised at the short stroke. I would have guessed at a higher rev limit because of it.

It's a cool old motor. Thanks for the info.

Paul Van Scott

Guys, I am really curious - what kind of power did the GMC V-12 pump engines develop?

And did it develop the same power on gasoline as on natural gas or propane?

Looks like a neat project - just saving it from the scrap yard is a good thing!

Thanks,

Paul Van Scott

This sounds like a TRD series duplex transmission, which may have been available behind the early Maxidyne engines.

If that is the case - the transmission, if it is direct drive, is a ten speed gearbox. (the overdrive version only uses nine of the gear combinations).

It is shifted by splitting each of the forward five gears, if needed.

However, with the huge torque and the wider power band of the 237 Maxidyne compared to the 673 or 711 engines that preceded it, you probably do not need to split each gear, all the time. Indeed, one of the more common transmissions of that time for the Maxidyne was a straight five speed direct drive box.

For more information on TRD transmissions, go to www.oldmacksrus.com and you will find a wealth of good stuff!

There is a very good possibility that the gearbox is not original to that truck, or the engine is a transplant. It was pretty common to upgrade to the "new" Maxidyne engines.

Good Luck,

Paul Van Scott

Cayoterun.

There are some people here who know a lot more than I do but I'll give this a shot -

I think that all of the B model cabs themselves are essentially the same dimensions. The fenders, hoods and radiator shells are different from model to model.

There are also, however, some differences in some of the cab panels. For instance, a concave, or curved back panel was an option on any of the B cabs. Its' purpose was to allow a longer trailer to be legally hauled. So it is primarily an East Coast option, where the length laws were shorter than west of the Mississippi.

On some of the heavy duty B81 & 83 cabs I have seen a different floor pan, which I understand may have been an option on any B cab. It provides a drop of about 2" to allow for a taller driver.

On the B-66 & 67, the engine protudes through the firewall into the cab which reduces the interior room by quite a bit. Add the concave back panel, and the B-67 is not a good choice for anyone but a skinny, small guy. I'm trying to figure out how I will fit in my own!

So to answer your question, I think you could get a B-61, 73, 75 or any of them other than a B-66 or 67. You might fab up a dropped floor pan like the factory option, and you really should be quite happy with the room.

Good Luck!

Paul Van Scott

Cayoterun,

You might contact B61 Fred on this site.

He has several B73 or B75 trucks that he might consider selling.

All are in need of restoration, but have decent sheet metal, if my memory is correct.

And, he is in southern Indiana, which isn't too bad for you.

Good Luck!

Paul Van Scott

This is good stuff !!

Thanks,

Paul Van Scott

Interesting !

I like the look too, Thaddeus. It does remind me of a pre-war KB International.

It will be fun to see how it is accepted by the buying market.

No matter how it looks - it still needs to work.

Paul Van Scott

If you go to the Bendix Air Brake site - they have a great schematic showing a basic air system in a truck, and the various tanks, valves and lines.

It is printable, and in color, to show you the pressure system, reserve system and emergency system.

Good Luck,

Paul Van Scott

It's interesting how you noticed the easy loosening of the bolts, even with years of rust.

I found the same thing on two of my old Macks, albeit 50's vintage.

I wonder if the quality of steel has anything to do with it?

A quick pop on the wrench, and even the worst looking bolt seems to come loose.

Sure is a lot different than some of the projects I have tried.

Sounds like you are making good progress.

Best of Luck,

Paul Van Scott

I've found that it pays to look in the weeds and behind the newer stuff in equipment yards, and in farm fields and behind people's barns.

With the price of scrap steel as high as it is, some of these old trailers are not coming to a good end.

Both of you are in good parts of the country for old trailers - not too many rust problems.

It just takes some patience and nosing around.

And I agree - Glenn, that is really nice looking B-61. Welcome aboard.

Paul Van Scott

Sounds like quite a find for you!

Did someone buy the truck and put it away for future use or what?

Paul Van Scott

That looks like a pretty nice old truck.

I paid $2,000.00 for a single axle in similar body condition and non-running.

Also had the original 673 diesel and transmission.

My guess is that the tandem is not worth a lot more to a restorer. Unless someone is really going to use it,

it just adds weight, brakes and tires to the project. And it eats into what limited power is available.

If you don't want the truck, would you mind sharing the location and contact info with

everyone here?

Hate to see a nice one like this go to waste, or worse, go for scrap and get sent to China.

Thanks,

Paul Van Scott

It has been a great year for me - Mack wise!

Thanks to everyone here for all of their help and comments.

Mery Christmas to all of you.

Paul Van Scott

Bob,

I have had great luck with the Mack Museum. For the B and H models, at least, they have been very accommodating.

You might try them with a phone call, or a letter with your request and a donation.

Good Luck - that sounds like a nice trio of trucks.

Paul Van Scott

I appreciate that, Thanks.

But I meant what I said about my old knowledge -

you guys who know about the newer trucks have a leg up on me.

And you're right - this is a great forum for the exchange of info, and don't ever be afraid to correct anybody here.

Thanks again,

Paul Van Scott

This is a real good idea!

I'm buying two for friends - Thanks

Paul Van Scott

I need some help, and I hope I can find it here.

The rear end of my B-67 is apart and ready for re-assembly.

I need a source for all of the seals, bushings and brake shoe clips required for the CRD78 carrier

and 541A rear end housing. (Single axle)

The brake shoes can be re-lined, or if I can find them, I would buy those too.

Specifically, I am looking for the old style brake cams (coarse spline, flat paddle cams), brake cam bushings and seals,

brake shoe seals and clips (16 pcs. each), new shoes & linings (if possible), brake springs and a pinion seal.

The seals at the cams and brake shoes are a rubber cup with a felt "seal" inside.

The cams are probably useable with some cleaning and sanding. They are rusty and pitted on the bushing wear surfaces.

But I don't think I will ever wear them out, so if necessary, I will reuse them.

The brake linings are "bolt-on", and I should be able to get those done locally. The shoes look like they are pretty good.

I would oil up the springs and reuse those too, if I couldn't find new ones.

It would be good to find 20 of the old style "fine thread and coarse thread" wheel studs.

Our local Mack dealer was not much help, even after an hour or so of looking at old microfiche.

Ultimately I will need three sets of these parts just to complete the trucks in "the pipeline".

I will be out of touch until Friday - so Thanks in advance.

Paul Van Scott

I have seen a bunch of them..just not sure what kind they were. Never owned a truck with one either. I remember some RD800's having them in the mid and late 90's but I really dont think they helped that much.

You guys are way too new for me. My experience and knowledge of Mack stops in the early 70's.

Sorry if I have given out any bad information.

It would be my guess that the reason for the exhaust valve spring beef-up for the optional combo engine brake was for

the pressurizing of the engine, as I said earlier here. That is the primary stress point of the exhaust brake.

Paul Van Scott

A jake brake kit would cost you around 15 hundred or a little more, you might be able to find a used one for a lot less, in my opion a dynatard is not the way to go I have one on my truck and it's pretty much useless, I also have a truck with a jake and the differernce is like night and day.

Jeff,

I suggest that you talk to Barry at Watts Mack - they have a TEC engine brake kit for all two valve diesel

Mack engines. TEC is a good replacement for a Jacobs brake. Jacobs apparently does not offer the two

valve engine brake for the Mack engines any longer.

Paul VS

Jeff,

There are several exhaust brake manufacturers, all with basically the same idea.

The units simply provide a controlled obstruction in the exhaust system to pressurize the

exhaust back through the cylinders, to provide resistance to the piston coming back up on the

exhaust stroke.

It's a very simple principle, and a very effective way of getting engine braking from a diesel.

However, it is not without risk.

First - the higher rpm diesels are more efficient at exhaust braking. Mack engines, with redlines of 2,100 or so,

are slow turning, and thus, not as good at exhaust braking as the new "pick-up" diesels, which wind up to about 3,500 rpm.

Second, and most important, pressurizing the exhaust system also provides resistance to the valve train by making the

valve spring work harder to close the exhaust valve. Therein lies the rub - particularly with older engines. The valve springs

need to be beefed up to stiffer units, if you are going to use an exhaust brake with substantial back pressure. (ie.: more than 25psi)

The unknown piece of this puzzle is "how strong does the spring need to be?" Too strong, and you will be doing damage

to the valve train and camshaft, and, if not strong enough, the valve will float, and potentially contact the piston.

That's not typically a desired result!

Other diesel manufacturers (Cummins, Caterpillar, and Detroit) have all offered exhaust brakes as options in the past.

The Williams exhaust brake was the pioneer in the field. As Jacobs engine brakes became more popular, exhaust brakes

fell out of favor, for the above mentioned problems.

Today, they seem to making a comeback with the advent of diesel motorhomes and pick-ups.

Mack, as near as I can tell, never offered a factory approved exhaust brake. There were a lot of units installed by the dealers.

Probably made for some interesting warranty conversations, when the engines failed.

From my research, I have found that the Mack 673 and 711 series diesels were designed for 35psi backpressure, as new.

Age and hours weaken the valve springs, so it stands to reason that a used engine will not stand that pressure.

With a healthy valve train, I would not be afraid of a 30psi brake unit. Again, however, you only have about 2,100 rpm

to work with. As the revs wind down, so does the braking effectiveness. In the end, I am not certain the effort is worth it.

Keep us posted.

Paul Van Scott

Morgan,

I have had really good results with Yellow Freight for moving a transmission and a rear end carrier with gearset.

On both occasions the rate was surprisingly reasonable. And - they deliver to your door.

The shipper has to be able to crate or palletize the transmission and load it onto the trailer, then you have to be able to get it off of the trailer. The rest is easy.

We just recently used them again for a large commercial air compressor - same great results.

Give them a try.

Paul VS