My '68 M715 Build Progress Page

[plumas.placer.miner]

Thanks for sharing that term; I had not heard it before. I did a little reading up on Babbitt and Chevy engines, and I found this forum thread:

https://www.chevytalk.org/fusionbb/s...hp?tid/277213/

They talk about a 235 inline 6, but after 1953 it seems most engines were changed from a splash oil design to a high pressure oil design, so they aren't manufactured using Babbitt alloy after that...I think.

The engine in my M715 is (by casting number) a 1973-74 Chevy 4.1 L (250 c.i.) inline engine. I think that means it's passed the dates of the Babbitt alloy used in the manufacture.

I am going to rebuild the engine at some point in the next couple of years. Right now, I need to make it safe to drive, stop the leaks, and abate the rust.

Plan my work, then work my plan.

[plumas.placer.miner]

The rust abatement got me thinking about sand blasting. I found a great deal on this compressor (I love Craigslist when it works as advertised), so over spring break I installed this beast outside my shop, and the manifold inside my shop. The 1 phase, 5HP motor and adapter brackets will be here in a couple of days.

[Von]

Great truck.
The 250 is a fantastic engine. If I remember right the rear main seal is a 2 piece you can replace without removing the crankshaft from the engine. And the valve cover is prone to leakage after they've been worked on... By that I mean they get bent out of shape easy when they're pulled and won't seal correctly after that. Usually if somebody used a wire wheel to clean the mating surface, that'll deform the metal just enough that it'll leak.
All tins are like that but the old Chevys seemed to be a little thinner metal to me. You might be able to find a new one if that's the case with yours.

And if it's like every other truck on here it'll need new wheel cylinders and rubber lines for sure. and if it's the original master cylinder, the old seal on it will start leaking when you start driving it regularly.
The E350 wheel cylinder conversion and a dual reservoir master cylinder conversion are pretty cheap and easy.

Beautiful plumbing job on your air lines!

[plumas.placer.miner]

It's been awhile since I have posted. Sometimes health issues and work get in the way of working on my truck. Who doesn't hate that? I am happy to say that I have refocused...

1. I got a little side-tracked by this trailer. 1968 M101A1 that matches my truck. I had to have it. My wife now thinks I am certifiably obsessed. I told her, "But look..it has matching tires!" She chased me around the house with a wooden spoon.



2. Brakes...yeah brakes. They all looked good when I bought the truck. No leaks and they stopped the truck. Good thing I bought new wheel cylinders because the bleed screws were so rusted I couldn't loosen them...at all. Not even after I took them out and put them in a vice....with heat, and...well, you get the idea.




Also, the brake lines have been replaced and they need attention...whoever did the work, didn't take time to do it right...or well. They go loop-de-loop. *sigh*



The shoes all looked good though, and don't need to be relined yet. The brakes were thoroughly bled yesterday and today I will adjust them. I put a little grease on the points where the shoes rub the back plate to keep down the chatter.



Another thing...it's practically impossible to get a wrench in between the rear U bolts and the backing plate of the wheel to change the wheel cylinders. I'll bet the military mechanics hated to change them.

I got so frustrated that I cut the rear U bolts just to be able to get a wrench in there. American mil-grade steel is hard. I wore out 3 saws-all metal blades cutting one U bolt out. I have the other new U bolts already and I will replace the the others soon enough.



3. There's strange news though...The salesman that sold me the truck told me it had a Chevy 250 in it. I was okay with that, but when I started looking closely, I couldn't find the casting numbers anywhere online. As it turns out, the engine is a AMC/Jeep 232. Did I mention that I am not a mechanic? So sure, go ahead and think it...I am a moron. I agree with you... haha. Did I mention that I am not a mechanic? *Ahem*.

Bromide: My 1968 Kaiser Jeep M715...I am trying to think of a name for it...something that describes what a beast it is, but my mind keeps coming back to: "learning curve", or my wife's favorite: "the disappearing bank account balance".

Next stop: Exhaust leak (where exhaust manifold connects with exhaust pipe), Engine oil pan leak (it's pretty bad) and transfer case leak (at front differential output).

[plumas.placer.miner]

Interesting fact I stumbled upon today...Yes, I know it's a wiki, but it was interesting nonetheless...

My 715 has the AMC 232 in it, which according to this wiki entry, could possibly be the original engine. That's how I read it anyway. My M715 is an Air Force vehicle, further complicating matters. I have not seen another M715 sporting Air Force insignia. There are Air Force stickers on the dash.

https://en.wikipedia.org/wiki/List_o...nes#Kaiser_230

Kaiser 230

American Motors neither designed the Tornado 230 nor used it in a domestic AMC-branded vehicle. Subsidiary Industrias Kaiser Argentina (IKA) produced this engine in Argentina after the 1970 merger and used it in a variety of vehicles. In the United States, this engine is often confused with the AMC/Jeep 232 cu in (3.8 L), which Kaiser Jeep purchased to replace the SOHC Kaiser engine 230 cu in (3.8 L) in 1965.

The Tornado first appeared in civilian Jeep vehicles in 1963 and was only used until 1965. The US Army M-715 and derivatives used it through the 1960s and early 1970s. The AMC and Kaiser engines do not share bell housing bolt patterns. Cam trouble on the 230 was common due to inadequate oil formulations of the time.

Its under-square bore and stroke endeared the engine for low-speed torque. It was a dependable engine with reports of them going 250,000 mi. with no major problems—with proper maintenance. Production continued through 1983 in Argentina where AMC used it in passenger cars and Kaiser in Jeeps.
____


There's one other strange factoid I found about the AMC engine and the T98 transmission. This is on Novak's page here:

https://www.novak-adapt.com/knowledg...ns/manual/t98/

it says:

AMC Jeep

The T98 and AMC eras are anachronistic and the transmission was never joined to an AMC engine. There are neither factory nor aftermarket provisions nor compelling reasons to do so.

Yet, that's exactly the config I have in my 715. Bizarre.

[plumas.placer.miner]

Here are images of the bell housing and adaptor between the AMC 232 and the T98-1Z transmission that Novak says is "anachronistic" (meaning an error in chronology).










Meanwhile...The master cylinder is not stock for this year Jeep M715, AND it leaks at the piston seal, so I bought a new one *sigh* ($73.00 at O'Reilly Auto Parts). No, I didn't buy a waterproof stock master cylinder (I don't need waterproof). The one in this photo is from a 1968 Jeep J3800. I like this master cylinder because there are two reservoirs...one for the front brakes and one for the rear brakes. Since I am going to use this truck up on my mining claims in the high Sierras, the idea of brake redundancy appeals to me. The dude will abide.

[brute4c]

I always knew there was a setup to do that but I had never seen one before...thanks for posting!

[plumas.placer.miner]

The guys at Novak were amazed. They had not seen one either. They said they might post the photos I took of it on their site.

It's an AMC 232 or 258 bell housing with a 7/8" adaptor plate. They said that the adaptation was "clean", which I took to mean that it was not a poorly made home-fab job.

Since the truck seems to be an Air Force model, and the VIN is late 1968, and Novak had never heard of an adaptor plate for this config, I am wondering if the truck was manufactured with the 232 in it. I guess I will never know.

[Beast]

Seeing as it appears to be a hodpodge of both 24v and 12v items, I highly doubt it was built that way. More than likely it was a swap somewhere in it's life after it left the military. All the trucks in the military have used a standardized 24 volt system since 1952, these are known as M-series vehicles and where an upgrade of the electrical systems compared to the old 6 volt systems in WWII vehicles. By standardizing the electrical systems in all M-series trucks it makes supply and service easier for the military.

[plumas.placer.miner]

You are certainly correct that the vehicle has been converted to 12v, and that some items are original, such as switches, etc. The truck came from Michigan (there are names and an address on the title), which explains the rust on the undercarriage, but before that, I don't have any info.

It's been fun to learn about this truck, and I am appreciative of everyone who has commented and offered insights and knowledge. It has been a fun project, but I have learned that if a person wants a fully restored, pristine vintage vehicle, it saves [lots of] money if you buy it that way. By attempting to make the mechanical and electrical systems safe and functional, I have spent more money than I thought I would...by a significant amount. I am trying to keep the exterior of the truck looking original, and those NOS parts are proving to be expensive.