Posted: Wed Feb 18, 2015 9:44 pm Post subject: 1952 M38A1
I picked up an M38A1 a while ago. I don't have a whole lot of experience in the automotive world, but I think it is pretty solid. I've got a couple of long-time military vehicle restoration artists helping me keep this thing running. So far, I have been able to drive it much more than I have had to not. I actually daily drive this thing since the end of last May.
I don't have any pictures. The thing was in good enough condition that major rebuild pictures haven't been necessary. In lieu of pictures, I have added the wiring diagram I did up after we completely ripped out all the wires that were in it and ran fresh wires in a better fashion.
The story goes that a previous owner swapped in a Chevy 153. I don't know when or what year, but that was one of the engines in the Nova and Chevy II. Consequently, he converted it to 12V. Some places, the wiring was duplicated. Other places, he spliced in new connectors. I say 'spliced'. Really, he twisted the conductors together and wrapped it in electrical tape. Everywhere.
Well. It never has run quite right. The thing finally died with the huge cold snap we had out here in Idaho a couple months ago. I blamed the battery. I was wrong. One of the two wires coming out of the alternator had corroded clear through. Being overconfident in my wrenching ability, I took out the connector from the alternator. It was really a brush. The parts store said they couldn't even get in repair parts for something that old. In goes a new, modern alternator. Remember, this is 12V, so don't feel bad.
Since the alternator was out and my two helpers had the vehicle at their mercy while I was at work, they ripped out the wiring. This is nowhere near the first M38A1 they have done in either 12 or 24V.
While in the project, I upgraded the headlights. They were always dim. They really needed replacing. But, rather than sealed beam, I found these sealed beam conversions:
The amber LEDs on the bottom make for a great turn signal, which allowed me to remove the trailer lights that were being used as front turn signals. The halogen bulbs do great, too. I am really looking forward to being able to replace the bulb without having to swap the whole unit. They fit behind the bevel perfectly.
So, that makes for new alternator, headlights, and wiring. The wiring was an adventure. I couldn't figure out why my fuses kept blowing. I blew 5 30A fuses before I figured it out. When you run wiring to the taillights, remember to go back and hang it correctly after terminating. Don't forget that it is draped on the muffler. _________________ Andrew
Joined: Nov 18, 2010 Posts: 75 Location: San Juan Island WA
Posted: Sat Feb 21, 2015 10:53 pm Post subject:
The f-head in my A1 works well, but if I ever replace it, I figure it to be replaced with a Chevy 153 (I have one I could use). How does the 153 do in the A1? Any insight would be good to hear. _________________ 54 M38A1 delivered 2-54
53 Strick M100 #79
70 DJ5A
I really like it. But, I've never driven any other A1. The last month or so I have been getting 20MPG. The engine has more torque and horsepower than the original, so my limiting factor is the T90 transmission. I have taken it up to about 55Mph, but it was a horrible idea. That transmission just screams at anything above about 35Mph. Now, I try to keep it down about 45Mph on the highway. My drive everyday makes this pretty easy. I only have a short stretch of highway faster than that, and I go in early enough that the few people on the road can go around me pretty easily.
I have some problems with dieseling when I shut it off. I don't think that is from the engine, inherently. I think that problem is between operator error and maintenance. I just haven't been able to get the mix and timing quite right.
Maintenance is dead simple. I have next to no mechanic experience prior to this thing. With that shortcoming, I am still able to keep it going. Most parts are even still available locally at part stores. I have put in a new alternator, mechanical fuel pump (that's actually a point to address in a minute), and new plugs and wires. The NAPA up the road had everything for me. I have what I assume is the original oil bath air filter. I also have a Carter single barrel carburetor on it. Again, rebuilt with NAPA parts.
As for the fuel pump. That was the only part that has been a major concern. A previous owner had put in an electric fuel pump. I don't know if there is such a thing as a metered fuel pump, but this one definitely wasn't. The electric one just gushed too much fuel into the carb. It would flood in a heartbeat. Other than that, all the maintenance has been easy to figure out.
I have heard of a few other A1s set up like this. There was one at the Tower Park show in California last year that was in great condition. That guy was just running up and down the lines the whole show in it, purring along. It was obviously tuned better than mine. But, even with the poor setup mine has, it does great.
I'm not really smart enough to comment on if you would need to do a 12V conversion. But, if you do, there is now a convenient diagram on how to do it. This one even lets you keep the military style start switch rather than have a keyed ignition. _________________ Andrew
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