The Stovebolt Site Forums The Parking Lot Big Bolts Untouched 1938 1.5 ton, want to make daily or every other day - driver

Hello All,
I have an untouched 1938 1.5 ton. .. seems rare to find. I have done a little reading but thought for my specific scenario I would just ask the experts here, so please no flames from those more learned. First, I really like the looks of the truck and want to keep it original BUT want to drive it daily. So I first thought:

A. I would keep it all original.. look for any potential safety issues and verify all components were working so I don’t get left on a side road.. I could go that route.. even down to the rims.. (split widow makers).. Tires are expensive.. looks like I ‘ve got 22”.. I am still learning.. Rear appears to be a 4.11. So my top speed will be 45mph.. I could deal with that and go side roads. But is that reliable for daily driver? .. probably 55 miles a day.. or every other day.. what breaks?
B. OR should I go with a different axle in the rear (which apparently entails new dually rims and tires.. ) bc the rear gears cant be changed..and a 235 or 292 engine?

If I go with “A” and change to “B” later.. are the tires a loss? Or do they make matching dually rears that will accommodate the tires I spend money to place on the old rims? Either way, it sounds like I should upgrade to at least front disk or dual breaking system for safety (I love the look of the rear drums and axle..) , 12v system, seat belts.

Side questions:
- What modern dually axle would fit my setup if going with “B”
- Are there less expensive tires?
- Can radials be put on split rim?

THANK YOU ALL!

Welcome the the Bolt.

You should read the first two sticky threads in this section.

Remember that if you want more speed, you will need more of everything to go along with it. First is brakes, then is more torque from the engine. I would say you have something up in the 6:1 rear axle ratio. I daily drove my 46 2-ton with stock everything but front disc brakes and updated electrical system. Could run 60 on the interstate, but more comfortable around 50-55.

Okay Thanks. I have read some of the sticky and intend to read more. I am only estimating 45mph after reading some other forums about piston speed and rpms on the iron piston 216.

I think the brakes would be fine if you have good shoes and use a dual chamber master cylinder. I would also think about the gas that it will take to drive every day, gas is cheap now but I have a feeling it will go back up in the near future.

Welcome to the Bolt!

Not knowing your skill set it's hard to tell someone which way to go with a project. Keeping it 100% stock is the cheapest way to go. There are lots of half done projects out there where the owner got all excited with the new toy and then after tearing it all apart realized they were in over there head both skill wise and money wise. You need to have deep pockets to modify these big old truck...nothing is easy or cheap AND it takes 10 times longer to get it done!

Mike B

Your split rims will accommodate radials. You will need tubes and liners. I ditched my split rims because I only had 1 truck tire shop near me. A normal tire store won't touch the split rims.

Just to foot stomp all of the above... Especially Mike B's spot on comments. But to synopsize (and to throw some cold water out there before this gets too far out of control) further, I only offer this as food for thought (and assuming your location means Baltimore, and with the further caveat that while I am by no means an expert in any of this and actually a pretty sorry mechanic, I have been running this web site for 25 years ... in 3 more days ... and have seen a lot of projects come and go):

Am I correct in assuming you have not yet driven this truck out in traffic or on any public access road?

Your Option A, IMHO, is not achievable. For a truck of that vintage, "All original" or even "mostly original" and "Daily Driver" are mutually exclusive -- Pick *one* Especially in a traffic environment like Baltimore City/County. Within the city limits ... no way would I contemplate running a vintage vehicle as a daily driver. Outside of the city limits would have its challenges, as well. Ask Billy Marlow -- He has considerable experience driving larger vintage vehicles in that region. You could try it, but I suspect you will quickly abandon this plan.

Your Option B will require Time, Funding and Expertise in copious amounts -- do you possess these or at last have access to them? Frankly, pre-War trucks (especially big ones) require a lot of modification before they are suitable for daily use.

My recommendation is to keep it original (for now, you can always modify later... but its only original once), get it running and driving safely and reliably and just enjoy it while you get to know it as is. The truck *will* tell you if it should get modified into a daily driver or not ...

And BTW, there are a lot of us in the PA/MD/VA region and we get together a lot. Check out the Old Dominion Stovebolt Society forum below this one (scroll down).

Welcome aboard!
John

I'd suggest you do some further research and/or measuring of the rear axle ratio. A 4.11 gear behind a 216 engine in a 1 1/2 ton truck isn't realistic. A 5-something ratio or one approaching 6:1 is a lot more likely. If it's got 22" wheels, that's also been changed from the 20" wheels it probably came with when it was new, probably looking for more road speed at the expense of performance on hills without downshifting. Unless you're an expert at adjusting the oil clearance on Babbit connecting rods, your daily driving is going to end up with a noisy engine pretty quickly, followed by serious rod knocks. I've been working with Babbit rods for over 50 years, and I would not attempt to drive a spray-oiler engine on a daily basis in a 1/2 ton truck, let alone a big rig. Then there's the "crash box" transmission- - - -how good are you at shifting up and down in a traffic situation with a non-synchronized transmission?

There are some engine and drivetrain upgrades you can do without sacrificing the "original" appearance to the casual observer. To anyone experienced at looking at vintage vehicles they will stand out like a polar bear in a coal pile. A 261 engine, a SM-420 transmission, and possibly a later model higher ratio rear axle and a Hydrovac brake booster for the stock brake system, or swapping the COMPLETE brake system from a newer truck would be some options. Trying to do half-donkey upgrades to a brake system by installing a bunch of mismatched parts is deadly dangerous, and ought to be illegal for anyone with less experience than an automotive engineer.

Just a few suggestions and observations from a "seasoned" wrench jockey. I'm 74 years old, and the guy in the middle of 5 generations of mechanics- - - -from my grandfather to my grandson.
Jerry

Another vote for keeping it all original.

Post some pictures when you can.

1938 1.5 ton mine will run 55 but is much happier at 45, keep in mind truck speed limits were lower back then. From the service manual 5.43 to 1 rear axle ratio may be identified by a 2 or 3 letter prefix beginning with T stamped in front of the serial number on the top right hand side of the differential housing the 6.16 to 1 ratio has a H stamped in the same position. Lock ring wheels can have a solid ring, Split ring or a solid ring with a second split ring. Read wheel post at top of page. Your truck would have had 20" tires new. There could be a variety of 20" tires depending on what the buyer wanted. 1.5 ton covered several versions. 131" and 157" were the wheelbases available. Either could be ordered with or without helper springs which would change the version of 20" tires required to meet capacity limits. The original 216 would not have a rear main seal. It relies on a slinger and a rear main bearing cap drilled to allow oil to drain back into crankcase to minimize leaks. It is not completely successful. Brakes are fairly simple, as others have pointed out it is a single reservoir system have a leak and you may lose all brakes. To replace shoes or cylinders requires removal of hub, bearings and drums as a unit unlike modern versions where you just pop the drums off. Emergency brakes to the rear axle, you have rods going to the back, they join metal sheathed cables which in turn move the mechanical blocks to move the shoes. those cables have a tendency to freeze in the metal sheaths. After market replacements are available. If it has the original torque tube driveline instead of a open drive shaft there are seals or packing in the torque tube which can fail allowing gear oil in transmission to leak thru to the rear end. suggest you pick up a service manual and look it over. Good luck with your project.

Wow, What a great forum! I am novice mechanic. I am excited because I am working with a relative who is an excellent engineer/mechanic, 2nd generation that has worked on these trucks. HE can fabricate ANYTHING, including doing brakes/linings..etc.. I am still absorbing your posts..

From what I have read from your replies so far, I would go with option a- keep it original, check it for safety, etc.. make sure drivetrain doesnt leave me on the side of the road and slowly upgrade what doent work .. again after listening to all of your advice.. I will edit this post or add as I go - reading this thread.

Wayne - "Your split rims will accommodate radials. You will need tubes and liners. I ditched my split rims because I only had 1 truck tire shop near me. A normal tire store won't touch the split rims."

Jerry - "If it's got 22" wheels, that's also been changed from the 20" wheels it probably came with when it was new, probably looking for more road speed at the expense of performance on hills without downshifting." Wow I did not know that.. Now I have to figure out whether to get 20" or keep it like it is.. Options: I would have to figure out where to get 20" at a reasonable price and ideally not split rim or 22" inch or keep it as is.. got a truck place here that is great.(PA) from the pic you can see they look awesome..

K - I have the 131" wheelbase.. I dont know how I found this truck,, it is exactly what I wanted and hard to find..

H- I wont be driving in traffic. I would only take back roads until I can get time and money to upgrade if I hate driving it the way it is. "Unless you're an expert at adjusting the oil clearance on Babbit connecting rods, your daily driving is going to end up with a noisy engine pretty quickly, followed by serious rod knocks. " I will ask my brother in law if he knows how to do this. Is the adjustment every so many miles?

"Then there's the "crash box" transmission- - - -how good are you at shifting up and down in a traffic situation with a non-synchronized transmission?" I am a really good driver but still learning. I saw a video on this, I will have no problem. I havent driven it yet until I check I it all out.. Apparently the engine, trans, (closed) driveline and read ALL GO TOGETHER (wow) . so does this wear out or if its been greased - last forever? How do you know when its bad? They drove it up on the trailer and it sounded GREAT! and quiet lol...

KJ - "Am I correct in assuming you have not yet driven this truck out in traffic or on any public access road?" Yes I have not yet. Yes, I want to get to know the truck as is first - I agree.

People were stopping us on the road. Three people wanted to buy it and on the highway, cars were slowing.. lol

**Please note - I just posted a huge reply with pics but a moderator must approve before it hits..

Other q&a:
- The cab is missing a key. I dont know where to get it?
- Can I put regular 87 octane in this? I think it takes 30W oil or 10w30.. oil looks pretty clean.
- K, still catching up.. yes it is the original driveline. I will have to find a manual on this.. interesting setup. I dont know what trans oil or gear oil it takes or where to get gaskets or seals/

Pull the door lock out and look on the mechanism. There should be a 4 digit number stamped on it between 8000 and 9499. That's the key code. Give that to a locksmith and they can cut a key to fit it. Tell them it's from a 38 GM vehicle.

FWIW, here's some pics of a truck we saw at the Macungie, PA ATCA show in 2010. It may have been a factory express 1.5-ton set up, I don't remember. The experts will remember. Anyway, shows what could be done with a truck like yours. The bed would be easy enough to fabricate. And with a few mods, make a nifty big dually pickup.

Ideas to tuck away ...

pretty cool. thanks for posting. klhansen I will do just that.

"Jerry - "If it's got 22" wheels, that's also been changed from the 20" wheels it probably came with when it was new," - I will have to figure out how to measure the rims.. at the bead or at the rim edge.. at the bead its 20", at the rim edge, its 22."

Wheels are measured at the bead, not the outside diameter of the flange. Look om the tire sidewall- - - -it should show something like "8.25-20" or something similar. The "20" in that example is the rim size.

Today's standard shift transmissions are "synchronized", meaning that the speed of the gears is matched with each other during the shifting sequence to prevent gear grinding. The older truck transmissions, up to the late 1940's, were not synchronized, so a driver had to carefully match the speed of the gears while downshifting by doing something called "double clutching"- - - -letting the clutch out in neutral, speeding up the engine RPM, pushing the clutch pedal back in, and trying to slip into the lower gear without clashing teeth. It'd definitely an acquired skill!

Pre-1954 stovebolt engines do not have replaceable connecting rod bearings. A "soft" metal called "Babbit" is bonded to the big end of the connecting rods, and fitted to the size of the crankshaft journals, then shims are added between the connecting rod and the rod cap to establish clearance for the oil to flow between the rod and the crankshaft. That oil is sprayed into dippers bolted onto the bottom of the rods by nozzles attached to the inside of the oil pan. The proper bearing clearance is about the thickness of a strand of hair, and as the bearings wear, thin layers of shim stock are removed to restore the proper clearance. Too tight, and the rod bearing burns for lack of lubrication- - - - -too loose, (like two strands of hair stacked together, and you can hear a little bit of a rattle. Three hairs worth of clearance, and the rods begins to knock. The more a vehicle gets driven, especially at highway speeds, the more frequently you'll need to adjust the clearance. It's a pretty good system, but it's also somewhat labor-intensive to keep the clearances right!
Jerry

38, that's a cool truck! I like it just the way it is!
Good luck with whatever you decide to do with it.

H- excellent synopsis for the shifting and babbit bearings. I totally get it. Worst case, I will replace the drivetrain but KEEP it for purposes if I ever want to convert it back.

On tires.. I looked at the sticky.. the vendors link doesnt work. I am pretty sure I have 20's now. I still do not understand what 7.50x20 vs 6.00x20 means.. I am pretty sure my tires read 6.00x20 32 and cant see anything else on them.. I am unsure of what to put in for a search to find this tire for sale. I am not sure how wide the rim is but I *think* 5" ..? I want to find radials that will fit these rims and place tubes in it. And I am looking for a modern diff that will fit the rims too.. ANY help is appreciated!!

[edit] I think the 6.00 is the width of the tire. Strange but some of these vendors dont tell you the width of the rim it will fit! It may be that only 5" rims take 6.00-6.50x20...

"I still do not understand what 7.50x20 vs 6.00x20 means."
Basically, the first number is tread width, and the second is wheel diameter, so a 7.50x20 is wider (and likely a little taller) than a 6.00x20 tire.

Okay , this makes more sense.

The old inch-measurement tires follow the pattern explained above- - - -tread width in inches is the first number and rim size is the second. Later model metric-dimension radial tires get a little more specific- - - -Tread width in millimeters, then "aspect ratio", and then rim diameter- - - -usually still in inches for some reason! For instance: 225/75R15 would translate to 225 MM of tread contact with the road, a 75% "aspect ratio" which means the sidewall from the rim to the tread is 75% of the tread width, on a 15" rim. The "R" stands for "radial". As the aspect ratio getc smaller, the height of the tire from the rim to the ground decreases, so an 85, a 75, a 70 and a 60 series tire will get progressively shortet (and ususlly wider) as the heoight of the sidewall gets shorter. Some radials for vintage trucks run very tall sidewalls in relation to tread wifth, but that's an exception to the usual practice.
Jerry

I am in the process of making my 46 1 1/2 ton a daily driver. I live in the mountains and generally the freeway is the only way to get anywhere (especially in winter). The 6.13 gears in my diff top me out at 45mph. I've done 55 but it's not sustainable. My replacement rear axle is a Dana 70HD, factory disk brakes out of a Chevy based 2 ton motor home. The lug pattern is the same but the studs are 5/8" instead of 9/16", the hub pilot is larger than the period correct wheels and the wheel mounting surface is 1/2" narrower than stock. All workable problems for me and to my knowledge this is the closest axle to "working" without going custom. The stock 46 drums seemed to need to be adjusted every 100 miles to keep the pedal where I want.

The old 7.50x20, 8.25x20, etc can be found here:

https://www.stausaonline.com/tires/sta-super-transport-2/

They also sell the military tread tires in those sizes and more for the 20 inch rim, but our rims are so narrow you’ll never be able to install an 11x20 for example. But there are tire highest and widths in these listings. Using the tire height and the online calculator on www.4lo.com along with your gear ratio and speed, you can calculate rpm at that speed.

Hopefully some pics will shed light! Doing some homework, I think I actually have the third arrow in my chart or 6x20 (10ply) and 6" rims all the way around.. but I am only assuming that bec they are 10ply.. Brian, are you saying our setup is the same? To fit the lug pattern of these rims I would go with a Dana 70HD setup? I am closing in on this fast and intend to hit the junk yard this weekend to try and match a rear axle where I can keep at least the original rims.

It looks like you have 5/10 bolt wheel pattern, 5 on the front, 10 on the back, although all wheels have 10 mounting holes, so they fit front or back. That pattern has been on Dana 70 and 80 rear axles for a long time, so start looking for that pattern in wrecking yards. Get the associated front axle, some came with IFS while early ones had solid axles. Baby school buses are one good place.

The problem is wheels. 19.5’s are on all modern axles which look undernourished but are used by many. Late ‘50’s GM had 22.5s on the first tubeless wheels but are very hard to find and new ones are very expensive and have a long lead time. Look for farm trucks and school buses. Modern tires and associated wheels that are tubeless are designated by .5” dimensions, I e 19.5 or 22.5” while older tube type split rims are designated by even inch dimensions. Many tire shops will not deal with split rims.

Next best option unless you are very lucky in to use 20’s, however, late axles have a slightly larger hub diameter which must be bored out. This is a machine shop operation, not home backyard operation.

I’m sure others will chime in. Good luck.

Ed

As Ed said, the center hole on your wheels won't fit over the hub on a modern axle without turning your wheels on a big lathe. I had this done on a set of late '40s lock ring rims year's ago so they would fit on a late 50's axle...the hole went from 4.75" to 5.25".

Also bear in mind that by just change the rear to modern faster gears doesn't mean your actually going to be able to go faster...your engine won't have enough torque or HP to turn the faster gears unless you're going down hill. The factory spent a lot of time working everything out so the engine, trans, rear and tires would all play nice together. If you change one of these items it will effect performance in a negative way.

Mike B

Okay, I will have these turned. Like I said I love the original look. I intent to preserve the old components and place a 292 in her.. You folks that used the dana rear.. did you find it measured the same or near same width of the original? I see there are single danas and dually.. My truck is not at my house and I have to go measure things.. Home owners assoc..... enough said there...

[edit] side topic.. I just read a guy who used a 261 engine that hooked right up to the existing trans :o Any thoughts on this idea!? I will try to find specs on what that trans can handle! I would consider this along with the 292 option!

Dana rears come in different widths, if lug bolts are long enough, duals can be fit on both. Perhaps Grigg will chime in, he knows all. I just put an 80(70 would be like) in my ‘55 GMC, that fits a 7’ bed, probably C and C unit, other units fit an 8’ bed.

With some creative fitting, older, narrower springs can be made to fit 70 or 80 axles. 80’s are 4” OD; to fit narrower spring perches, get a suitable piece of 4” OD pipe, get a suitable piece of, say 2” wide steel, half the thickness of the diameter differences, lay the perch in your press, place steel plate on top, put pipe on top, squeeze pipe into perch with steel in between, OK to have steel too long to start, 2” steel fit mine, cut to fit length. Have to adjust welded perch on 80 to allow spring bolts to fit, get appropriate angle shims to adjust properly, make sure spring bolt heads engage perch properly, make extensions if necessary.

Ed

My 38 1.5 ton came with 3 different size tires on it, thanks to previous owners ingenuity. Another thing you have to watch is rim depth. The deeper rim tire combo for 8.25x20 tires may rub the rear springs or ebrake cables on the inside, they did on mine. If you change to the dana axle set up others have mentioned you will also need to change the transmission and drive shaft to open from the original torque tube design. When you do this you may need to fabricate mounts for the brake and clutch pedals if you use a different bellhousing as they are mounted differently on later models. Later models also used different mounting points for rear motor/transmission mounts so you will need cross member from donor vehicle as well. If you do wind up with different height tire sizes front and rear make sure rear is taller per owners or service manual. My guess is this was due to the lack of rear main seal in original drive train but I don't know for sure.