M37 help

[deuceman51]

I just bought my first M37B1. It's a 1962, with 5800 mi on the odometer. Problem is, it doesn't run worth a dang. I can get it to start with the choke, and sometimes it will go for a bit, but as soon as I start to drive she starts to sputter and kill out (usually in the middle of a busy intersection, lol). When I got it home, I changed out the spark plugs, put in fresh gas, and put Sea Foam carb cleaner in it. As soon as I got it started it smoked like crazy from the sea foam, which is what it should do. We took it for a test drive and I got about 4 blocks from home and she died on me. Could only get it to start for a few seconds with the choke out fully. Sometimes it will start and idle just fine, but if I step on the gas it sputters and dies. My guess is that my carb needs a rebuild. The other problem I have is my oil pressure is nothing at idle, if I step on the gas and rev it up I can barely get the needle to move an 1/8 inch on the gauge. I'm hoping the gauge is bad since most of the wiring is frayed and bad. It has a few oil and coolent leaks( I can see drops on oil in one place and antifreeze in another spot on the bottom of the oil pan). Does anybody have any advice or have dealt with these problems before. I find it hard to believe that an engine with only that few miles on it can have so much wrong with it. Any help would be appreciated.

 

[clinto]

first, before you fiffle with the carb, put a mechanical oil pressure on it and find out if you have pressure. if you don't, the carb is a moot point as you'll be pulling it apart......

If it actually has acceptable oil pressure, then once the ignition is up to snuff, rebuild the carb.

 

[CGarbee]

AGE and LACK OF USE is why an engine with so few miles would have so many problems... I agree, check out the oil pressure and see if you have bigger problems first before going after the carb. I suspect that things are ok, but that the engine just needs a bit of exercise (and that the carb needs to be rebuilt, as will the gas/vacume pump). If the wiring is frayed, your best bet is to bite the bullet and replace the entire harness. Nothing spoils your day like a bad harness shorting out in places that you can't see or get to...
Good luck, let us know how it is progressing, and ask questions...

I have some info on these rigs at my website located at:
www.garbee.net/~cabell

And, CONGRATULATIONS.

 

[citizensoldier]

Drain tank??

I agree that the oil pressure needs addressing first. Does it hava a fuel filter on it? Did you drain the tank? Many times the tank is full of rust. If it still has the original fuel pump it could be your problem too. After oil pressure I would address the fuel lines and pump before you tare into the carb. You may have filled the whole thing with rusty crud gas. Also if they sit with bad gas they are prone to stuck valves or vavles that dont shut all the way.
Maybe hook up external gas tank and see how it runs...Hope this helps a little..

 

[citizensoldier]

Wiring!!!

Another thing is if the wiring is bad wich most of them are do not leave the power hooked up or get you a cut off switch for the battery box. You could come out to a smoldering pile of charcoal. Replace the wiring if you can. Very prone to falling apart and shorting out things...Not something to let go if you can help it.
Oh... And is there a sheild between the exhaust manifold and the fuel pump? If not it will vapor lock on you... If oil pressure is good, fuel is good, then maybe check the points and distributor.. it could be a mess in there causing it to stall out....

 

[deuceman51]

The first thing I did was replace the inline fuel filter and put fresh gas into it. When you crank the engine without the filter in place it sprays fuel at a pretty good pressure, so I know the pump is still good. If i'm right in guessing the oil pressure sensor is on the left side of the engine with one wire coming out of the top? I was planning on unhooking that and putting a pressure gauge on it to check the pump and make sure that the oil pressure is good. Since I don't have any manuals on it yet, what is the correct operating oil pressure? The guy I bought it from said the carb probably needs work and i'm sure that is where most of my problem lies. Where is the best place to get parts on these trucks. I know ebay, memphis equipment, vintage power wagon and a few other places, but who usually has the best prices on carbs and parts. I will either get a rebuilt carb or a rebuild kit if it isn't too pricy. I payed top doller for this truck and need to save as much as I can to get it restored before I have more into it than it's worth, lol. Does anybody out there have any NAPA part numbers or crossreferences for parts and gaskets for the M37? Thanks.

 

[citizensoldier]

Parts..

There is ABlinn, Midwest Military and Sid Beck... Sid has the best prices and seems to have the most in stock. Midwest has the hard to find stuff but can be a little pricey, There is also Andirondac not sure of spelling . Here is Sids email g741@ccwip.net Midwest has a good site you can visit. ABlinn runs stuff on ebay and you never know what he will have or what price.. He does come accross good stuff once and awhile.. Oh there is Vermont Comercial Salvage (George M) VTCSM37@aol.com.
If you did'nt drain the tank I would bet its part of the problem.. I Bet the carb is full of gunk...
Let me know what you find... There does not seem to be a good price place anymore..You just have to shop around..
Have you been to the G741 site? Its a must if you own a M37.. Lots of good guys on that site and they will answer all your questions.

 

[dementedmopar]

RE: Parts..

I''m a mechanic at a local shop in my town and i just went thru similar problems with a mini van, dont assume the pump is good because it shoots fuel... the more you press the gas the more volume you need not pressure... just always keep that in mind...

 

[CGarbee]

RE: Parts..

Go to www.military-media.com/ and order up the cd with all the manuals on it (less than twenty dollars...).

 

[Jones]

RE: Parts..

As a rule of thumb for oil pressure; 10# per 1,000 RPM is sufficient to keep an engine alive. More is better to a point; you can actually have too much oil pressure and wash the bearings out by shoving dirty oil across them at high pressure (high velocity fluid erosion if you want to get teknicul). A high volume oil pump is better than a high pressure one.
Take a look at your radiator top tank and see if it or the tops of the tubes's are rusty or have scale. If it's rusty looking, flushing the cooling system is a good idea. While the radiator's out, pull the water pump. There's this little tricky part on the flathead sixes called a water distribution tube. It's folded sheet metal and can be found by removing the water pump and looking down the passage that runs back to the rear of the block. The water distribution tube's job is to take coolant put out by the water pump and deliver it to the rear of the block. If the tube is broken, water will get to the break then circulate back forward and the rear cylinder(s) won't get cooled water-- creating a hot spot. The tube has slots down it so when you remove it to put in a fresh one, go after it with a piece of welding rod with a hook bent into the end to snag one or more of the slots. Compare the tube you pull out with the replacement to make sure you've gotten it all. They have a nasty habit of breaking off and leaving a section in the block. DO NOT reassemble without it. If you do, the front one or two cylinders will be fine but you'll cook the rear of the engine. The tubes are different lengths depending on which engine you're working on; Dodge sixes are shorter than Chrysler sixes. And there was a movement when I was playing with the M37s to put the Chrysler sixes into the weapons carriers for a little added power so it is possible to find the odd one that's been re-engined.
Good luck and happy motoring.

 

[n1vbn]

I had a 1948 Ford F-100 Pickup that ran great sitting still six or eight blocks down the road and would die every time. Rebuilt carb, replaced fuel pump, fuel filters and still died!!!

Finally removed fuel tank from behind seat and poured over a 100 pounds of sand out of the tank. It's always the simple things that stop ya dead.


One last thought to get rid of the junk/varnish (old gas residue) the semi easy way is remove the fuel line from the carb and hook up a temporary can of GUNK carb cleaner (liquid not an aeresol can) hung from the hood with a clear plastic fuel line so you know when it is empty. The siphon effect will supply the carb and be aware it will smoke like crazy until it runs on gas again but will get rid of a lot of crud from inside passages. Works about 50 % of the time and is cheap and worth the shot. If it doesn't do the trick......


Yank the tank!!!!

 

[Jones]

Good idea on cleaning out the fuel tank!
If you have rust in there and can't find a better tank, try this. With the tank out and drained, pour about five or ten bucks worth of pennies in there; rock & shake the tank and the pennies will break loose the loose rust and scale. Do this 'til you think your arms are gonna fall off, then go inside and have lunch. Come back out and do it some more. Pour out the loose pennies and coat the inside with fuel tank sealer. Wash the pennies and redeem for a tube of linament for those sore arms.
Pennies are better than sand because they're too big to clog a fuel line or filter, won't leach back out of tank seams for the next few years like chemical dip solutions do and won't create a spark if there's still fuel or fumes in the tank.

 

[devilman96]

I use hydrochloric acid (muratic acid, pool acid)...

Pull the tank, remove any brass / copper plugs... Use 1 gal acid : .50 gal water... Sometimes I have to go stronger but that generally does the trick in a hour or so. Just don't leave it sit unattended for hours on end. Flush it THOROUGHLY with water and then a gallon of water to a box of sodium bicarbonate (baking soda) and flush clean... The tank will be spotless when done. I've done this over the years to more tanks than I can count... Works extremely well but is not a method for the forgetful!!!

Also works well for soaking small parts... Avoid aluminum!!!!! (remember your HS chemistry) and be very mindful of cast iron parts or they will be reduced to steel wool over night.