1952 M135 W/Winch

[USMC 00-08]

I am trying to sort out another problem. Today I took the M135 to go out to the parts trucks to get a few needed pieces. The truck was running great until I went to accelerate from a stop at an intersection. As I was accelerating there was a huge backfire and I mean huge enough that it blew out the back side of my new muffler! No more quiet truck now.

Anyway, after the backfire, the engine acted like it was running out of fuel, but all of a sudden started running fine. I drove a few more blocks then it started to stumble again. It died and I could not get it to start back. I got the truck home, pulled the carburetor apart and made sure that nothing was blocked. That was not the problem. I ran out of daylight but I am thinking maybe something happened with the distributor or a spark plug.

It has been suggested that maybe something in the distributor broke or the backfire made the timing go out or the crankshaft broke or the backfire blew out a part of the intake manifold gasket.

I am at a loss right now but will try to tackle it again tomorrow. Have any of you had something similar happen? Know of a fix?

This truck was running great after the carburetor rebuild and new exhaust until the backfire. One day I will get all these kinks worked out, but it is sure sometimes frustrating when you fix something which exposes a weak area somewhere else.

On a positive note, I got the truck to coast into a parking lot and while I was checking things before I pulled it home, an old Army Veteran who I go to church with stopped by. He had driven M135/ M211s in the Army!!! He suggested that maybe water was in the carburetor, so we sprayed some WD-40 in there and tried to start it with a little ether. The truck tries to fire but not enough to stay running. The man said that he wanted to come by on a warmer day and would like to look the truck over and would help fix anything I needed help with. I'm going to make this happen but hopefully I can get the truck running before he comes over so he can just drive it instead of help me troubleshoot.

Any ideas on a fix?

 

[NDT]

Mine did that. Blew apart my muffler. It was the condenser.

 

[USMC 00-08]

I will try that tomorrow. The condenser was replaced with new 3 months and 80 miles ago so is the last thing I would have considered. Hopefully that is the problem. I'll post back what I find. Also I might pull a distributor off of a parts truck and compare everything.

 

[m1010plowboy]

With luck like that there's still a chance the Veteran you ran into has the spare parts you need in a drawer in the garage. I'll bet you made his day.

I have no experience or solutions for symptoms like that but I think I know now why the mufflers are rare and hard to find!

 

[USMC 00-08]

Yes and they just got a little more rare. That was the only good one I had.

 

[USMC 00-08]

I pulled a distributor off of a parts truck. The internals look nice and clean. Does anyone know how to test the ignition coil, ignition coil capacitor, primary circuit resistor and condenser? I don't see in the manual where it says how and didn't see anything in the search function here that is specific to the G749. Could be I am typing in the wrong thing.


Edit - Page 156 and 157 of TM 9-8024 tell how to test to see what is working and what is not. It does not say what the ohms are supposed to be on a good ignition coil.

 

[NDT]

I pulled a distributor off of a parts truck. The internals look nice and clean. Does anyone know how to test the ignition coil, ignition coil capacitor, primary circuit resistor and condenser? I don't see in the manual where it says how and didn't see anything in the search function here that is specific to the G749. Could be I am typing in the wrong thing.

To bench test it, install the plugs and wires, and connect a 24V source to the connector and distributor housing, and spin the shaft by hand. It will be obvious if it is working. Check for corrosion on the points first.

 

[gerrykan]

Does anyone know how to test the ignition coil?

Here is some reading for you:

1. http://g503.com/forums/viewtopic.php?f=14&t=148284
2. http://mightymo.org/Proj_No_Spark.html
3. http://www.g741.org/PHPBB/viewtopic.php?f=3&t=5627

 

[USMC 00-08]

I tested the ignition coil from the parts truck. Primary is 1.5 ohms. Secondary is 8,280 ohms.

If weather cooperates tomorrow, I'll test what is in the truck currently. I am sure NDT is right about it being the condenser. Just thought I would test the coil out of the parts distributor in case.

 

[USMC 00-08]

Mine did that. Blew apart my muffler. It was the condenser.

NDT...you are the man!! It was the condenser. I pulled one off of my parts truck installed it and it fired right up.

Could someone test a known good coil for or on the G749 and let me know the ohm reading? I pulled the coils out of my parts trucks and tested them and the coil currently in my truck out of curiosity. All three consistently read.... primary 1.5 ohms and secondary 8,280 ohms. I have a coil out of an M715 and it read primary 6 ohms and secondary 14,000 ohms like some of the above posted links say it should.

Either all three of my G749 coils are consistently bad or that is how the coil for a G749 is supposed to read. I would like to confirm one way or the other. The TM doesn't say. Page 156 and 157 of TM 9-8024 tell how to test to see what is working and what is not. It does not say what the ohms are supposed to be on a good ignition coil.

 

[NDT]

NDT...you are the man!! It was the condenser. I pulled one off of my parts truck installed it and it fired right up.

Could someone test a known good coil for or on the G749 and let me know the ohm reading? I pulled the coils out of my parts trucks and tested them and the coil currently in my truck out of curiosity. All three consistently read.... primary - 1.5 ohms and secondary - 8,280 ohms. I have a coil out of an M715 and it read primary - 6 ohms and secondary 14,000 ohms like some of the above posted links say it should.

Either all three of my G749 coils are consistently bad or that is how the coil for a G749 is supposed to read. I would like to confirm one way or the other. The TM doesn't say. Page 156 and 157 of TM 9-8024 tell how to test to see what is working and what is not. It does not say what the ohms are supposed to be on a good ignition coil.

Those coils with Delco Remy written on top NEVER go bad.

 

[USMC 00-08]

I checked out a carburetor from one of the parts trucks. Everything is the same size as what was in my other carburetor. The pieces in the new kit have smaller openings.

The other day I ordered some condensers from Alpha Heaven so that I have a few spares. I spoke with majortom and asked him about the carburetor jets and the size differences in the kits we got. He said we definitely do not want to use the parts with smaller openings. He recommended taking a torch cleaning tip that is one size larger than what will fit in the original jets and enlarge them to that size. He said it will help us greatly.

I may experiment with this later on the parts that came in the kit. Just thought I would pass this information along.

My brother (firewarrior...here on Steel Soldiers) came up to get his M818 to take back to Texas. He bought it from a local fire department that had surplused it out. On December 30th, we and OkieM1008morrison drove our trucks on a 50 mile round trip.



With my rebuilt carburetor, new condenser and a plug put back in place of the small breather hose (pictured below) that a previous owner put on my distributor for unknown reasons, made the truck run great! I was able to maintain speeds of between 55 and 61 mph on flat ground. I would loose a little speed going up hills, but not near as bad as I used to. I was able to stay in the 45-50 mph range on hills. Before, it would drop to 35 mph or lower on an incline.

 

[hendersond]

The other day I ordered some condensers from Alpha Heaven so that I have a few spares. I spoke with majortom and asked him about the carburetor jets and the size differences in the kits we got. He said we definitely do not want to use the parts with smaller openings. He recommended taking a torch cleaning tip that is one size larger than what will fit in the original jets and enlarge them to that size. He said it will help us greatly.

With my rebuilt carburetor, new condenser and a plug put back in place of the small breather hose (pictured below) that a previous owner put on my distributor for unknown reasons, made the truck run great! I was able to maintain speeds of between 55 and 61 mph on flat ground. I would loose a little speed going up hills, but not near as bad as I used to. I was able to stay in the 45-50 mph range on hills. Before, it would drop to 35 mph or lower on an incline.

I had the same experience when I ran a 12 psi fuel pump across South Dakota. Now I have the 3-4 psi original. it makes me quite sad actually.

 

[m1010plowboy]

Did you race em' off the line? They're fast trucks when running right so I'm pushing for some 1/4 mile time slips from everyone in 2015.

Does that one have the reb shifter on it? I need to find a way to get the 2nd to 3rd shift a little more crisp so wondering if you go through the gears or let the truck do it.

You're still wearing the 50 mile smile I bet!

 

[USMC 00-08]

We didn't race them, but did push them a bit to see what they would do.

My truck does not have the REB shifter on it. The 2nd to 3rd shift in high range does not shift as hard as 1st to 2nd. Really I don't notice it much at all except for the sound of the engine changing. In low range the 2nd to 3rd really pops hard into place. If I keep the petal all the way down in high range, it does not want to shift into 4th until I let off the gas at the desired speed, then it will put itself in 4th. If I am in 4th and want more speed, I push the gas most of the way down and it drops back into 3rd and the process repeats.

I have to listen to the truck and can manipulate the gear I want by how much gas I give or don't give. Hopefully I am not doing it wrong, but in my mind it seems better to do it this way so that I am in control. When I am trying to accelerate quickly to get onto the road, I hold the gas all the way down and the truck shifts through the 1st, 2nd, and 3rd like most normal vehicles and only into 4th when I let off the gas.

If anyone sees any issues with anything I am doing or how the transmission is functioning, please let me know. I don't want to mess anything up.

I am really happy with how the truck performed on the drive but am still sore about that muffler. I did talk to the man who drove G749s while in the Army in the 1950's. He told me tonight that they used to cut open the mufflers, remove the guts and weld the ends back on to make the trucks run better. I may do the same with my ruined muffler and see what happens.

 

[Another Ahab]

I am really happy with how the truck performed on the drive but am still sore about that muffler. I did talk to the man who drove G749s while in the Army in the 1950's. He told me tonight that they used to cut open the mufflers, remove the guts and weld the ends back on to make the trucks run better. I may do the same with my ruined muffler and see what happens.

You talking like baffles, inside the pipe?

 

[USMC 00-08]

Yes. That is what he said.

 

[m1010plowboy]

I know there are a few used mufflers still on the shelf here. I haven't checked all the trucks so if you're on the "historical restoration" wagon, you can grab a muffler when you pick up a hard top. Looks like a guy should keep one on the shelf to hide it away from those crazy kids who like to blow em' up. Did we ever decide how we can prevent that from happening? Can condensers and capacitors be tested early to prevent this or is a booming muffler the sign?

I did a little reading on the exhausting challenges of scavenging the velocity of the pulsing gases from our big 302's. All big words which I found in this article,

http://www.dsmtuners.com/threads/exhaust-the-straight-scoop-on-backpressure.168578/

What a well exhausted 302 can sound like https://www.youtube.com/watch?v=DXF4eQBMiBE
https://www.youtube.com/watch?v=ZZRhCtnDtGM

Some options for our future http://www.americanclassic.com/asp/...+Intake+Items&iyear=1955&ytype=to&exyear=1955

Ideally we get a manufacturer that will build us some mufflers without all the hassle of making a big profit. I'd like a half dozen new mufflers and need the cost to be under $100.00. If it's just an oval wrap, end caps and 2 flanges without the baffles, maybe it's possible.

 

[Another Ahab]

What a well exhausted 302 can sound like

That block is just so sharp; clean and simple.

As an engine the 302 is plain "purty". And nice to the ear, too.

 

[USMC 00-08]

I know there are a few used mufflers still on the shelf here. I haven't checked all the trucks so if you're on the "historical restoration" wagon, you can grab a muffler when you pick up a hard top. Looks like a guy should keep one on the shelf to hide it away from those crazy kids who like to blow em' up. Did we ever decide how we can prevent that from happening? Can condensers and capacitors be tested early to prevent this or is a booming muffler the sign?

If I can make a trip up there happen in the near future, I may take you up on the offer and bring you all the metal pieces for a canvas cab top.

I have two mufflers here. One that was on the truck that is hollow and the back side is cut out. I could have an end welded on to test that method. The other muffler is the one that blew up. The plan for that one is to take it to a local exhaust shop that does a lot of custom work on old collector vehicles to see if they can duplicate it. If not, I may have my brother try to weld it back together.

As for how to not make a muffler blow up.....I think the problem was a new condenser that I put on a few months ago. It lasted exactly 80 miles. Someone provided the part number for our part list. The number given was O'Reilly's number G102A. I had thought a condenser is a condenser, but it is probably for 12v systems and the 24v caused it to fail. Delete G102A from your lists!!! I am on the hunt for a proper replacement now.

When I talked to majortom the other day, he said he was surprised that the condenser even worked at all and even more surprised it lasted as long as it did. I guess everyone can learn from my mistake.