Dually M1028A2, South Florida Rebuild

It's time to get my M1028A2 Dually back on the road. The CUCV-II rebuild is still on going with little things here and there. overall it turned out well.
CUCV-II, South Florida Rebuild - Steel Soldiers::Military Vehicles Supersite

Now for the Dually. A little history first: about 5 months ago I made a trip to Redstone, AL to pick-up a 30kw generator. Then I headed onto SC to pick-up a new 6.5L GEP from Jackson, SC. About 15 miles from Jackson I dropped a valve and bent a rod(my son was driving and may of be pushing to high of RPMs). It was after midnight and I was broke down on I-20 so I got on Steel Soldiers and asked for help. FERRO showed up with an M818 to tow me to the nearest hotel.
The next day SCSG-G4 showed me SC and helped me get parts. After the next day FERRO towed me to MITCHG place were FERRO, MITCHG, BIGUGH20, JWALLER and SCSG-G4 helped me and my son swap out the dead 6.2 for the 6.5. Thanks again guys for the help.
After the swap I test drove the dually and it had a lot more power and seemed to be running fine at the time.

I headed out the next day around 4:00 pm and when it started to get dark I saw my lights were getting dim. I just made it to I-95 and stopped at a truck stop to see if I could fix the problem. A ground wire was off the #1 Gen that hooks to the top of the engine, because of this it wasn't charging.
The truck stop didn't have any batteries so if I turned it off I wouldn't be able to start it back up. I left it idle all night with me and my son in the cab(that was a long, cold night).
In the morning we headed south on I-95 and after about 40 miles found a Sams and bought two new red top batteries and got fuel. The truck was running so good I didn't want to switch out the battery just yet, so back on I-95 we go. After another 20 miles I turn to my son and say this 6.5 is sweet and has a lot of power. Not 30 sec later the engine started to knock. Long story short, the glow plug on the rear driver side came apart and went into the piston.
I used AAA to get me to Exit #2 in GA. and RECOVRY4X4 drove his Duce from West Palm Beach to towbar my dually and trailer back to his place.

Pictures of the old 6.2 and the new 6.5 GEP.

Some more pictures: Piston with glow plug chewed up on top.

Plans are to use parts from the CUCV-II 6.5 engine to fix this engine. Also adding a new Banks turbo system that I bought last year, a new water pump and maybe go with an electic fuel pump. I'll know more after I pull the engine.

Good luck with this endeavor.

another great build or ah... rebuild.

Nice, another rebuild. The CUCVII was awesome. I'll be watchin, I love that dually... Good luck.

do you think its possible that the valve dropped due to the newer eng oils that are out? due to the new emissions/ lack of zinc in the oil?


my old shovel head dropped a valve after a 800 mile trip. I was in bfe and needed oil...the only thing the gas station had at the time was aviation oil on 70 wt. I used it and didn't think anything of it....about 1 month later and 1k miles I dropped a valve on the highway...I feel it was due to the oil...


I read your other rebuild..good job.

Yeah oils today suck compared to the engine oil 25 years ago.

sweet build up man you really go in to detail and make them worth reading!

An very nice find and sweet build we need more photos thank you.

Phil - that is one great looking 1028 that you have there. Hopefully, all goes well this time around.

Worked on pulling the 6.5 engine out of the Dually today. Took about 5 hours to do by myself. I'll open up the engine Sunday and see if there are any problems inside. Hope all I have to do is replace the bad piston.

Phil, I love that truck. Keep me posted if you ever decide you want to part with it (or your green M1028A2).

BKubu said:

Phil, I love that truck. Keep me posted if you ever decide you want to part with it (or your green M1028A2).

Click to expand...

Will do, Bruce

Well, I couldn't wait until morning so I did a little work on the engine. Everything looks good except for the one piston with the chewed up glow plug.
The piston I removed from the CUCV-II's old engine looks like it will work(see pictures)

The 6.5 piston skirt looks a little smaller than the 6.2 skirt.

Do you have a scale to weigh the pistons? Also check the rod for straightness while you have a chance.

I see wreckerman must have made the trip with you and his best friend "Murphy".

If you have the pistons pulled take them to a machine shop and have the rods, pistons, reconditioned and get some arp bolts for $200.00 bucks its cheap insurance. I really enjoyed your cucv 2 thread and this one i like the info and pics!!!!!

Most certainly need to get that piston on a scale. Can't do anything without knowing the weight is correct. I would also check to see if you can find any casting numbers in the piston.

The numbers Inside each piston are the same:
10238517

339P
52

GM 83806 (the 8 could be a B)

Next set of pictures will show a differance on the outside of the piston(see black arrows)

One piston(good one) is out of the old 1999 CUCV-II 6.5l turbo-charged engine with 16,000 miles. The other(bad one) is out of a 2007 GEP 6.5l non-turbo engine with 150 miles.

I was trying to do this a cheap way by using parts onhand.

1. Could I just replace all the pistons in the GEP engine with the pistons out of the turbo engine and replace the rings with new ones. I would only change the piston not the connecting rod.

2. Buy just one, new piston for the GEP engine(where to get one thats matches the others ??)

3. Buy a complete set of new pistons(not what I want to do) $$$

Complete sets available on one of the auction sites.

6.5L 395ci V8 Chevrolet GMC Hummer Diesel Piston Set - eBay (item 150578357094 end time Apr-16-11 06:38:20 PDT)

Before I went off to purchase a set of pistons, I'd weigh what I have and see if the weights are close, within +/_ 2 grams.

As for the piston weight, cleaning 2 grams of casting flash from the inside of a psiton is pretty easy.

If they are close, I'd purchase one set of rings and install them. Run a cylinder hone to remove the liner color, throughly clean the bore and install the piston.