M1078 cracked block

[Ronmar]

Ok, so what problem are you still having and on what truck are you having it?

 

[markgjsquires]

Nothing at the moment until I get the starter back and installed.

 

[Ronmar]

Nothing at the moment until I get the starter back and installed.

And that was on an A0/3116 right?

 

[markgjsquires]

Correct

 

[Ronmar]

Ok, I was getting confused with all the thread drift wanted to confirm I was sending you the right starter circuit info. It is a bit different for the A1R…

 

[Ronmar]

Hmm interesting, came with a 4x group 24 flooded lead acid setup

Cat specced a pair of group 31 batteries for the equipment that uses these engines. Thats about 100AH of battery and is usually paired with a 50-75A@24v alt. There are literally millions of vehicles motoring down the highway with a similar configuration… A 75A@24(~28v) alt Is good for ~2100Watts of power. Our 60@12/40@24, split voltage alt is only good for ~1960W of output with both sides loaded to their 60/40 limits. Ironically a 100A@24v(28v) alt is good for 2800W. If they used a 24-12 converter to feed the 12v loads(<15A@24v), a 100A@24v alt would have been adequate to feed the ~60A peak demand of a discharged 240AH wet cell and still feed the the other 24v and 12v(via converter) loads without exceeding its 100A limit… Charging batteries in parallel can also be problematic. whoever cooked up this split alt and quad series/parallel battery power system, did not fully understand how batteries and alts must interact… The tech bulletin General posted makes perfect sense and is long overdue Sinice the military looks to have shifted to AGM batts quite a while ago. AGM batteries want 45% of their AH rating from the alt during the bulk phase of charging. Thats 108A all by itself for the 240AH OEM battery config.

There is no legitimate reason to put any more battery in one of these trucks than ~100AH, particularly without putting in enough power generation to support it. Weird shit happens in the land of milspec though. That 240AH bank was done so this thing could set in the cold of Siberia for weeks(or some such) and still start the truck, instead of something more complicated like engine, trans and battery preheat… it really was stupid, and the reason these trucks have so many charging system issues…

 

[markgjsquires]

Got the starter back on yesterday morning and she popped right off. Have cycled it a few times and took it for a drive. Seemed to work fine. Charged well. All the lights etc still work fine. Ran through the gears as it always has. Starter repair shop said faulty solenoid was to blame. Bad batch maybe? Not sure. Now I’m paranoid next time I want to run it she won’t. But I’ll be really good and getting the starter on and off if nothing else. Pan gasket replacement didn’t work as I had hoped. It appears it’s leaking around the bolts themselves from what little I could see. I guess I should’ve just gunked it all up with gasket making material and hoped for the best. But for how I often I use it and how hard I run it. It will suffice. I’ll just keep cycling through cheap oil and assume I’ll be good on oil changes for a while. Perhaps by then something will grenade and on to the engine swap or parting it out. Either way thanks everyone for insight and help. Great website with great people.