Lmackattack

I was nervous, I'm not going to lie! Hopefully button it up after a valve adjustment and new valve cover gaskets

https://youtu.be/ZXFH3xLgHtM?si=ZVOMdnOkcFqnAi1L

Weather finally let up from the heat wave we have been dealing with. 67 degrees all morning so I jumped on getting the heads back on. Barely broke a sweat working outside until 2pm. You can see the carbon build up on the 2 studs that was not allowing the heads to come off. I spend 2 hrs removing the stuck nuts from about 30 studs then wire brushed all the studs and threaded holes. Ran a tap thru them to clean them out and was able to put the studs in with just my fingers. Scrubbed all the old gasket material off the mating surfaces, Pressure washed the heads put New head gaskets on with new fire rings. Was able to set both heads on as an assembly just how i had removed them with absolutely no trouble. One thing I noticed with this job is when I had removed the head studs/nuts all but a few came out with just a hand held 1' long 1/2" ratchet. They took no where near the effort of 175ft lbs to remove them. Today I used a 3' long torque wrench and it was pretty obvious the old gaskets were not held down as tightly. I suspect the old gasket was just soft with age or someone did not torque them properly. My book says to check them again after 1 hour of under load time.

I didn't get a chance to get pics today. But the heas gaskets with fire rings are on the way. Hope to button it up over the weekend.

Thank you. That's what I figured. My book made no mention of that they were all stamped the same

300+ made 1050ftlbs where the endt676 maxidyne makes 1080ftlbs. Both are tipturbine engines

I think the concept of the 315 (300+) was a great option for those who did not like the maxidyne with only 5 speeds. I the maxidyne made slightly more overall torque than the 315 but the 315s had more hp and their max torque more in the mid rpm range. The few 315s I drove seamed to pull better in the hills. And yes I was always surprised when a new diesel just needed a little reprogram to get +50hp. It goes against everything we learned on mechanicals.

I think that is correct. What's odd is the 285 tipturbine is a maxidyne where the 315(300+) was still considered a thermodyne. These 2 valves were pretty bullet proof and easy to work on

I'll get a better picture of it tomorrow. I got done with work around 4. And spent the next hour, pulling the heads off before i had to head home. I didn't feel anything but I also don't have a lot of experience with engine internals.

No clue. I could not feel it with my fingernail. I'll get a better Pic of it.

Yes sir. ITS A 283HP ENDT676

No way I could pull this assembly up by hand !!! I had a service crane with 4 chains to keep it level.

Hope not. Liners were very smooth so she probably needs new rings and a cross hatch. At that point might as well inframe it. I'm not sure if it's ever been rebuilt. Pistons looked very clean for it's age. No carbon build up on them or heads. What is the 542c stamp on the piston telling us.?

Thanks for the help everyone I was able to double nut the one stuck stud and wound it out. It was really gummed up. Had to wind the stud up and down with penetrant oil to get it pulled ot out all the others cam out with my fingers. With all the studs removed the Heads came off like butter as an assembly. I had all the studs removed but still sitting in their holes as I was trying to keep them in order as I'm doing this job outside and have limited work space. But That's another story. Yes i saw the tips, I sat the heads on a few boards as to not crush the injector tips. I'm just slapping a new head gasket on and going. Hopefully it's not a cracked liner and I'll be back up and running after I get the replacement head gaskets end of this week.

I can't with the factory nuts as it has a deep shoulder below the hex and very little thread is exposed when tight I can probably double nut it if I force the head back down to expose more threads and then grind down a nut and thread it on first. I'm going to tinker with it some more tomorrow after the rain clears. I just wanted to make sure I'm not missing something as it's been 10 years since I last pulled a head on a 2v

Just saw this. That's too bad he was one of the original members. A wealth of info. Rip sir

I'm trying to pull both heads off to do head gaskets. And one of the studs I think is carbon seized in the head. The heads came up off the block about 1/2" but to get that it needed lots of prying on the front head. The rear head is moving freely. it's just the front head and a middle stud that won't wiggle at all. I'm about to weld a nut to the stud just to see if I can remove the stud itself. Am I missing something here or is it likely what I'm thinking with a carbon build up siezed stud? Any tricks to try before I weld the nut to the stud? I did pull all hoses,the tip turbine bracket with 3 head studs under it. All studs are free or nuts came off the studs. It's just one stud that lookes like a tight fit and when I pry the head will not move up around it.

All I can tell you is dont get the epa involved or go to any scrap yard who might get them involved. Your best bet is to let them drain as long as possible so you reduce the oily sludge mess. sheer them up into smaller chunks if possible and then crush them flat so they don't look like a tank. Put them in mix scrap loads. When I do it this way the yards never even know because it just looks like normal scrap. If they are heavy with sludge in the bottom. fill it plenty with exhaust fumes from a truck before using a partner saw or plasma cutter to make a large doorway into the tank. This will remove oxygen inside and reduce its chance on flashing over. Once you have a doorway you can shovel the slop into buckets. And the tank is now safe to cut with a torch You just need to dismantle them so they don't resemble a tank and they pose no safety issues.

You have what many mack guys call a low rpm engine. It is set to 1700 in attempt to gain fuel economy. The trucks built with these engines would l have had different rear gearing to compensate for the reduced rpm. You will need the pump recalibrated to 2100 rpm specs to gain more rpm. Not sure if you can do it while its still on the truck but I know it can be adjusted.

.If you think the coolant is pressurized. You can bring a fairly cheap co2 tester with you. You will want the truck to run for a bit to see if combustion gasses are entering the coolant. RELD Head Gasket Tester Kit Combustion Leak Detector for 50 Tests https://a.co/d/4va7zaw

This was the cap end of one of the rods. Looks like it's a P1 bearing

On my b model with budd wheels. They are standard lug nuts with right and left hand threads depending on what side of the truck they are on

Many say that. But it just doesn't build pressure like any diesel I have driven. I'm used to seeing it snap from 30 psi hot idle to 60+ psi as soon as the throttle is touched. This thing has 35 psi at 1200rpm. That's when she's making all her torque !

I did not. I was hoping the bad plunger I found was the issue. Talking with others it seams .003 is the upper limit for good rod clearance. General consensus is I should just roll in a standard set of rods and mains next to see if it cures my concern. If that don't fix it it's probably worn auxiliary shaft or cam bearings. I may pull the valve covers just to see how oil flow up there is.

Pulled 2 rod caps down today. The bearings were spotless. If im reading the bearing numbers right they are noted as a P1 / standard size. I plastigauge them both. Got .003 clearance. Is that within spec? I shimmed the oil pump with new plunger and spring. Installed new plunger and spring in the upper and lower parts of the fuel pedestal. Put the pan back on and filled with oil. I Still have what I consider lower than usual oil pressure. Hot idle pressure is slightly better. Previous was 25psi now its 30psi. However i still have to spin it to 1600Rpm just to see 40psi. And at 2100rpm it is at 50psi. the oil pressure spec per my mack manual says 40-95 psi at governed 2100rpm every maxidyne I drove the oil pressure jumped to 50 right off idle and by 1200 it was pedded at 60-70psi all the way to 2100. This needle barely moves untill over 1200rpm then it slowly increases with rpm until high idle. Still scratching my head at this