HELP! 250 cummins

[Cowboy_Customs]

Bought a 1970 M818 with the 250 Cummins that was supposed to have been refurbed at letter kenney in 99 according to the data tag, has now 2400 miles. And on the drive back with the truck 10 miles from where we picked it up all of a sudden I got a VERY loud knock in the top end, sounds like a rod knocking, but in the middle rocker box. Got a hotel and had a heavy diesel mechanic look at it the following morning and couldnt figure out the problem. NO SMOKE, wasent missing, nothing bent, or not moving, ect ect ect. Well, we headed out that morning now 10 - 20 miles down out of a 180 mile trip. 80 miles later, something let loose with what sounded like a really bad gear grind, but went away, and then the blue smoke came rolling out, with a heavy miss, 1 probably 2 injectors down.
Again pulled the middle rocker box cover, but now, there is antifreeze in the oil, and heavy oil/antifreeze build up on the rocker box cover.

The engine was quite loud from the get go, not like your typical class 8 855CI Cummins. But had good power, NO smoke what so ever, minus your typical not ran diesel, blue injector haze on initial take off down the road, but clears up after after a minute.

I know I never over revved it I ran at 45 and 50 the whole trip (Tach cable is broken) and know how to drive a truck I have a class A CDL which I use.

Any help is GREATLY appreciated!

 

[Blood_of_Tyrants]

I would call the buyer and raise he!!.

 

[NDT]

Well lesson learned, any time you have a "very loud knock", that is a precursor to something even worse, now you will find out what that is. Sounds like something was ingested and now you have a busted piston, scored liner, hammered valves and head.

 

[WillWagner]

Coolant in the oil, knock, blue smoke. Sounds like a hung piston. Best thing to do is to drop the oil pan and look up the belly of it. If it recently..well low miles ago...had on overhaul, my guess, if it wasn't hot, is a rolled liner o-ring or crevice seal. Did you look to see if the belts were on it before you left?. If it was painetd beige, look to see if it is pink now, that indicates running real hot. If it is green, there will be no indication of running hot.

 

[JDToumanian]

With so many surplus trucks and engines available, you will find it cheaper to swap out the engine for a new one or running take-out than to overhaul this one that failed.

A forensic investigation could be interesting, I vote for a dropped valve or seat.... take off the muffler and dump out the chewed up parts. Post pics.

 

[avengeusa]

wow, that sucks, post pics

 

[Cowboy_Customs]

Thanks for the input, Pics will be taken, I have a couple decent ones from the trip. Didnt end up taking as many as I had hoped do to the lost hope!

Yes it did/does have all the belts and such before the trip. I checked everything as I do with a tractor trailer, right down to air pressures in the tires. The engine is green/black or mostly black panited from what I remember right now. I never got it over 185 on the trip. and that was only once, the rest of the time spent was between 160-175. Whch brings me to my next point and question as well.

When I did get er up to 180-185 which was pulling a hill in 5th and 4th once, with my trailer and our chase truck in tow (gross was maybe 12K in tow) it died on me, first time I sat for a minute to have a looksie at things, turned over fired up, no problem, second time, 4th gear hammer down not wound out either I might add, truck died, but this time when I hit the starter it refused to turn over!! Sat for 2 minutes turned over, fired, off we went. After that point I never used more then 2/3 throttle, except 2 maybe 3 times in 15 second bursts.

This was still during my "getting to know you" period, it was 60 miles later when the engine let go.

Anyway, the truck SHOULD be in the driveway in the next day or so, and then the tools come out, and the gloves come off!!

I look forward to spending many hours hanging out here and will have many questions I am sure! Thanks again for the help everyone.

 

[FreightTrain]

Scattered the injection pump maybe(well,the high pressure pump on the side of the block?).When you get it back.pull the covers and have someone hit the starter.Make sure all the rockers are rocking.Might have also sheered the cam.Kinda seams strange about the gear grinding noise....Normally when someone major lets go all you hear is a THUNK and then a little rattle or knocking sometimes a loud bang and then the ones that really drive you nuts.Silence.Just shut down and never runs again.

 

[Cowboy_Customs]

Well, we got the truck back and tore into the top end, we pulled the rocker boxes saw nothing wrong in there, so we dug a little deeper, pulled the middle head where we THOUGHT the noise was comming from, and nothing. SO onto the other 2, pulled the rear, nothing, pulled the front head, and well there it was, number 2 piston killed itself, on a 1/4 of it you can see the top ring. AND 2 SERIOUSLY bent valves, both exhaust, the other 2 intake were bent, but not pretzels! The number 1 has a minor little knick in it from the shrapnel, so I am waiting on the heads to get checked, injectors to be re-popped, and inframe kit (basically) to show up. Were going to replace the liners in both and the pistons and reassemble. UHH!!

OHHH and onto other things!! We desided to pull the fuel filter housing off. I have NEVER EVER seen such disgusting JUNK inside a fuel filter as this one has. I mean right upto the bottom of the lip the filter sets on is orangeish GOO, and the filter almost falls apart. If you were to acctually squeeze it, it would collapse!!! Just WOW!!! I am amazed the truck even ran, let alone as well as it did.

I do have pictures of the carnage, but I dont have time to post them right now. But they are comming.

 

[jwaller]

should have checked the filter before driving off pretty common for a truck that has been sitting for months or longer... might have ruined the inj pump. I'd have it and and all the injectors checked.

 

[Cowboy_Customs]

I did open the drain on the filter to try and drain any water off, but just like any other oriface a stupid wasp could get into on the truck there was mess of mud in it.

Being as I bought it from a member from this site, I am apalled at the issues.

 

[Cowboy_Customs]

Got some updates. Tore into the Cummins a few weeks ago, found the number 2 piston was partially missing, and 4 bent valves. The bottom 1/3 of the sleeve was non existant!!! Acctually the pieces were in the pan. Number one had a couple minor chips out of the top of the piston, but the bottom of the piston was a little chewed up from the debris of the number 2 sleeve getting scattared! One of the heads was no good, the other 2 needed to be milled. AND 6 new injectors!!! So, total bill is around 1700 and counting, for the engine.

What on earth could cause such a huge mess like this?????

Found the engine is a replacement, the data tag on the engine has a manufacture date of 2/85.

I havent uploaded any pictures as of yet, and will take a few more of the new found carnage.

 

[M215]

Check with john Winslow, last time I asked he had running take-out NHC250s for $1000.
I just finished rebuilding the heads on mine, 6 new injectors and gaskets was over $1000 in just parts with me doing all the labor.
Good luck,
Karl