We have been having a few issues with multiple trucks lately. On our old mack rd e6-350 the fuel pump died. Our duramax started smoking pretty bad like the injectors are about to give up. The VW TDI is shaking bad during regen. the 3306 cat is smoking bad. The rest of our diesel equipment is low on power and missing here and there. And the one that really upset me was our old cummins big cam blew up. It was an ntc 400 that was turned up. Ran great until it just stopped. Pulled a head and had broken the top of the piston. Checked a few other holes and all the other pistons are cracked. My question is would bad fuel do this or is there another cause I just don't see? Is this just a good run of bad luck? Other people running it have trucks that smoke bad but no major issues that I know of. We recently switched to this new fuel supplier and it seems that is when issues started showing up. When pumping fuel into equipment it looks almost black every now and then. Like there is a good bit of contamination in the fuel. We also had several water block filters close up about 2 months ago. I think we are going to part ways with the new supplier and go back to our old one. \ Anyone have any suggestions other than the fuel causing this? For reference the motor was rebuilt a few years ago and has less than 100k on it. Head gaskets were done about 5 months ago and we replaced the injectors at the time as pm. There were no signs of issues at that time. The supplier of fuel started with us about 3 months ago. Another thing that has me concerned is the crank and rod bearings were wiped. My guess at this point would be so are the cam bearings. I am struggling with what would be the most economical and best fix for this. We need the truck by the end of the week and don't want to spend to much on it. I have attached a pic of a cracked piston. The 1 that exploded I don't have a pic of. Suggestions, causes?
Time to send some fuel to the same place that does oil samples, they can tell you if there's an issue or not. Sure sounds like it to me.
Black fuel makes me think you have algae in the tank.
Our fuel goes through five filters before coming out of the nozzle. I figure filters are cheap compared to engine issues. You don't think the filters would have caught it? We also treat with algicide and power service every delivery. If we picked up algae it would have come from them. Is that possible with the amount of turn over a fuel truck has?
Could just be a run of bad luck too. I've had 4 differentials give me problems in the last month. And I know its just bad mojo so it does happen. Like they say test the fuel, and cut a few of the old fuel filters apart just for your own curiosity.
Agree with others , have the fuel checked out . As for the NTC 400 trouble replace all the piston spray oilers while you are rebuilding it . Have seen a bad oiler do that to an engine . Crank shaft look ok ?
The crankshaft looks ok. But with the bearings showing copper on The mains I am worried that the cam bearings are trash. What would cause the Pistons to crack? Did they mess up our injectors or was it water in the fuel?
Extreme heat would cause the cracks in the pistons . It's extra work but would be best to replace cam bushings as well while your at it .
Yeah tbone1471 , to elaborate on my statement and your question on the NTC 400 trouble . No , I don't think bad fuel caused the pistons to crack . To much fuel possibly . Not uncommon to pull the heads on a 855 cummins set up Hot and see spider web cracks forming on the piston . Noticed that in your first post the 400 had been jacked up . I have an old 290 small cam cummins set hot in a 1973 White 4000 tractor . It will pull with a 400 but you don't want to stay in the throttle very long as it's not after cooled. If ya aint careful the pistons could end up in the oil pan . Safer to gear down & keep rpm's up on a long hard pull . Like I said earlier , I would also replace the piston oilers . They are plastic & subject to cracking and are essential for cooling the pistons on the higher horse engines . I've had pretty good luck with engine kits from these folks . Ask for Steve . http://www.btmccorp.com/
The reason I was thinking fuel was because at about the same time we switched fuel suppliers we did head gaskets on the truck and there were no cracks. I only let 1 driver in this truck and he knows how to drive. He is very conscious of what goes on with the truck. He said a few weeks ago it started making a puff sound. It was very subtle and you really had to listen for it even then it wouldn't be noticeable to someone that wasn't in the truck everyday. We will be sending out fuel samples this week. It just seems with all the fuel related issues in the past month it has to be that?
tbone let me ask this.. have you also changed oil suppliers??
No. Our chemical supplier is the same. We have been using them for years with no issues. We seem to fluctuate with fuel suppliers though. They are like the tire people. Get a good price for awhile then all of a sudden it goes up. We had one that changed prices based on which employee came to pick up...
Hey tbone As for Cummins engine why did you replace head gasket? What did injector spray patterns look like on pistons with head off? Do all liners look as polished as this one? What exhaust temp does driver back out at? Does truck idle a lot? As for bottom end wear oil sampling can help in future determine cause.
The truck sat for a while and the head gasket started to leak when we put it back in service. That time and this time the spray patterns looked good. No hot spots or excess build up. The liners are a little polished but they are consistent among all cylinders. The driver backs out just over 1000. He keeps the rpm up and doesn't lug the motor. This truck idles about 75% of its run time. Fuel wash on the cylinders is a concern
Drain and shock treat your storage. Fuel has a shelf life of around 2 months. I never buy more than I use in a month.
We have only been using our 100 gal tank lately. We burn through it about every week and a half. So our fuel turn around is fairly quick. Nothing sits.
Cracks over the crown and down the side usually indicate some kind of a timing issue usually seen on the 3406B model Cats when the timing advance would slip or not operating correctly. If you knew what you were listening for you could often tell just by the sound of the engine when you revved it up. Not so sure on a Cummins Possible overhead settings? Injector settings to deep?
Add lucas fuel additive one half gallon to 100 gallons of fuel, works wonders.