cummins dead now what

[RStankevitz]

ok my neighbors 1st generation cummins is in Boston dead. he was running biodeisel and ran it to late into the cold. it started to gel on him a couple times then as he was driving one day the rpms just climbed rapidly and he quickly pulled over and shut her down. then he tried refiring it and it revved right out of sight again so he immediately shut her down again. he had it towed to cummins new england? or something like that and they did a bunch of tests on it and say it needs a new motor supposedly lost compression on 2 cylinders. would this be caused by bent valves from overturning? and any ideas what might have happened to the pump to cause the initial problem? anyone now a real good trusted diesel guy in the natick mass area?

 

[Tippin Spotted Cow]

Sounds like his governor spring may have snapped. Not sure how that would quite relate to the biodiesel though.



Theres really not much you can do to these beasts to need a whole new motor. Mainly if you crack the block. Other than that, almost every bearing surface in these motors can be bored O/S and/or fitted with sleeves. Anything else can be replaced or rebuilt.



I'd wonder if he doesn't have compression, maybe the head gasket is shot?

 

[RStankevitz]

well he said he got a bad feeling about the cummins guys. he felt they where trying to just get him to leave? if memory serves he was told something about a pin possibly breaking in the pump? as far as compression i don't think it turned enough rpms to hurt anything so i am not sure

 

[JLEONARD]

Theres really not much you can do to these beasts to need a whole new motor. Mainly if you crack the block. Other than that, almost every bearing surface in these motors can be bored O/S and/or fitted with sleeves. Anything else can be replaced or rebuilt.

Yes you can also bore the one or 2 cyls O/S and use O/S pistons... that is an authorized repair technique.



Sounds like you may need to pull the head to inspect a few things.

You might call Scott at Mass Diesel and get his opinion... he's a straight shooter.

Good luck

 

[Tippin Spotted Cow]

Yeah, you pull the head and you'll know right away if the gasket is blown. From there you can check the cylinders pretty easy, but I doubt that theres anything wrong with them or the pistons for that matter. Revving the thing out into orbit once or twice and killing it right away shouldn't mess up your pistons or cylinders. You might wanna check valve clearance if you have the tools at this point, it's possible you just floated the valves.



Scratch that all. First thing you should do is pull each individual injector, one at a time, and check for compression. If 2 really are losing compression, then move on and see why. The you'll also know which two to inspect, also.

 

[Tippin Spotted Cow]

I correct myself, the governor spring snapping would result in a lowered rpm. The lever for the governor may have snapped off the wheel with the flyweights... Im not 100% on how that could play out.