P7100 electronic timing .... impossible?

dirty_max said:
hmmm... yea ive been working on common rail engines for 5 years now and have never even heard of this. i would imagine its just as common as a mechanical engine running away
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Really? I dont work on commonrails and I know personally of 2 Cummins and 1 duramax that melted down from a bad injector.

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chevota84 said:
Really? I dont work on commonrails and I know personally of 2 Cummins and 1 duramax that melted down from a bad injector.

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wow i can honestly say that i have not heard of this until now, most of the common rail work that i have done is on stock engines though. and most of it not even being a cummins, psd, or duramax
 
Sorry I forgot I also know of a cummins that melted down from an injector, but I'm not sure if it was just random or from a tuner, because I know this dude might have driven the bag off it with lots of high EGT's.

The dmax and psd were both stock that i was talking of.

I don't think the issue is too rare, I've heard quite a few stories and I'm not just talking about internet forums.
 
Well I don't know what you guys have been working on, but my brother rebuilds at least 1 engine a week, usually two. Almost always stock commonrail 5.9's from owners running them with bad injectors. Melted pistons galore.
 
AHall said:
Well I don't know what you guys have been working on, but my brother rebuilds at least 1 engine a week, usually two. Almost always stock commonrail 5.9's from owners running them with bad injectors. Melted pistons galore.
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Exactly, one of the Cummins and the duramax I was talking about were stock. The other Cummins had a pressure box, and these are people I know directly in a town of 7000 so Its a pretty small sample.

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I'm going to have to call bs on the dmax giving no warning. They have huge injector knock for a quite a while before they destruct.
 
Bryce418 said:
I'm going to have to call bs on the dmax giving no warning. They have huge injector knock for a quite a while before they destruct.
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hmm yea this is more like what i was thinking. youd think you would notice some sort of miss or something to that effect long before it would melt a piston. but then again, a lot of people just dont pay attention to the little things
 
Caterpillar has a neat gear that uses centrifugal force to advance timing, not really anything close to adapting to our pumps, but its the theory that we want.

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Within 2-3 years of common rails coming out I read of several meltdowns on TDR. Often times it happens so fast and with hardly any drama that it caught the driver by surprise. The problem with a hung injector is it turns into a blow torch and some guys lost pistons before the pyro hardly had a chance to spike. A bad injector on a jerk-pump system nets you a slight miss, a little blue smoke, pretty benign issue.
 
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good god I can't imagine the forces required to 'centrifugally' advance the pump from the Cat design above
 
Hurley said:
good god I can't imagine the forces required to 'centrifugally' advance the pump from the Cat design above
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Its about a 10* advance on a cat iirc. It can be done, but with the space we are limited to. Maybe not. Right now everything is just speculation.
 
I was not arguing, btw, just thinking about it from an engineering pov - and comparing to mech advance on a gas engine's distributor
 
Bryce418 said:
I'm going to have to call bs on the dmax giving no warning. They have huge injector knock for a quite a while before they destruct.
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The dmax guy that I know said that his only warning was that the engine was running rough, and he took it in and the oil was over full, and full of diesel, and they found that 1 piston had a hole melted through it.

When they pulled the engine out for a rebuild, a bunch of other parts were damaged I guess and they tossed it before a complete teardown.

As far as wether you notice it or not, I assume it depends on to what degree the injector is damaged.
It seems like most of the times I hear about it, by the time you notice it, its usually too late to replace just that 1 injector.
 
For the record, I would have loved if the industry went in this direction:

Delphi E3 Diesel Electronic Unit Injector

.....Instead of common rail.

Basically they are mechanical unit injectors with precision electronics on each injector.

The ones above support pre and post injection events, split shot, etc so they are a little bit behind current common rail abilities, but there is no reason they couldn't compete.

Basically they run off the camshaft and each injector develops its own high pressure fuel, up to 32,000 PSI.

No HPFP, no high pressure fuel system, just simple reliable mechanics, and an injector valve and tip that have the needed electronics for emissions reasons.
 
Cummins uses that style injector on their big motors. I would assume that they dont use them on the B series because of the lack of space
 
cummins cowboy said:
Cummins uses that style injector on their big motors. I would assume that they dont use them on the B series because of the lack of space
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Thats awesome..

That design IMHO puts all the pickup diesels to shame.
But yes they are a little big... I think I remember reading they were 8 lbs each LOL :lolly:

Hopefully one day they migrate over to small pickup diesels and the end of the HPFP and HP tubing will come.
 
Modified plunger helix would be the easiest, but the timing change would have to be in correlation to rack travel.
 
parkland said:
For the record, I would have loved if the industry went in this direction:

Delphi E3 Diesel Electronic Unit Injector

.....Instead of common rail.

Basically they are mechanical unit injectors with precision electronics on each injector.

The ones above support pre and post injection events, split shot, etc so they are a little bit behind current common rail abilities, but there is no reason they couldn't compete.

Basically they run off the camshaft and each injector develops its own high pressure fuel, up to 32,000 PSI.

No HPFP, no high pressure fuel system, just simple reliable mechanics, and an injector valve and tip that have the needed electronics for emissions reasons.
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cat has been doing this for a long time, since like '96 or '97 iirc, but its not nearly that high injection pressure i dont think. and also on the caterpillar advance, i could be wrong but i though they were hydraulic as well not just centrifugal. but like i said not 100% sure on that one.
 
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