Threaded Mode | Linear Mode

Rawze · 02-04-2021, **(Subject: Rawze Bomb Squad )**

(02-04-2021 )tree98 Wrote:
(02-04-2021 )Mattman Wrote: Why Cummins did not step up and recall all these pumps and replace the ceramic parts is sorry if you ask me.

Like mentioned it is a total engine killer.

The steel plungers will do it too. These are the same types of pumps used on other brands of diesel engines(same failures as well) with high pressure common rail. Must be that nobody can figure out any other way to get fuel pressure up to 30,000 psi.

I don't even think that cummins designed that system... I think it was Bosch, as I have seen related info in the past on this... but not sure about it.

I used to work with industrial systems that had 30,000+psi pressures in the past. It usually takes several dozens of pump stages where each stage only has to deal with a much smaller differential pressure, stringing them in series. I would imagine that this is impractical on an engine where space is severely limited.

Personally, I don't know why they did not design a staged pump into the cylinder head on its right hand side so that no one stage had to deal with such extremes. There is plenty of room for a second cam that could have been used for just this purpose... just my opinion any ways.

Volvo8873 · 02-04-2021, **(Subject: Rawze Bomb Squad )**

(02-04-2021 )Mattman Wrote: Why Cummins did not step up and recall all these pumps and replace the ceramic parts is sorry if you ask me.

Like mentioned it is a total engine killer.

They did have a campaign for just this. They replaced the original 3 cylinder pump with a 2 cylinder. It was back in 2014 or 2015 when they had this I believe. But it has been closed since then.

JimT · 02-04-2021, **(Subject: Rawze Bomb Squad )**

(02-04-2021 )Rawze Wrote: I don't even think that cummins designed that system... I think it was Bosch, as I have seen related info in the past on this... but not sure about it.

I used to work with industrial systems that had 30,000+psi pressures in the past. It usually takes several dozens of pump stages where each stage only has to deal with a much smaller differential pressure, stringing them in series. I would imagine that this is impractical on an engine where space is severely limited.

Personally, I don't know why they did not design a staged pump into the cylinder head on its right hand side so that no one stage had to deal with such extremes. There is plenty of room for a second cam that could have been used for just this purpose... just my opinion any ways.

I did little digging some time back. Yes, these pumps are made by Bosch and yes they have the same issues on other trucks/engines (Big class action with GM related to Duramax fuel pumps failing). Try a google search for "bosch fuel pump failure". Reading about those other pumps lead to my speculation in other threads on here about poor lubrication being the underlying cause. Possibly due to differences in diesel fuel lubricity or, as noted in the class action, air pockets in the fuel (or even the oil) that inhibit lubrication. Given the pressures and stresses involved with these pump designs along with the tight tolerances of the parts it wouldn't take much to cause excessive and repeated wear, then eventual failure.

JimT · 02-05-2021, **(Subject: Rawze Bomb Squad )**

Oh, for those of you who are low mileage, high engine hours people, such as lots of PTO use, just estimate engine hours based on typical over the road truck usage. (not sure I worded that right, started the weekend early with a good drink, oh well)

For example, lets say a typical over the road truck has a lifetime average of 45mph (stop and go, highway, idle time...). So, 400,000 miles / 45 mph = 8,888.8888889 hours or rounded you can say 8,900 hours of engine operation is roughly the same as 400,000 over the road miles.

ahub86 · 02-05-2021, **(Subject: Rawze Bomb Squad )**

(02-05-2021 )JimT Wrote: Oh, for those of you who are low mileage, high engine hours people, such as lots of PTO use, just estimate engine hours based on typical over the road truck usage. (not sure I worded that right, started the weekend early with a good drink, oh well)

For example, lets say a typical over the road truck has a lifetime average of 45mph (stop and go, highway, idle time...). So, 400,000 miles / 45 mph = 8,888.8888889 hours or rounded you can say 8,900 hours of engine operation is roughly the same as 400,000 over the road miles.

Thanks for this. I was wondering what a over the road truck does for hours. With my dump truck I was just going to half the 400,000 suggestion and go with 200,000. But I averaged just above 20 miles per engine hour on my last truck. Your numbers put me at 178,000. Maybe I will be replacing parts every 150,000 or 125,000 just to be safe. That’s still 4 or 5 years for me.

JimT · 02-05-2021, **(Subject: Rawze Bomb Squad )**

That's an estimate based on realistic long term averages that I've personally seen. Back in my LTL days our trucks had lifetime average speeds of about 30mph. On the flip side someone who speeds a lot might see slightly higher average mph, but that extra speed means higher wear on components. In the end there is no perfect number, be it miles or hours. Use the info as a base and adjust to your needs and operation.