Need some info - goofy cummins - 8.8?

[HoleshotHolset]

I'd like to see some articulated pistons in a 6BT. I know a few pullers that would probably like to try them out and see if they last longer than the OEM pistons... .



Matt

 

[A Johnson]

Originally posted by will24

We just got a motor delivered to school by cummins inc. that I absolutely cannot find any info on. The data tag says it's a case/cummins. The model is 6DT8. 8



-Will

My guess is it was a preproduction engine, and there were probably a few do to all the invalid serial #s in a series, and it was changed to the ISL for production.



JohnE seems to have a pretty good source of info , so hopefully he will come back with more info for you.



A Johnson

 

[nickleinonen]

Originally posted by HoleshotHolset

I'd like to see some articulated pistons in a 6BT. I know a few pullers that would probably like to try them out and see if they last longer than the OEM pistons... .



Matt

atriculated pistons work great, but that steel crown makes for a heavy piston, that you don't really want flopping around in there at too high of a speed. most truck engines that have the articulated pistons are limited to 2500 max rpm [with no fuel, like compression braking] and fuel governed at 2200rpm...

 

[JohnE]

Yep, got more data.

The "8" on the engine number is a clue. "8" is used for experimental, prototype, & field trial units. The other clue is the model 6DTA 8. 8 I've heard rumours of D series.



It is very possible this engine is an 8. 8 liter proto. The crank & rods are ISC, but the articulated pistons are used in the ISL and bigger.



Source? I called the local Cummins service manager. I may contact our OEM engineer and see if more info is available.

 

[HoleshotHolset]

The Detroit 8V-92 uses articulated pistons... . and I have seen those engines in drag trucks turning a lot more than 2500rpm.



Any idea what the 16V-71/92 engines run for pistons? I have seen those turning some really serious rpm as well. Granted, a 2-stroke sounds like it's turning twice as fast as it really is..... (twice as many 'pops' in the same period... ) but the big rig pullers have to be turning at least 3krpm under load.....



I just want to be able to run hotter EGT's without having a meltdown... . and thought that the articulated pistons would help.



Matt

 

[nickleinonen]

Originally posted by HoleshotHolset

The Detroit 8V-92 uses articulated pistons... . and I have seen those engines in drag trucks turning a lot more than 2500rpm.



Any idea what the 16V-71/92 engines run for pistons? I have seen those turning some really serious rpm as well. Granted, a 2-stroke sounds like it's turning twice as fast as it really is..... (twice as many 'pops' in the same period... ) but the big rig pullers have to be turning at least 3krpm under load.....



I just want to be able to run hotter EGT's without having a meltdown... . and thought that the articulated pistons would help.



Matt

2500 is pretty high for a 2 piece articulated piston i think, but arn't most drag/pulling trucks with the b series running 3500-4000 rpm?



2 cycle diesel engines are also always downloaded on the piston [compression/power-scavanging/compression/power-scavanging]...



but those DDC 2 cycles are easy to make spin fast. all avalable right on top of the governor there :-laf:-laf

 

[Will24]

You guys are awesome!

 

[A Johnson]

Holset, I'm not much of a hotrodder, but what about ceramic coating? I know this was done for some of the 444 and STC N-14s' that people were really pouring the coal to.



A Johnson

 

[JohnE]

What about the triple nickle engines? They ran 3,200 rpm on the governor. Anything special there?

 

[Will24]

Didn't the 555s fly apart fairly frequently?

 

[AMeissner]

555s did fly apart quite often. We had one in a fertilizer machine, lacked power, so we threw on a turbo. Yep, it flew into pieces

 

[Phrogger57]

555 I had was a valve dropper

-Eric

 

[JohnE]

Ah, the shrill sound of a spun camshaft bearing.



I was just wondering if they did any tricks on 555 pistons being it was a higher rpm engine.

 

[A Johnson]

I still wake up at night to the sound of the cam bushings squealing!! (It was a 903 though). Almost all the 504 and 555s' I've torn down with any hours on them had spun cam bushings.



What I remember was the seized pistons and valve covers exploding due to the internal crankcase vents couldn't handle the blowby on the non turbo models.



Oh Yeah, then there were the left hand versions.



Sure glad Cummins got out of the V-6 / V-8 business, leave it to the boys in green coveralls.



I don't think there were any tricks, I think it was the shorter crank throws and smaller push tubes and such allowed a faster rpm without the inertia of heavy parts causing problems, but I may be all wet.



A Johnson

 

[JohnE]

Speaking of 903, How's the reliability of the VT-903 in the military?

 

[dpuckett]

I thought the L- series was a 10 liter? Seems like my 83 CHilton book (I know, not the BEST info source) listed the Lxx engines as 600-something cu in. I could be wrong, wouldnt be the first time.

 

[Will24]

L10s are somewhere around 606 or 611 cu in.

 

[JohnE]

The ISL is an 8. 9 liter engine. It replaces the ISC 8. 3 liter for on-road use.

The L10 was a 10 liter engine.

The ISM holds at 11 liter as the M11.



Piston material & construction technology is rapidly changing. 20 years ago cast alum 390 pistons were rare. Today we're seeing 2 & even 3 metal composite casting.

 

[HoleshotHolset]

I've heard about a few folks in the gasser world that ceramic coated their pistons... . and after a teardown, most of the ceramic was gone.



I'm not real big on coatings... . never was.



Matt

 

[Will24]

My diesel engines teacher talked about ceramic coatings etc for probably a week. He said the average life of the coating is anywhere from 30k - 50k miles...





I find that interesting since GM's fix for the vortec v8 piston slap issues is a set of ceramic coated pistons...