Piston Design

[Begle1]

Has anybody anywhere ever tried any other kind of piston than the bowl-shape?

What's the point of the bowl? Why does fuel burn better in the bowl than out in the open?

[dpuckett]

The bowl of the piston provides a place for the fuel to burn, as the piston gets REALLY close to the head. If it werent for the bowl, it would never get a place to burn, and the piston would hit the injector tip. So, you make a bowl, make an injector tip in which the spray pattern matches the bowl deisgn, giving maximum air fuel mixture potential, and BOOM, you have a direct injected diesel engine.

As for other bowl deisgns, there are guys who are running extreme HP that have gone to the lower compression marine pistons.

Daniel

[Begle1]

So, if it wasn't for the bowl, the stream of fuel from the injector would end up splattering itself all over the top of the piston.

And the piston itself could hit the injector.


So I take it that the marine pistons are basically the same design? What sort of compression do they run?

[KTA]

Marine pistons are 15.3:1 and have a lot bigger bowl.

[Cowboy_Customs]

Ok, I have to ask, what is the acctual benefit of running the low compression marine pistons? I understand for extreme HP u gotta lower compression. But what would happen if you put these on a street driven truck, with mild power, say 400, 450?
Im going to have my long block assembly to play with here (granted it survived the accident n didnt kill the block) so I want to "build it up" with some nice aftermarket pieces, pistons, cam......

[dpuckett]

Go read what these guys have to say about building high performance Cummins N14s- www.dieselinjection.net . I'd assume the theorise could be adapted to the B-series. Basically, when one lowers compression, the airflow needs to be increased to offset the lower compression & cooler combustion. The increase in airflow to the cylinders, along with the reduced cylinder pressures during combustion, allow for some serious high HP potential.

Daniel

[Cowboy_Customs]

wow.
I have been to their site before looking for the box for my freightliner, but never read any of the articles before on the NTC!
Now I really want that 82 Frightliner stretch frame with the bag cam IV for sale down the road!! lol

Thats some great reading

[charger 69]

For increasing air flow in our trucks these reground cams must be just what the doctor ordered. Correct me if I am wrong but wouldn't a cam would be right up there with a larger turbo when it comes to air flow??

[gman07]

Based on what I've read and the conclusions I've drawn, a cam and ported head would probably help a 1st gen out quite a bit. The cam is relatively inexpensive ($750 for a Helix 2 IIRC) but the work putting one in is quite a bit more than just swapping a turbo.

[charger 69]

gman07, you are right without a doubt on turbo replacement but i am just thinking of options as I intend to lay up my rig and do a major update-overhall-add on, in the next year or so I have the HP.and a drive line that can handle it.

[KTA]

I made 627rwhp #2 only with a stock cam. I will be running one of my cams in Old yellow version 2.0.

[charger 69]

KTA, I kind of like the setup you have on your towing truck as I pull about the same weight. If I move into a state that is tough on emissions I don't want to deal with excessive smoke for state inspection unless its easy to turn it down, not saying a cam would help at all.

[dpuckett]

A cam would probably help the smoke reduction, as they allow more air into the cylinders.