Pistons?

[CumminFast]

I am going to have to put new pistons in my truck because when it was rebuilt 20,000 miles ago aftermarket pistons were used and they are now cracking. I have not decided what I am going to use yet. I may use marine pistons are maybe just buy another engine. Do flycut pistons like the ones from Mitchell actually increase horsepower? I guess the purpose of flycutting and cam is to get more air in? My truck is built for the street and drag racing, would flycutting pistons and a big cam help me? Are marine pistons good for any hp or are they just stronger?



Thanks

Rick

 

[ToolManTimTaylor]

Originally posted by CumminFast

it was rebuilt 20,000 miles ago aftermarket pistons were used and they are now cracking.

Rick

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33623&item=2430277028



Were they theese? I dunno of too many aftermarketers that have the ISB pistons. But come to think about it there is some info on the ATS website regarding HO and marine pistons











<hr>



:EDIT:

in fact here is the thread



http://forums.atsdiesel.com/showthread.php?s=&threadid=53

 

[SRadke]

I'm sure somone will correct me if I'm wrong but I thought the pupose of shaving (fly cutting) the tops of the pistons was to drop the compression ratio and get more O2 in there. This could also be accomplished with a thicker head gasket right?



Here's another question. Are the OEM pistons forged? Forged pistons are tougher than cast.

-Scott

 

[Vaughn MacKenzie]

Weeeeelll it says they're for the "Naturally Aspirated Cummins 5. 9L B-series. "



Vaughn

 

[raychem]

SRadke,



The purpose of fly cutting the pistons like Mitchell's does is so that when high lift cams are used, the vales do not hit the piston crown when they are fully opened(compression ratio is affected some). Cam duration and lift are what control the amount of air that enters the cylinder. Also since our trucks are also turbo charged, the turbo's size is also a factor in how much air enters the cylinder in relation to the cam's lift and duration.



Richard

 

[SRadke]

Thanks Richard, that slipped my mind. I was in a high performance shop once and the owner had an engine torn down. He had smeared modeling clay over the piston crowns and was getting ready to put the heads on and roll her over to see exacly how much clearance he had. It can be a very precise deal.

-Scott

 

[F8LDOSE]

If your truck is gonna be a daily driver the use of marine pistons may yield a bit lower compression than you'd like. I think it's around 14. 5 to 1 with the . 020 gasket. It may be alittle hard to start.

 

[Jim Fulmer]

http://scottsram.homestead.com/Motor.html



I like this setup, it would be nice to get one of these short blocks for my truck.



Jim

 

[CumminFast]

Do any of yall know if something like Mitchells cam and pistons would work well on the drag strip? or will they just work well w/ pulling? I mean will they give me any more hp?

 

[WadePatton]

I'd talk to Diesel Injection of Pittsburg about pistons. They have experience with racing big diesels and ceramic topped/teflon skirted jobs. Might be $$$, but that's racing.