Engine/Transmission (1994 - 1998) Marine pistons

[RJMurphy]

I am rebuilding an early 91 Cummins for my 1983/1991 Crewcab, and have some questions. I am swapping to a modded P-pump, with 370 Injectors, a ported, and O-ringed late-model head, ATS Manifold, 4 " exhaust, hx35/40 hybrid turbo, and PDR cam. I want to know if the marine pistons would be worth it, I understand they are lower compression, so I can run more boost, bit is this a worthwile invesment? Is anyone here running them? I am going to have the motor torn down anyway so now is the time to make the decision. Also is there a Better oil pump (high volume) for the B-series, if so what are the part #'s. Furthermore is there anything else besides balancing, that I should consider while I am this far along? Thanks in advance. Murfman

 

[Forrest]

Didn't MY6EATSV8's use them?

 

[T. Baker]

From what I read on this site nobody is having trouble running regular pistons even with twins and 50- 60 psi of boost. Marine pistons might make starting harder due to the lower compression ratio. I am also intrested if the marine pistons might improve longevity. I would also like to know the compression ratios of both to compare them.

 

[F8LDOSE]

I am in the process of building a motor for my pulling truck, and had to decide on pistons. From what I gathered I decided to go with . 020 over 215 horse pistons and have them ceramic coated. I believe the marine piston will drop compression 2 full points to 15. 5 to 1. If your going with a cam with alot of lift you will have to have your stockers cut to clear valves. Idon't think the marines are much more pricewise( I paid 900 for my pistons and rings) If you want more info on that talk to Piers! I don't think you need a volume oil pump, I was told to use the stock one because they don't wear, When you put in your new bearings your oil pressure should get back up to 45-50pds. Definatley have your rotating assembly balanced , it will be worth it, you might also want to invest in a set of head studs, or at least new bolts, the stocks ones are torque to yield. I tossed mine and just got studs, Piers has those to...