The marines arent going to drop it that much is it? I'd like to stay above 17:1 personaly.

 

If your going with a cummins marine piston...it will be 15.3:1. There are a ton of options. Take your time and do the research. Personally im partial to the industrial piston, 14mm top ring land height, 17.5:1 comp, slightly larger bowl, and the wide wrist pin at 82mm. Same piston the non-ic use.

 

Can you effectively use the wider spray marine nozzles with this piston?

 

Yes...it will accept the 155* spray angle tips. But you will be limited to the same timing range as you are with 145* tips and stock intercooled piston bowls.

A 145* tip with the 155* bowl effectively widens the timing range if your worried about the pattern being in the bowl.

 

makes sense, thanks for the confirmation!

 

I called the diesel shop to see about different pistons before they ship, and asked why they recommend pistons that will drop compression that much. They said they were going to check and call me right back. That was 2 hours ago and counting........

 

Never rebuilt a cummins but the motors I have I find a good machine shop have them double check what I need. Ill check the head and block for flatness but while it is over there any way to get bored - I have them clean the block and check clearance. If balancing they have the crank - check the journals they will have the piston and rods they can check that all. And normally have them redo the valve seats and so I have them put the seals on. Then they tell me the size of the parts I need. But that is how I do it right or wrong. Just chiming in

 

You do it the right way. I'm just terrible at waiting and want to get the truck up and running. Its my flaw. I dont want to cut corners however, because this motor is going to see some very high HP numbers and hopefully some 10 second passes in time. So building it right is important.

I spoke with the machine shop and parts store I got the rebuild kit at and they agree the compression will be 16.3:1 with the marine large bowl pistons. That should leave me room for more agressive timing and boost.