12v Marine pistons on the street

roachie

roachie

Taco Master
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Nov 2, 2007
Messages
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Ok Im considering swapping up my builds a bit.

Is there any real gain with using the marine pistons and corresponding injector spray pattern on a mild (700-800 fuel) build?

May use my 13mm for a while on this one, or a benched 215, 66/74 S300 over a 74mm S400 1.10ar, some form of cam also.

Im on the fence if the drop in compression will be worth the any gains in timing or HP.

No real purpose in the truck, some pulling, assing around is its main purpose.


If my new truck deal goes through Ill explain why Im asking this later.
 
marine pistons will work out just fine on the street, thay are a little bit stronger than the standard piston. i know we have different year trucks but i am going to be running the 480HP QSB marine pistons in my truck that i drive everyday. you shoud be happy with those
 
I was referring to a 12v engine. I want to say that the marine pistons have a 155* spray angle...or 145* hell, I cant remember.

This is mostly using crap that is laying around the shop, just a hot street truck.

Im trying to figure out if the trade off is worth using them or just some stockers.
 
FWIW I would not decompress a 12v Cummins thats going to ever run on the street, knocking down the static comp. will soften up the bottom end and thats no fun on the street exp. with to much charger. Ive said before I think decompressing these engines is way over rated. Its more important to know where your at with bowl design, inj. patterns, and amount of timing available. More than your goal of power can be made at 24-26* and this can be done with out diff. pistons. Think, keeping the inj. close as poss. to the piston so more timing can be ran, shaving pistons down is the wrong direction IMO.
 
What about early 1st gen pistons?

Or while you have it out you could shave a little off the block to get your quench area back closer to stock?
 
Not sure about the early 12v's for sure but I think thier the 286030's wich looks like a great piston to me I acually was going to go with them but know one in the country had a set... from what Mahle told me. They are the small 44.2 cc bowl but have the thick 14.45mm TRL.
I burnt the TRL's out of my 97 and when I pulled them I found thier the tiny 8mm design wich I believe dont take the heat well and is harder on the top comp. ring, this design is the same from 96-98 12v 286040.
I went to the 286020's to stay with the tight 41.5cc bowl but has a nice thick 14.35mm top ring land to help protect from heat. I think the desision should be based on how much timing you need or -want- to run. Ryan
 
The motor I picked up has the 286030 (3919042) already in it stock :rockwoot:
 
I you want a street hot rod, I would not decompress much at all, you could go with a marine piston but I would't shave any off. And if your looking for something fun on the street why go with such a big twin set, Your gonna get your a$$ handed to you by someone with a 62/S400 twin set with your laggy setup.
 
My new street motor has 286020's, no compression drop, a cam and a 40/3B twin set with a 215 pump benched and DDP 4's.

Roachie, i'd drop down to a 62 on top also.

Jim
 
i'm on the fence as far as pistons to ,,, sending the block and head to the machine shop this weekend ,,,, would like to hear what other guys are running as far as pistons and are ya happy with them ....
 
Smokem said:
286210
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I agree that looks like a great compremise for keeping static up and allowing more timing. The bowls much wider, still a small 43.2 cc design, and a nice 14.13 TRL. It uses the diff. sized wrist pin though 40x75.8 rather than the 40x82.8mm?
 
for give if this is a dumb question ,,,, what would be done about the wrist pin ,over size bearing ???


stock600 said:
I agree that looks like a great compremise for keeping static up and allowing more timing. The bowls much wider, still a small 43.2 cc design, and a nice 14.13 TRL. It uses the diff. sized wrist pin though 40x75.8 rather than the 40x82.8mm?
Click to expand...
 
impmouse said:
for give if this is a dumb question ,,,, what would be done about the wrist pin ,over size bearing ???
Click to expand...

Not a dumb question at all, and I dont know the answer. I just found a piston I liked with a matching WP size. You could call Mahle and ask though....800-223-9152, let us know what you find. If that number gets you no where fast call 828-650-5180 ask for Eric. Smart guy for sure. Ryan
 
haloman said:
Roachie we would all be happy to see one of your projects completed. LOL
Click to expand...

So would I. LOL After things are done Ill explain my new agenda..

dzlfarmboy said:
I you want a street hot rod, I would not decompress much at all, you could go with a marine piston but I would't shave any off. And if your looking for something fun on the street why go with such a big twin set, Your gonna get your a$$ handed to you by someone with a 62/S400 twin set with your laggy setup.
Click to expand...

Jim Fulmer said:
My new street motor has 286020's, no compression drop, a cam and a 40/3B twin set with a 215 pump benched and DDP 4's.

Roachie, i'd drop down to a 62 on top also.

Jim
Click to expand...

Like I said, this is all things that I have laying around. Trying to figure the best use of it all. The little charger is on the large side, the only other option is a CR turbo on top. Really looking for a setup that can still be reasonably streetable so I can use it for a secondary vehicle if needed. Mostly I want to get these damn parts laying around on something instead of letting them set and go to waste. So Ill need some kind of deal that lets me use that 13mm.

Smokem said:
286210
Click to expand...

What application is that?
 
FWIW, I'm running Mahle marine pistons in my 12V. I am doing nothing crazy as far as power goes by any stretch of the imagination, but I have never experienced anything negative from running these pistons....

Truck runs great, starts with no grids at 10 degrees easily.... etc. If I dig through old stacks of paper work I may be able to find the receipt and get a PN off of them....
 
what is the protrusion out of the block with the marines?


you could deck the block to bump the compression and use a stock gasket.
 
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