Cummins 12V pistons: Marine versus Mahle

stock600 said:
Boy, thats neat to hear that the 370hp engine is 24* stock. Never really thought of timing diff. in the higher hp engines, whats the highest known hp for a 5.9 right out of the box from cummins? Also i went with cummins .20 gasket myself and the block nor the head has ever been machined shouldnt this lower my static from 17.5 to in the 15's?? I miced the new gasket at .100" vers the compressed stocker i removed was .60", so my math came up with .40" thicker not .20" surly that sucker wont compress .20" would it? Thanks guys
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The 0.020" over gasket measures almost .0100" uncompressed and according to others, 0.090" compressed. My stock gasket also measured 0.060" compressed.
 
SINNER said:
I thought cutting the head had no effect on compression. Being a flat fire deck, and not a bowl like a gasser head.
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Never looked at it like that, I was just spitting out specs on that motor.......I smell what your stepin' in :)

Jim
 
mahle's are a good pistion i wouldn't even be be afraid of putting them in a mod pulling truck motor with the right work.
 
AsTroSS said:
Here is side by side pictures of Cummins original (at right) 370HP piston and aftermarket Mahle Marine piston.

Mahle piston bolw diameter is little bit smaller and not so deep as Cummins original.

Like you see, also piston ring landing is different.

Cummins piston looks heavier ,but I do not knew weight difference. I will try to weight it next week.
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The Mahle that you are showing in the pic is the piston used in the first gen Dodges 89-90 non inner cooled engines.
I have a set of 370 marine Mahle, and it is identical to the Cummins one that you are showing. The Mahle 370 marine set part # I have is 286140WR-040.
The WR-040 stands for "with wrist pins" and .040"in over sized.
 
Here is a picture of a MAHLE 370 marine that I will be putting in my motor. I have compared the Cummins 370 to the Mahle 370, other then for markings they are identical. The Cummins piston is made by Karl Schmidt Unisia Inc. a.k.a Kolbenschmidt. http://usa.kolbenschmidt-pierburg.com/print_kp_news2005sae_kus_01.html
Cummins Inc. uses both Mahle and Kolbenschmidt pistons in there engines, both companies orginate out of Germany.
Which is better? I don't think you will go wrong with ether in the 5.9L. If you own a Duramax the LB7's and LLY's ran Mahle from factory. Then came the LBZ and GM switched to Kolbenschmidt's and they have some piston cracking issues.
 

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AsTroSS said:
Cummins Marine should be 15.3:1 , Mahe might be around 15,8:1
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If you look on the Mahle piston you have it has a 17.0 stamped on top. That means 17:1 compression. And the Cummins manual states for the engine that its used in it is 17.5:1.
The 370 is in the 16-16.5:1 compression.
 
Voodoo Trucker you are right about my Mahle piston, its industrial piston for turbo engine (same as in non IC Dodoge Ram) and it have a 17.0 :1 comp ratio.

But you are wrong with Cummins Marine 370 HP (CPL 2208) comp ratio.

It have a ratio : 15.3 :1 , like i mention before
 
AsTroSS said:
Voodoo Trucker you are right about my Mahle piston, its industrial piston for turbo engine (same as in non IC Dodoge Ram) and it have a 17.0 :1 comp ratio.

But you are wrong with Cummins Marine 370 HP (CPL 2208) comp ratio.

It have a ratio : 15.3 :1 , like i mention before
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Could you tell me where you are getting 15.3:1. I'm not trying to argue, would just like to know. The Cummins spec's that I have may be wrong.
 
Voodoo Trucker said:
Could you tell me where you are getting 15.3:1. I'm not trying to argue, would just like to know. The Cummins spec's that I have may be wrong.
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My information is based on Cummins Marine engine data sheet. I will try tonight to upload it here .
 
Where is the best place to purchase a set of the 370 marine pistons?
I called my local Cummins distributor and was told about $190 ea. I believe that was with rings only and no new wrist pins.

Joe
 
RedPuller said:
Where is the best place to purchase a set of the 370 marine pistons?
I called my local Cummins distributor and was told about $190 ea. I believe that was with rings only and no new wrist pins.

Joe
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Pick me! pick me! $190.00 is way high. PM me if you are interested in a set. The piston kit comes with ring set and new snap rings for the wrist pin, but no pin. It's a floating pin so wear isn't an issue. However, new pins are cheap if you want to replace them.
 
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