Compression reduced pistons

Nicholas89

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Okay I’m new here I’ve had my 1989 f-250 with a 7.3 and a 5-speed I currently have the engine out for a overhaul and what to lower the compression slightly with Mahle pistons but I don’t know the part number and I can’t seem to find it anyone know what it would be much appreciated along with any other tips on making power

Thanks, Nicholas.
 

cozinsky

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Mahle makes reduced height pistons for decked blocks which would lower compression slightly with an unmilled deck surface, although I think they're only .010" lower than stock and that's not going to net much of a drop. I've heard you can't machine much off the top of them either for risk of heat buildup destroying the top rings. Lowering compression very much on these will make starting a real pain too.
 

Nicholas89

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Okay thanks do you by any chance know what part number it is because I see two different ones that seem to be the same pistons but different part numbers?
 

Dane Rickford

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You might want to give Justin at R&D IDI a call. If I remember correctly he can mill 0.040 off the piston and then also his pistons have iron top ring lands and he ceramic coats them for heat protection
 

Nicholas89

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Thanks and I did consider going to r&d i have there stage 1 injectors and built return rails I was just hoping I could just go with the Mahle pistons as far as I’m considered I’ve tried calling Justin multiple time and never got a response thanks for the input though supper happy you guys are willing to help!
 

cozinsky

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Okay thanks do you by any chance know what part number it is because I see two different ones that seem to be the same pistons but different part numbers?
When I rebuilt mine I sleeved all eight cylinders and had the block decked so I needed the reduced height pistons. I still have the box mine came in on the shelf and its 144171WR-STD for standard bore. For oversize you'd replace the STD with 020, 030, etc. These are old part numbers though and they've been superseded since so I'm not sure what the current part numbers are.
 

Nicholas89

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Okay thanks I can’t seem to find them with that part number hers the ones that I found they say they are compression reduced but when I find them on like jegs it says nothing about being compression reduced.

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hesutton

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I have the lower compression Mahle's in my 6.9. Went that route only because the block needed 0.007 taken off to get the head decks flat again. But, it doesn't start as easily as my 7.3 and you have to glow plug it if the weather isn't hot. Spring, fall, and winter... not going to start without glow plugs if the engine is cold.

So without planning on something crazy turbo-wise, I'd stick with stock compression (the one on my 6.9 isn't "normal" but not crazy by any stretch).

Heath
 

Dirtleg

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I have a 6.9 in the works that has been on the back burner forever. I used a .040 oversize sealed power set and milled .050 off the top.

I know it will be hard to start. Don't care. But as with you not a daily at all.

Hope to get back on it soon. Working hard to get my shop built.
 

IDIBRONCO

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Here's something to throw out there. First, an intercooler has nothing to do with engine compression. Adding one is a very good idea with a turbo. Second, your picture/link from Jeg's does say "compression reduced" below the bottom, left hand corner of the picture. If there's any doubt at all, call Jeg's and talk to a representative. That way you can be sure of what you're buying. Lastly, although I've never tried to contact him, I do know that Justin (R&D) is a one man operation and is very busy. I've seen people say on here that it can be almost impossible to get ahold of him on the phone, so don't give up on him.
 

u2slow

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Okay thanks I can’t seem to find them with that part number hers the ones that I found they say they are compression reduced but when I find them on like jegs it says nothing about being compression reduced.

You must be registered for see images attach

Aren't those factory turbo pistons? The clips are to retain the floating wrist pin?
 
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