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Discussion Starter #1
C'mon guys. The Cummins and Duramax boys now have stroker cranks at their disposal. Is anyone out there prototyping one for the 7.3 crowd? I think a 7.9 or 8.0 stroker has a very nice ring to it :evil Just curious if any are in the making or not.
 

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The Cummins and Duramax's could be improved with a longer stroke. The 7.3 is perfect as is.
 
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Have you ever seen inside the crankcase of a 7.3? There isn't much room for a longer stroke or a need for it... There are several other aspects as far as airflow and injection volume/pressure that needs to be addressed before displacement is increased.
 

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im prolly gonna get laughed at here, but here goes. if you put a bigger crank in, that would give you a power increase. so then you would be able to use smaller injectors and turbo to get the same power as our stock crank and bigger injectors. smaller inj's and turbo means less cylinder pressure, i think. there fore stock rods would go farther wouldnt they?? i dont know how much a crank is, but isnt it cheaper than new rods, lets say for the pmr crowd? if your no longer asking the rods to take the abuse. there is alot more to this that i dont know, just askin a question.
 

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you cant just put a stroker crank on stock rods or pistons, one has to change. usually pistons.
 

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I know of a 2 trucks testing right now:evil:evil
 

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you cant just put a stroker crank on stock rods or pistons, one has to change. usually pistons.
:whs:

A longer stroke with no other changes would make the piston come up out of the hole by half the length of the extra stroke you added.

Either move the wristpin higher on the piston, or use shorter rods to get it back to the height you want.
I for one would love to have one. About another .250 longer is what I'd shoot for if I did one. You could make the same tq with less cylinder pressure.
Putting less stress on head gaskets, and rods. Now stress on the block is debatable. Depends on who you talk to. Side loading on the cylinder walls is something to think about too, but since I see no one really having problems there, even on unfilled blocks, it shouldnt be too big of a problem. Since current rpm limits are so low, I cant see that being an issue either. Cummins are turning a ton more rpm than we can , and they have a much longer stroke already, along with heavier rods, and pistons. The only real drawback I can see is cost to make the stuff. Or if you wanted to get custom rods, just offset grind the stock crank, use a smaller diameter big end on the new rod.
 

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dunno how much it would help pullers since alot of classes say 460ci limit. a 30 over 7.3 is not far from that.
 

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cool, should be able to do that w/ just an offset grind right? i know you can make a 460 ford a 514 w/ an offset and bored. also what is a 7.3 when bored 30 over i came up w/ like 450ci iirc.
 

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How about rod/cylinder angle? The stroke is long enough on a 7.3. get more air in and out of the heads along with more fuel at the right time.

TreeTrimmer thats a good way of thinking, but sadly its wrong. The reason the 5.9's use smaller turbos and seem to do the same or more Hp on a smaller turbo is that the engine is a smaller displacement so thus it pumps less air, thus not needing a 70-80mm turbo. A engine that is 23% larger in displacement moves that much more air, so if you go and make the engine a even larger air pump, you're going to need even more air, 80-90mm wouldnt be unheard of for a lower hp daily driver if what you were proposing "could" happen.
 

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I think the rod angle is a non-issue. Its far from being too much angle.
The heads could def use some work though. Every other engine combo I've worked on , stroking always helps tq, might hurt peak hp a little, but most likely not. The extra tq should more than make up for any losses up high.
It will make the same tq using less cylinder pressure, so if you hold cylinder pressures where they are it will make a good bit more tq. I would think it would help lower hp engines more than fully modded ones due to what you are talking about.
It would make for a tq rise all the way across the powerband, and still make more power, even though it may not have a huge jump in peak hp.
 

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Discussion Starter #17
I apologize, i should have been more detailed. I was implying a stroker crank in that shorter rods or different pistons would be a given, as well as the air and fuel to feed the thing. I was just curious if anyone was working on one was all. Are these different grind of cranks strictly for the pulling market and limiting it to 460 ci's or is there one in progress for sheer displacement as well?
 

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i would guess you could go close to 500ci on an offset grind and bored. the question is how much can be done berfore you have to clearance the block, but i dont reckon that really matters either. i know some ford tractor guys that cut the crank and weld it all back together to make it a stroker.
 

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How would any puller know if the engine is over 460CI without tearing the engine apart. :evil.
 

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No one has yet to fullfill the CU potential of the 444. Why increase the size? BTW piston milling is the same as offset. Offset is multiplied by 2 to get stroke.
 
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