So just a hypothetical question here, I know the vq37vhr crank will go into the hr with vhr rods and hr pistons for a budgets stroker ( correct me if I'm wrong). And that the hr family has a slightly taller block to accommodate for the longer rods which make a longer stroke.... Stay with me here... But from some google ing and searching I've ( correct me again if I'm wrong) that the hr and de use the same crank...that it's the block and rods that the big difference here...so theoretically could the 37s crank be put into a de? Even if a lil machine work had to be done?

Here's a comp between the de and an hr and I'd post some pics of de and hr cranks too show the comparison, that there the same from what I can tell

http://m.g35driver.com/forums/showthread.php?t=408410&styleid=50

It'd be nice to be able to grab a 37s crank and make a poor mans stroker,lol any input would be good. Thankyou for your insight!

 

bearings are different sizes too this has been covered a few times hence they rule 7 of the terms of use.

 

By 5 mm if I remember correctly
59.95 to 59.97 on the de
64.95 to 64.97 on the hr
but that nothing a machine shop could take shave off correct ?
I've included this link about machine shops doing it but maybe I'm miss understanding , please don't take this as condescending I'm just posing a question with some support on it: not trying to argue and fight boss man

http://www.hoigto.com/tech/crankgrind.htm

I'm just saying that I've seen the cranks for the 37 for 300ish on ebay... So I'd gladly pay that and a machine shop some for a oemish stroker

 

So a bit more to the puzzle the connecting rod big end size is dif by 2mm but I've done some research and it seems like there's 2 options, either machine the 2mm off the crank or use a diff connecting rod . Here are some nissan bits


Vq37vhr
Rod Length (center dist): 149.5
86mm stroke
Rod big end dia: 57 mm
pin dia :22mm
Bore 95.5

Vq35HR
rod length center to center(mixed results)151.7~152.2
81.4mm stroke
Pin dia. w/bushing: 22mm
Rod big end dia: 57mm
Bore 95.5 mm

VQ35;
Rod Length (center dist): 144.2
Rod Stroke Ratio: 1.771 (81.4mm stroke)
Pin dia. w/bushing: 22.0
Rod big end dia. : 55.0
Bore 95.5 mm

VQ40;
Rod Length (center dist): 166.87
Rod Stroke Ratio: 1.813 (92mm stroke)
Pin dia. w/bushing: 22.0
Rod big end dia. : 57.0

VH45/VK45;
Rod Length (center dist): 147.0
Rod Stroke Ratio: 1.778 (82.7mm stroke)
Pin dia. w/bushing: 22.0
Rod big end dia. : 55.0

VH41;
Rod Length (center dist): 147.0
Rod Stroke Ratio: 1.934 (76mm stroke)
Pin dia. w/bushing: 22.0
Rod big end dia. : 55.0

VK56;
Rod Length (center dist): 154.5
Rod Stroke Ratio: 1.679 (92mm stroke)
Pin dia. w/bushing: 22.0
Rod big end dia. : 57.0


So you'd have to use a 134-8mm rod depending on what rod you use too accommodate for the block being 8mm shorter...so that leaves either custom rods or a certain set of gm rods to use ...so correct me if I'm wrong but 5mm off the cranks bearing journals, and 2mm off the connecting rod journals, a nice set off those gm rods or custom and and not machine the con rod journals then the correct 95.5 mm nissan pistons with the right pin height and you have a stroked vq35de correct?
So
300 ish for the crank
200-500 machine work
1000~ custom rods and keep the 57mm com journals
Or
600 for the forged gm ones if you go to 55mm
Free oem pistons or the pistons of your choice

So 1800 going the expensive route add in 500 -900 for new pistons and 2300 -2700 for a built bottom end with .2 more liters
Or am I just chasing smoke here?

 

and what about the width of the bearing? they arnt the same either, how much to have custom thrust bearings made? the small block chevy works because its easy. its not easy here, if it was people wouldnt be charging 3k for stroker cranks.

your also talking like a few mm is no big deal. .001 mm is a huge deal with engines. in your second post the proper price point would be
$300 for the crank
$500-800 for machine work because you need to get it machined for the width too AND custom slots for thrust washers
$1500 for custom rods or $1000 for custom pistons, the GM rods will have the same problem of width there is a reason pro mod guys use custom aluminum rods instead of honda aluminum rods even though journals are the same.
$300-600 on TOP of the regular cost of bearings IF you can even get someone to make them. mainly its the thrust washers.

so you now have $2100-3200 for what? if your staying NA, you will get MAYBY 20 hp, if your boosted you pick up a little spool but your dropping boost pressure and if your using a turbo large enough for it to matter you will be hurting its peak power from not being able to take advantage of the billet compressor wheels which means larger turbos and completely negated any benefit. you could just spend the same on a crank already designed for it and get even MORE benefit from a even larger displacement.

 

I'm not understanding what you mean with the thrust bearings, if you had the crank machine I don't understand why the de thrust bearings wouldnt work and just use off the shelf bearings. And the cost for for the rods and pistons your spot on, I'm not arguing with you here. I'm just seeing if some one that's planning on doing a rebuild could get .2l more for let's say your already going to spend 1200+ on carrillo rods and have the set of pistons of choice picked out. It's a little more feasible to get get the custom rods and pay the 1100 you said for the crank and machine work vs the 3000 for another crank to get to 3.8. For the gm rods your right I don't have a vq rod and a gm one with calipers to see how they compare. But on paper the specs I saw matched. I could be completely wrong since I've been doing it on my phone. Maybe I'm not understanding but if the 5mm was shaved off why couldn't you use the vq bearings?
Like I said this is hypothetically. It's the yard works done and the lady's at work and some googling and hunting. I do appreciate your input and the things you point out and I know mm is a huge difference it's just the can it be done and if it can what does it take ya know? I'm sure brighter minds than mine have pondered this, and well there's no how too lol.but like you said if you got something on the shelf you can order why would people look into it for the gains you get? But if the comparison is 3000 grand for just the crank ...then the rods and pistons vs 3000 for it all but eh I'm just blabbering now

 

because your only looking at the diameter of the journal bearings, they have completely different widths as well that means you need to find a way to account for that. more then likely with a bearing shell similar to the old small block chevys where the thrust bearing is a part of the bearing shell would be easiest. had it looked up and cant remember at the moment exact but iirc the HR has slightly wider main journals.

not to mention what about reheat treating the crank afterwards?
eliminating any stress risers?

its honestly just not worth the effort to do and mind you my prices are bare minimum the machine work can easily cost double that depending where you take it and likely winding up with a weaker product without a few other processes that just further add to the cost. there are way easier methods to make more power then increase displacement by a piddly 12 cubic inchs. if this was something about swapping cranks to convert a 3.5L to a 4.0L and you didnt need to machine the crank itself then it would be worth it. there are too many factors and your significantly risking failure unless your machine shop knows exactly what they are doing.