VG33E with VH45 Pistons

Post by **elwesso** » Sat Mar 10, 2007 3:27 pm

http://forums.maxima.org/showthread.php ... fi...79873

I wonder if you could get oversize pistons for a VG33E and put them in a VH45 for lower compression?

The point is we know the VH45 has a 93mm bore, the VG33E has 91.5mm...

Post by **T45** » Mon Mar 12, 2007 10:27 am

Why not just put 41 pistons in the 45? Aren't they identical but only with the wrist pin moved higher up to shorten the stroke?

Post by **SuperHatch** » Mon Mar 12, 2007 1:43 pm

T45 wrote:Why not just put 41 pistons in the 45? Aren't they identical but only with the wrist pin moved higher up to shorten the stroke?

The 41 location is lower, not higher. Not to mention a change that drastic would result in an extremely low compression ratio. It's good to think outside the box though...

Post by **Mettler** » Mon Mar 12, 2007 2:13 pm

6mm lower to be exact :p

Post by **doctorchee** » Mon Mar 12, 2007 3:07 pm

I heard VQ35DET pistons drop right in with a 9:0 compression....

got the information somewhere in here. but i am not sure....

Post by **elwesso** » Mon Mar 12, 2007 3:22 pm

its actually VQ30DET pistons and no one has done it to be sure.

Post by **doctorchee** » Tue Mar 13, 2007 12:40 am

likely i will try it.... but cash is running out at the moment...

properly buying 1 pc to make comparasion is good.

Post by **T45** » Tue Mar 13, 2007 11:25 am

Here's some great info on swapping Q pistons into a VG33 which is cousin to the VG30.

http://www.nissanperformancema...inder/

What about 45 pistons in the 41. What would that accomplish?

Post by **Mettler** » Tue Mar 13, 2007 11:35 am

VH41DE pistons have a pop up section on the top, unlike VH45DE pistons which are flat. This is probably what gives it that 10.5:1 comp ratio rather than 10.2.

Running the 45 pistons in the 41, You'd get an increase of 40.76cc combustion chamber volume at TDC due to the volume of the 93mm x 6mm cylinder shape that the compression height difference makes up.... plus the small CC difference between the two pistons tops.

Ultimately, I think this would decompress it far too much... can't be arsed running the maths but it'd probably be somewhere in the range of 7:1/8:1

Post by **SSDwellah** » Fri Mar 16, 2007 10:53 am

T45 wrote:Why not just put 41 pistons in the 45? Aren't they identical but only with the wrist pin moved higher up to shorten the stroke?

Changing the pin height does not change the stroke anyway. It just shifts the absolute minimum and maximum distances. Its analogous to changing the rod length. The stroke can only really be changed by making adjustments to the crank (machining the base circle smaller, rewelding the throws further out, etc...).

Post by **hannibal** » Fri Mar 16, 2007 1:11 pm

From looking at piston mfg'er sites, I dont see anyone that makes VG33 pistons, much less oversized VG33 pistons.

Post by **SSDwellah** » Fri Mar 16, 2007 5:54 pm

Yeah you would probably have to get super overbore VG30 pistons

alrighty · Post by **alrighty** » Tue Jul 24, 2018 7:43 pm

Been running Chevy small journal rods in 2 vk45 motors for a couple of years now.One with forged coyote pistons(wiseco) and one with stock vq30 pistons.Rods are Chinese knockoffs with arp bolts.The machining is what kills you, even on a cheap rod.Have to get rid of offset,and narrow which the Chevy rods come out perfect for Nissan rods,then have the big end resized for the 55mm Nissan journal.This is an old thread but thought I would post if someone had any questions.
Gday

VG33E with VH45 Pistons

VG33E with VH45 Pistons

Re: (T45)

Re: VG33E with VH45 Pistons (elwesso)

Re: VG33E with VH45 Pistons (doctorchee)

Re: VG33E with VH45 Pistons (elwesso)

Re: (T45)

Re: (SSDwellah)

Re: (IWannaS15)

Re: VG33E with VH45 Pistons

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