This may or may not have been discussed before but I'd like to hear from you engine builders on the possibility of mating Nissan's 4L VQ engine block ( used in the new Pathfinder and Fontier) with a stock 350Z head? I understand this question may be a little premature considering the Pathfinder is just hitting the market now but I just thought I'd stir the pot a little. Cheers!

 

I think it has a taller head because the ngine is stroked so much. You would probally have to use the connecting rods and the pistons along with the head. I couldn't imagine that they used a different crank, that would be expensive.

 

That's it!? I thought for sure I'd get a bigger response than this?

 

The bore on the VQ40 would probably be bigger. The VQ35 head might not work. But if the cylinder spacing is the same, the cams from the VQ35 might work, and the head could be ported to flow more.

 

What does the head have to do with increasing the stroke? How can they not use a different crank to increase the stroke??? The bore is the same as the VQ35, so I would imagine pistons would be interchangeable. As for the conrods, I don't know if the the VQ40 has a taller deck height or not. If it does, then the conrods might even be the same If it has not been raised, then shorter conrods would be required in the VQ40 to accomodate the extra stroke. If the deck height has been raised, then fat chance fitting a swap uncer the hood of the Z.

 

The cylinder spacing is the same, the bore is the same. The difference is the taller block to accomodate the 92mm crankshaft and longer rods.

It isn't likely that the VQ40 will go easy into any VQ35 powered cars. Hood modifications will be needed.

http://www.poweredbynissan.com/Engin...ngineSpecs.htm

 

The AEBS Stroker kit fits a 90mm stroke on their crank with a VQ35DE block.
I don't think that for 2mm more the block will be much taller.
Gary

 

For the money you'd spend in trying to cram the VQ40DE into the Z, you could just build the VQ35DE you already have, with stronger parts to boot.

Trying this swap is not worth the time or money.

 

The VQ20, VQ23, VQ25, VQ30 and VQ35 all use the same block height of 215mm with varying degrees of rod ratios.

VQ30; 73.3mm stroke 147.6mm rod = 2.01 ratio
VQ35; 81.4mm stroke 144.2mm rod = 1.77 ratio

A 2.0 ratio is considered ideal for prolong high RPM racing, which is exactly waht the VQ30 was originally designed for. A ratio of 1.75 is considered ideal for a broad range of HP and torque. Ratios of 1.5 or below are considered poor and cause much quicker wear on the cylinder walls because of side loading. One of the worst ratios to come form Nissan in recent times is the SR20DE (86mm stroke 136.25mm rod = 1.58).

The VQ35 piston design is already very cramped and there is almost no room left to raise the pin height for a longer rod or longer stroke. The AEBS kit probably comes with shorter rods than the stock VQ35 and if they managed to squeeze another 5mm out of the pin height and threw in a 139.2mm rod the ratio would be 1.55 which is starting to become un streetable for prolonged use.
Nissan would want to keep that ratio higher than this, probably somethign along the lines of a 1.7 ratio. In order to do that with a 92mm stroke the rod would be 156.4mm. Once you add the extra 10.6mm for stroke height and the 12.2mm for the rod height you end up with a block that is 22.8mm taller or 237.8mm. And based on the VQ40 photos on the NissanUSA site it appears to be taller somewhere in that vicinity. If you look at hte cutouts of the VQ35 and the VQ40 you can see it with the relation of the VTCs to other components on the engine.
Having said all that I realize this is still speculation but I will get the facts as soon as Nissan releases the '05 ESMs for that engine. I check for it regularly.

 

Joo so smart

 

So worst case we're talking a little less than a inch. I'm sure you can fit that under the stock hood with a slight mod to the mounts if any. You might be able to fit it just by removing the strut bar.

I doubt Nissan it going to worry to much with rod ratio on this one. Look at is intended use: a truck motor. The redline has been lowered and the power band is lower. So it looks like they aren't to worry about winding it out.

Is it possible? Yes.
Would it be fun? Probably
Is it worth the money? Not to me.

Gary

 

Yeah i see that get mentioned frequently. But everyone forgets the first VQ35 was also a truck motor ('01 Pathfinder).

 

junk yard dogs might find a good price on one and it would be worth it. I am hoping the compression ratio is low.

 

Hey guys check out this link: http://z1auto.com/index.asp they have all the 4.0L upgrade stuff you will need. I came acrost it looking for some mods for my Z.

 

Not the same thing.

 

The new Z will have the 4.0liter engine in it. Just swap that in instead of spending the cash on a stroker kit. Same ECU as well, just a different plug in. The engine is exactly the same, just rebored.

 

what?

 

Wrong. Go back and read what has been written.

 

The rumor in Japan is that Nissan is building a 400Z. Possible, since there already is a 4.0L, and seeing how the original Z went from 240 to 260 to 280.