USDM VH45 vs USDM VH41 vs JDM VH41

[thehelix112]

Guys,

 

I'm thoroughly confused as to the `best' choice of these engines for my car.

I've read that the JDM VH41 is the VH41 to have for several reasons including but not limited to, its port design [1, 2].

 

So not the USDM VH41 then.

 

The US VH45DE, pre '96, apparently has crap siamese ports, though reputedly this isn't the case with newer engines? Can anyone confirm that with pictures?

 

Which years have VVT? Pre '96 or post '96 or both or something else entirely?

Wikipedia says that the engine stopped coming to the states in '96 [3]? I'm very confused. Does this mean the crapper USDM VH41s power all Q45s from '96 to 2002, when the VK45DE was introduced?

 

The US VH45DE apparently has the alternator off to the side at the bottom making it slightly more difficult for translants. Does this impact how it fits in a zed? 450z, did this make you put the engine higher than you would have liked?

 

The US VH45DE apparently uses single duplex chains, though no reliability issues have been reported. Does anyone know if its possible to upgrade a VH45 to duplex chains from a VH41? Of course its doubtful I'd do that straight away, just wondering if its possible.

 

The US VH45DE uses plastic chain guides? Or was this something that was fixed late in the production? Is it possible to retrofit the metal VH41 guides? Once again, just wondering if its possible.

 

Many thanks,

 

Dave

 

References

 

1. http://www.gpforums.co.nz/thread/301359/?s= -- 1st and 2nd post

2.http://forums.nicoclub.com/zerothread?id=138826&page=2 -- elwesso post half way down the page.

3. http://en.wikipedia.org/wiki/Nissan_VH_engine

[mrcheeze36]

Hi Dave,

 

Here's a few threads I found on hbz that might help:

 

The US VH45DE uses plastic chain guides? Or was this something that was fixed late in the production?

 

From post 16 of the VH45de questions thread:

...The only weekness of the 90-93 VH45's is the plastic timing chain guides on the slack side. They will break and if ran long enough has the high risk of the chain jumping some teeth causing valve timing to go out and allowing the pistons to hit the valves. In 94 they went to metal backed guides, which can be swapped into the earlier VH's for a permanent fix.

 

 

Which years have VVT? Pre '96 or post '96 or both or something else entirely?

For the VH45 I believe VVT was only availlable from 90'-95' (see post 16, 24, and 25 from the VH45de questions thread)

 

VH45de questions

http://forums.hybridz.org/showthread.php?t=96538&highlight=vh45

 

 

See post 7 of this thread which compares the US VH41 to the US VH45:

VH41/45 external differences

http://forums.hybridz.org/showthread.php?t=126375&highlight=vh45+chain

[thehelix112]

Eric,

 

Thanks for the input.

 

Dave

[Jared]

you might want to check out the nico forum, there is a vh board there with a lot of guys who have done swaps

[WizardBlack]

The VH45DE in United States market limits you to 95 and earlier. You don't want a '96. Likewise, the first three years had the timing chain guide issue (which is easy to swap out) but had stronger rods, IIRC. There are differences in the inlet ports of the heads, but that's mostly just a slight variation in how you fab up a manifold to fit.

I won't comment on VH41's since I didn't follow them as much, but I personally don't see any of the VH41's "superior design features" actually causing a problem on a VH45DE.

 

However, nicoclub and vh45de.com are great places to start.

[mtcookson]

Definitely stay away from the US VH41... its nowhere close to the US VH45 and JDM VH41.

 

90-93 had the plastic chain guides but when you go to Infiniti to order them, regardless of the year you say, you'll get metal backed guides now. 90-93 also had the siamese ports... though, I haven't seen anyone claim yet which is better. I'd the oval port would probably flow more in the end but I'm not positive. I like my siamese ports personally.

 

94-96 VH45's had the oval port heads and metal backed chain guides. There were a few other small differences between these and the early VH but overall the same except for the 96 VH, which lost the variable valve timing.

 

On the JDM VH41, I believe they have the alternator between the heads and do also have the duplex timing chains. That would be stronger... though, I'm not sold on the duplex setup as it would only add more weight to a system that already works (though, that could just be because I like timing belts more... I hate timing chains period). Anyway... from what I understand you can actually put the VH45 crank in the VH41 to get your 4.5 liters. I can't remember if you retain the duplex chain setup or not though. Mettler over at NICO is the guy to go to for JDM VH41 info.