Mettler wrote:There's the VH41DE and the VH45DE, they are 4.1L and 4.5L respectively. There are various versions of each motor.

Here are Nico, we are most familiar with four main versions of these engines.

JDM VH41DEUSDM VH41DEPre '94 VH45DEPost '94 VH45DE

The JDM VH41DE and the post '94 VH45DE are the most desirable out of the four.

All four have the same strength internals and are largely built the same, with the exception of some crucial details, as follows:

* USDM VH41DE lacks main bearing beam, which was put in on the other motors to reduce NVH & add rigidity to the bottom end. USDM VH41DE also has smaller & differently angled oval intake ports, and doesn't have the nicely designed spider style manifold. I believe it also doesn't have sodium filled exhaust valves, which the other motors have (to be confirmed.)

Furthermore, it runs a timing chain setup with four chains, utilizing an idler on each side (rather than the 45's long chain setup), but only with single row/simplex chain. This motor is effectively the **** version, steer clear.

SeanDean wrote:Ports on the Y33 motors are the same size as the VH45's and larger in area than the twin port early motors.

Mettler wrote:There's the VH41DE and the VH45DE, they are 4.1L and 4.5L respectively. There are various versions of each motor.

Here are Nico, we are most familiar with four main versions of these engines.

JDM VH41DEUSDM VH41DEPre '94 VH45DEPost '94 VH45DE

The JDM VH41DE and the post '94 VH45DE are the most desirable out of the four.

All four have the same strength internals and are largely built the same, with the exception of some crucial details, as follows:

* USDM VH41DE lacks main bearing beam, which was put in on the other motors to reduce NVH & add rigidity to the bottom end. USDM VH41DE also has smaller & differently angled oval intake ports, and doesn't have the nicely designed spider style manifold. I believe it also doesn't have sodium filled exhaust valves, which the other motors have (to be confirmed.)

Furthermore, it runs a timing chain setup with four chains, utilizing an idler on each side (rather than the 45's long chain setup), but only with single row/simplex chain. This motor is effectively the **** version, steer clear.

* Pre '94 VH45DE has chain guides made from plastic, that eventually get worn and break, dropping pieces into the sump. It also retains the main bearing beam, stiffening up the bottom end slightly.

The VH45DE runs a single simplex timing chain per bank, from the crank sprockets up and around the cam sprockets... this direct drive setup results in very large camshaft sprockets.

This version also has siamesed intake ports where the manifold bolts up, two circular ports per cylinder, rather than a single oval port which splits. While reducing overall flow capacity to a very small extent, this port style can serve promote air velocity at low engine speeds. When flowbenched, oval port & siamesed port heads show very little difference anyway.

* Post '94 VH45DE has chain guide issues fixed, with metal backed versions available from Nissan as standard. These guides can be put into the pre '94 version to remedy the issue. This motor also retains the main bearing beam. This version however, has the oval ports rather than the siamesed intake ports. This is the most desirable VH45DE.

* JDM VH41DE has no chain guide issues, has a main bearing beam, oval ports, spider intake manifold, and basically all the best bits from the other engines, combined.

Furthermore, it runs a timing chain setup like the USDM VH41DE, with a single chain on each side going up to an idler, and then a chain from the idler around the cam sprockets.... however, with the JDM engine, the chains around the cam sprockets are dual row/duplex chains, which are 190% as strong as simplex chains.

The other benefits to this setup are that the ratio is changed at the idler, making the camshaft sprockets a whole lot smaller in diameter, drastically reducing the width of the front cover of the engine. This is where the common misconception comes from that the VH45DE is bigger... it's not, the block and heads are almost identical (totally not interchangeable though), but the timing chain area on a VH45DE is just way wider and takes up more room, as well as being weaker & more prone to stretch over time. Let it be known though, that this is hardly an issue, because having timing chains at all is overkill, let alone duplex ones. The VH45DE isn't exactly going to have issues with its chain setup, but it's still important to note the differences.

The alternator on a VH41DE is mounted at the top/front of the engine, rather than off to the side, and this helps because on the VH45DE it can cause chassis rail interference issues.

Also, JDM spec engines typically have the starter motor on the same side as cylinder 1/3/5/7 (this is the driver's side on the US, it's passenger side for Japan and NZ etc). This is an important fact, because when fitting a VH into some vehicles, the starter motor part of the bellhousing, or the starter body itself, can interfere with your steering column if it's on the same side. I noticed this when a guy from NZ tried putting a VH45DE into an S15.

There is one more difference that stands out to me. The way VTC works between the '41 and '45. The VH45DE has a solenoid valve on the end of the VTC drum that bypasses the oil pressure when required. On the VH41DE, there is a solenoid that screws into the side of the head and blocks/releases the oil feed through the actual gallery in the head. This further reduces the size of the VTC mechanism on the VH41DE.

The heathens will tell you that the VH45DE is better due to the extra 400cc... My reason would be due to the better bore/stroke ratio making the VH45DE achieve a faster intake charge velocity and increased cylinder pressure at intake valve closure as a result.

In my opinion, the JDM VH41DE is in fact the best base motor, and anyone who disagrees is just jealous their market isn't flooded with the superior JDM VH41DE in their country

I hope this helps.