1NZ / 2NZ Transmission Compatibility & Aftermarket 2NZ Rods

[jtw11]

Hi all,

My first post here - but have got quite a lot of useful info just from reading here... I don't actually own a Yaris, or even a Toyota - but am in the midst of a complete rebuild of a 2004 Smart Roadster, using a completely built turbocharged 1NZFE.

However, I'm looking instead at using the 2NZFE - although, a couple of questions holding me back.

I know the 2NZ has a shorter block than the 1NZ - however, does anybody happen to know the following?

- 2NZ connecting rod length and piston compression height.
- whether or not transmissions that come with the 1NZ such as the C50 will bolt straight up to the 2NZ? And which transmission code comes with the 2NZ, looks like it's a C54?

Another reason I ask, I work for a company who would be interested in developing rods for the 2NZFE that would allow one to run forged 1NZFE pistons - however, if the combination would ultimately mean using a short connecting rod - the accelerated bore wear wouldn't be worth it.

Hope you guys can help! Cheers.

[CTScott]

I am not sure about the specific differences with the rods, but the 2NZFE does use a different part number rod than the 1NZFE, so there is a difference.

For the transmission, the EPC shows the C153, C154 and C56 as all being used with the 2NZFE.

[jtw11]

The C153 looks promising, given it's standard with an LSD as opposed to an open diff - at least that's what Wikipedia says, says it's from a Starlet GT Turbo with the 4EFTE engine...

I'm trying to find a picture of the stock pistons from the 1NZ and 2NZ to compare.

Correct me if I'm wrong, but the head and cams are identical between the 1 and 2 yes? So it follows that 1NZ pistons will work with custom rods.

[CTScott]

Originally Posted by jtw11

The C153 looks promising, given it's standard with an LSD as opposed to an open diff - at least that's what Wikipedia says, says it's from a Starlet GT Turbo with the 4EFTE engine...

I'm trying to find a picture of the stock pistons from the 1NZ and 2NZ to compare.

Correct me if I'm wrong, but the head and cams are identical between the 1 and 2 yes? So it follows that 1NZ pistons will work with custom rods.

The piston, crankshaft and head part number are different for the 1 and 2 as well.

[jtw11]

Thanks for the info - that dosen't surprise me re the piston and the crank, if the piston is lighter / heavier the crank will of course have to be balanced differently.

That does surprise me though regarding heads - does Toyota list a head as head + cams, valves etc - or just a bare head? My first presumption would be it's the same head, with different cams.

I've got a 2NZ-FE turning up at work hopefully tomorrow, which I'll be tearing down. The first thing I'll be looking for is which option we'll be looking at going down.

a) producing a rod set that allows use of forged 1NZ-FE pistons in a 2NZ-FE,
b) producing a piston set that allows use of forged 1NZ-FE rods in a 2NZ-FE.

[CTScott]

The 1NZ and 2NZ head sub-assemblies share the same part number, as do the valves and camshafts (which are separate from the head sub assy)

[jtw11]

Hi CTScott - may you clarify what you mean? In one of your posts you have said

The piston, crankshaft and head part number are different for the 1 and 2 as well.

and in your latest said

The 1NZ and 2NZ head sub-assemblies share the same part number, as do the valves and camshafts (which are separate from the head sub assy).

From this I can gather the valves and camshafts are common between the 1 and 2NZ.

When you refer to sub-assemblies, what exactly are you referring to? The raw head casting, or parts such as the VVT housings?

[CTScott]

When I looked at it the first time I missed that the 1NZ and 2NZ engines from the same vintage (for example 2000 to 2002) share the same part number for the heads.

The image below shows what is considered the head sub assy:

Head Assy.jpg

[jtw11]

I see - thanks very much for the info. With that knowledge, knowing the heads and cams are the same - watch this space for like I say, one of two kits mentioned above.

It seems there are a number of people interested in forced induction with the 2NZ, but the lack of aftermarket internals puts people off and forces them straight to a 1NZ or other engine swap.