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Old 12-01-2020, 10:41 PM   #1
ryanquad
 
Drives: 05 echo sedan turbo
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Question information on elusive late 2003 roller rocker head

there seems to be hints of information that the 1nz had a limited run of a differently designed cylinder heads in late 2003. This head had hydraulic lash adjusters and roller rockers as well as 21* valves as opposed to the 33* in standard 1nz. should be good for some serious HP gains especially for those wanting to stay NA

I would greatly appreciate any information anyone has on this subject

here is one websites that I found information of this existing on
https://toyota-club.net/files/faq/05...faq_nz_eng.htm
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Old 12-26-2020, 06:33 AM   #2
RomanDave
 
Drives: 2NZ ITB NCP10
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I think that page was wrong.

Seeing how a prius even uses the same part number head as a standard 1NZFE I'm highly skeptical that they'd go reinvent the entire top end of the motor... then go back to using the normal one right up to 2012+

Also none of the EPCs that I've checked have any record of it, or is there any alternative mention of this engine outside of the link you posted.

I suspect they have crossed wires with one of the other motors, maybe 2ZR-FXE which does indeed have rocker arms.
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Old 12-26-2020, 03:38 PM   #3
enviri
 
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toyota did it to lose weight on their engines and better efficiency, I feel its less robust and besides, no cams are out for it. a rocker stopper was recently made a few months back for the newer 1nz. the valve cover also has oil channels for better all around flow. too bad its not interchangable.
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Old 12-27-2020, 04:13 AM   #4
RomanDave
 
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Does anyone have any pics of it, or seen one in real life?

It's interesting that they would have gone to rockers and then back to normal for the later motors (Prius C etc)
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Old 01-21-2021, 08:12 PM   #5
RomanDave
 
Drives: 2NZ ITB NCP10
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Okay so I stand corrected.

It turns out all of the Japanese NCP91 1NZ motors have the roller rocker head.

It looks like because of the motion ratio of the rocker, they have a cam that's only got say 4-5mm lift. So might be interesting to see how much lift you'd get with a standard 1NZ cam in there.

It was also interesting to see that the C56 in the NCP91 has a different casing to NCP13, and a gearbox mount and shifter arrangement which keeps everything much further away from the exhaust heat.

The rear engine mount is low down and slots into the crossmember from the front.

And the shifter arrangement has the cables facing north-south instead of east-west, but has a bunch of extra linkages to make that work.

But it means you dont get the melty cables issues from earlier ones.
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Old 02-18-2021, 07:43 PM   #6
Socaljdmchris
 
Drives: 04 scion xa with jdm 1nzfe typ
Join Date: Feb 2021
Location: Los angeles
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I actually ended up with the type '03 as a fluke when i bought a jdm 1nzfe to replace the blown engine in my 04 scion xa. The valve cover is, indeed very different and it also has an egr. It requires iridium plugs as well.

What i am now discovering, in the midst of doing several performance upgrades, is that when it comes time to repair/replace smaller outer components of the engine, some are the same as my original type '99 1nzfe while others are not(pcv valve, ignition coils). Those that are not sometimes can't be found in the us and must be sourced from japan.

I am currently trying to find a parts list with part numbers for it.
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Old 03-02-2021, 08:36 AM   #7
06YarisRS
 
Drives: 06 2ZR Turbo Yaris RS
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Does the 1NZ with rocker rollers have a tendency to spit them out on a high rev, misplaced downshift like the 2ZR? My 2ZR is boosted and I worry a bit about puking rocker rollers. I do have an automatic so and extreme over-rev however is unlikely. I wonder if the bucket style lifters make for a more robust valvetrain.
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Old 03-02-2021, 09:59 PM   #8
enviri
 
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yes, they do spit out like a 2zr, either by misshift or hitting 7k rpm+ regularly by being tuned.

There's a company that races with these engines that make stoppers like the SR20 boys that are always selling out.

the company even says, it greatly reduces the chances but it still can happen!

yes, i feel the old one is more robust.
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