1UZ: advancing the intake cam does 'what' to the exhaust cam... ??

[CrUZida]

Nice pick up on the 2ZZGE head there.

This is supposed to be a 1ZZFE, and it clearly shows two gears.

[oldcorollas]

I beleive a keen machinist would be more than capable of modifying stock 1UZ gears to add extra adjustability.

I wonder if TRD do any such parts. I reckon they'd be mad not to if they ever did any tuning to the UZ's

yah, my bad on the pic.. i just grabbed it.. however.... on the toyota japan site, they list a 1ZZ VVTi as current release in the corolla sedan.
http://toyota.jp/corollasedan/grade/grade/index.html

BEAMS 1ZZ‐FE VVT‐i *5
総排気量： 1.794 L
最高出力〈ネット〉： 97kW (132PS)>*6/6,000r.p.m.
最大トルク〈ネット〉： 170N・m (17.3kg・m) *7 /4,200r.p.m.

from http://toyota.jp/corollasedan/dynamism/engin/index.html
the problem is that they are in the middle of the camshaft, making it a bit of a bitch to get to... not like you can just bolt them on the front.... however, if you were to convert to a front gear arrangement......

cruz i think that pic is still a 4AG.. the 1ZZ is definitely chain driven, so it has to be lubricated..

this is Definitely a 1ZZ pic..

[oldcorollas]

and here is SAE paper on 1ZZFE developement, showing (edit, my misreading ) chain driving two seperate gears.. not scissor gears (in the mass comparison of valve drive weights on page 8, No.4)
http://locost7.info/files/engine/1zzfe.pdf
however, it is from 98, so the VVTi is probably after then...

hmm the below pic is meant to be from 1zz also....
http://photobucket.com/albums/v620/f...just%20Valves/



shim under?

[tricky]

cruz i think that pic is still a 4AG.. the 1ZZ is definitely chain driven, so it has to be lubricated..

Dammit! Beat me to it! I'm on fire!!!

Naughty naughty on the ripping of the SAE article too... Just don't read the $7 article fee on the second page and she'll be right!

Stu, shimless. They use the same calibrated buckets as 1nz AFAIK. (Popular 3s upgrade).

Kinda OT though. Would be nice to find an SAE article on the 1UZ though.

[CrUZida]

cruz i think that pic is still a 4AG.. the 1ZZ is definitely chain driven, so it has to be lubricated..

Yeah, I did wonder about it still being a 4AG, wasn't sure if the 1ZZ was chain.

Ahh ya can't trust google image, who can ya trust!

[fuzz!]

the problem is that they are in the middle of the camshaft, making it a bit of a bitch to get to... not like you can just bolt them on the front.... however, if you were to convert to a front gear arrangement......

the front gear mod would be interesting.. but do you know of any cam-gears small enough to fit side by side on the anorexic 1UZ head?

[tricky]

the front gear mod would be interesting.. but do you know of any cam-gears small enough to fit side by side on the anorexic 1UZ head?

I think what he means is to shift the scissor gears to the front as per 3UZ. Not sure this would be too feasible though. Isn't there a depression in the head to accomodate the scissor gears?

[oldcorollas]

you are talking about same thing

how about a terribly complex twin chain system with one cam sprocket ahead of the other one

[ed]

im just wondering what advantage vvti on a fe head actually is ??

on a ge head you can obviously shift both the timing and overall overlap around as the cams are driven by the belt, and the intake cam can be adjusted withing this independent of the exhast, but with an fe head, all youre doing is moving the overal in&ex cam timing forwards and back as theyre 'stuck' together with the scissor gears?

or perhaps ive got it wrong? the vvti scissor gears are perhaps built into the vvti assembly such that it does actually change the relative cam timing??

hmmm - might have to take the cam covers off tomorrow

does anyone know of a 3uz engine manual online??

cheers
ed

[tricky]

Well... We know that the cams are linked by the scissor gears, and by advancing one you advance the other. This in effect makes it behave as an SOHC engine with less friction. The same cam tuning tricks thus apply.

In an SOHC engine, advancing/retarding the cam moves the power band to higher/lower in the rev range respectively, as does advancing/retarding cams in unison for a DOHC engine.

So, VVT-i allows you to produce the best possible torque curve (or best while all other things remain constant).

[ed]

yup, i know that bit...

question is, does the vvti on an fe head incorporate some funky think with the scissor gears themselve, such that the intake cam is variable 'within' the scissor gear, thus changing time AND overlap



see that image... where are the scissor gears? theyre up the front of the head behind the vvti...

ed

[Nim]

The 1ZZ-FE only has VVTi on the intake cam. However, if I'm not very mistaken, the 1GZ seems to have it on the master cam gear, thus effecting the exhaust cam too. So it makes me wonder about the 3UZ (EDIT I said 1UZ, I meant 3UZ... oops)... perhaps it has advance on both? Perhaps it just has advance on the intake? Unless we get a better photo of the head opened up on the 3UZ (EDIT: again, oops) it's gonna be hard to figure out.

[tricky]

Well the 3UZ has the scissor gears up front so this is more feasible, but the 1UZ? You'll just have to pull yours apart and take lots of photos for the benefit of the toymods community

It doesn't look like the scissor gears on the 1GZ are influenced by the VVT-i, and I'd be pretty sure the 3UZ would be a similar design by the look of the housings in your pic.

[Nim]

Tricky, isn't that the VVT on the master, so thusly both the exhaust and intake will advance together?

[ed]