2JZ head porting.

[TK]

All done bar assembly & valve clearances, will be finished before I go home.
Crower 1mm oversize valves, crower valve springs, crower titanium retainers, full port - all port cross-sectional areas matched (prick of a job, they vary a lot).















TK

[hotgemini]

Tony, off topic a bit here, what can you tell me about CA18 heads, stock and potentialwise?

[TK]

hotgem - stock = shit, especially the exhaust, terrible bowl size & no real proper short turn to speak of, lot's of potential for improvement, moreso than 2J's I would think.
I've done a couple of budget 'cleanup' port jobs on them, but never had any flow tests done - people don't seem to want to spend that much on them.


Anyhoo, 2J is DONE, valve clearances all set with no issues, all assembled & handed over to a smiling Reaper.
With any luck it'll be running on the weekend, but maybe not quite.
Tentative time frame for tuning & results is approx 2 weeks.

TK

[jzx83]

Excellent thread TJ. Very Interesting. Any thoughts on 1JZ, given that you've now done the 2JZ?

[Bass Junky]

What about an Skyline, R34 GTT with the Neo Engine??

[TK]

jzx - I've never seen one!, but you'd think they'd respond in a similar fashion.

Bass - What's a Neo engine? RB26? - if so, I'll be doing one in the not-to-distant future (maybe 6 months, guy is saving his coin for a stomper), I'll post it up, it's for an R32 GTR, gonna be a bad mother.

Haven't had a chance to price up headwork etc yet for the 2J's - porting will be about 16-18 hrs - they're a bitch to port, but I gotta price up the valves, springs etc.

TK

[GTSBoy]

Bass - What's a Neo engine? RB26? - if so, I'll be doing one in the not-to-distant future (maybe 6 months, guy is saving his coin for a stomper), I'll post it up, it's for an R32 GTR, gonna be a bad mother.

TK

Tony, In case Bass doesn't answer soon, the Neo is the last of the RB25s. It had variable cam timing, was rather high compression. Made 206kW stock. Otherwise rather similar to the preceding generation of RBs.

[Bass Junky]

Hi GTSBoy and TK.
Yeah, the NEO is the last iteration of the RB25 head. It's quite different to the R33 and R32 heads in that it runs solid lifters and as I understand it, it's a different casting.
Can't use R33 bits on an R34 and vice versa.

I've got cams in it at the moment, Poncams 260 x 9.15mm lift.
GCG Highflow, makes 250rwkw.

Would be interested to see how she responds to a Port and polish.

Daily driver.

[TK]

If the ports are like a regular rb25 then they are much like a ca18det, ie. crap.
Mind you, I'd say that for most production heads - 'cept maybe the german stuff, they seem to have casting a nice bowl down pretty well.
Virtually all mass production heads will benefit from some time on the seats, bowls, turns & ports.
I think there'd be plenty to gain on the rbxx 24 valve heads, valve sizes are good(ish) but the exhaust bowls & ports are rather nasty - wouldn't take as long as a 2J, all the ports are the same so there's not to much fart-arseing around.
But again, I don't have any figures.

I'm fairly new to this porting late model jap heads stuff, the only reason I'm any good at it is the 50+ sets of wrx heads I've ported, several years of playing with them has taught me a lot about porting multi-valve heads & how the shapes used differ markedly from traditional V8 port jobs.

For interest sake, a WRX engine I did the heads for just cranked 346kw atw on pulp 98 & only 22lbs of boost - getting up there, not far short of the rigoli stuff, but without the price tag - that engine could hit 400kw atw with a better intake (stock intake atm).

Another bit of info to chew over, was thinking about this the other day, this is a list of variables you need to consider when porting a head, starting from the chamber & heading out:

Intake:
Intake blending radius into chamber
Intake blending angle
Intake top cut angle & length
Intake seat width & position on face of valve
Seat bottom cut angle & width
Secondary bottom cut angle & width (& whether one is required at all)
Throating cut angle
Bowl diameter & shape
Short turn width, radius, amount cut back & approach angle
Intake port cross-sectional area
Port entry size

Exhaust
Same as intake up to seat (not the same cuts, just the same variables)
After seat:
Bottom cut or radius?
If bottom cut, how many & what angles & widths?
bowl diameter
Short turn shape
After short turn same variables as intake

Both:
surface finish
knife edging or radius?

Any and all of the variables can have a big effect on flow at various valve lifts, further complitated by the fact that different cams with different lifts will require different approaches to maximise usable flow, also, different operating rpm ranges directly effect the choice of cross sectional areas, different air velocity (ie big ports, low rpm - small ports, high rpm being the extremes) will require different port shapes.

Can give you a headache trying to figure out the best approach, the worst bit is there are no hard & fast rules to stick to - there are some general rules that usually produce good results, but you can never be sure untill you try them - the 2J was a good example, despite using an intake design that almost always produces improved low/mid lift flow the biggest improvements were still at higher lift, some time spent studying the why-is-this-so has taught me a lot more about porting low approach angle multi-valve intakes - enough that I do not believe there is a solution short of filling the bottom of the port & raising the port - which is beyond the scope of even a fairly serious port job - the 2J intake port will never flow much better at low lift than it will stock, not with any improvement at higher lift anyway.

TK

[BigMuz]

GTFO of this thread with your rb bullshit :D

[Tripper]

GTFO of this thread with your rb bullshit :D

why say that when there is that ban button in the mod panel problem solved

[Ze]

Any chance of seeing before and after side by side?

[Cameron_Datto]

Found this link to pics ported 2jz & rb26 heads , from some overseas Company


http://www.theoldone.com/components/..._supra_2jz.htm


http://www.theoldone.com/components/...heads/skyline/

[2JZR31]

Nice, but no figures?

[Reaper]

Engine and tranny back in, hoping to hit the rollers on Friday.
Will report back then.

A big thanks to SuperCrown again for helping me out with shoe-horning the 2J back in. The man has clearly done this sort of thing many times before, and he didn't even give me a bill despite many attempts to pay him in beer etc. Thanks mate, ur a Champion, ta!

Unable to show shots of before and after since I didn't take any hi quality port shots of before (in fact any 'before' shots).

Will in time chuck up some 'after' shots but need time to compress/host them.

More interested in getting my car back now than image manipulation so that'll have to wait.

Ta,
Gaven