Fitting US jza80 2jz-gte cams into 1jz-gte

[chris davey]

To summarise,

There is an additional .55mm lift on the intake and additional 1.06mm lift on the exhaust. There is also about 10deg more duration but I haven't measured this yet. (Based on other people's specs)

The picture that has A and B marked on it has the 2 sections that need modifying to fit.

The front part (A) is approximately 2.5mm wider than on the 1jz cams. These need to be machined down my that amount so you can use the 1jz cams seals and to fit in correctly.

The gap (part B) is nearly identical on the intake side but the exhaust needs to be widened by 1.77mm for the exhaust cam to sit in place correctly. From what I can tell, the front part will need to be machined down so that the lobes are on the centre of the buckets.


Intake lift
1jz: 7.61
2jz: 8.16

diff: .55

Exhaust lift
1jz: 7.6
2jz: 8.66

diff: 1.06

Front A
Intake
1jz: 38
2jz: 40.45

diff: 2.45

exhaust
1jz: 37.94
2jz: 40.47

diff: 2.53

Gap B
intake
1jz: 21.74
2jz: 21.64

diff: .1

exhaust
1jz: 21.85
2jz: 20.08

diff: 1.77

This is to show what I mean by A and B



2jz USDM jza80 cams



1jz intake



2jz intake



1jz exhaust



2jz exhaust



1jz both



2jz both


This mod has been done in the US before. A guy with a 1jz powered ma61 went from trapping 112mph to 115mph. First run was 16psi and the second was 15psi. No other changes. From all reports, the low end is very similar but the car will pull all the way to 7500 instead of 6500. (This is on stock twins) I don't know if anyone has fit them on a single turbo car yet but I intend on doing this.

FYI people sell these for as little as $40 US. Postage was $90US (but I got a discount) and I expect machining to be about $50-$100max.

(This forum needs a way to copy in excel tables!!!)

[wilbo666]

Dude that is excellent

Also, as an idea is it worth checking if you can get a seal that fits the 2JZ cams and is the right OD for the 1JZ head?

Cheers
Wilbo

[2JZR31]

That is tops!! I want to do this on my brothers 1JZ and I want an intake cam from my 2JZ.

Where did you find the cams and how did you go about getting them here?

[82MKII]

Interesting stuff Chris.
I have one dumb question:
- will the additional lift change the 1J from a non-interference engine into an interference engine (in case of a broken cam belt)?

Regards

Peter

[chris davey]

Manny said no. I can't remember if it was 9.0mm or 9.5mm lift that it is interferance though. Definitely not in the 8's though. 2jz is 10mm.

[1JZ.747]

i believe its once you go above 9.0

thats why a lot of guys go 264in 9.0 lift and 272 exh 9.0 lift


the 272 exhaust cam is only 9.0 where as the 272 in cam is 9.3 lift.

so to run 264 in 272 exh they are both 9.0mm lift

[chris davey]

I didn't know that. (re the reason why people go that way)

I thought it was just because it was generally accepted that the staggering works well.

[1JZ.747]

I didn't know that. (re the reason why people go that way)

I thought it was just because it was generally accepted that the staggering works well.

according to carlos novais from millenium motorsport staggering cams has no great effects on the power curve.

he said the best combo he has found with his supra is 272 272 from HKS.

he tried the bigger 280 280 deg combo and didnt find it was worth it.

hes tried 264 272, 272 264, 264 264, 272 272, 272 280, 280 272, 280 280 and came to conculde the 272 272 was best.

his MPH certainly shows it.

[chris davey]

Interesting.

The guys in the SF.com group buy found out that there is a big difference in required cams between 1j and 2j though. The smallest available 2jz cam is equivalent to the biggest in a 1jz based on duration at .050".

I can't remember what some of the big guys in the US are using in their cars but I thought more people were going to the 280's?

Either way, way too big for a little guy like me

[Mr DOHC]

do u know what happens on stock computer etc

[Norbie]

There's no way you could use cams like this with a stock ECU.

[chris davey]

some US guys are AFAIK. As we know, the US guys love their piggybacks though

As the 1jz is map sensored and changing cams is adjusting the amount of airflow post MAP sensor then I would think some sort of tunability would definitely be required.

A guy with a pretty stock 1jz has just put the cams in and it idled low (not surprisingly)

I have no means of adjusting or measuring the A/F ratio, this is all on the stock ECU. No aftermarket electronics.

Used the throttle stop to up the idle which AFAIK you aren't really supposed to do when you are using stock ecu and ISCV.

The increased airflow may even lean it out to a decent AFR under boost

In short, I wouldn't put these in with at least a SAFC/DFA but preferable full stand alone ecu.

[Norbie]

some US guys are AFAIK. As we know, the US guys love their piggybacks though

Piggyback != stock ECU.

[chris davey]

Update: The machinist/mechanic has my cams at the moment and we know we have to lengthen the gap (B) by taking out some metal from behind cam journal 1 on 2jz exhaust cam. (Brown bit in pic 6)

The guy with the cams has said that he can get a seal with the same ID as the 2jz and the same OD as the 1jz however it is 8mm wide rather than 6.5mm wide like the stock one.

Here are some pics of the front seal part that I am referring to.




So if that is 1.5mm wider will that affect the way the backing plate or the cam gears are connected?

I am thinking that if the seal has a lip on it it may be possible to sand it down say .5mm on each side so it is only .5mm extra width which I think would be taken up when it is bolted together anyway.

Opinions?

[Mr DOHC]

usually the cam hangs out upto 10mm past where the seal sits anyway