Gasflowing of 4Y head

[Thys]

Is there anyone that can give me some insight into if it is worth changing the cam shaft to a "performance"cam and gasflowing + changing the valves to bigger ones on a 4y cylinder head.

[Mr_B]

Hi Niel,

I have gone through these mods, gasflowing, porting, brospeed cam andexhaust mani, efi... on the 4Y. Gasflowing did have a performance effect, but I must be honest with you, it's not so big that it's worth the expense of redoing the head! The Brospeed cam I eventually tossed out, it delivered nice top power/pull, but the low end torque was very negatively effected, in fact the lack of torque was terrible offroad. I eventually removed the Brospeed cam, and on the advise of Allan Venter, got a custom cam cut by Malcolm Hartley of MasterCams... this cam maintains the low end torque and gives the top end pull, a very nice 4Y performance cam indeed.

Personally I haven't done the big valve head, but I have been involved with fuel injection of a 4Y with big valves. The engine never performed well, couldn't rev over 5200rpm. After many many diagnostic exercises it was found that the big valve head was the problem, so I'm not sure if it's worth it.

If you are planning a total engine rebuild, then I would suggest the following performance mods to the 4Y:
- Brospeed exhaust manifold(with 2 box free-flow exhaust system, 4Y needs exhaust back pressure for torque)
- Gasflow and port head
- Balance engine parts
- Up compression via head skim, or performance pistons(I have heard that a certain Cressida piston can be used)
- MasterCam custom 4Y cam
- Chev Hi RPM/racing hydraulic lifters

Other than that, if you want to spend some money on worthwhile performance mods, I would definitely suggest looking at an EFi conversion, this makes a huge difference! I was told I was wasting my money, but it was the best engine enhancement by far!

With the above mods you can get 90kw out of the 4Y, while maintaining the reliablity. 90kw may not be mind blowing, but it's certainly better than 65kw!

Mr B

[kfxnando]

yep when one goes bigger valves and bigger port and cams with more duration and lift, one tend to move the point in the rev range where the motor makes peak power and peak torque further up the rev range!!

one cant really get the one with out the other!!
with a mild cam it is less noticeable!! is about how far one is willing to compromise drivebility and power!!

hence why its so important to get someone who has a wide knowledge on cylinder heads porting!!

sometimes the wrong combination of port size, valve size, cam profile, inlet manifold and exhaust manifold can create disasters as in the case of Mr B's motor that would not rev past 5200!!
all it takes is one wrong component and the whole system falls flat!!
sometimes something like a vernier pulley can help solve the issue!!

as is the case where some back pressure is needed in the exhaust!!
back pressure uses/wastes energy that could either wise be used to propel the vehicle!!
so something there was out of place!! could be something as simple as the runner lengths on the branches having been incorrect!!

is it worth it???
all depends on how much power is needed!!
like Mr B said, going from 65kw to 90kw . . . . . . . . . .
that is a big jump in % wise, and that might satisfy the needs of some drivers and their needs!!

on the other had, ''too much power is never enough"

good luck and enjoy!!

[The Legend]

Mr B

What is the kilowatt output of your 4y with efi?

[Mr_B]

Dyno'd @ and 70kw on the wheels and 92.6kw estimated on the flywheel... ... 33 inch tyres

Mr B

[Spartan]

As daar iemand is wat iets weet van heads is dit oom Dave Repsold sy nommer is 011 917 6378 of 083 302 7209. Hy is die ou wat die vinnigste 4 cylinder gebou het wat die japs by hom terg gekoop het en die Carrola staan nou in Tokyo in die Toyota museum, dit was n 4A as ek dit nie mis het nie, ek dink behoort te kan help.

[coronan@gmail.com]

I'd like to know more about increasing compression ratio.

The 4y uses 86mm pistons

the 5mge, 6mge, 7mge (celica, Cressida, supra, '82 -'92) All use 83mm pistons.

however a Toyota 1JZ (1990 to 2007) , 2JZ (1991 until 2002) series has 86mm pistons.
http://en.wikipedia.org/wiki/Toyota_JZ_engine" onclick="window.open(this.href);return false;

[zepplin]

Nathan, I'm guessing that the numbers you are quoting are for the cylinder bore which relate to engine displacement.

The only ways to increase compression are to skim cylinder head/ skim the block/ use pistons with a taller crown.

[Yashveer]

- MasterCam custom 4Y cam
- Chev Hi RPM/racing hydraulic lifters

does anyone have prices of the above?

chev lifters? info pls?

[The Legend]

- MasterCam custom 4Y cam
- Chev Hi RPM/racing hydraulic lifters

does anyone have prices of the above?

chev lifters? info pls?

I bought my chev lifters ( part nr HYT04-04) for my 4y from Masterparts in Kenilworth tel 021 657 5757 for R318.08 vat excluded for a set of 8 lifters.

[Agteros]

- MasterCam custom 4Y cam
- Chev Hi RPM/racing hydraulic lifters

does anyone have prices of the above?

chev lifters? info pls?

I bought my chev lifters ( part nr HYT04-04) for my 4y from Masterparts in Kenilworth tel 021 657 5757 for R318.08 vat excluded for a set of 8 lifters.

My bakkie hardloop ook met die Chev lifters van Masterparts.

[Willied]

Wat maak hierdie lifters beter as die oorspronklike stel?

[Agteros]

Wat maak hierdie lifters beter as die oorspronklike stel?

Willie ek glo nie hulle is beter nie maar sover ek weet is hulle baie baie goedkoper as die Toyota part. Dis wat ek onthou van 'n paar jaar terug toe ek myne laat doen het.

[Agteros]

Wat maak hierdie lifters beter as die oorspronklike stel?

Ja, ek het bietjie teruggekyk na my ou thread - viewtopic.php?f=3&t=9510&start=30" onclick="window.open(this.href);return false;

Die Chev lifters was 8 keer goedkoper as die Toy lifters en volgens Mr B (Bretton) dieselfde kwaliteit. Hulle kan ook hoe RPM goed hanteer. Nou nie dat die 4Y saam met 'n RSi kan rev nie.

[Willied]

Dankie.. Het met 'n groot diens my lifters vervang en dink amper hulle was R200 vir almal.. Kan verkeerd wees, was 'n hele ruk terug.

[coronan@gmail.com]

How much do you recommend shaving off the head?
Do the valve seats need to be set deeper?
What is the new compression ratio after the work is done?

Stock compression is 8.8:1???

[LouisZ]

What is the price on the cam?