Big port cams into 4agze

[ae86 slide]

I have to replace the valve stem seals in my ZE soon and was talking to a mate about the benifits of putting big port cams in while I had the head off.

We figured it would give a bit more top end but still be a mild enough upgrade to still run with standard computer etc fine.

Question is, has anyone done this? Is it worth it? And was it as simple as pull out the standard cams and put in the big port ones?

Cheers all

[rthy]

2HP gain on a smallport motor

[jaz_ae86]

Yes it's worth doing as you get both and increase in duration AND and increase in lift.

I have run 263's on factory computer and am currently running bigport cams on my turbo motor. AE92 DLI Map computer.

Any 4ag engine repair manual explans how easy it is. Just need to re-shim upon cam installation.

[Frak]

big port cams 240deg duration
small port cams 232deg duration

[Tim.duncan]

jaz ae86 DONT MOVE!! your post count is perfect!

wow im board

[blair]

Yeh you will have to setup/buy shims, piece of piss if you have the manual!

[Sam-Q]

2HP gain on a smallport motor

hearsay or proven?

[jaz_ae86]

Bigports have more duration and lift:
232deg 7.1mm
240deg 7.5mm

Either would be good, but for both and little cost, it's worth the effort.

[munki]

I think the lift would be beneficial to a gze engine, if you want to frig around with shims go for it!

[ae86 slide]

Ok, hmmm. This is sort of what I thought. My plan was remove head, aquire cams, buy valve stem seals, give all of the above to a head workshop and say "make it happen".

Is it a job that alot of places won't want to know about? Because of the fucking around with shims business?

[blair]

Just do it yourself man! I've only done it once (im an electronics tech for fucks sake lol!)

But i'd be 100% confident in doing it right every time now...

all u need is

- 1 x set of micrometers (0-25mm is what i used, you only need the sub 10mm range)
- 1 x 4age manual
- 1 x special Valve Spring remover/compressor tool thingo
- 1 x torque wrench
- a PASS in year 1 Maths
:)

if the workshop doesnt know about what to do, then its the wrong workshop lollll!

[Golberg]

Maybe think about the 1SZ shimless bucket setup?

Although if you're not running high duration and lift cams its probably not work bothering with.

http://www.toymods.net/forums/showthread.php?t=4385

[ae86 slide]

As the song goes "it's a whole new world". All this is new to me, I'll have to do some head research, I recon Blair is right, DIY is best

[munki]

You can put a length of rope down the cylinder (thread it down the spark plug hole and coil it up) then move the engine by hand until its pushed against the head. Saves you pulling off the head. I have done it before (although not on a 4age) and it works a treat!

[blair]

As the song goes "it's a whole new world". All this is new to me, I'll have to do some head research, I recon Blair is right, DIY is best

haha that song sums up everything ive done to my car over the past month or so. i got through it though man. If you get stuck on something theres plenty of blokes willing to help out :)


You can put a length of rope down the cylinder (thread it down the spark plug hole and coil it up) then move the engine by hand until its pushed against the head. Saves you pulling off the head. I have done it before (although not on a 4age) and it works a treat!

This is what i did. worked without a hickup!

[ae86 slide]

OK guys I have the head off and Im about to pick up some bigport cams, I have also downloaded the 4age manual (which has been alot of help), and I am going to buy a micrometer today.

Now here comes the possibly stupid question,

The cams at the moment have 7.1mm of lift, the bigport cams Im getting have 7.56mm of lift, obviously with a .46mm difference. My plan was to buy micrometer, remove existing shim, measure, then buy new shims that are .46mm thinner?

Is this correct? and if so wouldnt installing the thinner shims just equal out the extra lift of the new cams anyway?

Ahhh my brain hurts

[Sam-Q]

no it's matched off the low side of the cam (the base circle), if your lucky you can just mix and match with your existing shims

[ae86 slide]

Yeah thanks Sam, I actually just found another section in the 4age manual (its completly out of order) that explained that.
Alright now im buying a micrometer, caliper gauge and flat blade feeler gauge.

[--Redwork--]

There is merrit in letting a workshop do it...
Firstly... you don't have to do it your self.. Big plus.
And secondly you can gett them to do a good valve job while there at it for some extra HP..
Plus your shit will come back a clean and shinny and nice and square..

[ae86 slide]

Clean and shinney doesn't really bother me, square does.
I recon I'll have a go myself, once it's all back together I'll get a head place to flow test it and make sure it's completly flat.

This has been a massive learning experience, thanks for all the advice gang