4agte 16v head mods

[bluemaumau]

pretty open question really.

not wanting massive cams.

just wondering watsort of mods i should do to improve reliability performance etc.

its a smallport 16v head and will probley get bluetop cams.

im getting the head rebuilt for cheap so am looking up upgrding parts

cheers for any input

[IH8TEC]

with your power goal, just bluetop cams will be sweet. or you could spend the money and get port and polish etc, dont really need valve springs unless you want some stupid revs, mine are std and i rev to 8k.

maybe valve grind to make sure they all seat perfectly, (had done to mine)

[bluemaumau]

im no head guru but uprated or new
stem seals
valve guides
valves?

im thinking of a 3 angle grind

[RedMist]

im no head guru but uprated or new
stem seals
valve guides
valves?

im thinking of a 3 angle grind

That's pretty much it. I wouldnt bother with new valves unless the existing ones are damaged. If you're after serious HP could install new oversize ones.
In regards to port and polish. Dont do either. Some headwork will increase flow, but its marginal and won't produce the HP/$ dollar gains of other modifications. Porting is oldschool, unless you're expecting huge HP gains. If so then you might wish to start with a bigport head. Polishing is also oldschool. You want a rough finish for boundary layer effect. This increases flow without increasing port diameter. Which means velocity is up.
An engine is a sum of its parts. Pick a realistic HP figure then aim all your components towards that figure. Bill Sherwood has a good basic outline for modifications on the 4age for a specific HP.

[Mr Revhead]

you kow the only person i know to have dyoned a smallport on stock cams and bluetop cams reported a power loss.....

[QikStarlie]

yeh maybe not port an polish. but theres alot that can be tidyed up in a 16v head tho.

[bluemaumau]

yea im not sold on the bluetop cams either.

redmist do you agree that i should get new valve guides and stem seals aswell as a 3 angle grind?

[RedMist]

It's certainly a good start. You want to gain back whatever horsies have escaped over the last 20 odd years.

[bluemaumau]

yea looks like a good start,

ill be in touch with warwick next year,

can anyone tell me the approx price on tgp valve guides and stem seals?

[Bazda]

ur goal is 200kw, you really dont neda do anything to the head, other than use bluetop cams.

the specs show about 0.4mm more lift and 8 deg more duration

http://www.billzilla.org/4agstock.htm
near the bottom.

[bluemaumau]

200minimum

ive got a 5bar map sensor
and im getting 700-800cc injectors so with enough boost id be praying for 20-30kw more.

id rather uprate the head now so i can push more power thru if i want.

[Bazda]

200minimum

ive got a 5bar map sensor
and im getting 700-800cc injectors so with enough boost id be praying for 20-30kw more.

id rather uprate the head now so i can push more power thru if i want.

u want to uprate it properly, send it to kelfords, get the works, about $3500-4k

[Trls250s]

Looking at a bluetop head and the size of the ports (i have a couple spare) i would have thought that running one of these with a new intake plenum minus TVIS would be a go with a churbo.

Definately bigger port size for more flow when on boost. But would be a bundle of crap down low.

[d1 mule]

has anone ever done a comparison small vs big port on a folw bench?? iv heard of some big figures on small port heads

[QikStarlie]

Looking at a bluetop head and the size of the ports (i have a couple spare) i would have thought that running one of these with a new intake plenum minus TVIS would be a go with a churbo.

Definately bigger port size for more flow when on boost. But would be a bundle of crap down low.

massive ports compared to the valve size is poinless tho. smallport ports arent "small" anyway. its just that bigports are massive. if you were to make new inlet manilold for a bigport, the runners would need to be 2" pipe! (squashed into shap of course) to match the port size

my stinky little 5e is around the 200kw mark, ports on that are alot smaller than smallport ones.

[~SlideWays~]

My smallport head is standard, nothing but bluetop cams. and 212kw's seemed a piece of cake

8.9:1 pistons + smallport + T3/04E (from Barry) + measly 17psi + **GOOD TUNER** = easy power

If I wanted more all I'd need is bigger injectors, my 510's are at a safe limit with this figure.

I think if you use a decent turbo and those big injectors you'll crack 200kw's EASY!

Just one question though, how much more do you want and why? Unless it's for drag racing then I think you'll be fine with 200?

My car is plenty fast for track days, all it needs now is a diet!

[bluemaumau]

yea the high boost setting would only be used in drag racing.

i eventually want to put it all in a RWD chassis and hit the track.

my specs are the same as yours slideways except im going for bigger injectors.

im going to get a 3 angle
and price up new guides and seals next year

cheers all

[Trls250s]

I dunno how you could run 212kws in your ae86 man.

I was comming home today in my recently 4ag converted 85, pissing down with rain, with my gf in the car, open diff, and the thing got wild on me at 70 kmh.

Turbo would kill me.

Also is there a massive difference in valve size between the smallport and bigport heads?

[darkwolf]

You gotta remember that there is a difference in chassis between the AE85 and the AE86. That's going to be a factor. Have you looked at your tyres/suspension? Was there maybe a large amount of surface water?

212 rwkw is a nice figure from a 1600. But the boost seems high for a 1600. What's the lag like?

[Trls250s]

I dont think there would be a major difference in chassis between a AE85 and a AE86, you have to remember japan and NZ are the only countries that even call them AE85's, everywhere else they are known as ST5 AE86's.

I think i have good tire and suspension choice. Just as a car 212kw in a 900 kg chassi is a bit loose.