I'm Going To Start Some Performance Work On My 4ac.... Help!?

[choonga]

Howdy!

 

At the moment i have my ae86 sitting on the front lawn with a standard 4ac in it with a busted head... either cracked/warped or blown head gasket, as there is steam coming out of the exhuast, it misses and when i crank it with no plugs it shoots water out the holes.. hahaha

 

Luckily for me, when i bought the car it came with another head that had been rebuilt, port n polished, fitted with dual valve springs and had the compression raised. It also has a custom ground cam in it too(I'm going to find out what the specs are soon). I also received manifold with two fully rebuilt weber carbs on it. I am unsure of what the carbs are though.. is there any markings on them that i can use to determine what they are?

 

So the plan is.. remove everything from the top down to the block. Then start putting on the new stuff. What do you guys recommend i do while i have all these items off? Any other supporting modifications that i should do(going to get extractors made up)?

 

Also in regards to the massive amount of vacuum lines n random rubber hoses all over the standard carb.... i really can't see that many places to plug stuff in for the new ones... anyone know what these are for? can i just ignore them?!

 

and it then comes down to... what do i need to do to fit these items? Obviously new head bolts... new gasket.. what else?

 

Thanks all!

 

p.s. can't wait to get it all together.. tuned then start sliding!(hopefully.. if it makes enough power.. ahhhahaha)

[LittleRedSpirit]

You can just chuck the vacuum gear away

don't leave holes open or you just breath carbon monoxide

Loop the remaining ones back in and or plug them with a screw and short piece of hose

As far as I know thats about all you can do once the EGR and vacuum stuff comes off for modifications.

 

While the heads off Id say throw the block away, cause if its full of water its probly well n truly shit-house by now.

 

Id have to say a 4age is the best option. You have the mounts, clutch, gearbox, radiator all in the car already.

 

By the time you get custom extractors made it will be not much more expensive.

 

Drop the tank out, bung in an efi pump and surge tank and swap the motors. Will drift loads better than a 4ac.

 

If you were just building a street car you could have a nice single overhead cam, twin carb monster, and it wouldnt bother

you, but you want to drift don't you? What about a 4ag, a 4age on carbs?

 

Just buy new genuine head bolts if you can.

 

Good luck bud.

Edited December 5, 2007 by LittleRedSpirit

[KE30_KE35_KE55]

You can just chuck the vacuum gear away

don't leave holes open or you just breath carbon monoxide

Loop the remaining ones back in and or plug them with a screw and short piece of hose

As far as I know thats about all you can do once the EGR and vacuum stuff comes off for modifications.

 

Ball Bearing balls are great to block off vacuum hoses, get a size that fits the hose tight.

refit the hoses in the correct positions and it will all still look compliant.

[ae174agze]

cam, exhaust, carb and compresson

or just 4age

[flat out]

performance and 4ac shouldn't be used in the same sentence sorry

 

4ag is the go!

[KE30_KE35_KE55]

performance and 4ac shouldn't be used in the same sentence sorry

 

4ag is the go!

Its basically the same bottom end just get it to breath better,bigger valves, porting, free flowing exhaust, face the head. and you will have better performance.

[ke kid]

i got a 4ac I'm my ae71 thats been rebuilt with port/polish, bigger valves, mild cam and electronic ignition and i can safely say it could take on a tired bigport! It revs to 8k and i can slide 2nd gear with a locker so don't discount the old 4ac for performance potential. If i had the time, i would make up an adjustable cam gear so i could shave the head a bit more and bump up compression... but make sure you run it on 98 RON at least.

 

or

 

if you don't give a crap about the engine and its life, get an oxy bottle, and run a line to the top of your air filter hat... :dance:

[SLO-030]

if you don't give a crap about the engine and its life, get an oxy bottle, and run a line to the top of your air filter hat... :dance:

 

hahaha....might have to hit up BOC

[Ella]

lol and a nice big fat braket to hold that bottle still, a apprentice at work knocked one of them oxy bottles over on friday, didnt even hit the ground that hard but BOOOM the top bit of the bottle blew, flew 25m to the side of the shed then went through the roller door (which was shut) like it was hot butter, then flew about 10m more and smashed one of the blokes from works back windscreen... :dance:

 

f@$k the guy was spewing that hed done that, the bloke whose window got smashed was a big kent and was gonna smash him, but the kid paid out for a new rear windscreen lol.

Edited February 28, 2009 by Ella

[LukeAE71]

Remove 4AC chuck what you don't need in the bin.

 

Replace with 4AGE 16V or 20V

 

Done

[Johno]

I don't think there is anything wrong with a 4ac, modify it a bit and be happy for what it is. No matter what you do to a 4ac, a 4age will always be better. If you are going to spend 1k on a 4ac just use that 1k for a 4age. Because you already have a 4a motor the mounts are going to be the same.

[trav_555]

yea and if you look around 4ages can be picked up dirt cheap, one on ebay current bid around 56 bucks a few hours ago? with loom and everything!

[mikey_m]

Keep up the 4AC POWER!!!!!!

 

Mine is that, I have a worked 4AC with twin carbs, puts alot to shame, there is alot to be said for this head for its day.

 

I stay with the 4AC, as I race in Production Rally, a 4AGE is a NO NO.

 

Keep up the tops work, you will have a heap of fun. with the twin carbs, there is no vacume required except for brake booster (If you have one) and advance on points dizzy, thats it, just remove all the rest of the shit.