4G54 2.6 Heads...

[mr_sikma]

Hey,

I am looking at putting an Astron 2 magna head onto my astron 1 sigma block. I have been told its pretty easy but i may occur some problems.

Any got any info, tips, help etc?

Anything will be great :D

Cheers

[WidebodyWoody]

From memory, I heard that the only difference is the lack of Jet Valves. Thats it. But I haven't done it so I am not sure.

[mr_sikma]

Jet Valves???

what are they on?

the magna head has bigger ports, valves than sigmas and some have roller rockers!

[Chryzla]

from my experience the studs are on the opposite corners and the waterjacket is slightly different

[MrBishi]

From memory, I heard that the only difference is the lack of Jet Valves. Thats it. But I haven't done it so I am not sure.

Jet valves are only on import Astron motors. All Aussie delivered stuff do not have jetvalves.

-Astron II head will bolt onto Astron I block.
-Exhaust manifold is the same.
-Inlet manifolds are different.
-Cams are not easily interchangable.
-Combustion chamber is larger on astron II.
-Rocker cover not interchangeable.

There are also minor differences between RWD & FWD astron 11 heads.

[Chryzla]

I thought id be nice and share my research.


Astron 2's:
GN sigma head: small valves
GJ Scorpion head: largest valves on the market for Astron heads out of the factory (best head IF rollerrockers will go onto it)
TM-TS Magna: RollerRockers, dont know about Valvesize yet.

[mr_sikma]

so GJ scorp head is the easiest way to go? Is that the last of the scorps?

If it has roller rockers does that mean you cant run aftermarket cams?

Is magna head only better because of the roller rockers?