Austarion

Hey guys, which Magna head seems to be the most popular to swap onto the G54B engine. I plan to purchase a head soon to be ported/polished for a rebuild this winter.

Most talk in the US is for the Gen2 head, it's reported that the Gen3 raises the compression too much. What have you guys learned from swapping these heads? What about over-sized valves? Any info will help me decide what to buy. Thanks!

US guys are the ones to talk to, we can't use Magna stuff on 2 litre motors.
Check prices for what you can get a head for here + freight + rebuild versus Marnal heads or whatever you can get over there. Apparently they are fairly similar although I am just going by what US guys say.

Like I said (and Alspos above) before we only got 2.0 litre 8 valve SOHC 4G63 Starions.

My Conquest was already fitted with a Magna Astron II head by a previous owner. So I don't even know what the US Jet valve head looks like up close.

I assume it is similar to our old RWD Sigma 2.6 head except with jet valves. Anyhow yes the combustion chamber is very different on the 3rd generation Magna head not sure what compression ratio you would have etc using the commonly available forged pistons.

Most people here use the 2nd generation Magna head if they are going to modify a 2.6. Be advised there are a few other types of cars here that ran 2.6 in RWD form (all late 1980's cars so getting a bit thin on the ground now). There is the Scorpion(Sappiro) RWD (imported from Japan) and Sigma RWD (this car built in Australia).

Be aware only about 3 people on the austarion list are using 2.6 G54B in Starions!

I think we have about 4 people using 4G63 DOHC 16 valve conversions the rest have the standard 4G63 SOHC 8 valve (modified or whatever).

This engine is seen as older technology with chain drive cam and is considered a bit of a heavy lump although you can make pretty good power until you run out of head flow. Because no Mitsubishi turbo versions of this motor were sold in Australia there are no turbo manifolds, etc around in the wreckers (junkyards) so not as obvious a Starion conversion as it may appear. The 2.6 is about 20kg heavier than a 4G63 SOHC!

However because this engine was available in Australia since 1974(!) there is a lot of knowledge about the G54B. Also it was used by Ralliart Australia in offroad racing for quite a few years.

Anyhow let me know if you want a head maybe I can help you out.

HotrodTSi wrote: Most talk in the US is for the Gen2 head, it's reported that the Gen3 raises the compression too much. What have you guys learned from swapping these heads? What about over-sized valves? Any info will help me decide what to buy. Thanks!

I may make the 4th on list to run a 4g54 soon

ATM I run a N/A 2.6 that spins 7000 in all gears which is zipping right along in 5th
I prefer the M6 gen 2 head it come standard with 42 mm inlet runners and a nice inner radius VG for flow these heads respond well to larger valves
and I think the open chamber is also better for flow
so if it works well N/A it should work even better pumped up

thats the way I'm going with my turbo build hope its some help

stephen

There are a few 2.6L 12 valve Magna wagons with 4 point MPI etc at my local pick a part, not really sure if these are considered rare or not, but if somebody needs something, I go there alot and can grab it for next to nothing.

SpidersWeb wrote:There are a few 2.6L 12 valve Magna wagons with 4 point MPI etc at my local pick a part, not really sure if these are considered rare or not, but if somebody needs something, I go there alot and can grab it for next to nothing.

I'm fairly sure you are mistaken about the 12 valve heads. To my knowledge no such thing exists unless you call jet valve heads 12valve? I'd love to be proved wrong however.

I too run a turbo 2.6 albeit not in a starion and run a gen 2 head. These run larger intake ports and minimal other differences to gen 1.
Glen @ 4Gmitsubishi.com was selling brand new heads to some of your US compadres - I think his price was damn head to beat too.

Another thing to consider with the Gen 3 heads is they are prone to hot spots.

Well there was more than one.

Labelled Mitsubishi Magna's, were station wagons, had '12 Valve' printed on the rocker cover and '2.6 injected' on the side panels, and had ECI Multi style injection units. They were front wheel drive also.

Never heard of 12V 4G54B's, but definitely heard of 16V DOHC 4G654B's.

Next time Im there Ill double check they are 2.6 and not 2.0. If they are 2.0 that would be very handy for DASH owners - MPI manifolds!

Thanks for the replys mates. I talked to Glen earlier about a Gen2 head, but wanted some imput from owners that have installed these on thier car.

MrBishi...thanks for the tip on the hot spot problem.

cheaterparts...do you know how much over-size I can go on the intake/exhaust valves? What would you use for replacements if you went this route?

thanks