Alright first of all im not sure what the gen 2 magna head is. I'm talking about the g54b block, I tihkn you guys call it the astron? I'm from starquestclub.com and a happy owner of an 86 plymout conquest tsi. There has been some rumors about a magna gen 2 head that can seat 50mm valves. I also read that its possible to get roughly 285cfm flow with these with the oversized valves and a agressive port and polish job.

If any of you know anything about our starion/conquest. The stockheads suck, and the best aftermarket head here which is a marnal, and a vvery strong head; can only flow maybe 220cfm with crazy porting and polishing along with larger valves.

I've also gathered from a few members on sqc that the m1 and m2 castings of the head are to be avioded, while anything beyond that is good. I guess there was something about casting quality issues? I was told a m3 or m4 head casting is what I want.

I'm in the process of tracking down a gen 2 head, but I have no idea which years or models even had them.

I'm also curious if there are any roller rockers available for this head?

I'm getitng ready to pull my engine and do a rebuild, and I want to see how much more top end I can get out of a magna head without going with a larger turbo. The stock starions suffer so much from bad head design that our power drops off at 4800ish on a stock car -_-

We can put pretty agressive cams in teh cars, but the only thing that really gives us more top end is the magna tp intakes, or custom mpi intakes, and a big arse turbo. My friend has a car that revs over 8k and still pulls strong, but he has a t77 exhaust housing, and a t66 compressor housing on it. He only has 6 miles and he has alreayd broke a transmission and a driveline lol. He is also the guy who owns one of the only HKS dohc heads for the g54b, which is a work of art.

I seriously think if I can get anywhere near the cfm rating that i read, it should help with the top end on my engine.

I also read that there was a kidney shaped head for the g54b, which was called a gen 3 head? Its suppose to flow even more, but I would have to do some custom pistons for it on my car unless I wanted to run race gas every time I drove it.

Any information you can give me would be greatly appreciated.

Thanks,
Shaun

I dont know much about the 2.6's but the astron is known as a 4G54.

I know the TM-TP range of magna's had cracked head issues, but I dont recall hearing problems like that with the TR/TS ones. FYI: TM, TN, TP are from 85-90 and TR/TS are from 91-early 96.

I'd be hunting down an astron II head (if it's the right one you're after?) as they'd be revised and I'd guess better flowing and better made.

Also those 4G54's respond really well to flow mods - porting and polishing etc.

It's not much info..but I hope it helps.

Actually that helped out quite a bit. It sounds like the head im looking for is off the tr/ts astron II then. I do know the astron has the same head bolt pattern. I know the b in the g54b stands for the wide bell housing, and the 54 is 2.6, but I have no idea what the 4 in 4g54 stands for.

I really appreciate the info, its really hard to find out anything about them ver here in the states.

I know the b in the g54b stands for the wide bell housing, and the 54 is 2.6, but I have no idea what the 4 in 4g54 stands for.

4 = 4 cylinder

I guess that would make perfect sense :).

Which years had the kidney shaped combustion chambers? Is that the astron 3?

Do any of you know any online shops that deal in ported and polished heads along with oversized valves for the astron 2 engine? Or where I can buy parts for them?

And yet another question. Does anyone know what some of the maximum flow numbers you can get with the gen 2 heads, and the gen 3 "kidney" heads? I'm talking fully ported, polished, and oversized valves.

I'm also curious to what compression ratio the kidney shaped head has.

Astron3??? I didnt know that they existed :confused:

ok well how about astron with kidney shaped heads? lol

no such thing as the astron 3? there was only the astron I 2.0L and the astron II 2.6L (i think its 4G52 and 4G54?) i think the TR's head was still 8 valve but had a slightly higher compression ratio to the TM/TN/TP heads. think the TR compression was 9:1? i think the TS had a different head, was 12 valve? not too sure on the compression ratio. the TM/TN/TP astrons had a compression ratio of 8.8:1. the 4G52 (2.0L astron I's) were in sigmas... think 1982/83 or around there. maybe even before i dont know alot about the sigmas.

maybe u are thinking of the 2.4L engine in the 3rd gens. but i didnt think this was an astron at all? totally diff engine? someone else will b able to comment abit better than i have but yeah, hope that helps

brendna

Well here is what i was told was a 3rd gen magna head

http://www.t-racing.com/Image%20file/starquest%20mods/gen3magna.jpg



http://www.geocities.com/boybeyers/magnahead.html

And from what I gather this might be the gen 2 head?
I was told that the good castings of the gen 2 head have a m3 or m4 designation, while the m1 and m2 castings were bad.

damn 4g54 and 4g54b motors came out in many different vehicles sold in australia some were built localy and some out of japan. the balance shaft design in the 4g54 is patented by mitsubishi, the balance shafts are required to control the vibration inherent in a 4cyl motor that big (does anyone build a bigger 4cyl petrol?) this design is used under licence by Mazda. from japan we got Mitsubishi 2wd and 4wd triton pickups and Pajero 4wd wagons with 2.6 petrols and Mazda B2600 bravo 2wd and 4wd also sold here as the Ford Courier, Mazda also sold a 3 tonne truck in australia powered by the 4g54. in locally delivered mazda B2600's under 10 years old they have a 12 valve head and efi, i don't know of this is on top of a 4g54 but i suspect it would be.
locally built cars were the sigmas and magnas, sigma was a rwd car built from 78-87 and the magna is a fwd car that was sold with the 4g54 from 85-96. the tm/tn/tp magna motors (85-91)were pretty much the same except changes for ulp in 1986 and changes in the inlet ports for efi. these models are the ones that had problems. in the 4cyl tr magna (91-94)there were changes to the efi system but not the head from what i can figure (not certain....correct me if i'm wrong). the ts magna (94-96)had a revised combustion chamber design but retained the efi system from the tr, I suspect the 4cyl TS magna head is the one ur looking for.

Yeah, the engine came in a variety of flavors here also. As far as I know the only head improvments came from the magna cars though.


Was there many reports of head problems with the magna TR 4g54 cars? That could possibly explain the deal I read about the m1 m2 m3 and m4 head castings. I was told the m1 and m2 were bad, while the m3 and m4 were good. Maybe between the tp and the tr, the head casting was improved a bit?

Yeah, the engine came in a variety of flavors here also. As far as I know the only head improvments came from the magna cars though.


Was there many reports of head problems with the magna TR 4g54 cars? That could possibly explain the deal I read about the m1 m2 m3 and m4 head castings. I was told the m1 and m2 were bad, while the m3 and m4 were good. Maybe between the tp and the tr, the head casting was improved a bit?

I've not heard any problems from the 4cyl TS's at all, in regards to the head.

That's what I'd be tracking down, a 4G54 94-96 model.

Do you know of any companies down there that offer oversized valves and heavy duty valve springs for the ts 4g54 head?

I'd try Racing Performance Works in Perth, Western Australia. David Thomas is the man to talk to. They've done a fair bit of Astron work before I think. If he can't help you, he'll surely know where to send you.

I actually dropped rpw a email yesterday. I'll wait and see what I hear back from him, thanks.