94 Galant GS pistons [Archive]

Galanttuner10

08-22-2010, 10:06 PM

did a quick search in the mitsu caps

3 different part numbers according to the system

94-mid 95 7gs had MD188114

mid 95-98 7gs had MD303070

and the gs does have its own part number

MD193495

now if you look it up the GS pistons are the cheapest, not sure what that means as in quality. i couldnt find anything about different compressions though either.

mysticj

08-23-2010, 12:40 AM

I had both in my hand, the recess noticeably less on the GS pistons than the std ones. Mitsu stated that they are 'no longer available' as they have their own part number. Whats up with that?

As well as the "64D" stamped on the top of the pistons. They may finally ending production for the GS pistons. If you want 10:1 compression, I will suggest swapping either the Hyundai G4CN or G4CR/G4CP head as the compression chambers are smaller than the 4G63 head. The G4CN heads are found in the 93-95 Elantra 1.8L, the G4CR found in the 93-95 Elantra 1.6L, and the G4CP in the 92-98 Sonata 2.0L. The difference between the G4CN and G4CR/G4CP is the shape of the intake ports: G4CN is the same as the 1G 4G63 while the G4CR/G4CP is somewhat oval shape close to comparsion to the 2G 4G63 intake ports.

Galanttuner10

08-23-2010, 12:58 AM

i really didnt think they were different as when we dohc swap we end up 10:1

Joel91GS

08-23-2010, 07:20 AM

Hey thanks for the info, I KNEW they were different, I bought them from a guy on another DSM site 2 years ago for that specific reason. Its no big deal. I actually have used the Hyundai heads on other applications, in fact I think that we used a 1.6 hyundai head with the 94 GS pistons and had really good results. Im considering updating the trans on my galant from auto to manual ( auto is a pain in the a$$) and I just acquired cams from that actual 2.4 GS motor, also have the head and intake too, but someone had already taken the block. This would be the 4th dohc 2.4 7 bolt that we've built with really good results, they run great and realiable. Would be awesome to throw one of these into a 92 Mirage GS if I could find one, Im too lazy to try to rewire a base model and making mounts etc.

mysticj

08-23-2010, 11:36 AM

Stock GS cams are okay, they are based on the Euro NA 4G63 cams but with smaller lift. You are better off getting some used 264/272 cams

As far as intake manifold goes, try to get an Evo I-III or RVR SSG/HSG. They have shorter runners.

Joel91GS

08-23-2010, 01:22 PM

I have a short runner intake on it now, the stock one. The 2G (7g) head and intake have the long runners and a huge plenum. I dont want a race car, just wanted to add some bolt ons to give it a few more hp....the 9.5:1 2.4 in it now works really well. So you actually own a 94 GS? Ive never seen one on the road and the u pull it I go to had one but wasnt in a position to try to get anything that day, 3 days later I went back and the block was gone and the head and cams were literally thrown on the ground. One cam was 2 cars away. I dont get it.

mysticj

08-23-2010, 02:32 PM

The GS is a nice car, even in NA form. I guess the person pulling the engine has no clue about the GS.

Joel91GS

08-23-2010, 03:27 PM

That was my thought. They took the block probably assuming its the usual 94-98 block which it is but they are going to have a few more hp with those pistons in there. I didnt bother taking the head for myself, I have a head from a 98 Sonata and its EXACTLY the same, intake and all. ( with the long runners) I felt lucky just to get the cams once I found them. People are brutal at these u pull its, they will destroy an engine just to get a piston or 2 and leave all the rest in the mud. Youll have to fill me in on your mods to your GS, 4G67 head? Is that how you got that CR?

mysticj

08-23-2010, 03:55 PM

Yep. 4G67=G4CN from an Elantra, bump the compression to around 10.6:1. So far the head, 1G TB and IM, but I have JDM Cyclone IM with a 01 Diamante TB on it sitting in the garage...

Galanttuner10

08-23-2010, 04:46 PM

whoever pulled it if they are using it for a regular 94-98 sohc they will encounter issues as it doesnt have the oil passages needed for the SOHC.

now i dont know if the pistons will cause more power even though they may have different design. i would figure if they were better they would cost more but they are cheaper than any other 7g piston and when the SOHCs do the head swap we end up in the same ball park with our pistons as it will never be the exact same setup as the OEM GS, diffterent HGs and other parts can lead to differences.

i want a GS as a project car to make awd turbo

Joel91GS

08-23-2010, 06:10 PM

Yeah thats right, even tho its 2G block, they blocked the oil passages at the factory, the same five that I PLUGGED on the ones I built, so yes, it wont work unlss they drill them out which they could. The passage is there, just blocked I think. I talked to wiseco and they can make 10.5:1 CR pistons custom, and he said that is the max for pump gas, so I could use hi test if there were any detonation issues. But for 550.00, wow. The factory 10:1s are alot cheaper, and i can use the part number you gave me to try to find them. Thanks, that helps.

Joel91GS

08-23-2010, 09:12 PM

Hey Mysticj, are you still running your original pistons or did you replace them?

Galanttuner10

08-23-2010, 10:12 PM

glad i can help. i have the CAPS program on my lap top if you need any more part numbers

mysticj

08-24-2010, 06:41 AM

Hey Mysticj, are you still running your original pistons or did you replace them?

Original GS pistons. If 10.5:1 is the max for pump gas then I guess I reach that threshold. One day I will plan a shortblock with G4js pistons to bump compression to 11.5

Joel91GS

08-24-2010, 07:37 AM

My first attempt at a 2.4 was a few years ago, I had a 2.4 sonata 1g block given to me, and just for fun I tried to mount the dual cam head and it fit! So I fenangled the timing pulleys and sich and was able to time it with the 2.0 belt ( 2.4 has one more tooth) cause I didnt know that they even made a 2.4 belt so I ran it with those 2.4 oe pistons and the compression was REALLY high, and it went like hell, but all kinds of detonation and oil burning issues. I never got one to work right, tried another block later but still burned oil like crazy. I never had luck with any of the older 1g blocks, 1.8s, 2.0s, 2.4s, but the 2G has served me well. Hone the cylinders, new rings, and they are great. My current one just turned 100k miles since I built it and its just starting to use some oil, not alot, but some. Since I have all the makings for the OE GS setup I figured I throw it all on there and put in a 5 speed and Im good to go.

Joel91GS

08-24-2010, 03:47 PM

glad i can help. i have the CAPS program on my lap top if you need any more part numbers

Hey I did give mitsu that part number and no go, they said not at all available. So I will have to get the Wisecos or JDMs and may as well go for 10.5. :040:

mysticj

08-24-2010, 07:23 PM

Have you thought of using the Hyundai G4JS pistons?

Galanttuner10

08-24-2010, 10:04 PM

all of those part numbers are gone? i have oversized piston part numbers and 2 more std size part numbers for each piston

Joel91GS

08-26-2010, 07:58 AM

Have you thought of using the Hyundai G4JS pistons?

I did that once before as an experiement, but the CR was so high I couldnt run anything that didnt detonate like crazy. AND, the wristpins are a different size, 1mm different. I did realize then tho, that the valve reliefs dont have to match unless youre planning on redlining it. Did you ever try them?

Joel91GS

08-26-2010, 07:59 AM

all of those part numbers are gone? i have oversized piston part numbers and 2 more std size part numbers for each piston

I contacted two seperate dealers, but it was only the GS piston that is gone, the standard ones are readily available.

Galanttuner10

08-26-2010, 08:59 AM

I contacted two seperate dealers, but it was only the GS piston that is gone, the standard ones are readily available.

now they said they are just discontinued? out of production? they didnt say a new piston took their place? weird.

Galanttuner10

08-26-2010, 09:01 AM

i entered the GS piston part number at oemmitsubishiparts.com and they came up, maybe see if they can get them. i will talk to my dealer today

mysticj

08-26-2010, 12:13 PM

I did that once before as an experiement, but the CR was so high I couldnt run anything that didnt detonate like crazy. AND, the wristpins are a different size, 1mm different. I did realize then tho, that the valve reliefs dont have to match unless youre planning on redlining it. Did you ever try them?

Switching to a 1G rod should have done the trick.

I was planning to in the future but I guess using a milled 4G67 head to raise compression should do the trick.

Joel91GS

08-26-2010, 07:28 PM

i entered the GS piston part number at oemmitsubishiparts.com and they came up, maybe see if they can get them. i will talk to my dealer today

Oh yeah, they come up, but when I attempted to order they emailed me and said not available in any warehouse anywhere. But sure, throw the part number at your dealer and maybe youll get a different story. Hey how many of these GSs did they make in 94?

Joel91GS

08-26-2010, 07:30 PM

Switching to a 1G rod should have done the trick.

I was planning to in the future but I guess using a milled 4G67 head to raise compression should do the trick.

I think the 1G rod journals are wider and you would have to have them reduced but maybe only by a mm or 2. They take a wider bearing as well. Do you know anyone that retrofitted a 1g rod into a 2g setup?

mysticj

08-26-2010, 09:40 PM

Hey how many of these GSs did they make in 94?
About 1660 of them.

I think the 1G rod journals are wider and you would have to have them reduced but maybe only by a mm or 2. They take a wider bearing as well. Do you know anyone that retrofitted a 1g rod into a 2g setup?

How about using the G4JS rods with the G4JS pistons?

The reason why you had so much knock with the high compression is because of the use of stock cams and 4G63 ecu. The ignition maps are too high and the stock cams increase the dynamic compression. There is only so much room allow to increase static compression and still run pump gas. The reason to increase static compression is not only to increase horsepower but to regain lost dynamic compression when using a bigger cam.

Galanttuner10

08-26-2010, 11:03 PM

Joel91GS

08-27-2010, 07:57 AM

The 10.5:1s are readily availablefrom wiseco and I wouldnt have to change anything at all, cept them of course! I have the 2.4 cams and head / intake already, 32k on the head that I have!

Wish you guys lived closer, would be cool to check out your car. There is a local guy that just got a 91 VR4, and has been calling me for help with it, the manual trans in it is shot, and I dont think he will ever find a new one, or someone that could fix it. And the the timing cover swelled and is rubbing on the belts.

Galanttuner10

08-27-2010, 10:22 AM

the gs cylinder head assembly part number has been obsoleted too and is now the 2g head assembly as well just so you guys know

mysticj

08-27-2010, 03:26 PM

everything from the GS is completely obsolete and unavailable. the only parts still available are the rods. honestly go aftermarket or even go 96-98 64. and for rids, do the frankenstein setup. 1g rod bored out for the 22mm pin

Even the cams aren't worth spit, IMO. That's why I'm going HKS 272 on the intake side but keeping the exhaust, which is 264.

FYI, The GS cylinder head = 95-96 Eclipse = Lancer Evo III.

What ECU are you going to use?

Galanttuner10

08-27-2010, 09:48 PM

Even the cams aren't worth spit, IMO. That's why I'm going HKS 272 on the intake side but keeping the exhaust, which is 264.

FYI, The GS cylinder head = 95-96 Eclipse = Lancer Evo III.

What ECU are you going to use?

i have a 96 ecu setup, but will be going 95 eprom with link

Joel91GS

08-28-2010, 05:23 PM

the gs cylinder head assembly part number has been obsoleted too and is now the 2g head assembly as well just so you guys know

WEll fortunately the Hyundai Sonata in 97 and 98 had the exact head and intake and I have one! Thats why I didnt bother to buy the head and intake at the junkyard once I saw it in person.

Joel91GS

08-28-2010, 05:25 PM

i have a 96 ecu setup, but will be going 95 eprom with link

I think I have one of those, is there an E somewhere in the part number? I think its on my shelf....I also have the Hyundai 2.0 ECM, same plugs, and I cant notice a difference in performance between one or the other.

Joel91GS

08-29-2010, 05:01 PM

Here is a pic of the 2G head and intake / exhaust that Im switching to . Im starting to prep it. I have enough spare parts that I can pretty much assemble the entire assembly.I just have to have an o2 sensor port welded on the header.

http://a.imageshack.us/img827/7615/0829101709.jpg

Galanttuner10

08-29-2010, 10:22 PM

there is an E on the cover if the ecu in the bottom right, regular turbo ecus hace the T there. if it is eprom what is the part number?

and what IM is that?

mysticj

08-30-2010, 06:41 AM

I believe it's 96-98 Sonata.
http://i386.photobucket.com/albums/oo303/ftwmotorsports/IMG_0669.jpg?t=1228935871
http://i386.photobucket.com/albums/oo303/ftwmotorsports/IMG_0670.jpg

If you are using that Sonata head, then your compression should be around 10:1. If you milled the head, you can reach 10.5:1.

Joel91GS

08-30-2010, 05:06 PM

Yeah, same one. You think the Sonata head is less than 47 cc in the combustion chamber? It would be cheaper to get it milled down maybe 1mm than to buy those expensive pistons.

mysticj

08-30-2010, 05:19 PM

Yes, just CC's the head to confirm it.

Joel91GS

08-31-2010, 09:07 AM

You know theres not alot of room to work with on that, the valves are right at the edge, almost looks like if it were milled the blade would hit the vavles...

mysticj

08-31-2010, 05:46 PM

Well, try a .027" head gasket from Comestic, it should raise compression by .3 and see if you could let .020" milled off the head. If you could, your total compression should increase by .5

Joel91GS

08-31-2010, 10:06 PM

Well, try a .027" head gasket from Comestic, it should raise compression by .3 and see if you could let .020" milled off the head. If you could, your total compression should increase by .5

And bring it up to about 10:1!

mysticj

09-01-2010, 01:41 PM

And bring it up to about 10:1!

That's if you are not using the Hyundai head.

Joel91GS

09-02-2010, 07:48 AM

That's if you are not using the Hyundai head.

So what exactly is the 4g67 head? What model and year is that from? Did mitsu ever use a piston that was higher than 9.5:1 in recent years or are they all pretty much the same like the 2g?

mysticj

09-02-2010, 08:03 AM

4g67 = G4CN. Hyunday 93-95 Elantra 1.8L

All Hyundai DOHC heads from 92 to 98 have a smaller combustion chambers than the 4G63. So your Sonata head is just fine.

Joel91GS

09-03-2010, 07:38 AM

My car that I sold, had the 10:1 gs pistons that I was lucky enough to get from someone, but I ended up using the 1.6 head.........it worked well, and barely pinged with 87 octane, so I was using medium grade fuel with good results. I really couldnt see a VISIBLE diff from the 1.6 head to the 2.0 or the 1.8.

Joel91GS

09-10-2010, 05:53 AM

Check out this site, these are mitsu pistons for a newer model, but see how flat they are. Bet I could get some CR increase out of these huh? I know a guy that has a machine that will mill out a recess of my choice, even can do valve reliefs. I already calculated about how much he would have to take off these to get my 10.5:1, about 1.5mm. I guess as long as the pin fits my rods. 200.00 as opposed to 550.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?VISuperSize&item=260575504533

Galanttuner10

09-10-2010, 10:54 AM

link didnt work for me

Galanttuner10

09-11-2010, 02:01 PM

i found something for ya. a member on here got pistons and a full headswap on here and the pistons read 64SA on them and they were stock on the GS, then i saw a picture of a kid doing the DOHC swap and his pistons say 64SA as well and look exactly the same, granted in the pictures you cant tell every nook and cranny but they have the same exact markings, so i think that the GS pistons got obsoleted part number wise becuase the 96-98 are the same. now the 94-95 have the marking 64S so there may be slight difference between those, but i bet as said before my myself and others, the pistons all have the same compression ratio

mysticj

09-11-2010, 02:38 PM

Galanttuner10

09-11-2010, 02:54 PM

its funny, even though there was one year GS they have 2 different blocks used, maybe 64D in one 64SA in the other. all i know is both blocks are now obsoleted from mitsu and can only be found used.

now the GS does have the 10.0:1 compression ratio, but why once we do the head swap do we go from 9.5 to 10.0 then if there was any true difference.

also, the 94 and 95 had one piston, the 96-98 another.

also, i would think that if the GS pistons were special, they would be more expensive, but looking back at how much they charged for them the was a good 10-15 bucks cheaper than the other pistons, so i dont think there is any real advantage to it at all by getting gs pistons.

and that info you gave about the 64S markings is weird as these came right out of a stock 95 galant.

so maybe the markings and maybe little design things here and there, but i believe the overall compression ratio is the same and it is the design of the chambers on the different heads that leads to the ratios.

like you guys were saying about how to bump up CR by different heads with the same pistons that gave that 10.0:1 would be the same idea. i bet if we took the stock gs pistons and put it in the SOHC setup it would retain the 9.5 CR

Joel91GS

09-12-2010, 11:54 AM

I just bought them, so as soon as they get here I will try to get a pic of them in here or somwehere you can see them.

Joel91GS

09-19-2010, 08:04 AM

Wel no go, they are flat becuase they shortened them to avoid a recess and valve reliefs so no go. Those 500.00 Wisecos are lookin better and better.

Galanttuner10

09-19-2010, 12:04 PM

what pistons did you have the GS? as the gs should have 4 reliefs instead of just the 2 on the intak side as the SOHC has. i am going with JE or ross pistons as ive been reading too many piston slap issues with the wisecos but ive always wanted wisecos

Joel91GS

09-19-2010, 02:57 PM

These were flattops for newer 4g64 applications. But they ended up being shorter cause they eliminated the reliefs. I just put them on craigslist for 60.00. They look like this

http://img820.imageshack.us/img820/3233/flattops.jpg