I bought a 1g head, how can I tell if it's a 6 bolt or not? [Archive] - DSM Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum: DSMtalk.com

: I bought a 1g head, how can I tell if it's a 6 bolt or not?


maximuspaynimus
12-05-2006, 10:29 AM
Exactly what the title says. I bought a 1g head a while back, and that was back when I never thought to ask if it was a 6 or 7 bolt. It supposedly came off of a 1993 tsi awd manual trans. I havent been able to find anywhere how to tell the difference...

4g64fiero
12-05-2006, 11:06 AM
Exactly what the title says. I bought a 1g head a while back, and that was back when I never thought to ask if it was a 6 or 7 bolt. It supposedly came off of a 1993 tsi awd manual trans. I havent been able to find anywhere how to tell the difference...


If it came off of 93 then it *most likely* is a head off of a 7 bolt block.
Why do you care anyways?

maximuspaynimus
12-05-2006, 11:30 AM
I dont really care. But I was thinking of sometime down the road doing a 6 bolt swap after I blow this 7 bolt I have. It has 97k on it.

Turboeagletalon
12-05-2006, 11:36 AM
any pre 95 head say 89-94 dsm 2.0L heads are all the same unless its a turbo or non- turbo. then the only diffrence is the cams

4g64fiero
12-05-2006, 11:41 AM
any pre 95 head say 89-94 dsm 2.0L heads are all the same unless its a turbo or non- turbo. then the only diffrence is the cams

Right, and the only differance with the cams is between the A/t models and the M/T. It actually has nothing to do with turbo or not.

spooling_high
12-05-2006, 12:26 PM
The only thing that you have to worry about is what the guys said above. If it is a AT head, then you dont want it if you have a MT car. So other then that, dont worry about it being 6 or 7 bolt.

T_K
12-05-2006, 12:44 PM
I thought there was a difference in the head studs between 6 and 7-bolts?

EclipseRST
12-05-2006, 01:06 PM
There is... 6 Bolt motors have larger head studs. So If you cant easily fit a 6 bolt head stud through one of the holes, then you know what block the head came off of.

T_K
12-05-2006, 01:14 PM
So what do you do if you want to put a 7-bolt 1G head on a 6-bolt motor? Drill it? And vice-versa, if you want to put a 6-bolt head on a 7-bolt 1G motor doesn't the smaller size of the studs give problems?

EclipseRST
12-05-2006, 01:53 PM
To put a 7 bolt head on a 6 bolt block, the correct way is to drill it. Some people say it is ok to just push the studs through the head but honestly I dont want little metal shavings floating in my oil from the stud having to push through the metal. Its not about what you can get away with, its about doing it the right way the first time.

To put a 6 bolt head on a 7 bolt block is different. The block has dowl pins that hold the head in place, so using the smaller head studs doesnt hurt anything.

1gawd4g63
12-05-2006, 02:39 PM
You guys are confused with 1g to 2g stuff. All 1g's have the same exact head, and the head bolt holes are the same also.

seefour
12-05-2006, 04:05 PM
You guys are confused with 1g to 2g stuff. All 1g's have the same exact head, and the head bolt holes are the same also.

No, 1g 6-bolt heads have 12mm headstuds, while 7-bolts have 11mm headstuds.

punisher
12-05-2006, 05:19 PM
All 1g's (except 1.8's) use the same head, it doesn't matter whether its a non-turbo, turbo, 6 bolt or 7 bolt, all have identical heads. The cams are the only difference.

2g's use the redesigned head with smaller head studs.

Do a search if you don't believe me. Even look at various vendors pages, ever notice how when they sell heads they will only ask if its a 1g or a 2g.

JaxTalonTurbo
12-05-2006, 08:18 PM
Wow. I thought this shit was common knowlege.

As far as cylinder head port sizes and how the head flows, 90-94 4G63 NA, and 90-94 turbo are IDENTICAL. The difference between 6 bolt and 1g 7bolt heads are the headstud sizes, 12mm on the 6 bolt and 11mm on the 7bolt. The 7 bolt head can be drilled over 1mm in those holes to accomodate the 6 bolt studs/bolts.

NA 4G63 heads have different valvetrain parts including cams and valvesprings. So if you use one of those, make sure when it is assembled it is assembled with turbo valvetrain. As far as the different cam profiles between the auto and the manual tranny, I doubt that it's noticable with regular bolt ons, but who gives a fuck anyhow, just swap out the cams.

seefour
12-05-2006, 08:27 PM
Thank you for helping stop the spread of bad information. I can't believe someone can have over 300 posts and not know common things such as this.

turbo_spyder
12-05-2006, 08:37 PM
i thought 1g head had a bigger intake port and smalller exhaust port than a 2g and a 2g head had a bigger exhaust port with a smaller intake port then the 1g???

JaxTalonTurbo
12-05-2006, 08:40 PM
i thought 1g head had a bigger intake port and smalller exhaust port than a 2g and a 2g head had a bigger exhaust port with a smaller intake port then the 1g???

Don't hold me to this, but I'm pretty sure the exahust port on the 1g and 2g are identical. Or at least pretty damn close, I've never broken out the micrometer to measure the port openings. The 1g intake port is way bigger although. But we know the 1g and 2g head flow different, that wasn't the question. The confusion was the difference between the 1g 6bolt and 1g 7 bolt head, not the 2g 7 bolt.

gay_for_miatas
12-05-2006, 08:56 PM
Wow. I thought this shit was common knowlege.

As far as cylinder head port sizes and how the head flows, 90-94 4G63 NA, and 90-94 turbo are IDENTICAL. The difference between 6 bolt and 1g 7bolt heads are the headstud sizes, 12mm on the 6 bolt and 11mm on the 7bolt. The 7 bolt head can be drilled over 1mm in those holes to accomodate the 6 bolt studs/bolts.

NA 4G63 heads have different valvetrain parts including cams and valvesprings. So if you use one of those, make sure when it is assembled it is assembled with turbo valvetrain. As far as the different cam profiles between the auto and the manual tranny, I doubt that it's noticable with regular bolt ons, but who gives a fuck anyhow, just swap out the cams.


Guess my FSM is wrong. :confused:

JaxTalonTurbo
12-05-2006, 08:57 PM
Guess my FSM is wrong. :confused:

Gay For Miatas, thats a sweet name, hahah.


What does your FSM say?

gay_for_miatas
12-05-2006, 08:59 PM
Gay For Miatas, thats a sweet name, hahah.


What does your FSM say?
It says 90-94 heads have the same cams unless theyre automatic. And it gives measurements. The automatics appear smaller.

But I'm not suprised by typo's.

JaxTalonTurbo
12-05-2006, 09:02 PM
It says 90-94 heads have the same cams unless theyre automatic. And it gives measurements. The automatics appear smaller.

But I'm not suprised by typo's.

No, thats correct. 90-94 turbo heads have the same cam specs unless it's in an automatic car. NON turbo 4G63 cams are also obviously different.

turbo_spyder
12-05-2006, 09:03 PM
Don't hold me to this, but I'm pretty sure the exahust port on the 1g and 2g are identical. Or at least pretty damn close, I've never broken out the micrometer to measure the port openings. The 1g intake port is way bigger although. But we know the 1g and 2g head flow different, that wasn't the question. The confusion was the difference between the 1g 6bolt and 1g 7 bolt head, not the 2g 7 bolt.

oh...ooops my bad, i guess i did know my dsm head flow stuff....i guess he was talking something different then what i was thinking...:wall:

gay_for_miatas
12-05-2006, 09:05 PM
No, thats correct. 90-94 turbo heads have the same cam specs unless it's in an automatic car. NON turbo 4G63 cams are also obviously different.

It says the m/t non-turbo car s have the same cams as the m/t turbo,
and the a/t n/a share cams with the a/t turbo.
With exceptions for the 1.8.

JaxTalonTurbo
12-05-2006, 09:10 PM
It says the m/t non-turbo car s have the same cams as the m/t turbo,
and the a/t n/a share cams with the a/t turbo.
With exceptions for the 1.8.

Hmmm, it says the manual NT cars have same cams as turbo manual cars? Thats crazy, that differs than the service manuals used at our local shop, we went over this a couple of times, and I've had tons of heads taken over there. Thats crazy, I guess the only way to find out for sure would be to measure the lift or duration somhow and compare the two. I've always just swapped in the turbo cams when rebuilding an NA head anyways just for good measure.

gay_for_miatas
12-05-2006, 09:18 PM
Hmmm, it says the manual NT cars have same cams as turbo manual cars? Thats crazy, that differs than the service manuals used at our local shop, we went over this a couple of times, and I've had tons of heads taken over there. Thats crazy, I guess the only way to find out for sure would be to measure the lift or duration somhow and compare the two. I've always just swapped in the turbo cams when rebuilding an NA head anyways just for good measure.


Well, I'm gonna check with a local shop here that works on these and see what they have to say. I swear I'll burn this book. Theres bluntly some things wrong it sometimes.

punisher
12-05-2006, 10:36 PM
Thank you for helping stop the spread of bad information. I can't believe someone can have over 300 posts and not know common things such as this.


Haha thats pretty funny, post count doesn't indicate knowledge. I was wrong on the headstuds. But lets clear this up. The 1g 6bolt and 7bolt do have the same head. The 7bolt does have 11mm headstuds and the 6bolt does have 12mm headstuds, but the heads themselves are identical.


http://www.dsmtuners.com/forums/showpost.php?p=50429466&postcount=6

gay_for_miatas
12-05-2006, 10:44 PM
Haha thats pretty funny, post count doesn't indicate knowledge. I was wrong on the headstuds. But lets clear this up. The 1g 6bolt and 7bolt do have the same head. The 7bolt does have 11mm headstuds and the 6bolt does have 12mm headstuds, but the heads themselves are identical.


http://www.dsmtuners.com/forums/showpost.php?p=50429466&postcount=6
So judging by that you could upgrade from a 7 bolt 2g head to a larger intake valve 7 bolt 1g head with no issues?

Still confused on the cams.

punisher
12-05-2006, 10:57 PM
So judging by that you could upgrade from a 7 bolt 2g head to a larger intake valve 7 bolt 1g head with no issues?

Yes. Well, the install will be the same as installing a 6bolt head except you don't have to re-drill the headstuds to 12mm.
http://www.roadraceengineering.com/1g2gheadswaptechtip.htm

Still confused on the cams.
Here's a breakdown of 1g cams. Its kinda long and there are a few worthless posts but there is good info.
http://www.dsmtuners.com/forums/showthread.php?t=17110&highlight=protractor

Dream On
12-06-2006, 02:44 PM
I think also that the outer exhaust manifold studs will be larger if it is a 7 bolt head. My car (late 92 7 bolt) has the larger studs, while my buddies has head bolts of all the same diameter.