1G 2g 7 bolt head on 7 bolt 1g block

[4gfun]

I have a built 2g G6/8 head that BogusSvo built for me a while back. It was going to go on my 6 bolt TSI AWD Block but instead it will be going on my 1g 7 bolt Laser.

He did the oil port mod and reamed out the bolt holes to 12mm for use on a 6 bolt.

I'd like to know:

1) Which intake manifold would be best with this combo e.g. 1g 7 bolt IM or 1g 6 bolt IM.

2) If the fact that the bolt holes are now 12mm will matter.

Also wondering if the CAS being used has anything to do with it. I thought I recall that being a factor but can't be sure.

Thanks.

 

[1990TSIAWDTALON]

Don't pair it up with a 1g intake, the runners are larger and when they meet the head, the flow is like hitting the edges of a brick wall. I use a Evo3 intake, as its runners are the same size as the 2g head/intake are.
Can't help with reliable info on the 1mm over holes, but my 2g head had the bigger studs POUNDED thru the head with a hammer by the wonderful PO, who is/was a army mechanic....I am using the bigger studs though so it works out.
I am a 90 DSM dude so the CAS question I will pass on to someone else.

 

[4gfun]

Don't pair it up with a 1g intake, the runners are larger and when they meet the head, the flow is like hitting the edges of a brick wall. I use a Evo3 intake, as its runners are the same size as the 2g head/intake are.
Can't help with reliable info on the 1mm over holes, but my 2g head had the bigger studs POUNDED thru the head with a hammer by the wonderful PO, who is/was a army mechanic....I am using the bigger studs though so it works out.
I am a 90 DSM dude so the CAS question I will pass on to someone else.

Well looking back, the head that I received *might* be a 7 bolt 1g head. I don't know if the markings tell it all, but this could very well be a 1g 7 bolt head. I'll come back and take some measurements and/or pics.

Of course, I'd prefer to look at the casting to be sure. Hate to compromise an IM gasket if not needed.

Be back soon with some facts.

Thanks for all of the help.

90's are cool.

 

[1990TSIAWDTALON]

I have 2 '90 Talons, 1 '90 Laser and 2 '90 GSX's. 2 of these 5 are parts cars because '90s are the odd ducks for parts.
Oh, and 1 98 TSI,
What you will really want is just to mate the intake to the same size runner on the head for the smoothest flow. My car came with a 1g intake on a 2g head so I know all about the mismatched stuff.

 

[talon77]

The 12mm reamed bolt holes shouldn't be an issue. I am currently running a 6-bolt head (with the larger holes) on my 1g 7-bolt block that uses the smaller head studs without any issues whatsoever for the past 2 years. The dowel pins on the block hold the head in the place laterally so it's not like the head will be sliding around because the stud holes are bigger. Just my experience. Might make a difference if you are one of those super high HP guys though.

 

[4gfun]

I have 2 '90 Talons, 1 '90 Laser and 2 '90 GSX's. 2 of these 5 are parts cars because '90s are the odd ducks for parts.
Oh, and 1 98 TSI,
What you will really want is just to mate the intake to the same size runner on the head for the smoothest flow. My car came with a 1g intake on a 2g head so I know all about the mismatched stuff.

Lol! Yeah, I have parts cars myself. They are all in my signature!

The 12mm reamed bolt holes shouldn't be an issue. I am currently running a 6-bolt head (with the larger holes) on my 1g 7-bolt block that uses the smaller head studs without any issues whatsoever for the past 2 years. The dowel pins on the block hold the head in the place laterally so it's not like the head will be sliding around because the stud holes are bigger. Just my experience. Might make a difference if you are one of those super high HP guys though.

Lol! Yeah, I have parts cars myself. They are all in my signature!

Kind of sounds similar to my scenario. Per Dale, no problem with doing that for the same reasons you stated. The dowels hold it in place. High HP guy? Nah! It's live and let live on this build. I HOPE!

So the head is a 1g head and a 7 bolt at that. My research shows that all 1g heads and 1g intake manifolds are big. Looks like I am set. The 10mm outer EM studs are another tell. I'll keep poking around. Hate wasting gaskets and getting dirtier than necessary.

I appreciate the help!

Below is actually a picture of the head.

Measuring head thickness
http://www.dsmtuners.com/forums/cyl...how-measure-4g63-cylinder-head-thickness.html

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New head thickness is 5.200
AREA Min thickness is 5.185
Mitsu factory allows a combined total .007 milled from head and block


Head #914 (This number was stamped by another machine shop)
1G
head markings G6/8
10mm exhaust corner studs
Oil port mod has been done

(I-F) Intake-Front 5.191 (E-F) Exhaust-Front 5.187
(I-R) Intake-Rear 5.188 (E-R)Exhaust-Rear 5.182

Also this post here:

http://www.dsmtuners.com/threads/is-this-a-2nd-gen-or-1st-gen-head.431917/#post152931766

I still had a hard time, but the circled dot position made it easier for me. Dot clocked over to the right on the 1g.

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Finally extra clearance around the 7 bolt head studs seems meaningless as far as performance and even required.

See post 8.

http://www.dsmtuners.com/threads/6bolt-head-to-7-bolt-head.431615/

 

[1990TSIAWDTALON]

When you start pushing big boost is when you use them. When I see 44.3 lbs on link, I am glad I have big studs made of hard material and have the head clamped down good. Bogus knows his stuff.
Got any pictures of the intake side?

 

[4gfun]

When you start pushing big boost is when you use them. When I see 44.3 lbs on link, I am glad I have big studs made of hard material and have the head clamped down good.

Oh I wasn't saying anything bad about the head studs...although I have certain thoughts about them.

I was talking about the extra space around the studs being a non issue even under high boost.

 

[1990TSIAWDTALON]

Yeah I finally realized that. The extra 1mm isnt a thing.

 

[4gfun]

Yeah I finally realized that. The extra 1mm isnt a thing.

Well you did read my mind though. I don't know if I grudge spending $120 on ARP head studs more than I grudge that the last person didn't put them in for me in the the first place.