6 bolt head, 7 bolt block/studs

[BLOHS7844]

I need to replace my head and I was wondering if I can use a 6 bolt head with a 7 bolt block and head studs. I know the 6 bolt studs are 12mm and the 7 bolt studs are 11mm. Is the 1mm gap in size going to cause a leak? If so can I put any type of a sleeve in?

 

[bryanwheat]

There is no need for any sleeve or anything. It will bolt together just fine and work perfectly fine.

 

[BLOHS7844]

ok kinda thought it would. thx man

Is there anybody else that can confirm this? I don't see any reason it wont work but I just want to be sure be I rip everything apart

 

[BogusSVO]

Just make sure you use the matching intake also.

Bryanwheat is telling you correctly.

 

[BLOHS7844]

I figured he was; just making sure. Now when you say matching intake, do you mean that I need a 6 bolt intake manifold? Can my current manifold be ported slightly to match the head ports?

 

[Tyeler18]

Why would you go to the 6 bolt head? If anything its a downgrade to the 7 unless you plan on running a huge turbo capable of over running a 7 bolt head.

 

[bryanwheat]

I figured he was; just making sure. Now when you say matching intake, do you mean that I need a 6 bolt intake manifold? Can my current manifold be ported slightly to match the head ports?

No it can not be ported. IT isn't even big enough to cover the big ports on the 1g head. You will end up with a massive boost/vacuum leak. You can get by with a 1g intake on a 2g head, but not a 2g intake on a 1g head. If you need a 1g intake pm me, i've got a few sitting around.

 

[BogusSVO]

Also of note.. depending on what year 7 bolt head you had, you may have the "CAS" that fits behind the intake cam gear, if this is the case the 6 bolt head will not have the mounting boss for it, you will have to rewire for the back CAS.

What is your reason for doing the head swap?

 

[BLOHS7844]

I need a new head and I know a guy who's got a bunch of 6 bolts sitting around so I figured why not. I'll have to look local for a mani because I can't afford it and shipping on it. Is there anything else that's not compatible with a 6 bolt head/manifold? I know the throttle body is different but will it bolt right up? How bout the fuel rail? Anything else?

Also I know that the cas's aren't compatible. What are some solutions to that? And if I rewire it or anything like that, would it affect performance? I'm guessing not because it's just saying where the crank is.

 

[BogusSVO]

WHy do you need a new head? bent valves? warped? bad seals?

Looks like you will be better off to just get another 7 bolt head and roll on, then trying to go to the 6 bolt.

 

[BLOHS7844]

Also what the hell is the deal with 6 bolt/7 bolt and 1g/2g heads/intakes? It seems that intake manifolds and heads are always classified by 1g and 2g but the 6 bolt heads had different sized studs than the 7 bolt.

Theres just way too many stripped threads from the previous owner and I'm done with all that bullshit. The exhaust manifold has never sealed. The right most exhaust stud is drilled out for a 1/2in and it's still stripped

 

[BogusSVO]

Most of the time the 6 bolt is a 1g and a 7 bolt is a 2g

The main diffrence in the heads between the 1g/6 bolt and the 2g/7 bolt is the intake runner cross section. Also the 2g/7bolt head , on what years I forget, use the front mount CAS.

Other minor differances exist , like you said the 10mm studs found on some year 1g heads.

Oh something else if you go on with the swap, you will need a 6 bolt/1g thermastat housing.

Here are some side bty side pics of the 1g and 2g heads...
http://www.dsmtuners.com/forums/dsm-build-journals/417422-4g63-head-build-ups-6-bolt-7-bolt.html

 

[BLOHS7844]

Ok so I need the head, intake manifold, and t stat housing. Can anybody think of anything else? Do the throttle bodies bolt up?

 

[BogusSVO]

You will want the 1g TB, I believe it is a common upgrade to the 2g TB

 

[BLOHS7844]

I will need a 1g tb or I will want one? Yeah I'm that dirt poor right now. Isn't there something with the coil pack too?

 

[BogusSVO]

Coil pack... I do not know...

When going with the 2g head on a 6 bolt block, I know the something with the tentioner arm needs to be done, I do not know if this is the case for you. But it needs to be looked into.

Now you know as much as I do for what you will need.

I hope some others will chime in and fill in the rest.

 

[BLOHS7844]

You have been very helpful so far. Hoping someone can seal the deal here .

To sum up what we have so, what I know is, I need a 1g head, 1g intake manifold, and 6 bolt t stat housing.

Anything else that anyone can think of? Throttle body, coil pack, fuel rail? Does anybody have any suggestions about what to do with the CAS?

Anything with the tensioner arm?

http://www.roadraceengineering.com/1g2gheadswaptechtip.htm
This link has info on this exact thing but I'm not sure if some of these are recommendations or requirements. Extremely minimal budget. I have a 16g so I don't think I need to do anything with the water pipes. Is that right?

 

[bryanwheat]

You have been very helpful so far. Hoping someone can seal the deal here .

To sum up what we have so, what I know is, I need a 1g head, 1g intake manifold, and 6 bolt t stat housing.

Anything else that anyone can think of? Throttle body, coil pack, fuel rail? Does anybody have any suggestions about what to do with the CAS?

Anything with the tensioner arm?

RRE's Eclipse 2g Turbo to 1g Head Swap Tips
This link has info on this exact thing but I'm not sure if some of these are recommendations or requirements. Extremely minimal budget. I have a 16g so I don't think I need to do anything with the water pipes. Is that right?

You can run the 2g throttle body on the 1g intake, it will work ok. You will need a 1g water pipe, 1g thermostat housing, and 1g intake manifold. you can use the 2g coil and ignitor, but you will have to custom mount them to the manifold or but the 1g coil bracket and ignitor bracket. You won't have to change anything on the timing side at all. Being that you have a 97 with the cas on the passenger side of the head you can use that on the 6 bolt head, it bolts to the same spot as a 1g sensor. You will have to use the intake cam from the 97 engine also because the end of the cam is threaded for the cam sensor trigger to bolt to it.