1g head on 2g 7-bolt block??

[cintrona07]

I don't know if anyone has posted this question yet, and if they have can you direct me to the forum. But I was wondering if a 1g head and intake manifold would fit my 7-bolt 2g block? If it does what else would i'd have to get in order to have it fit and how would i go about doing it? Thanks

P.S. I have a 97 Eclipse GST

 

[fwdmaster]

Try looking for a 93-94 head.A 93-94 head is still a 1g head but they came 7 bolt & there head bolt size were 11mm same as 95-99 7 bolt engines making it a direct bolt-on,while a 89-92 cylinder head came 12mm head bolt size,making a 1mm gap if you were to use a 89-92 head

 

[SeMi380]

I just wouldn't do that at all cause the 2g head has smaller runners than the 1g head. Basically you'll drop the 1g head on your 2g block then go to bolt on your 2g intake manifold and it'll end up bottlenecking. The ports on the 1g head are almost twice the size of the 2g head.

 

[ezz-e]

The 1g head does fit the 7bolt 95 and up block. you need the 1g intake manifold and you will have to run the 1g cam angle sensor since there are no bolt holes to place the 95 cam sensor on. You would have to do the magnus mod in order to run the 1g cam sensor. Its a good upgrade if you combine it with a 1g 92-94 throttle body and a better turbo than the stock t25.

 

[kingjust]

I don't know if anyone has posted this question yet, and if they have can you direct me to the forum. But I was wondering if a 1g head and intake manifold would fit my 7-bolt 2g block? If it does what else would i'd have to get in order to have it fit and how would i go about doing it? Thanks

P.S. I have a 97 Eclipse GST

I have that setup as we speak on an engine stand. 2.3 to be specific. All you need is the head if your going aftermarket intake mani. And since you have a 97, you CAN put on the 97 and up Cam Angle Sensor housing, bracket, and sensor. It works and has the holes for it from the hall effect and optical CAS bolt hoels depending on year of head you get. You'll be fine, just do some light porting, remove some flashing, smoothing out the radius before the vavles and you'll be straight. Oh yeah, change your valve guides and a new 3 angle valve job for good measure and a good seal.

KJ

 

[DSM_PWR]

....you will have to run the 1g cam angle sensor....

The results are in..

and that was a lie ...

He's running a 2gb CAS which bolts straight up.





I say go for it, not only are you getting rid of those tiny ports that EVO owners can only dream of getting rid off But you'll be setting up for any future mods

I don't know if anyone has posted this question yet....

and yes.. its been discussed 100000xxxx times

 

[cintrona07]

So thank you for your reply's i just have one more question. Fwdmaster mentioned above that the head bolts are different since i have a 7bolt. Is this true? and if it is how would i go about installing it? Thanks again

 

[SeMi380]

So thank you for your reply's i just have one more question. Fwdmaster mentioned above that the head bolts are different since i have a 7bolt. Is this true? and if it is how would i go about installing it? Thanks again

yea the head bolts are smaller by about a millimeter and a half on the 7 bolt compared to the 6 bolt. The dowel pins should hold the head in place but the only other thing you can do is drill out the holes in the block which isn't the best idea because it changes the flex characteristics of the block.

 

[cintrona07]

Would drilling the block really mess up the flow characteristics that much?

 

[SeMi380]

Once the head studs are torqued down it will change the flex characteristics of the block but I don't know how big of a difference it's gonna make. It's been done a million times before so I don't imagine it being a huge problem or anything but I would assume under high levels of boost it's not the best for your block. Personally I would rather not do it and would rather just slap on a 2g head but that's just me.

 

[gsxeclipse97]

the only reason you need a 1g cam sensor is if you do the six bolt swap because the 6-bolt motor does not come with a crank sensor. This question has been asked many times so just search. The head bolt from a 2g will bolt down the head of a 1g you only need to adjust if you put a 2g head on a 1g block. you also need a 1g water neck and thermostat housing. Also if you do the swap you should need to do a timing job also since you will already have everything apart already.

and one other thing you need the rubber hose that connects to the 1g water neck

 

[VETTE_50_TH]

Two questions. If you have a 95 with no CAS, what should i do. And i have all the water piping and water neck and shit from my 1g, but with the head studs, should i drill out the block or what? If i dont, and use 7 bolt head studs, will oil get passed the bolts or what?

James

 

[snowborder714]

You have a CAS James - it's behind your intake cam gear.

 

[VETTE_50_TH]

You have a CAS James - it's behind your intake cam gear.

Right, but if i put on a 1g head, i cant put that on.

James

 

[bpestilence]

Wire the 1g CAS to your wiring harness. There are how-to's on here.

 

[VETTE_50_TH]

Wire the 1g CAS to your wiring harness. There are how-to's on here.

Ok, thats what i thought.

James

 

[snowborder714]

RRE Instructions

 

[kimcheefists]

I'm in the market for a used head and it seems that 1G heads are more common than 2G heads. So I'm thinking about doing this swap if I can't find a 2G head.

After going through this thread, I wanted to just confirm a couple things. To make this swap as simple as possible, I'm going to need a 93-94 head that has the same bolt hole size as the 2G head. With that head, the CAS I already have will bolt right in. I'll also need a 1G intake manifold because the ports are different sizes and 1G thermostat housing with water neck. Is all of that accurate? Is there anything else that I'm missing?

 

[19Eclipse90]

After going through this thread, I wanted to just confirm a couple things. To make this swap as simple as possible, I'm going to need a 93-94 head that has the same bolt hole size as the 2G head. With that head, the CAS I already have will bolt right in. I'll also need a 1G intake manifold because the ports are different sizes and 1G thermostat housing with water neck. Is all of that accurate? Is there anything else that I'm missing?

Sounds like you've got most of it figured out if by "water neck" you mean the water pipe that runs from the water pump. The only other thing to worry about is the MAP sensor on top of the 2G intake manifold. You will either need to tap into the 1G manifold for it or find some other way of installing it.

 

[kimcheefists]

Actually, by water neck, I meant the water outlet pipe that connects to the thermostat housing. So I'll need the water pipe from a 1G as well? Is that everything?

 

[hubz91talontsi]

2g head is better than the 1g head. The runners are straigher leading to the combustion chamber. Alot of people run 2g heads on there 6 bolts because of that. It doesn't look like you're going to be pushing a lot of power but in the future you may.

 

[kimcheefists]

2g head is better than the 1g head. The runners are straigher leading to the combustion chamber. Alot of people run 2g heads on there 6 bolts because of that. It doesn't look like you're going to be pushing a lot of power but in the future you may.

The only reason why I was looking into putting a 1G head in my 2G is because they seem to be more common on the market. I honestly would prefer getting another 2G head since I won't need to get additional parts but I couldn't find any for sale.

 

[19Eclipse90]

Actually, by water neck, I meant the water outlet pipe that connects to the thermostat housing. So I'll need the water pipe from a 1G as well? Is that everything?

Yes you will need a 1G water pipe with a 1G thermostat housing. The 2G unit recirculates back into the 2G thermostat housing while the 1G pipe connects straight to the lower radiator hose.

Sorry I was a bit confused about the water neck -- I was assuming it was considered a part of the thermostat housing and would be included with it.

One final thing deals with routing of the coolant return line. The feed line I would not anticipate being any trouble as you can simply run longer hose to accommodate. The return line on a 1G pipe loops under the bottom of the turbocharger while the 2G return has a hard line coupled with a hose going back to just before the thermostat housing. You should be able to bend the 1G line to fit the T25 or you could remove and replace that line with a bung and try to utilize the 2G return pipe. There are a lot of options here and one way isn't necessarily better than the other.

Here's a thread that deals with the issue and offers a possible solution:
My "1g head w/ 2g block" water pipe solution

 

[kimcheefists]

-_- This swap seems to be more of a hassle than I thought..So I'll also need 1G coolant lines for my turbo? Just to recap, I'll need 1G thermostat housing, 1G water outlet neck, 1G water pipe (pipe that connects to the water pump), 1G coolant lines for the turbo, and of course the 1G head. I hope that's it..

 

[19Eclipse90]

For your situation (1G head), you will certainly need a 1G thermostat housing, 1G water neck, and 1G water pipe.

The turbocharger water feed and return lines, again, depend on how you want to do it. The 2G feed comes straight out of the block, as seen in this thread: 2g Block Coolant Line. You will want to use this metal line and the accompanying metal line at the turbo with a little longer hose in between. That is easy to do.

The return line is the one you will have an issue with. Below is a picture of the 91-94 water pipe setup. On the left hand side you will note the boss on the bottom of the water pipe and the return line attached there. You can remove the return line (it's threaded into the pipe) and replace it with a bung, as in the thread I posted last time. This allows you to keep your current return line on the turbo by, again, using more hose to connect the two. I'd imagine this would be the easiest approach. The thread size in the water pipe boss is M16 x 1.5mm pitch if you choose to go that way -- and be sure to use thread sealant.

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