2G 1998 Eclipse GST engine swap with 97 GST engine

[LA_gst]

My spark plugs ignited and blew up in 98 GST after my timing belt gave out... bottom end of block is done..

I found a 97 GST 7 bolt engine and I'm wondering if anyone has done this swap before .. I keep reading that the swap is straight forward (plug and play) did anyone find any issues I should look for?? Or did any one get CEL??? Any help or advice would be appreciated

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[pottersgst]

97-99 are identical, easy as it sounds.
95-96 7 bolts have some slight differences, but nothing crazy. Just stay within ur years and it will be easiest

 

[LA_gst]

97-99 are identical, easy as it sounds.
95-96 7 bolts have some slight differences, but nothing crazy. Just stay within ur years and it will be easiest

Thanks , I was worried I would have an issue .. glad to hear it's a smooth transition

 

[19Eclipse90]

For all of the critical components, the 97 and 98 motors will be similar enough. Be aware there may be some differences with emissions components.

 

[LA_gst]

For all of the critical components, the 97 and 98 motors will be similar enough. Be aware there may be some differences with emissions compone

Can u explain

 

[pauleyman]

Can u explain

Different years 2g move charcoal cannister etc. Maybe different vac line routing. Easiest thing to do is just use Longblock only. Use you existing intake manifold etc. Car doesn't know you're using a 97 instead of 98. Everything you have that bolts to this new motor, use that. You use the new motor oil pump. Accessories etc if you wish or switch them. Up to you. It's very good idea to change seals, gaskets etc while you're doing this as it's easy to do now with motor out of the car.

My spark plugs ignited and blew up in 98 GST after my timing belt gave out... bottom end of block is done..

I found a 97 GST 7 bolt engine and I'm wondering if anyone has done this swap before .. I keep reading that the swap is straight forward (plug and play) did anyone find any issues I should look for?? Or did any one get CEL??? Any help or advice would be appreciated

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That's physical damage. Likely a valve head snapped off destroying everything in its wake. All 4 like that?

 

[LA_gst]

That's physical damage. Likely a valve head snapped off destroying everything in its wake. All 4 like that?

Yeah, it started from the timing belt going out n me trying to start it on the freeway... All bad

That's physical damage. Likely a valve head snapped off destroying everything in its wake. All 4 like that?

I'm gonna be using the manifold and turbo (t25) from the my 98.. should I expect any differences??

 

[pauleyman]

I'm gonna be using the manifold and turbo (t25) from the my 98.. should I expect any differences??

Nope.

Do not assume your new engine is all original. Verify. Make sure somebody didn't do a swap or change to a 1g head etc

 

[LA_gst]

Do not assume your new engine is all original. Verify. Make sure somebody didn't do a swap or change to a 1g head etc

What should I look for??

 

[pauleyman]

What should I look for??

Different intake manifold. Larger intake ports.
Great time to change out all the manifold studs too.

 

[LA_gst]

Different intake manifold. Larger intake ports.
Great time to change out all the manifold studs too.

This is what I found over the weekend.. guy said it is a 7 bolt n it looks like the one in my 98, head looks rebuilt but couldn't verify.. he had no paperwork but claimed it has less than 20k miles

Took a shot hopefully it pays off

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[19Eclipse90]

It’s a 2G 7-bolt. But those intake ports look large, which is strange, because everything else on that head points to a 2G.

Refer to comparison picture here: How to distinguish 7 bolt head, 6 bolt non-turbo head, & 6 bolt turbo head

 

[pauleyman]

It’s a 2G 7-bolt. But those intake ports look large, which is strange, because everything else on that head points to a 2G.

Refer to comparison picture here: How to distinguish 7 bolt head, 6 bolt non-turbo head, & 6 bolt turbo head

I agree. Something isn't right. Unless those ports have been enlarged. Look at #3. Bottom isn't very smooth.

 

[LA_gst]

I agree. Something isn't right. Unless those ports have been enlarged. Look at #3. Bottom isn't very smooth.

After some digging.. I figured out that this head might belong to a Hyundai.. can anyone confirm.. n does anyone know if it will be a problem????

 

[pauleyman]

I can't remember but I want to say you can't bolt a 2g intake manifold to a 1g big port head. I don't think it will seal. Even if it did you would have a huge difference in port size. If you find a 1g intake manifold you will have to deal with the different port locations and the map sensor as 1g doesn't have one.

 

[19Eclipse90]

It could be a Hyundai head. Neither here nor there - as Paul mentions, you would need a 1G intake manifold to properly seal on those ports. A 2G manifold doesn’t quite do it.

 

[pauleyman]

It could be a Hyundai head. Neither here nor there - as Paul mentions, you would need a 1G intake manifold to properly seal on those ports. A 2G manifold doesn’t quite do it.

I thought that was the case and I was looking for that exact post.

 

[LA_gst]

Balance shaft is deleted.. the head is a lil different from the cam side... And the ports have been ported. Confirmed.. I'm still tripping over this head

..

Can anyone recognize if ur 97 has this discrepancy

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Moderator edit (picture flipped):

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[pauleyman]

Your top two pictures the heads are upside down so that's exhaust side. Your third picture you're showing intake side. Go look again.
If it's just some mounting boss it doesn't matter. Your bigger problem is somebody enlarged the intake ports.

 

[LA_gst]

The more I examine the head.. it really reminds me of a non turbo 4g63 head .. mechanic hasn't confirmed if the turbo oil lines are natural or have been added.. if that would be case.. it explain the manifold ports being ported n the balance shaft deleted.. because of the small difference in compression ratio.. this might level it out.. ?? Am no expert is what I've come to this conclusion through research.. does this make sense to anyone??

 

[pauleyman]

The more I examine the head.. it really reminds me of a non turbo 4g63 head .. mechanic hasn't confirmed if the turbo oil lines are natural or have been added.. if that would be case.. it explain the manifold ports being ported n the balance shaft deleted.. because of the small difference in compression ratio.. this might level it out.. ?? Am no expert is what I've come to this conclusion through research.. does this make sense to anyone??

Why would that explain porting and how does compression ratio come i to play if it were a non turbo head? If I recall it's the same casting, just different cams.

 

[LA_gst]

Based on a thread I found..

1. Naturally Aspirated 4G63 (S6G head):

Compression Ratio: Typically 9.0:1 to 10.0:1 (varies slightly by model and year).

NA engines have smaller combustion chambers and/or pistons with less dish (or even domed) for higher compression.



2. Turbocharged 4G63 (S6K head):

Compression Ratio: Typically 7.8:1 to 8.5:1.

Turbo engines use pistons with a deeper dish and slightly larger combustion chambers to lower compression. This helps reduce the risk of detonation (knock)
under boost.

 

[pauleyman]

Based on a thread I found..

1. Naturally Aspirated 4G63 (S6G head):

Compression Ratio: Typically 9.0:1 to 10.0:1 (varies slightly by model and year).

NA engines have smaller combustion chambers and/or pistons with less dish (or even domed) for higher compression.



2. Turbocharged 4G63 (S6K head):

Compression Ratio: Typically 7.8:1 to 8.5:1.

Turbo engines use pistons with a deeper dish and slightly larger combustion chambers to lower compression. This helps reduce the risk of detonation (knock)
under boost.

Going purely off memory I recall all 1g heads having the same combustion chamber size. Reference the thread.

 

[LA_gst]

Ive been hunting around and searching for information but havent come to anything yet.

Ive got a couple of spare heads in the shed and trying to work out the differences.
One of them is a G6K off a 1995 RVR turbo. Its cooked, its soft and I just use it for a jig now.
The other is removed of a n/a RVR 2.0, its a G6S castings and I will potentially use it to build for the race car, or as a spare

I cannot for the life of me work out what the differences are though, The intake ports are the same entrance size, visually look the same. Combustion chambers are the same. Does anyone know?

It costs a bunch of money to build a head, so want to make sure that I dont start with an unsuitable core.

My race car currently has a G6K head which I believe came from an evo however I don't know for sure. Its definitely small port anyway.

Update: Just found a difference. The Lifter oil gallery doesn't go all the way to the end on the G6S. That in itself wont make any difference to performance, presume just a casting revision.

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[pauleyman]

That's not an apples to apples comparison. Stick to dsm. You start pulling JDM stuff or hyundai etc it's best to confirm what you have.