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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[LA_gst]

How do definitely confirm what I have??

 

[pauleyman]

A little research turns up g6s as a 2g head. You said it's been ported intake side. Looks like your choices are get another head or a 1g intake.

 

[19Eclipse90]

IMO, it’s a wasted effort to determine, definitively, what it came from. The majority of the compression change you keep referring to is due to pistons, not the head. If memory serves, there are some compatible heads that did provide some additional volume to the combustion chamber, but it was on the order of like 3cc per cylinder. Practically insignificant.

We have provided our best guess as to what it is - a 2G head with enlarged intake ports. We’ve provided guidance as to what you would need in order to utilize it properly - a 1G-style, large port intake manifold, due to the enlarged intake ports. You can choose to do with that information as you see fit.

 

[LA_gst]

IMO, it’s a wasted effort to determine, definitively, what it came from. The majority of the compression change you keep referring to is due to pistons, not the head. If memory serves, there are some compatible heads that did provide some additional volume to the combustion chamber, but it was on the order of like 3cc per cylinder. Practically insignificant.

We have provided our best guess as to what it is - a 2G head with enlarged intake ports. We’ve provided guidance as to what you would need in order to utilize it properly - a 1G-style, large port intake manifold, due to the enlarged intake ports. You can choose to do with that information as you see fit.

Dam.. .. thanks for the info really appreciate ur time n expertise.

 

[DSMPT]

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.

I think you got misinfo or confused.
The early dohc 4g63 combustion chamber CC should be the same between turbo and non turbo, 6 bolt and 7 bolt. The only difference that affect the CR is the piston dish CC. The ones that came with smaller combustion chamber than the early 4g63 is 4g61, 4g67 and some of late 4g63.