Yay I finally have a question worthy of putting into this section.

Is the 4G94 in the US Lancer an open or closed deck design? Just wondering it's potential for overboring.

 

I'm not totally clear on the definition, but I believe it's open block. If I were looking at a picture how would I know?

Regardless, the 4g94 is basically a 4g93 bored to its safe production max. There's not much room to overbore before you start hitting the coolant jackets.

 

If you look at the top of the block with the head off, do the top of the cylinders "float", or is it a solid peice.

 

I'd be surprised if it was open. I've never seen an open deck Mitsu block before. Seen it before on Hondas, though.

 

I helped build the bottom of a B16 motor the other day that had an open deck, we put a brace in.

 

After reading through some of the larger engine tech threads, I see that boring out the 4G94 doesn't look to be possible. I was just curious because I was thinking of going turbo, and then buying a seperate engine down the road and building it up. Looks like stock replacement forged parts are the only way to go.

 

I'm still not clear on the definition...I'll keep reading up and get you a definite answer, even though you're right about overboring. Not at all likely. You won't get anywhere significantly larger than stock.

 

I finally understand! Closed deck.

 

I thought the difference was that open deck has spaces all around the cylinders for better cooling while closed deck does not. Am I right? If not, what is the difference?

 

That is correct. Though the water jacket is visible, it does not fully surround the cylinder wall at the deck. I guess that qualifies as a semi-closed deck, but it's not open.