Blew my engine. Anyone here build a 3.8 or 4.0?

[BYprodriver]

Originally Posted by Bigsmoothlee

So 8/22-8/23 I drove my 3.4 equipped 986 from northern NJ to Devens, MA for the PCA Zone 1 AutoX.

My car was on 275mm wide Hankook Z214 DOT slicks on all 4 corners with a suspension and alignment to match, and it felt like a very fast combo.

Day two, without any warning, there was a sudden rattle ( hard to hear over a loud exhaust ), a boom, and a connecting rod went through the block and left both coolant and oil all over the pavement.

Being 220 miles away, I rented a U-Haul 10' box truck and a tow dolley and dragged it back home.

That being said, I'm now on a journey to build a bigger engine. Boring to 101mm and stroking it with a 3.6 crank will give me 4.0l, but is it safe? Should I use the 3.4 crank, bore the engine to 101mm, and have a 3.8? Or is it safer to gain 200cc from the 3.6 crank and bore enough to get a 3.8?

Im going to be autoXing and doing DE events.... this time with an Accusump and oil pan baffle.

Any input would be appreciated, thank you.

Increasing stroke increases load on the connecting rods & cylinder walls of a M96. If you have a 99-2001 3.4, the valve size is optimum for 3.6L & becomes a limiting factor for bigger displacements.