986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Blew my engine. Anyone here build a 3.8 or 4.0?

Bigsmoothlee · 08-31-2015, 02:51 PM

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.

08-31-2015, 02:51 PM	#1
Bigsmoothlee Registered User Join Date: May 2011 Location: weehawken nj Posts: 240	Blew my engine. Anyone here build a 3.8 or 4.0? 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.