Engine is a 4g64 2.1 destroked with 162 mm aluminium rods, failure at 38 psi with a 76 mm Borg Warner, in region of 1000 whp, after inspection other 3 cylinders have no signs of wear, bearings are ok, any idea about why this happened? Is the case to put Darton sleeves on next engine, or hard blocking would be a better option? This engine lasted about one hour, maybe a bad block? Any help would be much appreciated.....

 

Is that a cracked block I see? I was just reading a thread where a well respected builder commented on never seeing a 4G64 wreck the block by cracking. Goodluck, it sounds like a sleeved block is in your future.

 

Thank you for your reply, yes, it's a cracked block, i tried to find external causes but i haven't seen anything wrong, in the engine..... Btw the car has exclusive drag mission, i'm thinking about the use of darton sleeves bored to 85 mm instead of the usual 87 for adding strenght, might it be a good idea? Or i should go for the hard blocking way? I'm a little confused, i expected any kind of problems, but this failure really surprised me.....

 

Cracked cyl walls can happen on the 4G63; going with stock bore will give you the most strength.

I've never heard of anyone sleeving an iron block...this is not an aluminum open-deck 4b11 or honda...

You sure you didn't drop a valve or something? The top of the piston looks just murdered...