There is alot of internet talk that Black tops are stronger than Silver top blocks.

Why is this?

Where is the proof?

I suspect this is someones opinion rather than actual fact.

Just because it looks chunkier it doesn't mean its stronger.

I personally think the silver tops have a stronger bottom end as the main caps are alot thicker.

Approx 10mm thicker.

The Black top CGI WRC blocks are supposed to warp under the first few heat cycles which can cause imediate engine failure.

I know someone personally who this has happened to and know of one other person who suffered the same fate too.

I wonder if this is a common fault with these?

Supposedly the Ford WRC team moved back to using the standard block after several failures with the CGI block, not sure how true that is though.


Has anyone ever had a block failure on a zetec engine?