After having seen a couple of cracked 3XV cylinders in the web, and having seen my own cylinder also cracked on both exhaust bridges, maybe a discussion about ways of preventing this is in order.
To the best of my understanding, this damage is caused by the stress the bridges are subjected to. They are always in contact with very hot exhaust gases, this making them expand/protrude into the bore, and be a very stressed part of the cylinder.
While this a well known problem to the single bridged engines, and the most common method of preventing this is relieving the bridge by couple of hundreds of mm, I couldn´t find any reference to this method being used on cylinders with doble bridged exhaust port.
Pictures on the sugo manual seem to point to relieving the piston.
Now, since even std. 00cylinder exhaust bridges also have been proved to crack, and tuned engines even more prone to this happening, perhaps a healty discussion about ways to prevent this would be beneficial to us all.
The bridge relieving method looks like it is a better solution then piston reliev. I suppose that in theori, the reliev on the bridge(s) when done correctly will allow for a fully straight bore at ideal engine operating temperatures, while relieving the pistons is just a method of compensation for the deformation that occours at the exhaust bridges.
What do you guys think?
