Cylinder porting and cracks

[fourbarrel]

I had been pondering over a notion lately while trying to sort out a cause for the crack in a cylinder of my 01 SRX,the narrow bit of material between the exhaust port and the small rectangular transfer port.Would porting a cylinder make it a bit more prone to this sort of damage?My cylinders are Bender trail ported,they were done before I bought the sled.I can't imagine with the number of sleds out there that have ported engines that cracking cylinders would be a common failure,perhaps I just had a fluke.

 

[mrviper700]

its common to crack them at the triple ports. Even stock they will crack.... but yes, when you port them this area can crack there as well because it does get thinner. Its not like it happens all the time but it does happen if the cylinder has been run lean, more heat and it cracks this area first.

its easily fixed but it needs to be stripped, welded and rebored/replated. Usually its around $250 to repair the cylinder like new condition.

 

[fourbarrel]

I'm getting ready to send the cylinder to CVT Tech in Quebec to be repaired and I was just wondering about a possible cause.Thanks Don.

 

[mrviper700]

cause: lean, excessive heat

 

[fourbarrel]

Well I got to thinking and when I pulled the engine apart after the first piston meltdown and bent con rod I found an offset timing key which from what I've been told that when used in a trail sled it would most likely cause too much heat from the advanced timing.I've since then put in a stock key but the damage was already done,little did I know,so I'm hoping that once I get this cylinder fixed and the engine back together with all stock pistons it'll be good for the long run.