Quote:
Originally Posted by SenorFunkyPants
I have to say I've always thought that this photo looked odd:
Doesn't the build up of carbon round the edge of the piston suggest that the fuel air mix in that area is igniting before the flame front reaches it (from the center)? |
Honestly, the top of that piston looks like crap, I have looked at some engines that were clean on the top and some that were like this. This engine is an example or how poorly some of the engines seal up. You could be correct but that engine is burning so much oil it is very hard to even know what is going on with it. I hate it is apart and a lost cause now but we have taken engines that have this trend, changed to a different oil and over time they clean up. The type/brand oil can make a difference too. I am not trying to side step your question it is just difficult to answer with the pieces we have.
Something else I wish I could have accomplished and I didnt have a block and pour plate with me and maybe RG could do it is repour the cylinder with these highly carboned pistons and see how much it raises compression. A few of the pistons had enough build up to effectively raise the piston height by about .002, this adds another tenth or two to the overall compression ratio and compounds the problem.
Furthermore I shoud have taken a side picture of that because it is hard to see how high the carbon was built up from the top view. There was alot for sure.