valve reliefs

DTanklage

DTanklage

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Jan 2, 2009
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i saw a bottom end that was assembled and someone had notched the pistons for a bigger cam. know these are not gassers but shouldnt you radius all sharp corners on the dome (top) of the piston? i spend a lot of time 'pro prepping' pistons and its important to do so even with race gas but i am curious how it is different with diesel?

what happens if you have sharp edges in the combustion chamber of a diesel?
 
well that cant be good...

i am gonna pro prep the tops of mine, then get em coated

do the piston manuf debur the sharp edge at the top of the bowl before they ship em?

or do they leave it razor sharp?

i am gonna round off any edges created by fly cutting but am thinking i should leave that edge (top of the bowl) pretty much a 90. hit it with a roll real quick and call it good. unless anyone suggests different?
 
If you start taking even more material off pay real close attention to compression ratio.
 
The reason you would do this on a gasser is because the sharp edge would get hot enought to cause preingnition. I dont think it would be an issue with diesel because of the higher flash point.


I do agree that the hot spot still wouldnt be good, and at least taking some emery cloth to the sharp edge wouldnt be a bad idea.
 
i got these pistons from haisleys earlier this spring for the engine i just built. the picture is not the best, but none of the edges were sharp or anything. i dont want to say they were "rounded", but they seemed to have an eased edge. they are 12v pistons with an opened bowl. mahl stock bore, 15:1, and coated. is this what we are talking about here?

 
hard to tell in your picture but some of the corners look pretty sharp

joe answered my question perfectly

thanks joe
 
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