lookforjoe
True Classic
I've got no more 87.0mm 0872 pistons to sell I'm afraid Hussein ...you'll have to hunt around. KS/Mahle did sell pistons individually, so you might get lucky and find a single sitting around...the other option is adapting /machining a set of taller CH pistons to suit the longer stroke 1600, or getting some forged pistons custom made.
What is the crushed thickness of the replacement head gasket you used? When did you change from the Felpro?
You static CR might be higher than what you think if the crushed thickness is under 1.5mm.... as all my calcs are based on using a Felpro headgasket on this style of build.
Broken lands are definitely a detonation issue... and judging by the shiny area next to the crack and the residue under the broken section, probably hasn't just happened, it's been like that for a while.
SteveC
Dang. No luck searching over here so far. Summit Racing lists a custom order for single Mahle pistons. I'll contact them tomorrow & see if they can manufacture one to 0872 modified spec.
My HG fire rings are .060" compressed - this is a thicker than stock gasket - .078" new vs. .070" for stock thickness HG fire ring.
Both the thicker & stock (Italian) HG have a fire ring ID of 87.2mm (or slighter larger). All your computations should be valid. My combustion chamber volume ended up at 34cc, which I think put my CR * between 10.6 - 10.7:1.
I'm looking at cupping the intake valves & recessing the exhaust valves to reduce CR as you mentioned in earlier posts.