OK, so I plan on building up my z6 just to deviate from the norm a little as well as build it on my own to get some experience......Much cheaper to replace a FUBARD d series than b series

Not that any sohc guys are cheap per se, but a budget and very well proven option is using the p29 pistons which at least according to the c-speed comp. calculator would give me a compression of 13.6:1....great for race gas and purpose built race motor....not so much with a daily driver on 91 octane.

So I went looking into HGs for a possible solution...cometic makes a .074 thick HG which is twice as thick as OEM(.037). By doing this it would drop the compression to a much more manageable 12.25:1....a little high but doable on 91.

My ? is is it safe to run a thick HG and higher compression?

 

http://zealautowerks.com/dseries.html

the numbers don't come out the same as the zealautowerks calculator. I got roughly 12:1 with the p29's and a stock headgasket putting the same info in there... wonder which one is right?

 

something isn't right because bumping up the head gasket thickness by less than a mm isn't going to lower your compression by more than a whole point. theres no way it would drop from 13.6 to 12.25

 

I figured it out...I didn;t realize p29s sat in the hole by 1mm, taking that into account I get 12.0something to 1

can't explain the HG issue on the comp calc, but that's all that was changed when I used it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by unusual71 &raquo;</TD></TR><TR><TD CLASS="quote">something isn't right because bumping up the head gasket thickness by less than a mm isn't going to lower your compression by more than a whole point. theres no way it would drop from 13.6 to 12.25</TD></TR></TABLE>Yes it will. As compression gets higher, it takes less diminished volume to halve the volume. It's an exponential, not a linear.