Page 1 of 1

Best Way To Check Squish

Posted: Thu Oct 08, 2009 8:42 pm
by eadmr04
I've had a search but can't really get any spot on definitive answers. What is the absolute best way to check the squish. I've tried the 2 pieces of solder in a v shape like Sticky's book but is this sufficient to check it all around the piston head? Would it normally just be around the edge of the piston which needs to be checked as the centre is ok because of the combustion space? Might sound obvious to most people but I'm a bit of a novice :oops:

Re: Best Way To Check Squish

Posted: Fri Oct 09, 2009 12:40 am
by tony
Quite a few ways from a 'mechanical way' using verniers/feeler gauges etc or use plastigauge.. or the solder method. I do 4 points with plastigauge usually.

Re: Best Way To Check Squish

Posted: Fri Oct 09, 2009 12:52 am
by sean brady scooters
yes,deffinatley check around the four points..........north ,south,east and west as it were...............and take the minimum
a lot depends on how central your head is to barrel,as there can be some lateral discrepances unless it has been dowelled......

Re: Best Way To Check Squish

Posted: Fri Oct 09, 2009 8:02 am
by eadmr04
I've done a rough check and it's in the region of about 1.5mm with one of the heads (skimmed) without a gasket but with the other head (not skimmed) it was well over 2mm so would imagine using the skimmed one would be best. What would be the minimum I wouldn't want to go below? Would I be ok using the skimmed one without a gasket but just using some of the blue head gasket sticky stuff (not it's real name ) smeared around the top of the barrel?

Re: Best Way To Check Squish

Posted: Fri Oct 09, 2009 11:52 am
by jonny snatchsniffer
if you got a base gasket it is not needed, removing it will reduce your port timings a little bit depending on its thickness but improve your squish

Re: Best Way To Check Squish

Posted: Fri Oct 09, 2009 12:45 pm
by eadmr04
I've just tried re-measuring with some digital verniers and doing it the Sticky book way I get the following readings on each end of "triangle" nearest the barrel wall: 1.7mm & 1.79mm onside and 1.58mm & 1.67mm the other. More than a couple of mill from the edge of the piston towards the centre it goes up over 2mm and I can't see any marks on the solder at all. Would these sort of readings be ok, bearing in mind that I wil slightly lap both the cylinder head and top of barrel on a mirror with some grinding paste/wet and dry to get a good mating surface?

Re: Best Way To Check Squish

Posted: Fri Oct 09, 2009 2:39 pm
by jonny snatchsniffer
plasticene works too, just lightly oil the surfaces to stop it sticking, yo really want to be aiming for 1.5mm max, and like ive said the base gasket if you have one is probably 0.5mm thick so doing away with it will get your squish good