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Squish v Compression Ratio
Posted: Sun Jun 21, 2009 3:38 pm
by soulsurfer
I have a new AF Cylinder head to fit on my TS1 225 which has been machined with 23cc in the combustion chamber. When checking the squish, it varies from 0.65mm to 0.88mm if I add a 0.5mm gasket, that gives me 1.15 to 1.38 squish with a compression ratio of 9.15 to 8.89 (average 9.02). Is this going to be okay or not?
Re: Squish v Compression Ratio
Posted: Sun Jun 21, 2009 5:32 pm
by bristolmod
I'd rather go with the gasket than without. C/R seems OK as does squish
Chris
Re: Squish v Compression Ratio
Posted: Mon Jun 22, 2009 8:15 am
by jonny snatchsniffer
id prefer no head gasket and use a thicker base gasket to do the same job
Re: Squish v Compression Ratio
Posted: Mon Jun 22, 2009 8:17 am
by soulsurfer
So would I, but what effect would 0.5mm have on the port timing/performance?
Re: Squish v Compression Ratio
Posted: Mon Jun 22, 2009 11:01 am
by drunkmunkey6969
soulsurfer wrote:So would I, but what effect would 0.5mm have on the port timing/performance?
Having the extra 0.5mm at the bottom will increase the timings in comparison to not having one......but put one in, and see where your piston is at BDC.....does it line up with bottom of transfers or exhaust etc.....or does it fall above/below them.....have a look and tell us.
Re: Squish v Compression Ratio
Posted: Mon Jun 22, 2009 1:01 pm
by soulsurfer
drunkmunkey6969 wrote:soulsurfer wrote:So would I, but what effect would 0.5mm have on the port timing/performance?
Having the extra 0.5mm at the bottom will increase the timings in comparison to not having one......but put one in, and see where your piston is at BDC.....does it line up with bottom of transfers or exhaust etc.....or does it fall above/below them.....have a look and tell us.
My cylinder had the MB road tune where 0.5mm was machined off the bottom and I've had a look to see where the piston sits at BDC at the moment without an additional gasket i.e just the one gasket fitted, and the piston sits just under the transfers but about 1mm over the exhaust. I guess this is gonna be okay?
Is it okay to fit two gaskets with sealant on all sides of the paper?
Re: Squish v Compression Ratio
Posted: Mon Jun 22, 2009 1:46 pm
by drunkmunkey6969
So packing the base 0.5mm just gets you back to standard spec then, you can do that no problems......you might even prefer it that way! ;o)
Re: Squish v Compression Ratio
Posted: Mon Jun 22, 2009 2:00 pm
by soulsurfer
drunkmunkey6969 wrote:So packing the base 0.5mm just gets you back to standard spec then, you can do that no problems......you might even prefer it that way! ;o)
Just what I was thinking
