erickson483 Posted April 17, 2012 Report Share Posted April 17, 2012 To start, I'm assembling my first banshee motor and have been searching here for a while to see everything that I need to do once I get it together. (leakdown, squish, etc...) I've used the search here to see how to do the squish and all that, but am wondering exactly how important it is to be in the correct spec range? I'm definitely not racing, I'm just trail riding for fun with this thing. It seems like if my squish is too large my compression wouldn't be as high. Is that correct? Quote Link to comment Share on other sites More sharing options...
gotta_goatsfast Posted April 17, 2012 Report Share Posted April 17, 2012 Improper squish will break your engine (literally). Do you know what detonation is? 1 Quote Link to comment Share on other sites More sharing options...
Buckwheat Posted April 17, 2012 Report Share Posted April 17, 2012 What is squish? I'm thinking it is the size and shape of the combustion chamber at TDC? Quote Link to comment Share on other sites More sharing options...
erickson483 Posted April 17, 2012 Author Report Share Posted April 17, 2012 Nuff said lol. Thanks Quote Link to comment Share on other sites More sharing options...
erickson483 Posted April 17, 2012 Author Report Share Posted April 17, 2012 Actually, what would I need to do if my squish is too large and I have a fresh top end? Get smaller domes or smaller base gasket? Like I said, I'm a first timer haha. Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted April 17, 2012 Report Share Posted April 17, 2012 Actually, what would I need to do if my squish is too large and I have a fresh top end? Get smaller domes or smaller base gasket? Like I said, I'm a first timer haha. Just get some custom domes cut for your setup. Changing base gasket thickness changes your port timings. If your cylinders are ported, ask whoever did your porting what size base gasket you need. Assemble the top end and torq the cyls down and check your squish, if its too loose with the appropriate base gasket, then you need to get some new domes cut. Call up your builder or dave @ noss machine and he can custom cut you some domes, but the dome profile will greatly depend on your porting and other setup variables. Fuel type, pipes, style of riding, etc etc etc Call kevin @ HJR, he can help you out with getting everything set up right. His number is in my signature. - Jared Quote Link to comment Share on other sites More sharing options...
fuller1986 Posted April 17, 2012 Report Share Posted April 17, 2012 so i am throwing a whole new motor together also and i guess i have never heard of this (squish) term what exactly is that procedure Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted April 17, 2012 Report Share Posted April 17, 2012 Squish clearance is the clearance between the crown of your piston and the squish-band profile of the dome. Anywhere from .035 to .055" is acceptable depending on what your setup is and who built it. .050 to .055" is very typical and generally pretty safe. Make sure you don't have any convergence in the squish band (caused by your piston crown profile not matching the squish-band profile). Convergence is bad. Divergence is ok, but not optimal unless your top end was designed for it. Your domes play just as much a role in your performance as your porting. Its well worth the extra $$ to get a set of custom domes cut for your engine setup. - Jared Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted April 17, 2012 Report Share Posted April 17, 2012 Too tight of squish (this will depend on your setup and fuel) will lead to detonation. Too loose of squish will leave power on the table, but won't harm the engine. Squish won't affect your compression, but compression ratio will affect your squish velocity and both of these factors need to be taken into account to determine fuel requirements for your engine. Also squish angle, divergent (squish clearance gets wider toward the center of the bore) is optimal on most engines. Convergent (squish clearance gets tighter toward center of bore) is never a good situation. -Brandon Quote Link to comment Share on other sites More sharing options...
Buckwheat Posted April 17, 2012 Report Share Posted April 17, 2012 How do you measure squish? Quote Link to comment Share on other sites More sharing options...
Finch Posted April 17, 2012 Report Share Posted April 17, 2012 solder bend it and stick it in same direction as wrist pin then turn engine over. pull it out and measure Quote Link to comment Share on other sites More sharing options...
Strm Trpr Posted April 17, 2012 Report Share Posted April 17, 2012 Here you go. http://www.rb-designs.com/squish-band-test.htm Quote Link to comment Share on other sites More sharing options...
Buckwheat Posted April 17, 2012 Report Share Posted April 17, 2012 Here you go. http://www.rb-design...h-band-test.htm Thanks. That was very informative. Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted April 18, 2012 Report Share Posted April 18, 2012 solder bend it and stick it in same direction as wrist pin then turn engine over. pull it out and measure Mike FAILS. This is not the correct way to check squish. You will get inaccurate readings doing it this way. Quote Link to comment Share on other sites More sharing options...
stroking Posted April 18, 2012 Report Share Posted April 18, 2012 . Squish won't affect your compression, -Brandon this is not so....i tested this very thing a few weeks ago i took the squish down from .052 to .040 and compression went up from 185 to 209 NOTHING else changed except squish !!! Quote Link to comment Share on other sites More sharing options...
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