lt1bird Posted June 20, 2010 Report Share Posted June 20, 2010 Guys, tell me is im being anal...trinity cheetah When I measure squish, I get the following left cyl front of dome .045 left cyl rear of dome .044 right cyl front of dome .049 right cyl rear of dome .044 Im wondering why the right front dome seems to be larger squish. Ive swaped domes around and get the same reading so its not the domes. Could be the head off a bit... is this worth worrying about? Ive measured it many times, cannot figure it out. Only other thing im thinking is that the piston is rocking a bit mor in that cyl...maybe not as much oil on the bore? Thanks! Quote Link to comment Share on other sites More sharing options...
bonbon Posted June 20, 2010 Report Share Posted June 20, 2010 (edited) Guys, tell me is im being anal...trinity cheetah When I measure squish, I get the following left cyl front of dome .045 left cyl rear of dome .044 right cyl front of dome .049 right cyl rear of dome .044 Im wondering why the right front dome seems to be larger squish. Ive swaped domes around and get the same reading so its not the domes. Could be the head off a bit... is this worth worrying about? Ive measured it many times, cannot figure it out. Only other thing im thinking is that the piston is rocking a bit mor in that cyl...maybe not as much oil on the bore? Thanks! It's the piston rocking. There will be variation if you measure that way. You should measure squish in line with the wristpin. Edited June 20, 2010 by bonbon Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted June 20, 2010 Report Share Posted June 20, 2010 You shoudlnt even be measuering squish front to back. It allows the piston to rock in the bore which wont give you a true reading like your finding out. You want to measuer in line with the wrist pin. Got me by a Min. Quote Link to comment Share on other sites More sharing options...
bonbon Posted June 20, 2010 Report Share Posted June 20, 2010 You shoudlnt even be measuering squish front to back. It allows the piston to rock in the bore which wont give you a true reading like your finding out. You want to measuer in line with the wrist pin. Got me by a Min. LOL. It's my one piece of useful knowledge for the year. Quote Link to comment Share on other sites More sharing options...
lt1bird Posted June 20, 2010 Author Report Share Posted June 20, 2010 LOL bonbon, I was thinking that as I saw the piston rock when I push on it. Ill do it again(from writst pin side of piston) but does anyone still have an idea of how much variation would be ok from cyl to cyl? one at .050 the other at .054 etc....let me know what your folks remmeber wehn doing it... Thanks! Quote Link to comment Share on other sites More sharing options...
alcoholbanshee Posted June 20, 2010 Report Share Posted June 20, 2010 LOL bonbon, I was thinking that as I saw the piston rock when I push on it. Ill do it again(from writst pin side of piston) but does anyone still have an idea of how much variation would be ok from cyl to cyl? one at .050 the other at .054 etc....let me know what your folks remmeber wehn doing it... Thanks! In a perfect world you want it to be dead nuts on...........That said, I would say as long as at your 4 measurement points do not have a variation of more than .002................you will be fine Quote Link to comment Share on other sites More sharing options...
lt1bird Posted June 20, 2010 Author Report Share Posted June 20, 2010 .002" that seems very tight... im thinking I might have more than that. Typically dont folks usually give a range like .040-.045 Maybe they mean both side like .040 each side. some engine builder must know what the suish tolernace from cyl to cyl should be?? Thanks! Quote Link to comment Share on other sites More sharing options...
lt1bird Posted June 20, 2010 Author Report Share Posted June 20, 2010 Well, it looks like one is .050 and the other is .053 Tim from titan is making me some domes custom to work with 93 ocatane... he like to run .050 on the cheetah engines...says works great.... lose a tad low end but has a much wider longer powerband. Pefrect for my street bike thats only 300lb.... Quote Link to comment Share on other sites More sharing options...
lt1bird Posted June 21, 2010 Author Report Share Posted June 21, 2010 anyone? too much variation?? .053 to .050 Quote Link to comment Share on other sites More sharing options...
AKheathen Posted June 21, 2010 Report Share Posted June 21, 2010 lol, i would only start to worry about it when it gets a bit over .015" or even more variation in piston rock. that being said- throw those #'s out the door and go measure it correctly over the piston pins. lined up left and right of the cyls, all the way against the side of the cyl. you will probably find .035"-.040" squish as your actuall measurement. in the future, if you ever want to measure piston rock, you measure all 4, then subtract (right + left) from (front+rear) for total rock. for one-way rock- subtract (r+l)/2 from either front, or rear. Quote Link to comment Share on other sites More sharing options...
lt1bird Posted June 21, 2010 Author Report Share Posted June 21, 2010 Those are the numbers..... measured at the piston pin in line so minimum rocking effect on the readings .050 for one and .053" on the other cyl.... Quote Link to comment Share on other sites More sharing options...
sheefreak Posted June 22, 2010 Report Share Posted June 22, 2010 I like to hold two pieces of solder at the same time same bore both inline w/the wristpin. This will help give you a very accurate reading. Quote Link to comment Share on other sites More sharing options...
lt1bird Posted June 22, 2010 Author Report Share Posted June 22, 2010 makes sense to me... Quote Link to comment Share on other sites More sharing options...
AKheathen Posted June 22, 2010 Report Share Posted June 22, 2010 how the hell did that happen?you gained about .005 ruling out piston rock? there is something weird there...... Quote Link to comment Share on other sites More sharing options...
lt1bird Posted June 22, 2010 Author Report Share Posted June 22, 2010 Well, since the dome is tapered at an angle, depending on where you take the measurement depends on the reading. Im measuring in the center of the crushed solder... not on either end... kind of like the average. is this not correct? Should I be measureing someplace else on the solder like the very tip at the tightest piston/dome location? Thanks! Quote Link to comment Share on other sites More sharing options...
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