hercalmighty Posted June 7, 2015 Report Posted June 7, 2015 Hey guys. I'm having an issue with my motor. I just put my motor back together after getting a new crank ( 4mm to 7mm) I went to check my squish and I'm getting different readings between the cylinders. On my clutch side I'm getting .042, on my stator side I'm getting .048. I took the head off and swapped domes. I'm getting just about the same measurements on the same sides ( measurements stayed with cylinder, did not follow domes). So what could be the problem? The motor is a 499 7mm cheetah Crank from Andy at No Limit 0.032 base gasket Domes from Andy at No Limit Sent from my VS980 4G using Tapatalk Quote
hercalmighty Posted June 7, 2015 Author Report Posted June 7, 2015 Just a quick update. I had another head and set of domes. I'm getting the same results Sent from my VS980 4G using Tapatalk Quote
Coupelx Posted June 7, 2015 Report Posted June 7, 2015 what brand crank, the "in house special"? Quote
n2otoofast4u Posted June 7, 2015 Report Posted June 7, 2015 Are the pistons a match? Take head off and measure each piston to top of deck at TDC. Sent from my SCH-I545 using Tapatalk Quote
Strm Trpr Posted June 7, 2015 Report Posted June 7, 2015 I would contact Andy and talk to him. .006" is about as thin as two sheets of printer paper. I would imagine the difference is either in the domes or the crank/rod/piston tolerance stack. Either way, I'd imagine this can be corrected with domes to equal the same squish. One side of the crank/rod/piston assy can all be at the min tolerance and the other side can be at the max tolerance. -.003 one way and +.003 the other way. I'd pull the head and measure the piston's at TDC with a dial indicator. And if possible use a dial indicator to measure each piston's stroke. Quote
hercalmighty Posted June 7, 2015 Author Report Posted June 7, 2015 what brand crank, the "in house special"?Yes, it's Andy's crank that he builds Sent from my VS980 4G using Tapatalk Quote
hercalmighty Posted June 7, 2015 Author Report Posted June 7, 2015 Are the pistons a match? Take head off and measure each piston to top of deck at TDC. Sent from my SCH-I545 using Tapatalk As far as I know the pistons are matched. Sent from my VS980 4G using Tapatalk Quote
hercalmighty Posted June 7, 2015 Author Report Posted June 7, 2015 I would contact Andy and talk to him. .006" is about as thin as two sheets of printer paper. I would imagine the difference is either in the domes or the crank/rod/piston tolerance stack. Either way, I'd imagine this can be corrected with domes to equal the same squish. One side of the crank/rod/piston assy can all be at the min tolerance and the other side can be at the max tolerance. -.003 one way and +.003 the other way. I'd pull the head and measure the piston's at TDC with a dial indicator. And if possible use a dial indicator to measure each piston's stroke. I got what you are saying about the crank. Thanks for that insight.As far as measuring the pistons at tdc, I don't have a dial indicator. I'll have to try to figure out something for that Sent from my VS980 4G using Tapatalk Quote
J-Madd Posted June 7, 2015 Report Posted June 7, 2015 Mmmmm isn't it already clear that one piston is higher up than the other at TDC, due to his squish measurements? Or are you looking for deck related differences? Quote
Strm Trpr Posted June 7, 2015 Report Posted June 7, 2015 If you're referring to my post, I started writing that post before everyone else answered. Isn't his cylinder a mono-block? I also left that info there for others to read during their searches for similar issues. Even if the total piston height between each cylinder is off by .006" can custom cut domes correct the issue to equalize squish? Quote
Strm Trpr Posted June 7, 2015 Report Posted June 7, 2015 I guess anything is possible, but has anyone ever seen the deck height of a mono block be off by .006"? Quote
hercalmighty Posted June 7, 2015 Author Report Posted June 7, 2015 Yes, it is a mono-block. I'm sure I could get new domes made but I want to know if maybe there is something I should be looking. To me having domes cut to the different sides is a band aid fix to something else Sent from my VS980 4G using Tapatalk Quote
hercalmighty Posted June 7, 2015 Author Report Posted June 7, 2015 Hopefully someone can give me some insight. I will look into the deck height and stroke this week Sent from my VS980 4G using Tapatalk Quote
Atomic Monkey Posted June 7, 2015 Report Posted June 7, 2015 Tolerance stacking was the first thing I thought of too. Maybe try switching the pistons bore for bore. IMO for the most part when someone says matched set of pistons... they are the same part #, bore, and possibly run across a scale. Haven't heard much about matching up compression heights. Quote
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