JdiZzla Posted October 21, 2007 Report Share Posted October 21, 2007 I installed a noss cool head and when i started it and let it idle for a while i noticed a very small leak from one of the studs. When i looked, the acorn nut was not even touching the head. I tightened it down, but then the stud came through the top of the acorn nut. These are the stock studs and now i cant get it to stop leaking. I left off the thin metal gasket that was for the stock head, was i supposed to leave this on? or has anyone heard of stock studs not all being the same length? Quote Link to comment Share on other sites More sharing options...
bansheeseat$$ Posted October 21, 2007 Report Share Posted October 21, 2007 The front two studs are longer then the rest. Quote Link to comment Share on other sites More sharing options...
dlnoss Posted October 21, 2007 Report Share Posted October 21, 2007 If the cylinders have been bored or the studs have been removed for some other reason, they may not have threaded back down in the cylinders all the way. Otherwise, it may be a longer stud from the factory. I don't know how tight the tolerance is on factory studs. Try putting some silicone on the threads of the leaking stud. It should seal even with the stock nut. Give me a call if you need another acorn nut or some copper washers to stack on that one stud. -David Quote Link to comment Share on other sites More sharing options...
JdiZzla Posted October 21, 2007 Author Report Share Posted October 21, 2007 (edited) If the cylinders have been bored or the studs have been removed for some other reason, they may not have threaded back down in the cylinders all the way. Otherwise, it may be a longer stud from the factory. I don't know how tight the tolerance is on factory studs. Try putting some silicone on the threads of the leaking stud. It should seal even with the stock nut. Give me a call if you need another acorn nut or some copper washers to stack on that one stud. -David What type of silicone should i use? whould you suggest using like a liquid gasket? Edited October 21, 2007 by JdiZzla Quote Link to comment Share on other sites More sharing options...
dlnoss Posted October 21, 2007 Report Share Posted October 21, 2007 I'd use the high-temp Permatex stuff from the auto parts store. It's not really a high-temp application but it makes me feel better... Quote Link to comment Share on other sites More sharing options...
JdiZzla Posted October 21, 2007 Author Report Share Posted October 21, 2007 I'd use the high-temp Permatex stuff from the auto parts store. It's not really a high-temp application but it makes me feel better... Thanks for the help, i got it all back together and no leaks! Quote Link to comment Share on other sites More sharing options...
Tim Potteiger Posted September 21, 2008 Report Share Posted September 21, 2008 I have some leaking problems as well with my Noss head and before with my Pro Design as well. I not only have seen small amounts coming out around the studs, but I get compression back in my water jackets which of course causes it to puke the water out the cap overflow on the radiator. I have had this problem on and off with the engine since back when I was running the Pro Design cool head. The bike is currently .90 over stock bore, stock stroke and ported mildly for mostly pleasure riding. The old Pro Design head got too hot 1 too many times and finally cracked at the inner edge of the water jacket last year, so this year I replaced it with the Noss that did just fine until this last weekend, when the old problem of compression leaking into the water jackets started again. Upon removing the head I found traces of the o-rings from on the domes around the outside edge like the dome had lifted and pinched a little off and pushed it outside the groove and melted it to the cylinder top (the o-rings themselves are burned around the inner edge which indicate the dome lifted and they were exposed to combustion). I double checked the nuts before removal by setting my torque wrench to 21 ft-lbs and all the nuts measured 21ft-lbs except 2 that took about 1/8-1/16 of a turn before it clicked the wrench. I inspected the inside of the acorn nuts and I do see that most of the studs had bottomed out the acorn nuts and dug into the top. This was my original suspicion as well on the way home today. My theory is the bottomed out nuts were causing the added pressure to actually show 20ft-lbs torque, but had less due to the bottoming out, and after some run time, the domes finally started lifting enough to push compression back in to the water jackets. Is it possible that 18cc domes on stock height exhaust ports could be too much compression for 20ft-lbs of torque to hold down? The cranking compression as I recall is around 215 lbs. Has any one else had similar issues? I also back out spark plugs on occasion and reading here most are saying that is due to detonation. I have trouble believing that I am getting detonation. I am running 18cc domes, widened exhaust port but not raised, 4 1/2 degree advance timing, with Phillips B32 mixed 40:1 with Yamalube 2R, 36 Lectrons with 3-2 metering rod (which is actually too rich for my setup, it was recommended to run 3-1 metering rods) and .375 power jet, stock ignition and stator. I purposely run it rich for the time being thinking the water problems were starting from excessive heat due to lean fuel mixture. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted September 21, 2008 Report Share Posted September 21, 2008 I have 2 theories on your problems. #1 If you have gotten your banshee hot enough to crack the Pro Design shell then it has probably been hot enough to warp the tops of the cylinders #2 Since your are .090 over you should be runnin big bore domes. They are made for 66-68mm. They move the combustion o ring farther out for better sealing. Quote Link to comment Share on other sites More sharing options...
Tim Potteiger Posted September 21, 2008 Report Share Posted September 21, 2008 I have 2 theories on your problems. #1 If you have gotten your banshee hot enough to crack the Pro Design shell then it has probably been hot enough to warp the tops of the cylinders #2 Since your are .090 over you should be runnin big bore domes. They are made for 66-68mm. They move the combustion o ring farther out for better sealing. I have re-surfaced the cylinders for that very reason, however I had wondered about the massive over bore and whether or not the domes might need to be different. I will look into that, thanks. Quote Link to comment Share on other sites More sharing options...
dlnoss Posted September 22, 2008 Report Share Posted September 22, 2008 215 psi is pretty high. I wouldn't rule out detonation. The plugs backing out is a good indicator. 'Stock' domes are 66mm, or .080 over, so that could be an issue. Bigger bore domes with the oring groove moved to the outside edge would probably help. I'd consider going up a size or two also. If the acorn nuts are bottoming out, you can stack a couple of washers or use Parker Stat-O-Seals which are thicker and have an oring vulcanized into the middle. Just some ideas. -David Quote Link to comment Share on other sites More sharing options...
Tim Potteiger Posted September 24, 2008 Report Share Posted September 24, 2008 215 psi is pretty high. I wouldn't rule out detonation. The plugs backing out is a good indicator. 'Stock' domes are 66mm, or .080 over, so that could be an issue. Bigger bore domes with the oring groove moved to the outside edge would probably help. I'd consider going up a size or two also. If the acorn nuts are bottoming out, you can stack a couple of washers or use Parker Stat-O-Seals which are thicker and have an oring vulcanized into the middle. Just some ideas. -David I went up to K&N and purchased some more copper washers so I can stack 2 on each nut, but where can I get these Parker Stat-O-Seals? Gary looked at my domes and o-rings from them and said detonation for sure, told me to back off the timing. I am going back to 2 to 3 degrees advance. I smoothed up the cylinder tops with some light grit paper on a flat block. I am going to re-assemble it tonight and go to a B9ES plug for a little cooler spark. Hopefully it will alleviate the issue. I am tired of working on it. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted September 24, 2008 Report Share Posted September 24, 2008 I went up to K&N and purchased some more copper washers so I can stack 2 on each nut, but where can I get these Parker Stat-O-Seals? Gary looked at my domes and o-rings from them and said detonation for sure, told me to back off the timing. I am going back to 2 to 3 degrees advance. I smoothed up the cylinder tops with some light grit paper on a flat block. I am going to re-assemble it tonight and go to a B9ES plug for a little cooler spark. Hopefully it will alleviate the issue. I am tired of working on it. I didn't see you mention it, but I'm sure your running race gas, right? Quote Link to comment Share on other sites More sharing options...
dlnoss Posted September 24, 2008 Report Share Posted September 24, 2008 You can get the stat-o-seals at Sealco or Seal Company since you are in Tulsa. They are over by Grainger. You can ask for the 5/16" ones. I don't know if they have them in metric sizes. -David Quote Link to comment Share on other sites More sharing options...
Tim Potteiger Posted September 26, 2008 Report Share Posted September 26, 2008 I didn't see you mention it, but I'm sure your running race gas, right? Oh, sorry, yes Phillips B32 (111 octane) mixed 40:1 with Yamalube 2R. I finished up the re-assembly very carefully last night and took it out into the sand at the river tonight to test run it. Prior to previous times, the water leak/compression pushing the water back up through the radiator cap is already back. It usually goes for a good 2 - 3 days of riding hard before it starts doing it again, but not this time. I am at a total loss now. The water temp only got to 165 and yet i could hear it boiling and hissing in the motor and/or hoses. I have replaced the stock impeller with the pro design billet impeller, so I know the impeller isn't broken. I have a feeling it is pushing past the o-rings in the domes already again. Last time, I could clearly see where it had done this after the detonation issue had smoked the o-rings and they lost seal. I am going to test the water circulation first, but if that is ok, I guess my next course of action is to swap heads with one of my brother's bikes. One is Pro Design, one is Noss. If the problem moves to his bike, i guess it is safe to assume its the head. My Noss head now was new last spring and has about 3 hours of run time tops since I parked it all summer. I took the head over to my friends Machine shop and we checked to make sure it isn't warped. The cylinders measure the same and have the same base gaskets, so it isn't uneven cylinder height, nor warped cylinder tops. I cleaned up the cylinder tops thoroughly as well as previously stated. I am about to go set fire to it..... Quote Link to comment Share on other sites More sharing options...
dlnoss Posted September 26, 2008 Report Share Posted September 26, 2008 Your domes may be damaged. If you want to send them, and the head if you want, to me I will check them out. -David Quote Link to comment Share on other sites More sharing options...
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