Toomey Man Posted June 21, 2014 Author Report Share Posted June 21, 2014 alright just wondering what would happen with 18. Also as for pipes I got Toomey t5 pipes. also what are proprietary domes? so I don't accidentally get them. Quote Link to comment Share on other sites More sharing options...
oldskool Posted June 21, 2014 Report Share Posted June 21, 2014 Your wanting to go with the 18cc domes, but your engine will be destroyed from detonation on pump gas with 18cc domes Detonation can take out pistons, domes, rods, crank and cases. You will be left with a tranny and clutch. 21cc domes are recommended, take the advice. Enjoy Quote Link to comment Share on other sites More sharing options...
Toomey Man Posted June 21, 2014 Author Report Share Posted June 21, 2014 im not going to run 18's. I was just wanted to know what would happen with 18s. Quote Link to comment Share on other sites More sharing options...
tfaith08 Posted June 22, 2014 Report Share Posted June 22, 2014 Well, you'll run like a monster with 18s for a minute or so, if that long. What'll happen is that the mixture begins to burn under it's own accord (hence the term detonation) because the lack of available octane within the gas. Octane is very stable and takes much more coercion to get it to ignite with pressure alone, but it only exists in gas in small quantities. Since the rest of your gas is more chemically unstable and the octane required to keep it from igniting before you want it to isn't present in the amount that you need, the mixture will burn anyway. Since the mixture takes time to burn, it begins to burn before the flame front from the spark plug burns all of the contents within the chamber. Those 2 flame fronts meet and a great deal of heat and pressure are forced into a much smaller spot than they normally would be confined to. This is more than enough to get most aluminum alloys past their melting point. After the aluminum from the piston or dome start to melt and fly all over your chamber, it sticks all over your dome and piston top. When this happens, those aluminum beads start to get really hot because they have more surface area that the flame can touch. They get so hot that they begin to cause the surrounding aluminum to melt and separate. Then, the AFM begins to ignite from the heat of these beads and hot spots. This is called pre-ignition. By this point, you only have a few seconds before you're stranded with a partially molten piston with a huge hole in it. In small quantities, you can get away with detonation, but it is very, very highly recommended that you take all measures to prevent this from happening. I tore my head off yesterday and found one small pit on the right cylinder and will be backing my timing off by 2 degrees. Jetting and cooling capacity also affect detonation. Lean mixtures can greatly increase the risk of detonation. A radiator that isn't sufficient will be unable to pull enough heat from the head and have the same result. Keep it under 150psi, jetted properly, cool, and set the timing to a reasonable setting and you should be fine with your setup. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted June 22, 2014 Report Share Posted June 22, 2014 Propriatary heads/domes would be some head that requires it's own special domes. Usually that type of stuff is hard to come by or discontinued. Trinity, wicked, ADA, etc. Quote Link to comment Share on other sites More sharing options...
Toomey Man Posted June 22, 2014 Author Report Share Posted June 22, 2014 thanks everybody for the great information on cool domes and stuff. Quote Link to comment Share on other sites More sharing options...
south street speed shop Posted June 28, 2014 Report Share Posted June 28, 2014 when you get your new domes always measure the width of the squish band and the clearance, never more than 13mm wide on the band and never less than .045 on the clearance, you should not go over 150 psi and use premium pump gas, so invest in a compresion gauge and a roll of 1/8 solder. That way you can measure your width, your clearance and your compression. alot of people make domes and accidents happen so measure, measure and measure again Quote Link to comment Share on other sites More sharing options...
Toomey Man Posted June 28, 2014 Author Report Share Posted June 28, 2014 what is the squish band and clearance stuff? Quote Link to comment Share on other sites More sharing options...
tfaith08 Posted June 29, 2014 Report Share Posted June 29, 2014 http://www.macdizzy.com/1989ihopup.htm Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted June 29, 2014 Report Share Posted June 29, 2014 Good read ^ if you are really wanting to grasp these things . There is even a contributors forum there now. Quote Link to comment Share on other sites More sharing options...
Toomey Man Posted June 29, 2014 Author Report Share Posted June 29, 2014 ok that was pretty interesting to read.thanks Quote Link to comment Share on other sites More sharing options...
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