xcentric5 Posted November 16, 2009 Author Report Posted November 16, 2009 My jet sizes are 340 for the mains and 30 for the pilots with the 2nd notch on the needle. No cracks on the intake and everything was tight when i was taking it off. Yea im really kicking myself for not doin a leak test before i took it all apart. If the dome piece is chipped and a little dented is not usable anymore? If not then i have to replace the head too. What is the best head/ dome pieces to use with 65mm wiseco pistons and a 4mil vito's crank? Quote
xcentric5 Posted November 16, 2009 Author Report Posted November 16, 2009 If the dome piece is chipped and a little dented is not usable anymore? If not then i have to replace the head too. What is the best head/ dome pieces to use with 65mm wiseco pistons and a 4mil vito's crank? Quote
AKheathen Posted November 16, 2009 Report Posted November 16, 2009 If the dome piece is chipped and a little dented is not usable anymore? If not then i have to replace the head too. What is the best head/ dome pieces to use with 65mm wiseco pistons and a 4mil vito's crank? get a pic of the damage to the dome. a little bit can be ok. i have a head that i removed, where one chamber had been beatten pretty good, and all around by broken a ring. it ran fine, but had a bit of a compression imballance vibration. Quote
xcentric5 Posted November 16, 2009 Author Report Posted November 16, 2009 get a pic of the damage to the dome. a little bit can be ok. i have a head that i removed, where one chamber had been beatten pretty good, and all around by broken a ring. it ran fine, but had a bit of a compression imballance vibration. I circled the part where it is chipped and it also has small dents on the outer edge. Quote
AKheathen Posted November 16, 2009 Report Posted November 16, 2009 I circled the part where it is chipped and it also has small dents on the outer edge. oh, that's not too bad @ all. did you ever get info on what cc the chambers are now? it may be too much compression, also the squish angle/clearance will play a huge factor, and if it was milled in the past, not only will they be smaller, but one could be smaller than the other. here is what i was talking about...... Quote
Screaming Yellow Zonker Posted November 16, 2009 Report Posted November 16, 2009 That is not from detonation, but preignition probably caused by an air leak. What does the other side piston and plug look like? do you know what detonation is??? preignition is detonation... or spark knock... same with diesieling when trying to turn off an engine... Back on topic.... good luck with the repairs. check your jetting and also check for air leaks. is your timing adjustable? if so what is it at? Quote
AKheathen Posted November 16, 2009 Report Posted November 16, 2009 actually, detonation is when fuel ignites, or explodes on the hot surfaces, whereas preignition is where the fuel ignites from heat and compression alone, not nesicarily on the surface. even though, the result is pretty much the same- excessive heat. ....i'm leaning tward swquish issues. it doesn't appear from the pics, that there is the minimum 1.5mm extra cut from the head...also the angle might not be right. Quote
xcentric5 Posted November 16, 2009 Author Report Posted November 16, 2009 oh, that's not too bad @ all. did you ever get info on what cc the chambers are now? it may be too much compression, also the squish angle/clearance will play a huge factor, and if it was milled in the past, not only will they be smaller, but one could be smaller than the other. here is what i was talking about...... The previous owner doesnt know what the cc's are. But he told me the compression is at 190psi and to use race gas(VP100). Once the the new piston comes in im going to do a squish test and see what happens. Yea i guess that head isnt to bad compared to yours lol. Thats a relief cause i didnt feel like spending money on a new right now. Quote
AKheathen Posted November 16, 2009 Report Posted November 16, 2009 daym........you might want to move to higher octane fuel than that untill you can get your cr and dynamic compression verified safe for 100oct. Quote
Rodneya Posted November 16, 2009 Report Posted November 16, 2009 do you know what detonation is??? preignition is detonation... or spark knock... same with diesieling when trying to turn off an engine... Yes, I know what detonation is. But obviously you dont. So to help you I will refer you here. Dumbest/Funniest convo ever If you want to find out what the difference actually is, read thisclick click. (Originally posted by Blowit) Quote
crash&burn Posted November 16, 2009 Report Posted November 16, 2009 I thought i fowled a plug as well and so i decided to ride it back to the truck not haveing a spare with and ended up with two pistons with holes..... i had to high of compression with too low of octane which caused the predetonation to occur... Quote
AKheathen Posted November 16, 2009 Report Posted November 16, 2009 I thought i fowled a plug as well and so i decided to ride it back to the truck not haveing a spare with and ended up with two pistons with holes..... i had to high of compression with too low of octane which caused the predetonation to occur... haha, you said "predetonation".....sorry, i had to. that is a made-up word.....it's just deto.... Quote
crash&burn Posted November 17, 2009 Report Posted November 17, 2009 haha, you said "predetonation".....sorry, i had to. that is a made-up word.....it's just deto.... Predetonation is not a made up word................ Pre-Detonation / Pre-Ignition; is basically Abnormal Combustion. This is basically an uncontrolled explosion in the combustion chamber caused by any one or combination of more than one of the items listed above as restrictors of ignition timing. In normal combustion the spark ignites the compressed fuel/air mixture and a smooth burn travels through the combustion chamber and building combustion chamber pressure as it goes. This flame travels through the chamber by the time the crankshaft has moved about 15 to 30 degrees after top dead center (ATDC). In Abnormal combustion the air, something in the combustion chamber or even the whole chamber is too hot for the fuel or it is compressed too high which itself causes the temp to raise too high, causes the fuel to explode. This explosion produces extremely high temperature in a localized spot and causes a pressure spike so high and quick that it is like a hammer strike. This extremely high temp/pressure spike can cause extreme damage too. The weakest point in a chamber gives way first. This hammer like strike hits the top of the piston and attempts to go down between the piston and cylinder wall and hits the top ring. which slams down on the ring land below it, braking it down against the second ring. At the same time, the extreme localized heat starts to melt the aluminum piston. On true hemispherical engines (spark plug in the center of the chamber) The extreme heat can first weaken the piston closer to the center and the pressure spike can knock a hole in the center of the piston. In a more wedge shaped chamber (plug on the side of the chamber) the damage usually in done opposite the plug. Abnormal combustion damage is easy to ID. The underside of the piston crown is blackened, the ring land just below the top ring on the opposite side from the plug is broken in a downward pattern and the land above the top ring will be melted and burned away opposite the plug. There is also damage to the top rod bearing as the hammer effect usually beats out the rod bearing. Quote
AKheathen Posted November 17, 2009 Report Posted November 17, 2009 haha, eaasy killah..........the terms are detonation and pre-ignition....not pre-detonation. that is just a mixed up word. sounds like you did a little homework to try and back the word up, but if you read the whole thing, you will find where it states that the word is, in fact, made up. spark knock, or deto, is a latent occurence that comes tward the end of the burn, and not before regular ignition. preignition comes PRE---ignition, of a diesel type ignition. i suppose, if you fould a plug and don't get a spark, you could have both, during a deiseling scenario, you could have both, but it would be pre-nothing. just click on blowits' link.... Quote
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