Bansh-eman Posted March 16, 2007 Report Posted March 16, 2007 full of debris? im guessing is the abreviation.. either way they are syaing that a foreign object got in there like sand or metal nd casued damage in the first few sec by being thrown around in there and blown out the exhaust.. detonation would be more centralized or create large pits... this looks more like sand or something like stated above Quote
FireHead Posted March 16, 2007 Report Posted March 16, 2007 i took the head off because i was advise to my a few people on here to check the orings of my head when i had an over heating problem also what is FOD? The definition of FOD that I am familiar with is used a U.S. Navy carrier fleet. The acronym stand for Foreign Objects ans Debris. :thumbsup: Quote
FireHead Posted March 16, 2007 Report Posted March 16, 2007 full of debris? im guessing is the abreviation.. either way they are syaing that a foreign object got in there like sand or metal nd casued damage in the first few sec by being thrown around in there and blown out the exhaust.. detonation would be more centralized or create large pits... this looks more like sand or something like stated above If the detonation was caused by overheating you may get a dispersed pattern of pitting like what is in the picture. :thumbsup: Quote
Bansh-eman Posted March 16, 2007 Report Posted March 16, 2007 The definition of FOD that I am familiar with is used a U.S. Navy carrier fleet. The acronym stand for Foreign Objects ans Debris. :thumbsup: humm close enough lol Quote
FireHead Posted March 16, 2007 Report Posted March 16, 2007 humm close enough lol The problem is that definition doesn't really fit the context of where it was used in this thread. Quote
pokeatyou2 Posted March 16, 2007 Author Report Posted March 16, 2007 once again firehead thanks for your input it back together now im going to run with it. the only thing i did was put the dome with the pits on the other side so that i have a fresh dome over the piston with the pit i will pull the head off again in a couple of rides to hopefully find the smooth dome is still smooth. does this sound like a good way of check that debris is goon or its still not sucking it in? Quote
FireHead Posted March 16, 2007 Report Posted March 16, 2007 once again firehead thanks for your input it back together now im going to run with it.the only thing i did was put the dome with the pits on the other side so that i have a fresh dome over the piston with the pit i will pull the head off again in a couple of rides to hopefully find the smooth dome is still smooth. does this sound like a good way of check that debris is goon or its still not sucking it in? What you're doing sounds reasonable. I don't really believe that your engine sucked anything in. I think it is probably more likely that some dirt or something was left in the cylinder or intake system when it was assembled. One of the pseudo benefits of a reed induction two stroke engine is that the crank chamber acts as a particulate trap, thus not much of anything solid will make it into the combustion chamber. :thumbsup: Quote
ojcool Posted March 16, 2007 Report Posted March 16, 2007 K, if you can offer a MUCH closer pic of the piston or tell me if the pits are elevated on the edges around the pit? Are the pit centers shiny or very dull? I need to know the motor and head setup too. I am leaning on pre-ignition and not detonation. The random pattern would be WAY before TDC. Either that or you threw a hand full of sand in it. Also inspect the head for damage. If it is FOD, it will have damage in the head as well. If you are running wimpy fuel in a tuned up banshee, there you go. Brandon Pre ignition and detonation are the same thing. Quote
blowit Posted March 16, 2007 Report Posted March 16, 2007 (edited) Pre ignition and detonation are the same thing. http://en.wikipedia.org/wiki/Engine_knocking I have found this links thing helps get my point across much easier. No detonation and pre-ignition are NOT the same thing. That damage looks like the work of pre-ignition but VERY unlikely because the flywheel key would have to be missing or something extreme. Generally, there is hot spot from carbon build up that causes this and I know this is not the case. Those pits in the piston may collect carbon and at some point, start to cause pre-ignition but we'll let that go for now. Pre-ignition would only have this type of pattern if it has multiple ignition points thus causing multiple flame fronts. One flame front would just diesel and beat the rods to death but would likely not show piston wear. Brandon Edited March 16, 2007 by blowit Quote
FireHead Posted March 16, 2007 Report Posted March 16, 2007 I agree that pre-ignition (also known as auto ignition) and detonation are not the same thing. :thumbsup: Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.