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James Hebert wrote:
In article , "K. Smith" wrote: wrote: [material deleted] I also like to see more data and like to know where the original post came from. Here the reference to "the original post" is to a comment that three Evinrude E-TEC motors had blown up at a fishing tournament held in Lake Erie around July 24, 2005 [Karen replies] These are a few just for you: http://continuouswave.com/ubb/Forum4/HTML/003712.html Thanks for citing my website as a part of your effort to discredit the E-TEC, but I am afraid the article you cited contains not one word of any problems with the E-TEC motor at a fishing tournament in Lake Erie around July 24, 2005. As a matter of fact, all the articles in the cited thread were posted about a week before the fishing tournament held in Lake Erie around July 24, 2005. I don't see how they corroborate the initial claim about all of these engines blowing up. I am local to that area and have not heard anything about it. You see James this is the problem with forums such as yours, in this case you nopt onloy feel compelled to support your site you also support the latest DFI experiment called E-Tec? You even try to claim another forums posts "must" be wrong because you say so:-) I did not say "your" forum mentioned blown E-Tecs although the poster had asked for more data & where the original (blown E-tecs) post came from, but his request wasn't limited to just that, it's patently clear from the links where the information came from. Of course you'd never allow that:-). I had derided the latest "upgrades" your site conveniently gave material on them & clearly unbeknown to you much mo-) People can read James even though you'd prefer they just accepted your views without any review at all. Welcome to an open forum:-) If you had decided to actually find out about this technology you would already know why I say Ficht failed outright & to a lesser but still unacceptable extent Optimax. You're correct I am an Ozzy & was well familiar with Orbital long before Brunswick came into it. They'd been trying to flog it for years prior as had Ficht but none of the real engine people had taken it up & so far still haven't??? or do you say otherwise?? Over some years I've explained in detail why & exactly how the DFIs including Orbital Optimax would fail & sadly for many boaters, OMC employees & unionists' pensions I was right. Of course as you promote & boot lick the suppliers you don't wish to even acknowledge these facts. You should read a truly "open" forum like here, then you'd know that the OMC dealers were well aware of the defective nature of the Fichts & continued to push them because they were getting up to 30% agg of rebates & other sundry kickbacks on them. It was all well documented & discussed here as the bankruptcy court dealt with OMC & the dealers trying to get themselves onto the list of creditors for their so called rebates:-) A 101 so that even you may get a rubimentary understanding; (i) The only way it seems a crankcase transferred 2 stroke can viably get through the EPA rules is by running extremely lean mixtures at low to medium revs. In the early days OMC dealers were claiming 40-1 mixtures but once the failures started all hard technical material was withdrawn. (ii) The Ficht style injector is nothing more than an impact pressure pulse. There is no actual rail circulating fuel at any really high pressure compared to say the Yamaha's up to 800 psi. Now the new owners talk about injection pressures they're actually talking about the peak pulse of pressure, after that each following shock wave is progressively lower. Drop a stone into a full bucket of water. If you can search Deja news/google groups you'll find where years ago I posted the pressure graph that accompanied one of the early patent applications for Ficht. (iii) The suggestion is that a combination of a very lean mixture, very poor fuel atomisation caused by too low an injection pressure, prolonged repeated firing of the spark plug & maintaining that mode of operation up to reasonable levels of specific power might "sometimes" lead to excessive heat buildup in the piston. (iv) Here I originally suggested that this would lead to enough heat building in the piston to cause potentially disastrous detonation & indeed given the premises when they first came out, felt the failure rate would be huge much higher than the later claimed 1 in 5, indeed it was OMCs 1 in 5 claim that got me wondering how 4 out of 5 survived:-) (v) The answer seems to be that when in lean mode there just isn't enough fuel present to sustain detonation. This is a phenomenon well known & understood in aero engines since the 1930s (& they never try to run anything like a mixture of 40-1 if they did the engine just stops, you can't in the normal sense ignite such a mixture). By repeatedly firing the plug while the injector sprays fuel past (not at) it they can get an ignition. In the early days OMC had the dealers telling people it was like putting a match to a can of WD40 while you held the button down:-) WD40 is mostly kero & like most jet engines that also run on kero you can get a continuous ignition but don't try it with petrol:-) (iv) The submission was & remains that in "some" circumstances (say a large boat with a high top speed & therefore high prop pitch, being used for long periods at the upper end of the lean burn mode?), it's then that piston heat might become extreme. This possibility I say is admitted by the latest fixes special high melting point alloy in the pistons & special high temp oil why?? if there aren't any piston temp issues??? (v) If & it's an "if" one of the pistons gets even a little hot (say any point on it or the rings being over 250C) certainly then the situation has the potential for pre ignition once the mixture is quickly returned to "normal". i.e.the suggestion is that as the engine changes from lean burn mode to full mixture & a single firing of the plug, the sudden influx of fuel might get pre ignited by a possibly overly hot piston & then the heat/extreme pressure combination might send the particular cylinder into full detonation. (vi) It's also suggested the oiling is a part of the problem & also maybe a part of the proof of what I have said, because again excess oil possibly gets baked behind the rings? & then possibly more heat? possibly more pre-ignition? possibly more detonation is a risk? The proof part is that they have greatly reduced the quantum of oil available in all the so called DFI 2 strokes but again why?? & why the special super expensive dealer only hight temp oils?? again it's suggested this is support for the position put when Ficht was new. So James if you've read this & even partly got a handle on it, now go & re read the link I posted to your site, do you see the issue with the so called "upgrades"??? also ask yourself why do different boats, different props etc seem to experience the "roughness" at different engine speeds??? Given that the spruikers will not give any real technical material & the dealers certainly have none, then I'm happy to use your site's material in support of my position. So again just for clarity: I didn't allege your site said there were blown up E-Tecs because you clearly would have none of that:-) But I did note the OMC Ficht like "upgrades" were back & I was happy to link to you showing the symptoms as these engine get to or near the mode change point & the mixture is reverting back to normal, maybe just maybe on a very hot piston???? No need to thank me for publicising your site for you indeed I'm glad to & hope to again. K |
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