PTK Posted June 5, 2014 Report Share Posted June 5, 2014 Can the silicon carbide resistor be changed in Champion spark plugs or is that a no no! Is there any other purpose for the screw that can be accessed with a flat head screwdriver? Quote Link to comment Share on other sites More sharing options...
jetdriven Posted June 5, 2014 Report Share Posted June 5, 2014 unofficially, yes you can open them up to mess with the carbon stack resistors. Quote Link to comment Share on other sites More sharing options...
PTK Posted June 5, 2014 Author Report Share Posted June 5, 2014 If the resistance is all that's low and the plug is good otherwise, it seems that swapping new resistors should solve it. Are these resistors available? Quote Link to comment Share on other sites More sharing options...
jetdriven Posted June 5, 2014 Report Share Posted June 5, 2014 Nope, and Champion claims they are sealed with some voodoo chemical, that they are good for life, and that high resistance is meaningless. You can swap some better resistors from other spare Champion plugs if you got any. Quote Link to comment Share on other sites More sharing options...
scottfromiowa Posted June 5, 2014 Report Share Posted June 5, 2014 Stupid is not the word I was thinking on this... Quote Link to comment Share on other sites More sharing options...
pinerunner Posted June 5, 2014 Report Share Posted June 5, 2014 There are no stupid spark plug questions and since we owners can actually legally change them ourselves I think its great whenever anyone wants to learn more. I'd love to see heated discussions (and pictures) about what this or that spark plug deposit or burn pattern is and what it means. I wouldn't think of breaking into one or trying to modify it, however. The reason is I recall a Busch article (or was it a vid?) showing a case of detonation/pre-ignition he had run into where a chip off the spark plug had provided the hot spot that had started the whole thing. There were warnings never to use a plug that had dropped on a hard surface and stories of old time mechanics who deliberately demolished plugs they didn't trust to abolish the chance that someone might unknowingly install them. I'll try LOP things that make some folks cringe but I treat spark plugs as if I'm holding my life in my hands because I believe maybe I am. 1 Quote Link to comment Share on other sites More sharing options...
PTK Posted June 5, 2014 Author Report Share Posted June 5, 2014 I agree and am not suggesting doing this. But, again, what is the purpose of the removable resistor design? Seems they went to some lengths to design it this way for a reason. If not for the removal of the resistors the design otherwise is very bad! It introduces resistance drifts as we have seen. Just a question. Quote Link to comment Share on other sites More sharing options...
jetdriven Posted June 5, 2014 Report Share Posted June 5, 2014 Champion stacks resistors in the plug and then puts the screw in there to hold them in place. What happens over time is the resistors break down and the spark arcs inside the plug causing the resistors to burn, and the spark often finds it's way through the resistor to the jacket of the plug. It's a cheaper manufacturing method. Automobile spark plugs went to an integral fired-in-place resistor decades ago, and so has Tempest. It's just a better design because the resistor is part of the plug. Champion makes all sorts of excuses but they really are a crappy design that has been living off the brand name recognition. The TAT SB regards champion fine wires because the insulators crack and break off which has caused the demise of several engines. A champion engineer sent me a few pages of their opinion on this, they blame excessive chamber pressure on this from LOP operation. It's a classic case of blame the customer. No mention of Continental engines which recommend LOP operation and it's also in the POH of the planes with their engines, such as the Mooney Acclaim I flew. The Piper Malibu Continental engine is limited to LOP operation in cruise, for example. 2 Quote Link to comment Share on other sites More sharing options...
N33GG Posted June 5, 2014 Report Share Posted June 5, 2014 Not a stupid question at all...one of the more interesting threads. 2 Quote Link to comment Share on other sites More sharing options...
RangerJim Posted June 5, 2014 Report Share Posted June 5, 2014 To the contrary, that was an excellent question and I learned a lot from the replies. Thank you MooneySpace. 1 Quote Link to comment Share on other sites More sharing options...
kmyfm20s Posted June 6, 2014 Report Share Posted June 6, 2014 Maybe there is a opportunity for Tempest to make resistor that can replace the ones in the Champion plugs:) That would be great! Quote Link to comment Share on other sites More sharing options...
Hank Posted June 6, 2014 Report Share Posted June 6, 2014 Just a quick reminder that everything that was screwed together during the assembly process is not necessarily intended to be taken apart later in its life. Quote Link to comment Share on other sites More sharing options...
PTK Posted June 6, 2014 Author Report Share Posted June 6, 2014 Sooooo... let me get this straight.... Champion can screw with us...but we can't screw with Champion?! 1 Quote Link to comment Share on other sites More sharing options...
Hank Posted June 7, 2014 Report Share Posted June 7, 2014 C'est la vie . . . Quote Link to comment Share on other sites More sharing options...
wiguy Posted June 9, 2014 Report Share Posted June 9, 2014 I found that screw in the Champion plug to be rather tight, hard to take out. The slot is shallow and they may freeze in place over time. I just went with new Tempest 'massive' electrode plugs. They are working just fine. Quote Link to comment Share on other sites More sharing options...
PTK Posted June 9, 2014 Author Report Share Posted June 9, 2014 I just had spark plugs replaced at annual. I went with URHM38E. What a difference! Flew it for about three hours afterwards and I'm amazed! I don't know if it's my imagination because I know the plugs are new but it's silky smooth! That's the best way I can describe it. It ran OK with the Champions but now it runs remarkably outstanding with Tempest! I didn't know what I was missing! I'm very happy. Has anyone had similar experience? 1 Quote Link to comment Share on other sites More sharing options...
Buster1 Posted June 9, 2014 Report Share Posted June 9, 2014 Don't forget your custom spark plug trays fellas! Keep those plugs safe and in order when pulling them for cleaning and resistance checking! Also, once their in the tray, rotate the tray 180 and re-install. Your plugs will be swapped top to bottom, front to back! Quote Link to comment Share on other sites More sharing options...
MB65E Posted June 9, 2014 Report Share Posted June 9, 2014 PTK-Not your imagination at all. Tempest are great! The Champion debate is no longer! -Matt Quote Link to comment Share on other sites More sharing options...
Earl Posted June 9, 2014 Report Share Posted June 9, 2014 The question reminds me of one of ESPN's funnier commercials with Len Berman teaching a class of aspiring sports journalists. One raises his hand and says, "I have a stupid question". Len Berman says, "There is no such thing as a stupid question.....just stupid people asking questions......now what's your question?" Guy lowers his hand slowly and says, "Never mind..." However, in this case even Len Berman would not call that a stupid question........ Quote Link to comment Share on other sites More sharing options...
testwest Posted June 11, 2014 Report Share Posted June 11, 2014 Dr. K, that was a very good question. And your findings with respect to the Tempest plugs are corroborated by my own experience and by other test pilot colleagues of mine. I am sure you have seen my article on spark plugs called "A Tale of Two Sparks" ....for the Aerostar owners. If not, Google it...I included actual before and after engine data in the article. have a look here! Here is a link to the article: http://www.openclip.net/Benchmark/AOALog2011SpringTwoSparks.pdf The Chief Pilot for the Super Hornet for Boeing also owns a round engine Stinson that had rough running, bad mag drops and so on. He filled 'er up with Tempests after a great deal of other effort including rebuilding the entire ignition loom. He told me that after he put Tempests in, the difference was apparent immediately. My non GAMI engine on the Aerostar (think 1.5 M20J engines, turbo normalized), had a pretty big LOP fuel flow spread before Tempests, and the new spark plugs actually made it better. I would bet at least one of the old plugs was not firing 100%, which would result in higher EGTs and a little less power. Sent from my iPad using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
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