Blown Again

[jon2]

Ok I have wasted 2 new MC-59 plugs in one running each. I checked both out and seem that the element broke off about two "coils" from the top. I am thinking that the engine was runnning rich. I can only think that the engine was running too rich. The element was looked like it was also being pushed out. I used the traxxas factory settings 4 turns from close for the HSN and the LSN is fluch with inner carb body. WHen I ran it that way I noticed that at WOT she would bog. So I tried to lean the LSN 1/8 but she gave in after. What the hell is going on? Funny thing is that when I placed in a Novarossi plug I chucked from my old MT-12 that wouldn't work in the MT12 she ran fine. WTF? ANy suggestions?

Thanks
Jon

 

[SkyMaxx]

If the engine is bogging at WOT, the LSN is not the issue. The HSN is.

I'd suggest leaving the LSN right where it was (factory preset). If it idles fine and takes off fine, then the LSN is fine.

Reset the HSN to factory preset and tune from there. If after retuning the HSN you need to tweak (and I do mean tweak as in 1/16th of a turn at the most) the LSN, then do so. BUT I'd be surprised if you needed to adjust the LSN at all.

As for the plug issue, can't help too much there, but it does sound like your tuning might be killing your plugs.

 

[jon2]

Well I did try the 1/16 turn for the HSN as well but failed to mention that. I did run the car ac ouple laps and check the smoke out of the exhaust and temp and was fine. Te,ps wer in the 260 area. what else can I do? Traxxas said that the MC-59 was a great plug. I use that on my MGT and it works fine and when I was told that the MC-59 can be used I was stoked! Now I am wondering what the hell is really going on. Should I change to OS or oddonel? I was using Duratrax silver but they are hard to come by here.

 

[chrisexv6]

I was blowing thru plugs like crazy when I first started my TRX for the season. Turns out the engine bearings were bad, causing the crank to oscillate and eventually caused the piston to compress too much and destroy the plug. Went thru 4 plugs before I realized what was going on (I too thought it was a tuning issue).

Replaced the bearings and the engine ran. But now its overheated and dead, so I threw my Fantom in.

-Chris

 

[jon2]

Hmm I am not too sure if I am in the same boat as you as when I put an old plug it works fine. WTF is going on!!!

 

[SkyMaxx]

Perhaps you just need to switch to a different plug. As for brands, McCoy, OS and Fox are plugs I have used with great success. My current favorite are Fox Gold series plugs.

As for the cause, if you are 100% certain that it is not the tuning...then you need to look at other potential causes. Sounds like Chris (above) mentioned a good thing to take a look at.

 

[jon2]

Ok then How would that cause my plugs to blow? what do I actually look for?

 

[SkyMaxx]

It would cause the piston to ride higher and possibly crush the element against the piston head. It would also cause uneven compression strokes and or fuel flow leading to damage to the plugs.

 

[Hypedonrc]

If your spring is broken it normally means that it was too lean not rich. At the factory settings it should have been rich, but once you moved your LSN it was probably lean at an idle. You will definatly need to check the internals for damage since the spring was acually broke. There could be molten metal from the spring floting around in there. The only generally speaking thing that doesn't support this is that a plug spring (the element) normally is compressed up in the body of the plug if the engine is too lean not pulled out, unless it was compressed, and sprung out when it broke.