Rotec Spark Plug removal

[Roughhewn]

Well, there you are. First 25 hours of Rotec under your. Time to pull some plugs and have a look. Oh Oh! Plugs won't come out? Had this problem yet?

[cap01]

they do get tight , i have broken a plug when they break loose they really pop . the last time i tried a impact gun that worked pretty good . only be sure its set for lefty loosie .

[Roughhewn]

Probably stripped some threads, I'd imagine. The problem seems to be more with the milled heads rather than the cast ones. It appears the plugs Rotec uses is about a thread too long. This allows deposits to foul the thread. It appears they didn't allow enough head thickness for the crush gasket on the plug.
If you encounter this problem, and most likely you will, it probably will require boring out the plug hole and installing a permanent aluminum insert. Do not use a steel helicoil. The coil and the head will expand at different rates. The result would be poor transfer of heat from the plug to the head leading to overheating of the plug and pre-ignition. An insert kit is available from http://www.timesert.com/html/sparkplug.html. I made a guide for the tap and reamer to assure a perfect alignment.
Re-install the cylinder. I made some 1/8th in thick copper gaskets (similar to the standard plug gaskets on Lycs and TCMs. Antisieze and should cure the problem. PIB (Pain In the B---)

[paulc]

Plug seizure is not a common repeat problem. Just use anti seize all over the treads and it will get you to your next plug service easily.

No need to go crazy on tightening either.

I’ve been running the same set of plugs for 5 years and 350hrs!

[Roughhewn]

I've fortunately retained every e-mail we've ever exchanged. When I queried you about the spark plug issue you replied "I've not yet encountered that problem. I have accumulated over 350 hours and 4 years on my engine and have not removed a spark plug. I'll remove one this weekend and get back to you." (you never did)
Members should consider that many owners have not yet run the engines. If they have the early engines and use 100LL, they may well encounter the problem.
As a practicing A&P with over 35 years experience, I can assure you I know how to properly install a spark plug. No amount of antisieze compound will prevent lead fouling on the exposed plug thread.
Please note, it is not my intent to knock the manufacturer or the product. I'm forwarding information learned from my "school of hard knocks".

[paulc]

In 1997 I started Rotec in my back yard with a Chinese drill mill and South bend lathe, some screw drivers, wrenches and a hand full of files. So I'd be surprised if any one knows the school of hard knocks better than myself, I wrote the book. I designed both the R2800 and R3600 engines. Today we have a large CNC machine shop and over 1300's radial's sold. We also manufacture 6 types of TBI throttle bodies and Jabiru LCH (Liquid cooled heads) all under the same roof.

Of course like any developing engine we have had our bugs along the way but I can honestly say that spark plug seizure is not a common problem on either the billet or cast headed engines. Keep in mind we have 2 spark plugs per cylinder so on average 16 plugs per engine x 1300 engines sold = That’s nearly 21,000 spark plugs out there.

It could very well be that some earlier heads had a deeper plug recess and this allowed the plug to protrude one or two threads into the chamber. But we have never consciously addressed this.

I've fortunately retained every e-mail we've ever exchanged. When I queried you about the spark plug issue you replied "I've not yet encountered that problem. I have accumulated over 350 hours and 4 years on my engine and have not removed a spark plug. I'll remove one this weekend and get back to you." (you never did)
Members should consider that many owners have not yet run the engines. If they have the early engines and use 100LL, they may well encounter the problem.
As a practicing A&P with over 35 years experience, I can assure you I know how to properly install a spark plug. No amount of antisieze compound will prevent lead fouling on the exposed plug thread.
Please note, it is not my intent to knock the manufacturer or the product. I'm forwarding information learned from my "school of hard knocks".

[paulc]

I think cap01 is referring to a 912 engine here?

Either way I would NEVER recommend using an impact gun to remove a spark plug, tight or otherwise. Way too aggressive on the soft Aluminum threads! The rapid surface speed of the impact gun can set up galling really fast!

If you ever get a tight plug on any engine type, run the engine and get it nice and hot, the Aluminum head will expand a little more than the steel plug. The heat will also soften any crap sticking the threads. If you get one plug out you can then spray some WD40 into the open plug hole. This will work its way into the other plug which may be the tight one?

Slowly work the plug back and forth with plenty of WD40. Once out clean the threads with a new plug tap and use plenty of anti seize compound on the new plugs. Don’t over tighten. You could put spark plugs in with a screw driver handle! No big levers required in my opinion.

they do get tight , i have broken a plug when they break loose they really pop . the last time i tried a impact gun that worked pretty good . only be sure its set for lefty loosie .

[farmboy]

Call me crazy but I have heard of heating the area or object that is seized and forcing a typical wax candle in or around object.The wax hot wax will get sucked into threads and easy as that it will loosen with less force, don't call me crazy but let me know if you have heard of this or if it works.

[Jfquebec]

So.......this spark plug..you need to finish your story.