Kipor spark plug cross thread - Montana Owners Club

dsprik · 07-12-2009, 01:23 PM

Thought I'd throw this out here... I have no pride. I was working on my Kipor 3000 this afternoon and pulled the plug - first time in 3 yrs. It came out kind of tough and when I went to put the new on back in, I had an awful time getting it started. Not smooth at all. I finally started it at the angle I thought it was supposed to go in at and I was wrong. Cross threaded. Tried several more times and it is a lost cause.

Threads in the block are now shot - I have the spark plug out and the threads on it seem undamaged, but should probably not take a chance with it.

Going to the auto store tomorrow, but thought I'd give some experienced MOCers a chance to throw in some advice here. Is there a simple re-tap kit - not expensive - that will do the trick here?

8.1al · 07-12-2009, 02:30 PM

The auto parts store should have a repair kit. It's possible the threads on the plug stick into the combustion chamber and were caked with carbon and this damaged the threads on the way out. use some grease on the tap, this should catch most if not all the chips.

mtpocket2 · 07-12-2009, 03:46 PM

http://www.emhart.com/pdf/Heli%20Coi...%20Rev%204.pdf
Should fix it right up.

OntMont · 07-12-2009, 03:47 PM

"Helicoil" comes to mind. Installing one may not be a DIY project though. I think that you have to drill out the old threads, rethread the hole oversize, and then insert the helicoil to restore the original threads. A good repair shop, or maybe agricultural equipment place should be able to do it.

dsprik · 07-12-2009, 05:24 PM

I have been looking online at these kits and procedures. I would not be confident enough to perform all the necessary steps myself. I also do not want to buy a kit of 6 or so coils that I would never use. Guess I will call around to some mechanic friends I know and see if they have any experience with these helicoils. I was hoping a simple re-tap would work. Not sure that would be the case...

noneck · 07-13-2009, 02:44 AM

Right...helicoil but to do this right should pull the head so debris don't get inside cylinder...

Jolu · 07-13-2009, 03:07 AM

I agree with the others and noneck makes a good point about pulling the head. I have used helicoil more than once on the heads of hi- compression small racing engines with total success. Even small engines that ran a girdle to assist in holding the head on.

dsprik · 07-13-2009, 04:01 AM

Yep. Just returned from the auto parts store. Their verdict: pay $50 for a kit and try it yourself or bring in the head and it's done by them - $15. Now... has anyone tried to get to the head on the 3000 Kipor? Taking it off once I have access is not going to be the labor intensive part.

AND... will I need another gasket? Torque requirements?

Tom S. · 07-13-2009, 04:44 AM

I don't know the torque but maybe this will help. Using the old type beam torque wrench, you can read what torque is required to loosen the bolts. While this may not be 100% accurate, it should get you pretty close. As for the head gasket, most small engine head gaskets are reuseable if there is no breaks or tears in them.

dsprik · 07-13-2009, 05:40 AM

Thanks, Tom! Just getting set to tear into this little project.

ARJ · 07-13-2009, 06:56 AM

If you are going to reuse the gasket, Permatek makes an Ultra Copper silicon gasket maker. You could coat the old gasket with it and you would probably be good to go!

dsprik · 07-13-2009, 08:07 AM

Well, don't have to worry about the head gasket. I spent 4 hrs trying to pull the head and have discovered the tip of the iceberg. I have the covers all off and that is going to have to be what anyone who wants some extra $$ will have to work with...

At least there is a lot better access.

Tom S. · 07-13-2009, 09:32 AM

It can be helicoiled with the head on if it has to be, but I sure would prefer to remove the head if it was mine because of the metal chips that will fall into the cylinder when the hole is tapped out for the new threads. I helicoiled a snow blower head once and when I got rid of the snow blower 20 years later, it was still good. I used red Locktite on the coil and a center punch to stake the threads and I never had one problem with it trying to unscrew when changing the spark plug.

One way you might get away with doing the repair on the machine would be if you turned the crankshaft over until the intake valve is open and the exhaust valve is closed and then put a continuous air pressure source (air compressor) on the intake to keep a steady stream of air blowing out the spark plug hole, thus blowing out the chips as they are cut.

dsprik · 07-13-2009, 11:47 AM

Done! In only 7 1/2 hrs! I was also concerned about the metal shavings, Tom. I drove around a little with my stripped down Kipor in the back of my pickup hoping to find someone to work on it. I know... pretty pathetic.

I talked to the auto parts store, who directed me to the auto repair shop with the idea of borrowing a tap. What my auto repair shop owner came up with was something I had never seen or heard of before. A reverse, expandable tap that catches all shavings on the way back up. This way the tap also starts at the bottom of the thread, where it is still good and it can get the correct start. Then you thread back up the hole towards the outside.

Have to make sure you have room with the head of the piston. Mine was in the wrong position - no room under the threads, so we just took a screw driver and turned the flywheel a little.

Can't remember what he called it, but it was pretty slick. About 4 inches long with a little knob at the top that you tighten to expand the dyes at the bottom after it is in the hole. Kinda like the way those plastic drywall anchors work. Nice clean hole in about a minute and no shanvings in the hole.

ARJ · 07-13-2009, 11:56 AM

Might be a good idea to put anti-sieze compound on the plug before you put it back in.

If you get a chance, find the name of the tap. Probably never need it but would be good to know.

dsprik · 07-13-2009, 01:25 PM

I will try to find that name, ARJ, and I did think of the anti-seize, than forgot when we went to put the plug in. Then remembered when I got back home. Story of my life... I can still pull it, though. The sooner the better...

dsprik · 07-13-2009, 01:37 PM

Here it is. Took me a while to find the right one...

Reverse Spark Plug Re-Thread Tool

Also know as a Reverse Thread Chaser.

OntMont · 07-13-2009, 01:52 PM

That is neat. I don't mind paying a mechanic who knows his tools and trade.

HamRad · 07-13-2009, 01:59 PM

Dave,

Nice! Glad you got it fixed. And what a neat tool that is.

Dennis

ARJ · 07-13-2009, 02:31 PM

Thanks for the info! I wonder if they make it in different sizes.

And-lets see (seize) Oh, i before e except after c. OOPS-How did that go??? I guess its backwards. Oh well, so am I!

You may also like: