enlarging spark plug hole
 

Hi Guy's, I am working on doing a gas/glow conversion on a Stihl, 65cc, 4-stroke. The problem is the spark plug hole is for a 10mm plug. I need to enlarge this to standard plug size so my glow plug adapter will fit. I am actually looking for someone who can do this since I do not have the tools or skill to re-drill and re-tap the hole. I tried contacting Mark Brielli but no response so far. Suggestions please. Thanks for your consideration.

RE: enlarging spark plug hole
 

Probably cheaper to get another adapter that does what you need.

RE: enlarging spark plug hole
 

Okay, where do you suggest I find a 10mm adapter?

RE: enlarging spark plug hole
 

Call these people

http://www.ch-ignitions.com/ord.html

RE: enlarging spark plug hole
 

Yep we gottum.

RE: enlarging spark plug hole
 

John,
DO NOT enlarge the hole! The plug hole is VERY close to the valve seats/valves and running a drill/ tap through there will almost certainly hit them. As you may have noticed the head and cylinder is one unit and it is darn expensive to replace.

John

RE: enlarging spark plug hole
 

Excellent TKG, Just to re-confirm you have a 10mm glow plug adapter that will fit the Stihl, 65cc, 4-stroke? You'll have my order soon. Thanks.

RE: enlarging spark plug hole
 

Our 10mm to 1/4x32 adapter has the same threaded length as the CM-6. If your head depth matches your OK, if not you may need to machine the head

RE: enlarging spark plug hole
 

The stock plug for the Stihl 65 is an NGK CMR6H, which has a longer threaded length than the CM6. If there is an adapter for a Zenoah G-26, that MIGHT be the way to go.

J

RE: enlarging spark plug hole
 

Okay, thanks guy's, J glad you added that about the valves being too close. Really didn't want to machine the head.

RE: enlarging spark plug hole
 

The CMR6H is a very long reach and our adapter won't work. So you're going to have to spot face cylinder.

RE: enlarging spark plug hole
 

I'm real interested in how this works out for you. Please keep this going as I have a 32cc that would consider converting if you have good luck on gas glow.

Jim

RE: enlarging spark plug hole
 

Please explain,"spot face" the cylinder. Do you offer this service?

RE: enlarging spark plug hole
 

You take a big end mill and you start milling (cutting) untill the thread depth is correct. Zenoah does this on the cylinder for the G-26 EI. The G-26 magneto uses the CMR7H, so they face it down and install the CM-6 in the EI version.
WE DO NOT OFFER THIS SERVICE. Unless you know sombody who works at a machine shop and can do this on the side after you take the engine apart. You might be better converting it to EI and run just gas.