Medallion .15 Intake Exhaust Throttle Glow Plug

dckrsn Sat Apr 25, 2020 10:10 pm

I have a Medallion .15 that I've built up from all new parts.
I'm expecting a new thin wall Medallion .15 piston/cylinder to arrive here on Monday. This
will allow me too finally install a spray bar/exhaust throttle on her. I have several
stock .15 glow heads, but was wondering about about conversion plug heads, maybe like
the K&B 7311 idle bar plug with the K&B conversion head. This is uncharted territory for me,
so I thought i'd ask if anyone had any thoughts on this?
Here's the mill in question.

Medallion .15 Intake Exhaust Throttle Glow Plug Win_2011

Thanks brothers,
Bob

Jason_WI Sat Apr 25, 2020 10:20 pm

I have one of the .15 head adapters from MECOA and I had to use 2 head shims on the medallon thick wall cylinder with wrist pin piston otherwise the top of the piston would hit the head. Not sure where the interference was coming from. Just wanted to make you aware of this.

dckrsn Sun Apr 26, 2020 2:29 pm

Thanks, Jason. I'll be sure to look out for that.
I also heeded Ken's advise, and have the Fox .35 head gaskets at hand.
It'll be interesting to see which remedy has the least adverse timing effect
if I need it.
Bob

Ken Cook wrote:Peter, I have seen this many times and it was a very common problem with the Medallion .15. Make certain the piston isn't coming above the glow plug landing. I bet it is by a tiny bit. The solution is to add another head gasket or use a Fox .35 head gasket and shim the cylinder higher. You can place a wire laying it on the plug landing with the plug removed and rotate the engine and see if it pushes the wire off of the landing. However, excessive ball socket play if it is a ball socket version and not a conrod is unrecognized here and that play in itself can cause the piston to just slightly strike the plug causing the problem your experiencing. Ken

dckrsn Mon Apr 27, 2020 8:45 pm

Medallion .15 Intake Exhaust Throttle Glow Plug Win_2012

Single port beauty.
Bob

dckrsn Thu Apr 30, 2020 9:00 pm

Well now............., I faintly remember reading about Medallion .15 case/cylinder size conflicts,
and thought not much of it. As far as I can deduce(love that word), there were 2
different case/cylinder thread sizes. Ouch, I been bitten. DAMMIT!

Bob

All the whining aside, looks like the older .15 Medallion
pistons had aluminum rods.
Bob

Just checked, connecting rod is magnettable.
Bad day, Wah wah. bounce

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Medallion .15 Intake Exhaust Throttle Glow Plug

Medallion .15 Intake Exhaust Throttle Glow Plug

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Re: Medallion .15 Intake Exhaust Throttle Glow Plug

Re: Medallion .15 Intake Exhaust Throttle Glow Plug