Log in
Search
Latest topics
» Fox .09 Rocket Acquisitionby GallopingGhostler Today at 12:15 am
» Cox works tuned engines
by --Oz-- Yesterday at 9:43 pm
» Follow Rusty's Memorial Traveling Engines!
by GallopingGhostler Yesterday at 9:23 pm
» Guillows Typhoon CL job...not mine
by GallopingGhostler Yesterday at 7:55 pm
» cannot do Lazy 8s or Inverted with plane
by Yabby Yesterday at 4:58 pm
» Half A Starter Question
by SABOO Yesterday at 1:06 pm
» I have just bought a new Enya 15 CX
by Surfer_kris Yesterday at 5:57 am
» Cox Sure Starter
by davidll1984 Sat Mar 18, 2023 2:35 pm
» Just won a Cox .15 Sportsman
by MauricioB Sat Mar 18, 2023 11:45 am
» New Aluminum Backs
by Ken Cook Sat Mar 18, 2023 9:26 am
» And another geared twin is born...
by getback Sat Mar 18, 2023 7:27 am
» Cox Brushless
by getback Sat Mar 18, 2023 6:54 am
What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
Page 1 of 1
What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
As the title says, what are the differences between the Cox .09 TD and Medallion pistons/cylinders? Note, I am asking about the .09, not the .049. Thank you in advance to all you Cox enthusiasts.
mnarigon- Beginner Poster
- Posts : 5
Join date : 2020-10-09
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
TeeDee cylinders have tapered bore and 2x2 extra booster flutes in their bypass ports. Medallion cylinders are straight and have no boosters. This and the larger aperture on TeeDee cranks for fuel/air transfer add a massive surplus power to TeeDee-s. I mean 09-s too not just 049-s
balogh- Top Poster
Posts : 4347
Join date : 2011-11-06
Age : 64
Location : Budapest Hungary
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
I no longer own a Medallion .09. I have 3 TD .09's and they have sub piston induction as well. I'm pretty certain the Medallion doesn't offer sub piston induction on that cylinder. There's also a good chance that early TD cylinders had a tapered ground bore as well.
Ken Cook- Top Poster
- Posts : 5102
Join date : 2012-03-27
Location : pennsylvania
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
Thanks for the info.
mnarigon- Beginner Poster
- Posts : 5
Join date : 2020-10-09
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
And one more salient point-the Medallion 09 cylinder-in standard (ie FF or CL) form only has one transfer flute.....the R/C one has two.....likewise the Medallion 15
ChrisM
'ffkiwi'
ChrisM
'ffkiwi'
ffkiwi- Gold Member
- Posts : 278
Join date : 2018-07-10
Location : Wellington, NZ
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
I have a couple of used Medallion .09's. There is no provenence with them, but I can look to see what they were most likely built with.
944_Jim- Diamond Member
Posts : 1712
Join date : 2017-02-08
Age : 58
Location : NE MS
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
Thank you. I have a Cox .09 TD that has a damaged connecting rod. Since these appear to be very rare, from my question I was trying to determine whether an .09 Medallion might be a suitable donor. From the above comments, it appears not. However, searching on the web I didn't find any information on .09 pistons/cylinders so having a summary in this thread might help someone in the future.
mnarigon- Beginner Poster
- Posts : 5
Join date : 2020-10-09
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
I bet the piston and rod are about the same. It was the cylinder that got the taper bore and extra transfer flutes. I'll tell you what...you show us yours, and I'll show mine. I can have the Medallions popped apart first thing in the am. My build room is unheated, and it is uncomfortably cold in there right now.
Oh,.and I have calipers if you want OAL from piston crown to conrod end. Or crown to skirt.
Oh,.and I have calipers if you want OAL from piston crown to conrod end. Or crown to skirt.
944_Jim- Diamond Member
Posts : 1712
Join date : 2017-02-08
Age : 58
Location : NE MS
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
pistons and rod lengths are the same
Ken Cook- Top Poster
- Posts : 5102
Join date : 2012-03-27
Location : pennsylvania
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
I took some photos and measurements of the Cox .09 TD that I have.
The piston length is 0.4980 inches crown to skirt and the total length from crown to connecting rod end is 1.1690 inches. The piston diameter is 0.4965 inches with no detectable taper from crown to skirt.
The cylinder has twin bypass ports with no boost ports. The top fin is not milled. At the crown, the cylinder diameter is 0.4950 inches and at the skirt the diameter is 0.4980 inches, showing a measurable taper in the cylinder. The piston/cylinder combination has SPI as shown in the last photo.
The cylinder looks OK, but the connecting rod was damaged (together with the backplate and crankshaft, notice the galling on the crank pin and the abrasions on the connecting rod end, but I have found replacements for the backplate and crankshaft.)




The piston length is 0.4980 inches crown to skirt and the total length from crown to connecting rod end is 1.1690 inches. The piston diameter is 0.4965 inches with no detectable taper from crown to skirt.
The cylinder has twin bypass ports with no boost ports. The top fin is not milled. At the crown, the cylinder diameter is 0.4950 inches and at the skirt the diameter is 0.4980 inches, showing a measurable taper in the cylinder. The piston/cylinder combination has SPI as shown in the last photo.
The cylinder looks OK, but the connecting rod was damaged (together with the backplate and crankshaft, notice the galling on the crank pin and the abrasions on the connecting rod end, but I have found replacements for the backplate and crankshaft.)




mnarigon- Beginner Poster
- Posts : 5
Join date : 2020-10-09
Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?
The piston looks scored pretty bad . Can't tell about the cly.
getback- Top Poster
Posts : 9405
Join date : 2013-01-18
Age : 65
Location : julian , NC

» (Both sold) New Cox Medallion .15 cylinders and pistons
» Fitting Cox .049 pistons to cylinders..
» ISO plans for a V Twin glow engine using Cox 049 cylinders, pistons, glowplugs
» The truth about .051 Medallion pistons
» Aluminum Cox .049 Pistons
» Fitting Cox .049 pistons to cylinders..
» ISO plans for a V Twin glow engine using Cox 049 cylinders, pistons, glowplugs
» The truth about .051 Medallion pistons
» Aluminum Cox .049 Pistons
Page 1 of 1
Permissions in this forum:
You cannot reply to topics in this forum