What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

mnarigon Mon Jan 11, 2021 2:16 pm

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.

balogh Mon Jan 11, 2021 4:59 pm

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

Ken Cook Mon Jan 11, 2021 5:12 pm

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.

mnarigon Mon Jan 11, 2021 7:41 pm

Thanks for the info.

ffkiwi Fri Jan 15, 2021 7:22 pm

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'

944_Jim Fri Jan 15, 2021 8:24 pm

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.

mnarigon Fri Jan 15, 2021 8:38 pm

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.

944_Jim Fri Jan 15, 2021 10:36 pm

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.

Ken Cook Sat Jan 16, 2021 8:42 am

pistons and rod lengths are the same

mnarigon Sat Jan 16, 2021 12:15 pm

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.)

What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders? Img_1210

What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders? Img_1211

What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders? Img_1213

What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders? Img_1215

getback Sun Jan 17, 2021 9:17 am

The piston looks scored pretty bad . Can't tell about the cly.

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What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?

Re: What are the differences (if any) between Cox .09 TD and Medallion pistons/cylinders?