Re: Tee Dee .09 rebuild.. and run!

MauricioB Thu Oct 19, 2017 9:41 pm

Tee Bee wrote:I checked and neither the TD or Med piston had an oil passage hole like yours. Maybe it's a year thing?
While I was at it, I went ahead and attempted to straighten the rod just as you did. With just a bit of pressure, it snapped in two. It probably already had a stress crack. It was worth a try, though. The engine has been remounted to the plane for another go next week when I get another day off. A perfectly good Medallion has been relegated to the spare parts box until I stumble onto another piston. As for fuel, I use Sig Champion 25. I buy it in quart bottles and add 1.5 fl.oz. extra Klotz castor oil. It has served me well for many years in all my Cox engines for sport flying and I don't think the rod failure had anything to do with the mix.

That hurts my friend! What a shame to see the connecting rod broken, here in my country you would have run out of power since it is very difficult to find any part!
I suggested using the method of the bench vise as it makes the effect of a press and can gradually control the pressure, the clamp is a system of levers and multiplies the force, which many times we can not control ... even the supports are of hardwood, thing that make of fuse !!!! and the connecting rod does not suffer consequences! '...... it is also true that he may have been fatigued .... in short they are part of the experience of each one, this did not go well! ....

Tee Bee Thu Oct 19, 2017 10:07 pm

Mauricio, I would have considered your press technique but my rod was bent inside the piston skirt just below the ball/cup. I was unable to gain the leverage needed for that technique. It snapped at the base of the skirt just below the bend. As for another piston, it seems this hobby is a never-ending scavenger hunt. Smile

MauricioB Thu Oct 19, 2017 10:15 pm

Tee Bee wrote:Mauricio, I would have considered your press technique but my rod was bent inside the piston skirt just below the ball/cup. I was unable to gain the leverage needed for that technique. It snapped at the base of the skirt just below the bend. As for another piston, it seems this hobby is a never-ending scavenger hunt.

I understand, maybe use the clamp, but giving pressure with the bench vise .... the subject is to have control of applied force ......... it hurts ..... it's like sand in the eyes ... now ... now to find another solution or replacement.
The theme is that there must be lots of things out there stored by users ... so it's not complicated like here to get anywhere ... maybe that's why it hurts so much !! Sad

balogh Fri Oct 20, 2017 12:25 am

Roddie, Troy

vintage TD049 and 09 engines from the first generation had the oil holes on the crankpin end of the rod. My oldest 049 has it but neither of the later engines has it.
COX may have realized the hole did not add too much to the lubrication given the loose fit of the pin in the rod end that in itself already allows oil to reach the mating surfaces and gave up with it to save costs.

My TD051 with the longest service history of near 300 hours still has its rod to pin connection as new without the oil hole.

Tee Bee Fri Oct 20, 2017 12:55 am

Interesting. Sooo many variations of the same engines and parts over the years!

roddie Fri Oct 20, 2017 10:25 am

balogh wrote:Roddie, Troy

vintage TD049 and 09 engines from the first generation had the oil holes on the crankpin end of the rod. My oldest 049 has it but neither of the later engines has it.
COX may have realized the hole did not add too much to the lubrication given the loose fit of the pin in the rod end that in itself already allows oil to reach the mating surfaces and gave up with it to save costs.

My TD051 with the longest service history of near 300 hours still has its rod to pin connection as new without the oil hole.

Thanks for that Info Andras!! I can understand the reasoning. The machining of the Cox piston-rods must have been an intricate process in itself.. without having to "fixture" and drill that oil-hole afterward.

fredvon4 Fri Oct 20, 2017 1:31 pm

Do not know what a used PC .09 set is worth but I do run throught the RC Groups wants adds once a week

There is a Medallion .09 for $35 that I bet the guy would take $30 for...been there a while with no contact to the seller

You should also pay attention to the use engine LOTS that are always there... on time I got 20 engines for less than $2 bucks each with shipping... yes most of the junk was junk... but I did get 11 good no broken ear metal Cox back plates and a bunch of original beryllium/copper Star reeds that I like

balogh Fri Oct 20, 2017 1:59 pm

You may be interested in this...I assume this will end its auction around 35-40 USD and is a complete 09 said to be in very good condition...

https://www.ebay.com/itm/Cox-Tee-Dee-09-Glow-Engine/382253333729?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D41375%26meid%3De63ed8417b7541c69a66f95707fa8999%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D282695460311&_trksid=p2047675.c100005.m1851

roddie Fri Oct 20, 2017 2:12 pm

fredvon4 wrote:Do not know what a used PC .09 set is worth but I do run throught the RC Groups wants adds once a week

There is a Medallion .09 for $35 that I bet the guy would take $30 for...been there a while with no contact to the seller

You should also pay attention to the use engine LOTS that are always there... on time I got 20 engines for less than $2 bucks each with shipping... yes most of the junk was junk... but I did get 11 good no broken ear metal Cox back plates and a bunch of original beryllium/copper Star reeds that I like

Yes.. those Bee parts are good to have spares of for sure! As for Cox .09 engines.. The Tee Dee is the only one I have.. and it's "new to me". If it turns out to run ok with its "rod-issue".. I may look for some spare-parts like another P/C set, Cox 7 x 3.5 props and spare glow-head(s). I like the AL carb-body that ExModel engines/Matt sells.. but it just wouldn't be a wise purchase unless I can find another P/C set. A rod-reset tool would be nice too... but the only income that I'm generating right now is coming from band-gigs. silent

roddie Fri Oct 20, 2017 2:23 pm

balogh wrote:You may be interested in this...I assume this will end its auction around 35-40 USD and is a complete 09 said to be in very good condition...

https://www.ebay.com/itm/Cox-Tee-Dee-09-Glow-Engine/382253333729?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D41375%26meid%3De63ed8417b7541c69a66f95707fa8999%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D282695460311&_trksid=p2047675.c100005.m1851

That seller has a LOT of glow-engines for sale..

https://www.ebay.com/sch/m.html?item=382252659490&_ssn=edatzia&rt=nc

Tee Bee Fri Oct 20, 2017 3:31 pm

Good points. My internet search results for new .09 pistons mostly resulted in finding others also looking for them hopelessly. At least the Medallion pistons will work in the TD and complete Medallions can be found at somewhat reasonable prices as pointed out. In fact, I purchased one this morning. Smile

It still bothers me since I've now got another otherwise fine engine in the box that needs a piston. In my recent quest to put together a few more usable TD .020s and spare parts, I had to use the same technique of aquiring some decent Pee Wees for donor pistons and cylinders. While that gets the job done, I now feel a bit sad for those Pee Wees in need of a top end. Trying to make all your Cox parts add up to complete engines can make you bonkers and financially broke. Anyway, the good thing about all this .09 nonsense is that it has given me the desire to add a Medallion .09 powered sport plane to the build queue. I flew a Pong Two for years with one of those and had a blast with it. Without a throttle sleeve, I found you could tune the engine RPMs with head selection/compression. I ran it with stock Medallion, TD, glow plug conversion, and turbo glow plug conversion heads. The engine ran fine with either setup but put up different power and RPM performance accordingly. With the glow plug conversion head, the Pong Two with Med .09 made a nice and easy 2-channel trainer that helped my son learn to fly. With a Turbo plug or TD head, it was noticeably more powerful and fast. I'm thinking that a Sig Hummer or something along those lines would be fun with the easy-going Med .09 on it. Like most model builders, I think of projects way faster than I can actually get them done.

crankbndr Fri Oct 20, 2017 3:52 pm

I didn't read very far back so forgive me if I missed it but how did you determine a Medallion piston will fit the TD? My Medallion 15 pistons won't go past the exhaust ports of my TD 15s before they tighten up. I needed pistons for my TD cylinders and was hoping Medallions would work but no dice.

Tee Bee Fri Oct 20, 2017 4:32 pm

That's interesting. I have a used Med .15 and a NIB TD .15 but no mechanical experience with them at this point. To be honest, I simply laid out a TD and Med .09 piston side by side. The dimensions were the same so I reassembled the TD with the Med piston and gave her a few hand flips. Felt good so I mounted the engine back in the plane. We'll see how she runs soon. I'm working 12hr shifts again for now.

crankbndr Fri Oct 20, 2017 5:27 pm

Ya, if it fits and flips should be fine. I figured the TD cylinder is tapered and my piston not. the two later model TD 15s had iron pistons I believe, the Special and Mark II.

roddie Sun Oct 22, 2017 5:10 pm

I got the engine running today.

https://www.youtube.com/watch?v=z4fr6Isu7qw

balogh Sun Oct 22, 2017 5:32 pm

A very healthy run at length...congratulations Roddie.

roddie Sun Oct 22, 2017 6:01 pm

balogh wrote:A very healthy run at length...congratulations Roddie.

Thank You Andras! I had come close to giving up. I shot an earlier frustrating 17min. vid that was bewildering to say the least. I flooded the engine several times... flipped and flipped and flipped. I couldn't tell where the needle-setting was. The knob is so small, I couldn't see the registration-mark. I ran an .049 product-engine earlier.. and my tach wouldn't read.. so I didn't bother trying to get any #'s on the Tee Dee. I was just happy that I got it going.