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Got it!............... :)

Post  rsv1cox on Fri Dec 07, 2018 1:56 pm

Drilled three 1/8" holes side by side, torch, inserted big screwdriver, twist groan, groan snap.

Saved all but the plastic body, collar, and back plate. With new parts plus cylinder/head I will have all three running again.  

Are spray bars available for these?  Postage/Horseshoes won't fit.  Got plenty of those, but I don't see the Medallions anywhere.







Soaking in warm Hoppee's.  Works great Eric, cleaned up my other two engines nicely.

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Re: Got it!............... :)

Post  Cribbs74 on Fri Dec 07, 2018 2:36 pm

Good job Bob. Hoppes is good stuff.

Some very fine grit sandpaper(1000+) should clean that piston and cylinder right up.
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Re: Got it!............... :)

Post  NEW222 on Fri Dec 07, 2018 4:16 pm

Warmed Hoppes hey? Never heard of that before. I have not even tried Hoppes as it is straight out of the bottle, but I have heard a lot about it.

And Cribbs..... Are you saying to use 1000+ grit sandpaper on the outside of the piston, and inside the cylinder? I thought of that before, but decided against it. Once in the past, myself, I put a piston/cylinder assembly on the crankcase then chucked up the prop screw in my drill. I then placed a tiny bit of ultra fine polish on the sides of the piston through the exhaust, and a tiny bit on top. Ran it for a minute, then flushed it out. I repeated the process again with toothpase and rinsed again. The engine is now a strong runner. Just something I had done, as there is no wrong or right, but rather 'many ways to skin a cat'.
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Re: Got it!............... :)

Post  Mike1484 on Fri Dec 07, 2018 4:23 pm

That is the worst case that I ever seen ! I would put a new crank in it , that crank has seen better days . Can't wait to see this one run again .

Mike1484
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Re: Got it!............... :)

Post  Cribbs74 on Fri Dec 07, 2018 4:29 pm

NEW222 wrote:Warmed Hoppes hey? Never heard of that before. I have not even tried Hoppes as it is straight out of the bottle, but I have heard a lot about it.

And Cribbs..... Are you saying to use 1000+ grit sandpaper on the outside of the piston, and inside the cylinder? I thought of that before, but decided against it. Once in the past, myself, I put a piston/cylinder assembly on the crankcase then chucked up the prop screw in my drill. I then placed a tiny bit of ultra fine polish on the sides of the piston through the exhaust, and a tiny bit on top. Ran it for a minute, then flushed it out. I repeated the process again with toothpase and rinsed again. The engine is now a strong runner. Just something I had done, as there is no wrong or right, but rather 'many ways to skin a cat'.

Your way is fine. Nothing wrong with that. Yes I have used in the past some very fine grade sandpaper to clean up pistons and cylinders. I may be wrong on the 1000+ but It should feel like thick regular paper on your fingers.
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Re: Got it!............... :)

Post  roddie on Fri Dec 07, 2018 4:47 pm

Cool stuff happening here.. but I believe that the diesel-head hasn't been removed from the .051 cylinder yet.. (correct?) I'm really glad that the piston came out of the jug. I don't recall the particulars involved.. but if the rod looks ok.. it would be worth the time to re-check/fit the piston to the cylinder.. reset the socket-joint etc.

I have a notion that the diesel-head is something that you'll want to use. If the compression-screw turns; you may not have to remove the head.. (if it was stuck..)

Kudos on the brute-force removal of the backplate.. Shocked you got it..
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Re: Got it!............... :)

Post  NEW222 on Fri Dec 07, 2018 5:31 pm

Sorry I forgot to add in my earlier post that I'm glad you got it out!
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Re: Got it!............... :)

Post  GallopingGhostler on Fri Dec 07, 2018 6:12 pm

Well I'll be, good job, Bob, anticipate seeing the good in 3 runners returning to service. Thumbs Up Popcorn cheers Beer Cheers
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Re: Got it!............... :)

Post  Dave P. on Fri Dec 07, 2018 6:16 pm

Way to go Bob! Proof that it's not the destination, it's the journey.
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Re: Got it!............... :)

Post  rsv1cox on Sat Dec 08, 2018 12:37 pm

Thanks guys,

The piston out of the .051 diesel didn't make it.  Out of shape and wasted.  I have read references about the line at the bottom but I can't find anything about it on the net or in Sitter's book.



Saved all three crankshafts.  Rust was surface only.



Only the TD had a bakelite disk separator.



Finally removed the glow head from the cylinder on the TD.  Messy.



A .45 caliber bore brush cleaned up the cylinder on the TD.  #1 cylinder with dual boosters and bypass ports.





A second brushing polished the blued cylinders bore.



NVA is from the diesel Medallion.  Used a new venturi, rest is original.



Three running engines.  All have compression and have the original cases, and crankshafts. The TD is all original except for substituting the missing NVA from the diesel Medallion, back plate and collar.  I found a new NVA for the burned up original on the diesel Medallion, and the top ends on the Medallions are from parts. Still need a spray bar for one of the Medallions.  I didn't bother polishing the cases, pitting is to deep.  At least it's consistent.





A learning experience for me.  

Bob
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Re: Got it!............... :)

Post  GallopingGhostler on Sat Dec 08, 2018 1:36 pm

Quite a transformation, Bob, congrats, you turned rotten apples into good apple sauce. I wonder how the Tee Dee crank will perform in the Medallion venturi setup, probably have generously decent performance.
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Re: Got it!............... :)

Post  rsv1cox on Sat Dec 08, 2018 5:20 pm

GallopingGhostler wrote:Quite a transformation, Bob, congrats, you turned rotten apples into good apple sauce. I wonder how the Tee Dee crank will perform in the Medallion venturi setup, probably have generously decent performance.

I'm not sure George, all crank shafts were returned to the original cases. I kept all three engine parts separate from one another.

The Medallion has a different cylinder than the TD. The Medallion cylinder had only one booster per intake, while the TD had two.

Bob
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Re: Got it!............... :)

Post  GallopingGhostler on Sat Dec 08, 2018 5:40 pm

rsv1cox wrote:
GallopingGhostler wrote:Quite a transformation, Bob, congrats, you turned rotten apples into good apple sauce. I wonder how the Tee Dee crank will perform in the Medallion venturi setup, probably have generously decent performance.
I'm not sure George, all crank shafts were returned to the original cases. I kept all three engine parts separate from one another. The Medallion has a different cylinder than the TD. The Medallion cylinder had only one booster per intake, while the TD had two.

Bob, I was just a little curious. I've got a .049 Medallion, still planning to convert to RC with a kit from Cox International. It's a dual bypass non-SPI double slit cylinder set with a rotating exhaust muffler ring. My suspicions is that with non-SPI dual bypasses will provide better power than the original SPI single bypass especially when muffled. Since it has the R/C Bee style silicon muffler cover for muffling, can be easily tried with and without muffling.

I just need to find where I put my engine test stand. It got set aside when I was working on other projects like repairing and modifying Salvation Army Kettle Stands (built new wood frame wind resistant sign stands for them), painting and decorating 55 gallon drums for Christmas food and toy donations, motorcycle and house maintenance repairs.
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Re: Got it!............... :)

Post  Cribbs74 on Sat Dec 08, 2018 6:14 pm

This is something I have been planning to do because of suction problems with a TD. My honest opinion is I don’t think the crank will bring a lot to the party. The Medallion draws fuel well and is a top notch sport engine. Remember the baby clown George?

The Medallion venturi will choke it down on the intake side so any benefit the crank provides on the fuel draw will be somewhat negated.

There is a fudge factor and perhaps the crank opening will allow more air into the equation.

The Medallion engine by itself is a very good performer and with a number one or number four cylinder will really wake the engine up for plenty of fun.

Ron
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Re: Got it!............... :)

Post  Dave P. on Sat Dec 08, 2018 6:30 pm

The crank dimensions are slightly different between the Tee Dee and Medallion too.  The Tee Dee crankshaft is about a millimeter shorter, measured from the nose to the face of the web due to the extra thickness of the web.  I bought some Medallions with the intention of converting them to Tee Dees.  No dice.  The drive plate binds on the front of the case with the Tee Dee crankshaft.  

I haven't tried it yet but I'll bet that a #4 on a Medallion would run pretty strong and still maintain the easygoing Medallion personality.  It might want an extra head gasket or two though.
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Re: Got it!............... :)

Post  rsv1cox on Sat Dec 08, 2018 6:35 pm

Looking forward to you guys posting your results as I have little experience with these.

But, I did tell a story awhile back about not having any Medallions or TD, I found a couple while going through my stuff looking for repair parts for the gruesome threesome. Not pretty, obviously I never paid them much attention during my Enya years.



I will have to find my old beam mount engine stand and compare the repaired engines to the stock Medallion.

Just a side note George. I'm a supporter of the Salvation Army. Doing the most good as the majority of their contributions go to good causes, not just administration. On the news tonight a security camera caught a couple of thieves with bolt cutters cutting the kettles chains and making off with the kettle. Can't get much lower than that. Better make those wood frames steel. Sorry sign of the times.

Bob
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Re: Got it!............... :)

Post  Dave P. on Sat Dec 08, 2018 6:50 pm

Here's a picture of the two different cases, side by side.



You can see that the length of the bearing face is slightly longer on the Medallion case on the top.

Looking forward to hearing about how they run. Really nice work Bob.
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Re: Got it!............... :)

Post  Cribbs74 on Sat Dec 08, 2018 7:10 pm

Bob, what you see is the reason there is a #2 on the case.

There is a crank difference between the two cases. As alluded to by another post.
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Re: Got it!............... :)

Post  NEW222 on Sun Dec 09, 2018 1:31 am

I must now ask. What did you do, or use on the crankshafts? Moreso, I have cleaned a couple up previously, but I am reffering to the very back side with the pin that attaches to the connecting rod. When I got to that part I just lubed it up good and called it just that. Good! Yours look just like factory. Thank you.
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Re: Got it!............... :)

Post  GallopingGhostler on Sun Dec 09, 2018 9:13 am

Cribbs74 wrote:This is something I have been planning to do because of suction problems with a TD. My honest opinion is I don’t think the crank will bring a lot to the party. The Medallion draws fuel well and is a top notch sport engine. Remember the baby clown George?

The Medallion venturi will choke it down on the intake side so any benefit the crank provides on the fuel draw will be somewhat negated. There is a fudge factor and perhaps the crank opening will allow more air into the equation. The Medallion engine by itself is a very good performer and with a number one or number four cylinder will really wake the engine up for plenty of fun.

Ron, I looked at how wide the Tee Dee's crankshaft rectangular intake valve opening is to the Medallion's. Yes, there is more restriction to the Medallion venturi. This gives it better suction feed. However, the Tee Dee then basically gives it no airflow resistance versus some resistance with the Medallion.

It won't be an earth shattering amount, but I believe that there will be some advantage to it, may be say a hundred to several hundred RPM difference. The improvement might be more noticeable when using a non-SPI cylinder set.

The Medallion was purposely downscoped in power by Cox by using the single bypass Babe Bee cylinder-piston set. It is cheaper to mill a round hole in the crankshaft than the rectangular one in the Tee Dee. The front rotary valve design was more free flowing than with the reedies. The hole and crankcase hollow shaft passageway are larger than the reedies. Thus the air-fuel mixture is denser to start, boosted further by SPI.

With the Medallion hole design, the passageway size will vary due to the round hole forming the intake valve action. Greatest intake flow occurs when the hole is immediately below the venturi. With the Tee Dee, as soon as the crankshaft rectangular valve face hits the venturi area, you immediately have more open area versus a sliver of the round hole in the Medallion. Suction is immediate and thus more air-fuel is drawn, giving a greater volume through the valve opening cycle.

I think there will be a boost. It won't be huge, but enough to improve the Medallion's run to put a smile on someone's face. Perhaps one day someone will post their RPM results to give us a heads up on the extent of improvement.

And, I do intend to check how my Medallion .049 performs, first with its earlier Babe Bee single bypass with SPI cylinder-piston to the double bypass without SPI cylinder-piston set with throttle muffler, since I have have a tach. Babe Bee .049  Tired w/ Coffee Read  bounce

Just a little busy now with the Salvation Army's Christmas activities. Cold Lighting The Tree Bad Xmas Gift
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Re: Got it!............... :)

Post  rsv1cox on Sun Dec 09, 2018 10:38 am

NEW222 wrote:I must now ask. What did you do, or use on the crankshafts? Moreso, I have cleaned a couple up previously, but I am reffering to the very back side with the pin that attaches to the connecting rod. When I got to that part I just lubed it up good and called it just that. Good! Yours look just like factory. Thank you.

Bench mounted variable speed wire wheel carefully applied at low speed works wonders.  Did the same on all three rusted crankshaft faces.  The kero/MMO 7 day soak cleaned up the shaft and bearing surfaces with just a Simple Green/toothbrush application.  

Wish now I had paid more attention to the crankshafts machining, but I was so intent on keeping them separate and putting each back together correctly I failed to notice the ports or their configurations.  They will probably all come apart again after running so I will check them then.  

I appreciate the picture Dave.  Big mounting difference between first edition and a #2.  I was lucky to find that new plastic venturi complete with NVA among my spares to replace the one I damaged with the torch. Fit perfectly and self aligns.  Never knew that the case was tapered.  I still can't think of a way to remove it as the screwed on collar really seats it.  

Going to dump that diesel head cylinder in the AF crock pot and boil it along with a couple of other engines.  Never failed me yet in separating frozen parts.  If I can save the cylinder I will just replace the head with a new one and put it back on the Medallion.  I think the diesel head is toast.  

I am really impressed with the way the TD turned out.  Nasty piston and cylinder both cleaned up nicely, and back together I get that nice compression pop when spinning the propeller. Not bad, three engines --- $11.61.  Smile  Fun time worth much more than that for me.  

Bob
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Re: Got it!............... :)

Post  getback on Sun Dec 09, 2018 11:47 am

Good Job !! I just got around to reading this and the engines came out really nice > getting 3 TD / medallion engines for that price is the way i like to deal . A little work can make a big difference in these engines , Bee watching for the report on how they run but am sure they will bee good . If you haven't ran one before your in for some real fun!! Stick one those 4" props on there and let it turn up Eyebrows Popcorn
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Re: Got it!............... :)

Post  rsv1cox on Mon Dec 10, 2018 9:13 am

After an over-night A/F boil in the crock pot I finally was able to separate the diesel head from the cylinder.  Still, not easy.  Two wrenches one on the cylinders top relief the other on the head.  More groan, groan.  Very hot buffered cylinder and wrenches





Does that compression piston just drive out with a drift?  Both are probably toast but may be good for display purposes.

Bob
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Re: Got it!............... :)

Post  Oldenginerod on Mon Dec 10, 2018 3:01 pm

rsv1cox wrote:
Does that compression piston just drive out with a drift?
Bob
Just use the compression screw to drive the contra-piston out- save maybe damaging the thread with a drift.
These type heads probably dont have a super-tight fit as they use an o-ring to seal rather than a machine-fit like "real" diesels. Shouldn't be hard to find a replacement o-ring. Auto parts shop would be best rather than a hardware store.
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Re: Got it!............... :)

Post  rsv1cox on Mon Dec 10, 2018 5:10 pm

Thanks Rod, but I got it using a brass drift and a tapping hammer.  The compression screw and lock were pretty messed up at the time but cleaned up well.  It did have an O ring, seemed to be in good shape so I left it, but I have replacements.  

Same everything except the replaced plastic intake, piston, back plate, and collar.  I had to replace those parts but elected to keep the rest however nasty looking.  I still may be able to save the piston.  Right now there is very little to no compression with the replacement piston.



I surface cleaned my new to me OK Cub Diesel. Was locked up but carefully applied heat and Remoil loosened it up. It has compression but not like that found in a glow plug engine. I couldn't A/F boil it as that would lighten the already light anodizing.

It's marked .049B USA 2179683. I haven't checked my other OK's to see if it's unique to the diesel.


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