Tee Dee 049 / 051 Glow Head ID

Surfer_kris wrote:That looks like a DYI job to me...

I do it all the time, but mostly on the .020 heads in order to run well with 10% nitro in the fuel. The mod in the picture looks excessive though, it only takes about the thickness of a head-shim or two.

I'd tend to agree with you, but the six that I have were part of a larger lot of parts and were individually packaged in clear poly bags with three glow head gaskets.

EXModelEngines wrote:

Surfer_kris wrote:That looks like a DYI job to me...

I do it all the time, but mostly on the .020 heads in order to run well with 10% nitro in the fuel. The mod in the picture looks excessive though, it only takes about the thickness of a head-shim or two.

I'd tend to agree with you, but the six that I have were part of a larger lot of parts and were individually packaged in clear poly bags with three glow head gaskets.

Sounds kind of sketchy to me. You might be in for it if you sell them as real TeeDee heads. Better send them to me for verification runs.

The Quality Control Mark

batjac wrote:

EXModelEngines wrote:

Surfer_kris wrote:That looks like a DYI job to me...

I do it all the time, but mostly on the .020 heads in order to run well with 10% nitro in the fuel. The mod in the picture looks excessive though, it only takes about the thickness of a head-shim or two.

I'd tend to agree with you, but the six that I have were part of a larger lot of parts and were individually packaged in clear poly bags with three glow head gaskets.

Sounds kind of sketchy to me.  You might be in for it if you sell them as real TeeDee heads.  Better send them to me for verification runs.

The Quality Control Mark

Can always count on you Mark!

In clarification of my prior statement - I do not necessarily believe these were made by Cox, but based on how they were packaged wouldn't be surprised if they were done by a small aftermarket outfit.

I am pretty sure they were aftermarket Bernie had said at one time something in regards to that and the nurl on top !??! He had had some made up for sale .

If remember y se 50%of the time smaler glow plug les fins on kirn craft 051 modified engines look for kirn craft glow plug modification m'y self did the modification Not that mutch just flush To first fins wit
Just place for 1head chim To seal never see that mutch of hi compresshead machined tink m'y Venom cylinder piston nead 1 like that just To try see if drop rpm or gain

Based on my experiences with other larger engines with similar squish band areas, this usually results in plugs blowing. The Fox MK III, K&B rear rotor .40. This takes the plug element right out of the head. I've had to either add head gaskets and you can only add so many or hemi out the head to smooth out the transition. Fox later offered the double bubble head which was essentially what we see here on the Cox plug but they used a ball mill but didn't remove material all the way to the top. This created a additional step thus being noted as the double bubble. It certainly would be interesting to try but I feel high nitro wouldn't be a good suggestion to use with this plug. I would bet that this Cox plug would work with FAI fuel.

Thanks all!

Matt,
About 10 years ago I bought several large lots of Cox parts from the estate of a 1/2a mouse racer.
There were a number of brand new but modified 1702 heads with some identical to what you have that reduced chamber cc size for high compression and trued gasket surfaces.
The wildest of the bunch had the same surfaces but 1/2 to all of the fins removed with a lathe.
I may be wrong, but my best assumption is that he wanted greatly increased compression and a much "hotter" heat range head for use with very low or no nitro percentage fuel possibly for high ground elevation flying.
Steve...

66 Malibu wrote:Matt,
About 10 years ago I bought several large lots of Cox parts from the estate of a 1/2a mouse racer.
There were a number of brand new but modified 1702 heads with some identical to what you have that reduced chamber cc size for high compression and trued gasket surfaces.
The wildest of the bunch had the same surfaces but 1/2 to all of the fins removed with a lathe.
I may be wrong, but my best assumption is that he wanted greatly increased compression and a much "hotter" heat range head for use with very low or no nitro percentage fuel possibly for high ground elevation flying.
Steve...

Thanks Steve. I will get them listed with your and the suggestions of others in conjunction with the other large group of parts we have to offer.

Matt

EXModelEngines wrote:Has anyone seen this type of TD glow head before? It is an original Cox high-compression glow head that looks to have been modified by turning down the bottom section of the chamber OD which results in a smaller chamber.

I guess the question is was this done by Cox for a particular model (or aftermarket) or a customized version of the head a company or individual might have done on their own?

My Medallion with .051 ungrooved piston has that exact glow head. I will post picture when I get the tool to repair my MacBook.

Happydad.                          

Matt, if you think of it, maybe you could post
on this thread when they're available.
Bob

Matt-if they came in clear polythene bags-of a decent thickness...not cheap cellophane or clingwrap thickness (!) and the bags were stapled closed-then I'd say with 99% certainty that these were Joe Klause glowheads....from the time when he ran Kustom Kraftsmanship...and supplied not only tuned TDs...but a whole range of aftermarket parts for blueprinting and or improving Cox engine performance....in my day dealing with him-80s 90s and early 00s- he only offered these 'shaved heads' for the TD 049/051 ,not any of the other sizes...and just as with the Galbreath Nelson plug head you had to do a bit of fiddling with gaskets to get the ideal clearance...which of course depended on your prop, your fuel and your climatic conditions. I used them quite a bit-especially in Payload...and whilst they burnt out like any other Cox head will do if pushed hard...I don't recall them being any worse in this respect than the standard TD 049 head. Off the top of my head-and I could be wrong, I think I recall Joe saying-in answer to a query of mine-that he took 0.005" off the sealing face of a standard TD head.

Of course Joe offered a lot of other useful items like fine thread NVAs for the TD 020, 049 and 09, cylinder shims and housing for the 049s, backplates with integral pressure nipples for the 049 ond 09, socket head prop screws for the entire Cox range, modified cylinders, and of course the heads currently under discussion-as well as other bits and pieces aimed more at the vintage fraternity...

ChrisM
'ffkiwi'

Ken Cook wrote:           Based on my experiences with other larger engines with similar squish band areas, this usually results in plugs blowing. The Fox MK III, K&B rear rotor .40. This takes the plug element right out of the head. I've had to either add head gaskets and you can only add so many or hemi out the head to smooth out the transition. Fox later offered the double bubble head which was essentially what we see here on the Cox plug but they used a ball mill but didn't remove material all the way to the top. This created a additional step thus being noted as the double bubble. It certainly would be interesting to try but I feel high nitro wouldn't be a good suggestion to use with this plug. I would bet that this Cox plug would work with FAI fuel.

It might-but double bubble heads became de rigeur for FAI combat-which runs 10%...and didn't work anything like as well on std 80:20 FAI fuel-I know because I found out the hard way in F1c in the early 90s...I used to get my old burned out Rossi or Cox insert plugs turned into double bubble nelson plug inserts...whereas the best type turned out to be a straight cone....but of course that was before 'Mr Cyclon'- Aleksandr Kalmykov-came on the scene with his spiral swirl head setups....I still have a box with about a dozen in it. The only advantage was unlike an insert-once you'd got the clearance right-you didn't have to mess around and start again if you blew a plug....and flooding off-certainly in F1C .15s running 28,000rpm+... can be a bit hard on plugs...

Getting good reliable performance out of straight fuel gets trickier the smaller you go...what works in a pylon 40 may well be marginal in a .15....and you're on a hiding to nothing in an 049...

ChrisM
'ffkiwi'

ffkiwi wrote:Matt-if they came in clear polythene bags-of a decent thickness...not cheap cellophane or clingwrap thickness (!) and the bags were stapled closed-then I'd say with 99% certainty that these were Joe Klause glowheads....from the time when he ran Kustom Kraftsmanship...and supplied not only tuned TDs...but a whole range of aftermarket parts for blueprinting and or improving Cox engine performance....in my day dealing with him-80s 90s and early 00s- he only offered these 'shaved heads' for the TD 049/051 ,not any of the other sizes...and just as with the Galbreath Nelson plug head you had to do a bit of fiddling with gaskets to get the ideal clearance...which of course depended on your prop, your fuel and your climatic conditions. I used them quite a bit-especially in Payload...and whilst they burnt out like any other Cox head will do if pushed hard...I don't recall them being any worse in this respect than the standard TD 049 head.  Off the top of my head-and I could be wrong, I think I recall Joe saying-in answer to a query of mine-that he took 0.005" off the sealing face of a standard TD head.

Of course Joe offered a lot of other useful items like fine thread NVAs for the TD 020, 049 and 09, cylinder shims and housing for the 049s, backplates with integral pressure nipples for the 049 ond 09, socket head prop screws for the entire Cox range, modified cylinders, and of course the heads currently under discussion-as well as other bits and pieces aimed more at the vintage fraternity...

ChrisM
'ffkiwi'

Thanks - this is exactly how they were packaged.

dckrsn wrote:Matt, if you think of it, maybe you could post
on this thread when they're available.
Bob

Yes Bob, will do. Right now I am assembling a list of all the parts that was recently purchased. I will probably also post in the for sale area the overall list so the forum members can have an early look since getting everything up on our site might take a bit of time.

Thanks, Matt.
Bob