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Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question. Babe_b10
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Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question. Empty

Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question.

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Help! Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question.

Post  Cryhavoc on Wed Aug 19, 2020 9:07 am

Now that I have a little time, I've been pulling out my Cox collection and refurbishing them. I've got a couple questions;

1) On the the newer tanks with the plastic reed valve keeper, is the paper gasket still actually necessary as well?
2) Did the TD.15 Special mkI have a gold or silver needle valve body? I can see clearly they had silver crankcase and gold prop drive but can't seem to find a definitive answer or pic about the needle valve body.

Thanks,
Mike
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Help! Re: Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question.

Post  getback on Wed Aug 19, 2020 9:39 am

Yes to #1 actually not a bad idea to put one one both sides . #2 all i can tell you is look at this pic Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question. Screen66
From Here > http://www.mh-aerotools.de/airfoils/cox_frameset.htm Looks like both ? Good to hear you got some spare time This Site Rocks!
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Help! Re: Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question.

Post  EXModelEngines on Wed Aug 19, 2020 10:09 am

Little extra detail on Question 1:

Cox was sporadic with using crankcase gaskets with the 'flanged' plastic reed retainer. Technically you do not need them since the plastic is flexible enough to form to any imperfections in the crankcase, but certainly not a detriment to use them. For engines with an aluminum tank (Babe Bee, Black Widow, etc.), I would encourage to use two gaskets (one under and one above). This is two-fold: the production on some of our newer tanks was causing some bending of the reed with this retainer so placing underneath helps to provide a little extra cushion and helps to square up the retainer when assembling.

Matt
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Help! Re: Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question.

Post  Cryhavoc on Sat Aug 22, 2020 6:47 am

getback wrote:Yes to #1 actually not a bad idea to put one one both sides . #2 all i can tell you is look at this pic Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question. Screen66
From Here > http://www.mh-aerotools.de/airfoils/cox_frameset.htm  Looks like both ? Good to hear you got some spare time This Site Rocks!

Yeah I've been all through this website. I've noticed he tends to show whatever he can get his hands on. I've seen pics with the gold one as well. Just wondering if there was a definite answer. The one I have now has a gold one but its not new in the box so was wondering if it added by a user.
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Help! Re: Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question.

Post  Cryhavoc on Sat Aug 22, 2020 6:50 am

EXModelEngines wrote:Little extra detail on Question 1:

Cox was sporadic with using crankcase gaskets with the 'flanged' plastic reed retainer. Technically you do not need them since the plastic is flexible enough to form to any imperfections in the crankcase, but certainly not a detriment to use them. For engines with an aluminum tank (Babe Bee, Black Widow, etc.), I would encourage to use two gaskets (one under and one above). This is two-fold: the production on some of our newer tanks was causing some bending of the reed with this retainer so placing underneath helps to provide a little extra cushion and helps to square up the retainer when assembling.

Matt

Interesting, So if I check the tank and crankcase with some blue Dykem and it shows square then it should be alright to just use the plastic retainer?

Thanks,
Mike
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Help! Re: Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question.

Post  balogh on Sat Aug 22, 2020 8:34 am

I too was wondering if it is good or not to put gasket between the flanged retainer cap and backplate. Adding a gasket will extend the travel span of the reed that may not seal instantly after the piston leaves the TDC and some fuel-air mixture may be pumped inadvertently out from the crankcase. I am not sure, just guess...
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Help! Re: Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question.

Post  Iceberg on Sat Aug 22, 2020 10:56 am

I tried not using a gasket on the backplates under discussion. I found after trial and error that my motors ran better WITH the gasket. I placed the gasket on top of the retainer cap. Not under it hence NOT affecting the reed travel length. Not sure the reason why it improved. However one of my widows has the newer tank with the cap. W/O the gasket I was getting performance parasitic loss. I did sand the back of the crankcase with micro fine paper and all but problem persisted. But after the gasket it improved a fair bit. That is what I found. Whether others found that or not that was my finding.

Thanks
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Help! Re: Do newer plastic reed cage still need paper gasket? And TD .15 Special MkI question.

Post  balogh on Sat Aug 22, 2020 1:40 pm

Darren I guess metal to plastic mating will not result in good seal, but plastic to plastic will. The combo of  alu crankcase and plastic cap will not seal unless you place the gasket in between. Whether the gasket between the plastic backplate and plastic retainer makes sense makes me wonder, not just because plastic surfaces may seal well if pressed even without a gasket, but because of the longer reed travel. Just my 5cents..
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