"1/2 A" & "1/8 A" airplanes These are the small ones...more popular now than ever.

Cox .049 Pistons

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Old 07-28-2015, 09:10 AM
  #1  
Cross Check
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Default Cox .049 Pistons

Hi All,
I know where to get good advice !

Can I use the many 'single port' pistons I have in 'Dual Port' cylinders? ???

I have many single ports, and they are dependable, and not far behind....

Should I keep pistons/cylinders together?

Or try to mix and Match?

I somehow, know the answer! ! !

Cheers, my Friends,

We are all on the same 1/2A the way there.....

The rest will show up....
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Old 07-28-2015, 10:15 AM
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Jennifer Curtis
 
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If they are old (pre Estes) they started out being
matched. After they are worn they may be "re-matched"
by trying different cylinders, new or worn, to find ones
that fit the pistons tightly. This doesn't get you much,
but a stack of pistons that are too small and cylinders
that are too big.

If they are Estes or later, they are not matched, and
if they come new with a really sloppy fit, you can match
with another new or used one for better fit and get
much better performance.

All pistons/rods for each size are basically the same.
They just vary in size slightly due to manufacturing
differences.

Jenny
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Old 07-28-2015, 03:08 PM
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GREG DOE
 
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I've swapped out many pistons and cylinders, but all were pre Estes. As Jenny pointed out, just check the fit, and performance. If everything is close, you should see an increase in performance, and fuel consumption when you go from a single bypass to a dual bypass cylinder.
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Old 07-28-2015, 03:18 PM
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Jennifer Curtis
 
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Right you are.

I forgot to mention that going from single to multi
port does make a difference, a big one. Also sub
piston induction will make a difference. Not all of
the cylinders are timed for it. It think some of the
reed valve engines don't have it. I never noticed
a big difference between open exhaust port
and dual slit port but there is some difference.

I also noticed that the best engines run better and
better until suddenly they wear out. They really
scream just before they are done. Sometimes you
can mix and match these "done" parts and get
back some performance, but it is never as good.

Jenny

Last edited by Jennifer Curtis; 07-28-2015 at 05:29 PM.
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Old 07-31-2015, 10:43 AM
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What she said.
With the cox engines, the tightest fit doesn't mean the best running motor. I've also found that re-setting the rod always made more of a difference than cylinder\piston fit.
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Old 07-31-2015, 12:30 PM
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I guess it's safe now to reveal a "secret" since I most likely won't be racing any of yuse.

When choosing pistons from your quart Mason jar full of pistons (You do have at least one jar full of used pistons don't you?) tweak & lock your mike to the size that allows the piston to just slide through with a slight drag. I have the number written inside the lid of my mike box but it's been a while and I've forgotten it now. Anyway, check each & every one in at least 2 places to cull out the ones that aren't ROUND. You'll quickly get a feel for the slight drag on the 1st check, rotate 90 deg & it either flops through or grabs. The good ones feel the same wherever they're checked. Most fellers forget that pistons must be round to seal properly and many of them are not actually round.

Pick a few ROUND, unscratched pistons, reset the rod & select fit them to twin fluted cylinders that allow the pistons to move up & down freely (dry) with a little drag at TDC and let me know how it goes.

Mix & match them long enough & once in a while you'll get one that's pure magic. Broad needle, great fuel draw, amazing mileage & fast enough to lap your buddies at least once per tank.
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Old 08-01-2015, 12:45 PM
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Hi All,
I was expecting a Yes/No answer, got Yes !

Did not expect the 'Cream of the Crop' of Cox performance Experts to reply....
I Thank You! Very Much ! I learned alot !

Going for a consistant run, more than 'see what it will do' performance...
My goal is to fire up the 'pre Estes' stuff, I have....

Soaking engines as I type.
The fun part is....

Telling the Neigbours who complain....
Methanol and Castor oil is....Solar Powered !
And how the Cox.010, is the most powerful engine/wt on earth.
Electrics, are wasing thier, time...

Cheers My Freinds,

Dave 'Cosscheck'Fallowfield
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Old 08-05-2015, 11:05 PM
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Cross Check
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Thanks All,
Got mild, medium and hot, Cox .049reedys, ready for the bench !
My BernieCox International piston reset tool is awesome!

I have some 'dual port/dual slit exhaust' cylinders that I cannot take apart.
I'm thinking filing/grinding flats on the top end, to match the Cox wrench I use on others.

Thanks for the hints and tips !

Some people like 'Vroom Vroom' , others, a steady decline of battery power.

I go: 1.5V/flip prop, weeeehwweeehweeeeeeeehweeeeeeehweeeeeeeeeeeeeeeeee e.burp E,E,E!e!e!...Deadstick Glide.

Cheers my friends,
Dave'crosscheck'Fallowfield
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Old 08-06-2015, 02:08 AM
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Jennifer Curtis
 
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Try using a torch on the crankcase before
grinding the cylinder.

Jenny
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Old 08-07-2015, 05:34 PM
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A leather strap with a dowel to wrap around the cylinder is an old way to remove a tight cyl. with no damage. I milled a few of my old cylinders because i did not like using the wrench in the port.
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Old 08-12-2015, 05:34 PM
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Cross Check
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Hi All,
Thanks for the hints and tips...
I'll save those 'wierd cylinders' till later... (Good project for my Dad, he loves projects for his lathe/mill...)

Bladders, bench run, I'm good to go.
Now, I know how big to make the firewall,
Now, I can figure out,
How to match the engines to the wing....
Then make them fly !
Cheers,
Dave'crosscheck'Fallowfield
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