Originally Posted by
jayseas
Question for you cox .049 guys, i know i can install a TD piston and cylinder on a golden bee.But will it increase the rpms? is there shimming that will have to be done?
Thanks
Jim
Hi Jim, did you ever ask a grand question. First of all, here are the generalities:
Yes, you can install a TD piston, cylinder and the high compression glowhead.
NO, do not just randomly install any number of head shims. Every High compression head has a squish band;
the distance from the band to the inside head chamber must be measured so that you can add that distance
to the head shims to get a total of .012"-.015" deck clearance. The higher the nitro content of your fuel, the more
deck(head) clearance you need, or you'll blow the element out of those expensive #1702 glowheads.
I used this range in my 1/2A Combat engines and got really good reliability, using 30%-38% nitro fuel.
I also used .012"-.014" head clearance in my class 1 reed valve mouse race engines. I got really good reliability and
fuel range using 30% and 40% nitro fuel.
Okay, you're not done; all Cox engines usually need to have the cylinder shimmed to raise the cylinder shelf
that's the thing the glow head with head shims rests against. The piston at top dead center MUST be even
with that cylinder shelf. Later I'll edit in where you can get those brass cylinder shims from. They come in a set
that usually has a .001", .002" and maybe a .003" size shim.
My best reed valve mouse engine would turn 22,500 rpm without breaking, using a breakin test prop.
One last thing, for Reed Valve Mouse racing, DO NOT Drill out the venturi. The more you open it up,
the worse your fuel consumption becomes. I apprenticed Class 1 with Joe Klause and John McCollum that at
the time were one of the top Mouse cl-1 racing teams in the country. They used the small .062" venturi
and added nitro into their fuel, until they got the best acceptable fuel range and speed in their models.
Of course, if you just want to sport fly with your Golden Bee, then you can ignore everything I've suggested.
But please do be mindful of the glow head squish band measurement. That's something everyone with TD
engine setups should be mindful of. Best of luck to you
Tony
Hi Again, The guy you can get TD cylinder shims from sells on ebay. His ebay name is Combatalbert.
Here's a contact link, so that you may ask him about the shim availability.:
http://contact.ebay.com/ws/eBayISAPI...d=371124032089
Best regards....