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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Wed Sep 14, 2011 2:50 pm 
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Location: Indianapolis, IN
Frank
This is the tool that is required to tighten the fit of the rod ball end in the piston socket on Cox engines. The piston sets in the Anvil and you tap the punch with a light hammer. The .049/.051 and the .020 tools are all steel but the Anvil on the .010 Set is a hard plastic like material.

I would loan them to either of you.
Clancy


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File comment: Cox tool set
Cox tool set.jpg
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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Wed Sep 14, 2011 5:31 pm 
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Mine is from Davis Diesel, and looks a little different.


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new stumpy 003 (600 x 450).jpg
new stumpy 003 (600 x 450).jpg [ 20.3 KiB | Viewed 2832 times ]

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Wed Sep 14, 2011 7:30 pm 
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Frank
The trick to using these tools is to keep moving the punch around the rod. Look at the picture Ray posted and see that the bottom of the punch is concave. You need to keep moving the punch so that the gap where the rod is held does not stay in the same place causing an off center rod connection.
Clancy

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Wed Sep 14, 2011 9:51 pm 
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ConVEX, not conCAVE...in other words it pooches out slightly in the middle. Not unlike many of us. It's to support the center of the piston, where you're pounding (uh, tapping).

The way I remember: conCAVE, like a "cave", curves away from you...so conVEX curves toward you.

Edit: Sorry Clancy, I was thinking of the anvil (with its convex shape) while you were referring to the punch (with its concave end). You are right. Correction corrected.

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Last edited by minnesotamodeler on Thu Sep 15, 2011 10:36 am, edited 1 time in total.

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Thu Sep 15, 2011 8:47 am 
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Guys I'm not just feeling left out in the dark. I am in the dark.
When you say rod to piston are you talking about the thingie that connects the piston to the crankshaft?
I'm sorry about being so dense. :roll: Please enlighten me.
Also could you get a picture of the punch in action? I'd like to see what part of the engine it punches.

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Thu Sep 15, 2011 10:32 am 
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You're kidding, right?

Just in case you're not, the "rod" is the bar from piston to crankshaft. It fits over a pin on the crankshaft, and ends in the piston in a ball-and-socket joint. that's why cox pistons can rotate in the cylinder. the piston contains the "socket" part of the joint, and the rod has a "ball" on the end that fits snugly into the socket. Often after a few break-in runs (and sometimes direct from the factory) the ball loosens in the socket and develops some play. It'll run quite a while that way, though not as well as it could; till finally the joint gets loose enough, giving the ball lots of play to pound against the piston, that it will break thru the piston crown (I have first-hand experience of this phenomenon).

To prevent that, the ball must be "reset" in the socket...that's what the tools pictured are for: You set the piston, top down, in the anvil with the rod sticking up. Insert the punch (with the conCAVE end, Clancy, you're right, I was thinking of the bottom of the anvil) into the underside of the piston, with the rod going through the slot on the side to keep it out of harm's way, so the cupped end of the punch rests on the socket flange inside the piston. Whack it (um, tap it) with a hammer a few times and it compresses the socket so the ball has little or no play. Usually doing this operation once or twice in the beginning suffices for the life of the engine. I think the socket gets work-hardened so it doesn't give under running stresses any more.

Obviously it takes a different-sized set of tools for each size engine. so Clancy is offering the loan of his .020 and .010 sized tools to reset the little guys, which I've never done. Never broke one yet either. But they may run better with tighter rods, so I may take him up on it. that's possibly why the .020 I sent you ran so unreliably, I'm gonna pull it apart and check it.

That oughtta be enough enlightenment for one day.

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Thu Sep 15, 2011 10:42 am 
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Frank
This is a sketch of how the Piston and Rod are assembled in a Cox engine. In place of a Wrist Pin they place the ball end of the rod in a cup inside the piston and then form the sides of the cup around the ball to retain it in the socket. The forces of running the engine has a tendency to open the cup so periodically the cup needs to be re tightened around the ball on the end of the rod. This is the tool designed to perform that tightening operation properly.
Clancy


Attachments:
Cox Assy. (454 x 185).jpg
Cox Assy. (454 x 185).jpg [ 12.84 KiB | Viewed 2809 times ]

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Thu Sep 15, 2011 11:38 am 
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I'm up to speed now guys. Thankyou very much. I've never known anything but that a wrist pin held the con-rod to the piston. The cup and ball set up is a brand new concept for this ole brain of mine.

Ray, I panicked and called Clancy (left a message on your machine for you also) Anyway Clancy is sending me a Cox .049 that I can screw into Dil-Bod and put up the proper qualifying flights next week. Then I'll send Clancy his engine and you your plane. Hopefully I'll be able to send a certificate or two along with Dil-Bod.
This is turning into an adventure. :D

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Thu Sep 15, 2011 8:13 pm 
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Frank
The engine is in the box and will go to the Post Office in the morning.

I have included in the box three props for you to use.
A Cox 5 x 4 and two Cox 4 1/2 x 4 Props. On the front of the hub of the 4 1/2 x 4 props is a warning "Do not use on RR-1, Space Bug, Thermal Hopper."

Throw the Nitro to it and go racing!!
Clancy

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Fri Sep 16, 2011 9:26 am 
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Clancy, I believe you have saved the day. :D Thankyou.

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Fri Sep 16, 2011 11:02 am 
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Those 4 1/2 x 4s sound like the ticket. But try them all, including what we talked about last night.

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Mon Sep 19, 2011 4:22 pm 
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Clancy----the engine got here today. It looks good and has compression. As you can see in the pictures I've got some Cox fuel. Thankyou Clancy. It's raining today but tomorrow will be dry and I'll get to work on Dil-Bod.
That was quite a box you sent it in. Kinda like a cardboard Fort Knox.

Ray---I will try all the props. :D


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Engione from Clancy 003AAAA.jpg
Engione from Clancy 003AAAA.jpg [ 25.88 KiB | Viewed 2756 times ]
Engione from Clancy 001AAAA.jpg
Engione from Clancy 001AAAA.jpg [ 24.81 KiB | Viewed 2756 times ]

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Mon Sep 19, 2011 8:06 pm 
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Frank
Glad it got there today. That is what they promised but when it was not logged through the Indianapolis Sort Center Friday, Saturday or Sunday I expected to find it still in my local Post Office setting on a shelf.

They did post that it was delivered this morning.

Hope it runs good for you. I took it off of my All American Junior then converted it to an attached fuel tank setup using the Cox conversion kit I had. All of My Cox .049's are setup for a remote fuel tank like the Sure Start engines.

How does the length of the engine and tank compare to the engine you originally installed?
Clancy

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Mon Sep 19, 2011 9:43 pm 
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Other than open the box (which took some doing) and look at the engine I haven't done anything with it. It looks like it'll fill the same space though.
Tomorrow I'll put it on a test stand and get a feel for it.
I'll tell ya Clancy, I'm starting to feel like we could win something with this one. I don't know how the judges will react in relation to the BOM rule though. Built by one guy-painted by another guy--engine provided by a third guy--flown by a fourth guy--pitted by someone else........hmmmmmm...................... :D

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 Post subject: Re: An engine for Dil-Bod?
PostPosted: Mon Sep 19, 2011 11:49 pm 
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the engine will fit, it has the large tank same size as the one the plane was built around.

Go get 'em tiger!

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