Lost Glider

I bought ten Cox Surestart engines about a year ago, and am getting around to trying to use them now. One engine I tried to start would not even pop. When I got back home I filled a small container with fuel, turned the engine upside down placing the glow head and the top portion of the cylinder into the fuel, and turned the crank over by hand. Lots and lots of bubbles came out from between the head and cylinder. I checked the other nine engines, and they all leaked to varying degrees. All heads have the copper gasket and are on tight. I took a couple of heads off to check for any foreign matter but didn't find any. Any suggestions on how to seal them up?

Thanks.
Randy

Mr Cox

Check the sealing surface on the head, these sometimes have shavings and/or scratches on them. This is easily rmove with fine grinding cloth and polishing paste.

It can also be from the sealing surface not being completely true (perpendicularly) to the threads. Then take a very small amount of polishing/grinding paste and mate the head to the cylinder, this can also loosen up the threads which will aid the alignment too. Tinker on!

dennis

My Feedback: (90)

There are a couple of things that could be wrong but basically you probably have unfinished edged on either the plugs or the top of the cylinder.
first thing is to check and make sure that the plug is indeed actually seating on the gasket and making a seal. This is apparent when you remove the plug and look at the marks on the gasket. If that checks out then you check the base of the glow plug on a plate of glass. If uneven then a little oil and600 sandpaper is used to lap the seat of the plug to get an even face. Do this on a plate of glass to assure yourself a flat surface.
As to the top of the cylinder unless Estes really sold all the seconds with flaws, you need equipment to fix that and I won't go into it. Or you can use another gasket on top of the first one and get a little more compression fit between the plug and the top of the cylinder and see if that helps. It woulden't suprise me at all to have them sell cylinders that are off spec as to depth of cut for the plug.
Oh and a lot of users don't realize that those copper gaskets don't last forever. Which means that you can't keep recompressing them and expect them to work as if they were new. Spare copper gaskets are getting tough to find but can be bought from Coxmania on Ebay. No I don't know the guy but did buy some stuff from him.
Dennis

flyinrog

My Feedback: (1)

? are the cylinders in the fuel and if so are the air bubbles coming out of the ports??,,they do leak down you know...and its going to be easier for air to leak out into fuel than for fuel to leak out in air...ie. air has no sealing qualities...fuel does so its not a real world test....only way to tell is get'm runnin...I have a 1/2 dozen of them myself....Rog

gcb

Swap the plug and gasket with another engine and see if the problem follows the plug/gasket or remains on the suspect cylinder, then proceed accordingly. Less work.

George