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I am about to rewind some teflon tape into the grove in the pistons. The engine had excessive blow by and produced very little power. The bore is 10mm and the slot in the piston is 8mm and is about 2mm high. Has anyone replaced the teflon with O rings and was the result satisfactory. I am willing to rewind the pistons with the tape but was looking for a better alternative. Any suggestions are welcome....
 

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Sal, I've actually gone the other direction, replaced orings with teflon tape. I think the teflon holds up better over the long run. But that's my opinion not based on empirical or scientific data as seems to be required on this website lately. Anywho, It might take a time or two to get the hang of wrapping it but I found after doing about 12 pistons using this method, that you wrap and pack until you can't possibly add any more, then place the piston in the cylinder rod end in first, through the gland until the teflon touches the cylinder. Then tap the piston with the wooden handle of a hammer. (That's straight out of the regner assembly manual.) It should cut a ring of the excess teflon, that's how you know it's seal all around.
 

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Thanks Dave......I'll retape it.....was just kickin a tire to see if someone tried something else.
 

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Posted By SalM on 02/26/2009 8:00 PM
Thanks Dave......I'll retape it.....was just kickin a tire to see if someone tried something else.


Sal, check to make sure the blow by is not caused by the face of the cylinder where it seats to the frame. I've seen a Primax run crappy and it was all caused by a streched spring. If you have issues with springs and you bought it from Ken, I believe he can provide warranty replacement springs for no cost.

If your springs look good, pull the cylinders off of the frame, put a drop or two of oil in each one. Then cover the steam ports with a finger and with the other hand pull and push on the piston rod. You should be able to create enough vacuum to cause the piston to slide backwards when you release it (easier if you are pulling, not pushing). It sort of like a cylinder compression check. Regner reccommends this method in their kit instructions to check the cylinders after assembly. Here's a video from Regner, it's kind of hard to see but you'll get an idea of what I'm trying to say.
http://www.regner-dampftechnik.de/service/montage/kolbenpackung.php

direct link: http://www.regner-dampftechnik.de/video/html/kolben_stoik.html


P.S. If you do wind up re taping it don't forget to twist it into a rope/string shape. Regner calls it "gezwirbelt" and the closest translation is twirly, like twirling a moustache! Their instructions are part of my enjoyment (and challenge) of the build.
 
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