Teflon Buttons

ian.stewart · Post by **ian.stewart** » Wed Apr 23, 2008 3:49 pm

Has anyone used Teflon Buttin Gudgon pin retainers on fully floating pins????
Ian

Post by **katanaman** » Wed Apr 23, 2008 4:31 pm

Yes but on bike engines not on car engines.

ian.stewart · Post by **ian.stewart** » Wed Apr 23, 2008 5:40 pm

Tell me more??

Post by **katanaman** » Wed Apr 23, 2008 5:56 pm

I used them mainly because they are a damn site easier to use than clips and bikes have a tendency to spit the clips out usually totalling a set of barrels. In your case (I think your looking to use floating pins on Rover pistons?) I think they would be perfect for the job. No machining needed and there is no way they can fail, just push them in (they aren't a tight fit) and the bore stops them from coming back out. Only thing I can think of that you might have to watch out for is there will be no oil gets in from the outside to lube the small end of the piston. I don't know how much oil gets up the inside of a rover piston. Will probably be absolutely ok but maybe something to look into just in case.
Anything else you need to know?

Boosted LS1 · Post by **Boosted LS1** » Wed Apr 23, 2008 5:58 pm

Ian, do you need pins and buttons

I know where there are some, lol.

Mind you thay are .912" diameter as I wanted more strength. Length is 3.12" appx plus the buttons, which are hollowed out aluminium to save weight. These were custome made pins with taper walls. I never used them as changed engine brands.

Lubrication to the oins is usually splash fed or scraped off the bores by the oil rings although some pistons are drilled for forced pin oiling.

Mike.

IainB · Post by **IainB** » Wed Apr 23, 2008 7:00 pm

With regard to lubrication, could you not make 4 'channels' at 90 deg to each other around the button?
I cant see it getting a huge amount of oil, but it could help?
Just another of my crazzzzy thoughts

Boosted LS1 · Post by **Boosted LS1** » Wed Apr 23, 2008 9:06 pm

^ You don't need to. Pin to piston gets oiled by oil scraped off the bores and by splashed oil in the crankcase, the mist. Sometimes oil is force fed to the pins by a drilling from the oil ring land to the gudgeon pin bore.

As for the buttons, they don't need dedicated oiling. It's pressed into the pin which is a floating fit in the piston. Say the bore is 3.740, the pin and both buttons would be 3.725" total or something like that. This means there's no pressure on the buttons and if/when they touch the bores there's surface oil there already for contact lubrication. The pins can slide within the piston and rod.

Wotland · Post by **Wotland** » Thu Apr 24, 2008 3:28 pm

Very interesting

.
How much costs an set custom wrist pins with PTFE Buttoms ? I am looking for an set for my 3.5'' pistons.

Boosted LS1 · Post by **Boosted LS1** » Thu Apr 24, 2008 3:48 pm

They're expensive, maybe £20-25 per pin because of the additional machining in the pin ends to accept the button. You have to buy the buttons as well. I have some here which are taper walled pins with the machined ends but thay are .912" dia. My buttons are aluminium with hollowed centres to save weight. They won't melt

I'm not using them but they're for a 94mm bore or thereabouts.