Just reassembling my engine, and remembered how much
I hate fitting spiro-locks.
I took some photos to show how I remove and install them, in
the hope that it helps some others.
I actually use them on one side of the piston, and on the other side,
I use normal circlips, so that it is easyer to work around the headstuds whilst assembling.
First photo is how I get them out.
I have two favourite screwdrivers that I have sharpened up a little.
The first one goes in vertically to pry the 'lock out of the groove,
and the second smaller screwdriver goes in underneath to lift it upwards
enough to continue the removal.

I put the new spirolock onto my finger so that the tip can be pushed
down the gudgeon pin hole, and stated in its groove.
At this point the majority of the spiro is above th hole and sitting flat.
Then a screw driver, or some other blunt object is used to push it down vertically in a winding motion, to clip into the groove.

The screwdriver is used to progressively push it down vertically in a circular motion.

And here it is almost all in...hope my description makes sense.
I fit these whilst the piston is on the bench, and then use a conventional circlip
in the other side after the gudgeon pin has been fitted to the piston and rod.

[ Edited on 7-1-2006 by dangerous ]

any reason you dont like teflon buttons? There so easy to use!! Ive built a V8 with spiro locks, twice as much fun!

These are lighter, and come with the pistons.
Also dont rub on the bore.
Have used teflon and mag buttons before and liked them
but some pistons like these dont have full support
right around where they hang out,(like a mahle)
and I dont want to have that in the back of my mind.

I use those spiro locks everyday on gas turbine aircraft engines, first time i used them took a while to install, but soon got use to it, sizes at work range from ones half the size of a 5cent piece even smaller up to ones about the size of the diameter of a coffee can. they can be very frustrating and very easy, but they do work the business especially when their turning up to 18000 rpm in the turbo prop engines. Found that the snap on pick set is the tool of choice in removal though, using the straight and angled pick, just thought i'd put my two cents in. I feel your pain Dave. Cheers Damien.