How to remove piston pin
 

73 911 e

have a broken, 12 year old, JE piston that needs to go. Have the heads and jugs off. Whats the procedure for getting the piston off. I don't want to split the case if possible.

Thanks,

Chris

Is the pin stuck even after the clips are removed? I usually support the piston and just tap it out with a wood dowel.

Remove circlip, support piston while tapping out pin with wooden dowel or something similar, as cgarr stated. You don't want to put stress on the connecting rod. It can be a bit awkward if it is the center piston if you are not removing the outer ones.

Heat the piston dome with a propane torch. The pin will slip out much easier that way.

Thermal expansion.......
 

+1!!!!! Do the same when installing back the wrist pin/s. They will slide in with minimal resistance.

I usually pop them in a little toaster oven right before re-installing them. Works like a charm.

piston pin
 

No piston (unless its a press fit) should need heat to install, when removing the pins they sometimes need help because of clip groove burrs from the pin bumping over time. but if you think about it they need clearance for oil to stay alive. we see this problem all the time even new rods and pistons out of the box need to be "fit " for clearance.

Mike Bruns JBRacing.com

Came right out once I got the clip out. Was a bit challenging as the other pistons and head bolts were in the way.

Chris

73 911 E

Right on Mike,

I only really warm the pistons when re-installing them. It just gives a little extra clearance when sliding the pins through the pistons and the rods.

I don't heat the pins.

I find that sometimes the pins can get "sticky" and need a little bit of "help" to get in their "correct plane " in the piston pin bore. In order to avoid any tapping on the pins or any other sudden movements when getting the pin installed. I use a little heat.

This is my method only and YMMV ;)

piston/pins
 

Actually I meant pistons not pins, we set up performance/race pin clear. at .0006 to .0007, for street stuff .0004 to .0005 thats on the 22/23 mm 911's even at the street clear. they will "fall" thru the pistons, when they are at size or .0001 plus they are tricky to get in, and thats what alot of them come out of the box at.
Mike Bruns

I don't understand why you would need or want clearance between the wrist pin and the piston. The bearing surface for this part is the small end of the connecting rod. This is where you need clearance. As long as the fit in the piston is not so tight as to crack the piston or be too difficult to install/remove then a tight fit is good.

-Andy

pin fit
 

Andy, it is common practice in performance engines to pin fit and set clearance in both rod bushings and piston pin bosses, they are floating pins by design, and need room for an oil film to reduce wear, prevent distress etc.. every piston has some way to get oil to the pin via oil ring feed or broaching the pin boss. On alot of OEM production engines they have press fit/floating because its cheaper. On some engines where you run hi vaccum and or dry sump there is a need for DLC coatings on the pins, even extra clearance. We never run them tighter than .0006 in. and always check them. In severe use we have found that they stay in spec much longer if they start out with proper clearance.

Mike Bruns JBRacing.com