Necessary to remove both wrist pin circlips for piston removal?

Dauner · Dauner's Garage

Hi everyone,

I've been mostly posting in Technical Forum, but may switch to this one. Not sure of protocol. Assume mostly same people? Car is 1989 911 Carrera 3.2 with 200+K miles. Tearing down for a rebuild. Sending cylinders out for bore out to 3.4 and coating, and buying new pistons.

I have engine disassembled down to point of piston removal. Question is, do I need to remove BOTH circlips to get wrist pin to point of piston removal, or just 1? Everywhere I read in formal texts (Wayne's book and Bentley), it says remove circlips in plural. If it's not necessary, why take the chance of damaging a piston during prying/pulling of circlip out?

Does it matter which circlip I remove and which way I press the wrist pin? One side is deeper to circlip than the other. Planning to start with piston 1 per Bentley, and press toward flywheel end. If authorized, I'd only remove the clip on flywheel side.

Also, per forums, planning on just using screwdriver handle as a drift. OK?

Thanks!

Mark

175K911 · 07-07-2018, 07:10 AM

You only need to remove one circlip. Then tap the pin out that side.

Dauner · Dauner's Garage

Excellent. Thank You!

Eagledriver · 07-07-2018, 10:44 AM

Heat the piston slightly with a heat gun or propane torch, the pins will slide right out.

-Andy

Dauner · Dauner's Garage

Thanks Eagledriver. Too late, already tapped them out with the screwdriver handle. Didn't really require much. I do have to admit that I was mildly concerned with the load on the rod bearings in an axis that they were never intended to see. If I had to do more than a tap tap, I'd have tried to figure out a way to hold the rod.

Next step, splitting the case. All uncharted territory for me...

Thanks again,

Mark

Jeff Alton · 07-08-2018, 05:52 PM

The 3.2 pins always slip out easy, while some 3.0 pins can be stubborn and require a touch of heat...

rxtrom · 07-09-2018, 03:40 AM

Quote:

Originally Posted by Dauner

Next step, splitting the case. All uncharted territory for me...

Thanks again,

Mark

Don't forget the "hidden bolts" in the chain through-way and the 3 behind the flywheel which needs to come off.

Drbraunsr · 07-09-2018, 07:24 PM

Buy Wayne's book: How to Rebuild and Modify Porsche 911 Engines.
Best $30 you'll spend on your rebuild. Especially if it's your first....

There's a complete section on dis-assembly

Jeff Alton · 07-09-2018, 07:30 PM

Great book. Good resource.

But, research some of the assembly techniques (sealing things up) before assembling your engine.

Cheers