K27

there is a slight ridge at the top of the cylinder bores, I understand this needs to be removed before trying to remove the pistons, does this need to go on a machine or will a hone do it ?

Thanks
Lance

pk951

At a auto parts store you will find a tool they call a ridge remover thats what i used on my vw so it should be good for porsche to.

Mike B

Not sure if your engine is still in the car but they can also be pulled out from the bottom.

K27

engine is out, putting them back in from the bottom would be harder, no?

thanks again
Lance

slevy951

If the engine is out, why not just pop the pistons out the bottom? .......

I don't think they'll go back in from the bottom. You'll need to get a ring compresor on them....

Mike B

Wha Scott said...If the engine is on an engine stand then the best way is out the bottom...Make sure you put some heater hose (or similar) on the rod bolt ends when you reinstall them otherwise you risk scratching the cylinder walls.

Installing them is easy...With the rings installed on the pistons you dip them in oil (I used 50W) and then slip the rod ends into the cylinder...Attach the ring compressor, compress and then use the wood end of a hammer to gently tap the tops of the pistons into the cylinder...

Presto, you're done...I think the Haynes manual explains this reasonable well.

Are you changing the rings?

K27

thanks, this is the procedure I thought would be fine, however in the manual it says you should remove the ridge from the top of the cylinder.
I would like to do rings while I am here, someone on the 911 boards recommended a ball hone for the nikasil otherwise the rings won't seat, any ideas?

thanks again
Lance

H2Opumpr

When I did the rings and rod bearings on my car this winter, I found a ring ridge also. IT was slight, so I didnt worry about it. My engine was still in the car, and I did'nt use a ridge remover. I just used a wooden hammer shaft and gave it a good blow on the rod end and they popped out no problem. Of course I was replacing the rings so I did'nt care if they were damaged.
If you have to use a lot of pressure to get them out, you might worry about damaging the rings lands on the piston.
I would be concerned about using a ridge remover on our Alusil blocks, ridge removers are primarily designed for use on iron blocks.

Julian Allen

I think solvent, like carb cleaner on a rag, will dissolve the deposit. You might try this before the hammer method. If you plan to use new rings it may not matter if they are scratched by the deposits.