scored cylinders 4-6

[tjonesmn]

2001 911 996 3.4l

cylinder 4 scored. cylinder 5,6 not much better. all pistons scored to some degree.

I know this has been discussed ad nauseam, but thought there might be recent revelations on this in regards to:

ways to fix/improve the existing cylinder to make it useable?
or
machine shops you can recommend for this repair (I am in the U.S.)?
or
any thoughts you may have

thank you.

[Tippy]

I believe Jake Raby can fix?

[Catorce]

I guess my question to you would be why do you want to keep that 3.4? With 996 values the way they are, I would either a) find another core motor, or b) use it as a chance to upgrade by either sleeving it or finding a 3.6.

[Mark Henry]

LN Engineering, stock size 3.4 or upgrade to 3.6 or 3.8, new machined in nikasil cylinders and JE pistons.
I'm having an a 996 3.4 case done right now to 3.8.

Not only are they scored they're also out of round.

[tjonesmn]

[QUOTE=Mark Henry;9574738]LN Engineering, stock size 3.4 or upgrade to 3.6 or 3.8, new machined in nikasil cylinders and JE pistons.
I'm having an a 996 3.4 case done right now to 3.8.

Not only are they scored they're also out of round.

This is the option i am thinking as well. Appreciate the input.

[Mark Henry]

Also was there a ticking sound you thought was your lifters that lead you to this?
There's likely nothing wrong with your lifters, it was piston slap.

[Jeff Alton]

Not uncommon problem. Likely started in cylinder #6.

It requires sleeving and new pistons. You can choose to go the LN route with aluminum or use a Ductile Iron sleeve produces by LA Sleeves and sold through many machine shops, independent shops or the likes of EBS. A displacement increase will cost no more than stock at this stage.

We see a few of these every year now. Just completed a 3.4-3.8 conversion and are working on a 4.0
conversion that both suffered a similar fate.

Cheers

[prschmn]

They all go out of round. Send the case to Millenium and they'll bore and replate.
Get pistons from Wossner, replace all the usual wear items and you're good.

[tjonesmn]

Originally Posted by Mark Henry

Also was there a ticking sound you thought was your lifters that lead you to this?
There's likely nothing wrong with your lifters, it was piston slap.

Mark, not sure about the ticking sound. I bought this engine used for a very low price and started the disassembly process. Visually the lifters look very good and the valve guides are solid. nothing outside the 1/64 spec. I thought I made a pretty good gamble until I saw the pistons and cylinders. I think you are very likely correct in hypothesizing piston slap.

this post has provided some solid options to pursue. thanks for your response

[tjonesmn]

Originally Posted by prschmn

They all go out of round. Send the case to Millenium and they'll bore and replate.
Get pistons from Wossner, replace all the usual wear items and you're good.

I will call them next. thank you.

[Ken911]

OK so if they go out of round they were overheated. You can get them cryo treated before they get replated. I sent mine to L&N along with the pistons. they recommended getting them cryotreated before replating. They came back individually matched to each cylinder. Millennium actualy does the plating but if you send them to L&N they will pre check every thing and make sure you had the correct finish etc. for the exact same price as sending them directly to millennium

[Mark Henry]

Originally Posted by Ken911

OK so if they go out of round they were overheated. You can get them cryo treated before they get replated. I sent mine to L&N along with the pistons. they recommended getting them cryotreated before replating. They came back individually matched to each cylinder. Millennium actualy does the plating but if you send them to L&N they will pre check every thing and make sure you had the correct finish etc. for the exact same price as sending them directly to millennium

Millennium won't undercut LN in price guaranteed.