nckwrnr

Oh wow never heard this information about the piston offset for the bore scoring issue. Sorry to hear OP. Man all of these threads make me want to sell the car while it is still running ok

Slakker

This thing is awesome. Thanks for the recommendation.

AWDGuy

Doug996InKC

Is a billet crank available for the M96 NA engine? Looking at EVOMS & Protomotive, it appears these are for the turbo and GT3. So 3.4 > 3.8 with nickies, billet crank, single mass flywheel is doable? I'll start a new thread if this is going too off-topic.

Charles Navarro

Billet cranks are indeed available and come with a hefty price tag. Something Jake uses in his builds exclusively.

kukaepe

Charles: Are the JE pistons that are included with the Nickies different for cyls 1-3 vs cyls 4-6 regarding piston pin offset? Thanks in advance.

Porschetech3

I'm not the Charles you were looking for , but can answer your question. The JE pistons included with Nickies are zero offset, therefore are ambidextrous.

Charles Navarro

Spot on. I have done them with offsets special order, and when we do, we make them side specific.

The DFI and Cayenne V8 pistons we make must have offsets or the engine sound like diesels.

nckwrnr

How is making one side more favorable while the other is left with a unfavorable offset chosen over just non offset pistons for all 6?

Porschetech3

Several things are effected when offsetting piston pins.

Offsetting piston pins in either direction will soften the "snap" when piston changes direction at TDC and BDC, this reduces the stress on the rods.

Offsetting opposite the direction of rotation will decrease the piston slap and reduce side loading of the piston.

Offsetting in the direction of rotation will increase slap and side loading, but will slightly increase power and dwell time at TDC, as mentioned above any offset in either direction will reduce "snap" stress on the rods.

Ultimately the decision on whether or how much to offset in determined by the engine/piston designer and/or their accountants.

Schnell Gelb

So if an absent minded M96 engine rebuilder muddles the offset for Bank 1 & 2 when reassembling the engine , what happens?

Ahsai

Impossible because all m96 pistons are identical within an engine.

Porschetech3

Ahsia is correct, on the factory pistons, you can't mess that up, they are all the same.

Ideally like Charles Navarro said, when they do offset them, they offset bank 1 to the exhaust side (major thrust side), and bank 2 to the intake side (major thrust side).

Then you have the best of all worlds, offset to reduce piston slap , to reduce side loading, and to soften the "snap" at TDC.But requires two different pistons be made, and close attention to orientation during assembly.

Porschetech3

It's just my opinion but I think the engineers of the m96 engine chose to use piston offset for the softening of the "snap"at TDC .And they figured they could get away with using one piston,( even running an unfavorable offset on bank 2) due to the surface of the Lokasil cylinder, the iron piston coating , hypereutectic piston material, and close clearance, would withstand the side loading and piston slap all to a minimum, but as we know , not so much.

911Dreamer

So you guys bring up the best info as 996 owners and builders....I've decided to go back to purchasing a 996 after looking for a 997 and it seems the Gen1 ones are getting below the $36k range but with the 996 offering better bang for bucks, but still having issues. Would a PPI catch scorned pistons? Or this something one will have to ask for?