This ^^^^!

Yes and do the things you can do to avoid it from happening:
- don’t push car above ~3k RPM until oil gets to temp (180+)
- don’t let the car sit and idle unnecessarily at startup
- add LN options - Low temp thermostat, spin-on oil filter adapter, magnetic plug (consider 3rd radiator if warm climate or car is tracked)
- perform used oil analysis at every oil change
- Use Driven DT40 or similar oil w/ good molybdenum content
- change every 5K miles or 6 mos whichever comes first

drive and enjoy!!!

 

The cylinder coating on .1 cars is Lokasil, not Nikasil. If they were Nikasil, they would likely not be prone to scoring. The inherent weakness of M96/97 engines is the Lokasil coating of the cylinders. Porsche went to Alusil coatings in .2 cars with 9A1 engines, which is why the risk of bore scoring is lower. Any cylinder scoring found in 9A1 engines is problably not due to cylinder coating but likely due to cold seizure: "Over a long period of time and hot and cold heat cycles, the bottom of the cylinder bores minutely shrink inwards across the thrust diameter - reducing the piston clearance until on a cold day with a rapid heat cycle the piston expands quicker than the bore and that reduced cylinder clearance causes a typical cold seizure all round both sides of the piston."

This is a terrific thread by Baz that explains the differences: https://rennlist.com/forums/997-foru...1-engines.html

 

Thx for the correction Busta. It is Lokasil. Nickasil is what the LN guys use to re-sleeve the 997.1 engines that need to be rebuilt.

 

I'd be curious how your mechanic reached out to us as this is very odd that he did not get an answer or hear back unless he didn't leave a message or send an email.

That said, we're not taking on any RND builds at this time due to the tremendous backlog we have in the shop.

 

Lokasil, like Alusil, does not have any coating on the bores. The bore itself is hypereutectic aluminum and through a specific preparation process, the silicon particles are exposed. The oil film that surrounds those particles coupled with an iron clad coating on the piston makes the whole system work. If the piston coating fails or too many silicon particles are damaged, the system fails (and you get bore scoring).

 

When the cylinders start to wear, it's common to see elevated aluminum, silicon, and iron content in the oil found through used oil analysis. However these particles are much smaller than what the oil filter can catch. Most filters on average capture particles that are 30 micron and larger.

 

We commonly see bores that have streaking which like mentioned above you can't catch with your fingernail. It's typically transfer from the coatings put on the piston rings onto the cylinder bores and is purely cosmetic.

 

Short of having the grease seal pulled off the original non-serviceable 6305 bearing used in 06-08 model year 911, Boxster, and Cayman engines, I wouldn't worry too much about the later IMS bearing. They do fail, but very far and few between. When the engine is apart for rebuild, that's the time to update it.

 

This is an important point and the reason why I've never understood scoping the bore in the absence of symptoms (unless it's part of a sale). There's no upside as you can't stop it once it starts, there's no "treatment" like a medical condition. There is a risk of a false positive though, which can lead to stress and unnecessary repairs. Don't go looking for problems, if they are there they'll find you soon enough.

 

A trained eye can tell the difference between streaking and scoring. If the person scoping the bore can't tell the difference, they probably shouldn't be doing the work as they indeed may be recommending work that is not needed.

We commonly have people email us the photos and we'll look them over and tell you either way.

 

Thanks Charles, your comments are always informative and a great resource.

This may have already been posted but I came across this Vinwiki from a few days ago where car dealer Euroasian Bob (of Hoovies Garage fame) talks about getting burned by a bore-scored 997.1. I remember an older Hoovies Garage episode where Bob was dropping off a 997 at Johnnie's shop due to an engine thunking noise. At the time I thought uh-oh, looks like it was confirmed.

Seems this issue is getting wider exposure, it will be interesting to see how it affects the market.


Edit: Oops, sorry for the repeat, looks like this was already posted upthread.

 

I think is true if an owner is willing to do all the things required to minimize the chance of bore scoring. Some people may not deem the expenditures (e.g. LTT, Spin on Adapter, magnetic plug, shorter Oil change intervals, oils w/ Molybdenum, not using car above 3k rpm until oil is at operating temp) worth it unless they have an issue. . .

 

Second that Charles, really appreciate you dropping your knowledge here!

As you can tell, some of us are neither engine builders nor mechanical engineers!

 

Glad to help where and when I can!

 

Currently working with FSI on my motor, actually just shipped it out today. I can say that if you can wait it is certainly worth it. I challenge that if you compare apples to apples it isn’t even more expensive (FSI you get things like injectors and new clutch). For me the biggest thing has been the level of service and process that they have, these guys really care about the work they do and it shows. From start to finish the only thing you have to worry about is what “extras” you want to add, they have everything else covered.

Today is a great example, I was a bit worried about shipping, I have never shipped an engine before, to make things more challenging the driver had to navigate a long gravel drive backing down. Jud assured me that it would be fine, he only uses R&L because they have never let him down, keep in mind he probably pays more for this. Sure enough it went flawlessly, the driver was more concerned about putting ruts in the grass then the fact she had to back a semi down a narrow gravel drive. All I had to do was point her to the packaged engine, slap a label on it Jud provided and hand her the paperwork Jud had completed and also sent me.

That same level of care and service is in everything they do that and while I haven’t personally witnessed them rebuilding a motor, I am certain the level of care and detail is beyond expectations.