Oh No, It's BS (Again)

[husker boxster]

It was almost 5 yrs ago Sydney was diagnosed with Bore Scoring. Spent a lot of money ($28K) and time (almost 1 yr) on a rebuild with new Nikasil cylinders. Was supposed to solve the problem. Here's a link:

https://986forum.com/forums/performance-technical-chat/80281-its-bs-4.html

Fast fwd to mid-Jan and I start to hear a ticking sound during our annual winter cold snap. That's not good, as that's generally the starting signal of bore scoring. Keep an eye on oil consumption. She's now starting to drink a bit and the ticking is getting louder. Took her to SLM and they scoped her. Here's what they found in the #4 cyl.



Crap. Why did this happen?

SLM did some calling to see if there might be someone interested in doing some goodwill exploring but to no avail. The shop who did the rebuild has been sold and I think the mechanic / owner who did the rebuild has retired. Jake Raby is busy with other projects. No shops want to look at a rebuilt engine. Not many options.

Talked to SLM today about having L&N do the rebuild. They're taking steps in that direction.
The saga / nightmare continues...

[Smallblock454]

Damn…

Maybe i would go with steel sleeves next time.

[husker boxster]

Originally Posted by Smallblock454

Damn…

Maybe i would go with steel sleeves next time.

Steel dissipates heat at different rates (slower) than aluminum, so your engine runs hotter. You'll also have potential trouble with head gaskets. This isn't an issue when they're used in race engines since those are rebuilt more often than a street engine.

But if I'm having to rebuild every 4 yrs, maybe I have a race engine.

I would just like to know if it was something I did or if there was an error made assembling last time. The #6 cyl was good and that's the one that always fails.

[Qingdao]

Originally Posted by husker boxster

SLM did some calling to see if there might be someone interested in doing some goodwill exploring but to no avail. The shop who did the rebuild has been sold and I think the mechanic / owner who did the rebuild has retired. Jake Raby is busy with other projects. No shops want to look at a rebuilt engine. Not many options.

Talked to SLM today about having L&N do the rebuild. They're taking steps in that direction.
The saga / nightmare continues...

I am going to be picking up another 986 project car. I won't need the M96 you can have it for free if you come get it. I usually send the OE engines to the scrap yard.

[Smallblock454]

Originally Posted by husker boxster

Steel dissipates heat at different rates (slower) than aluminum, so your engine runs hotter. You'll also have potential trouble with head gaskets. This isn't an issue when they're used in race engines since those are rebuilt more often than a street engine.

But if I'm having to rebuild every 4 yrs, maybe I have a race engine.

I would just like to know if it was something I did or if there was an error made assembling last time. The #6 cyl was good and that's the one that always fails.

Yes, i know that steel has a different expansion coefficient that aluminium. But it seems to work. Over here in Germany we have different engine builders that are specializes in that topic for M9x6 and Mx7 engines. It works. But there are a lot of things to take into consideration. Gaskets is only one.

A full engine rebuild every 4 years is definitely not the way to go.

I would check if the piston ring clearance was OK and if they were mounted in the right direction. Also i would check if the cylinders are really round over the whole length. The oil supply for the oil spray nozzle for that cylinder might also have caused a problem. And of course you have to check the overall piston clearance.

[husker boxster]

UPDATE

SLM, my go-to independent shop, has been doing some research on potential options. As mentioned before, options were very limited. A new one is L&N advertises a swap option on their website where you send them your short block and they send an already rebuilt engine back. You'd lose your original serial numbered engine, but at this point who cares? However, they don't have any engines on the shelf to swap, so that option is out.

After striking out repeatedly, SLM came up with this proposal: they'll pull the engine, tear it down, send the halves to L&N for new sleeves, and then rebuild the engine when the halves return. Alex, one of the co-owners, and his dad rebuilt a 997 turbo engine so they've done that type of work before. I'm excited about this option. Not sure the plan is to replace the sleeves with the same sized ones (leaving the displacement at 3.8) or if they have to bump it to 4.0. I'm fine with either.

We're finalizing details and getting me on their schedule, but that's the direction.

Qingdao - thank you for your offer. Not sure if an M96 block would work instead of my M97, but you can do what you want with it.

[husker boxster]

The journey begins. I dropped Sydney off at SLM this morning. It didn't take them long to remove her engine. It will be disassembled and the engine block halves will be sent to Ill for new cylinder liners. Could take 6 mo start to finish. The longest journey starts with a step.

[husker boxster]

Engine is apart and block halves ready to ship to L&N.

#4 piston. Skirt has totally lost its coating, hence the scoring



#4 cylinder with all the scratching.



#6 cyl (far left) is fine as are the 4 other cyls. #6 is where scoring usually happens, but not uncommon for #4.



#3 piston. Skirt coating is starting to flake off. Bad set of pistons from last rebuild?

[Gilles]

Husker, I am sorry about your issues (and very surprised..), and hoping that you will get it right this time and you will be able to enjoy your car for a long time.
.

[husker boxster]

Originally Posted by Gilles

Husker, I am sorry about your issues (and very surprised..), and hoping that you will get it right this time and you will be able to enjoy your car for a long time.
.

Thanks Gilles.
This has been very disheartening. Facing the options "provided" by bore scoring are never positive. Having it twice really sucks. I love my CSS and always said my brother and sister would have to deal with selling because I'd keep her til I die. But this has made me wonder. Should I sell after I get her back? Some options I've considered:

Sell my CSS and 928. That should get me around $100K and buy a 997T 6-spd. Would have the bulletproof Metzger engine. Used to be you could find a turbo 6-spd in the $75-95 range, but people have realized their value and now they're $125-160. That ship has sailed with me not on it.

Get a 987.2 or 981 with the 9A1 engine. I liked the '14 Cayman S I had several yrs ago as a WD car. Even commented at the time that it would tempt me to replace the CSS. However, as those cars have aged, they appear to have a variation of bore scoring too. No need to jump from the frying pan into the fire.

What I've decided to do is keep my CSS and buy an Mk 2 Audi TT as a winter car. I hate having to have so many cars each with a specific duty, but that seems to be the most effective and cheapest route to take. I'm leaning towards keeping my shark since it's a nice one, so if I buy a TT, I'd have 5 cars for just me - Box, Cayman, 928, Model T, and the TT. Seems kind of ridiculous. I know I can't afford to rebuild my engine every 4-5 yrs at close to $30K a pop and something has to change. Taking the CSS out of winter duty seems like the logical solution.

By my count, I'm at wk 15 since the block halves were sent to L&N. The est was 16 wks, so fingers crossed it won't be too much longer before they return. I'm excited for the new 4.0L size and hopefully some added HP. I wonder if the lack of noticeable HP inc from the last rebuild was due to a misaligned piston or two? Will never know and can only guess, just like the true cause of bore scoring.

[husker boxster]

I ran into Alex from SLM this morning at Super Car Sat car show. He said he got an email from L&N saying my block halves go to Quality Control this week. May not be too much longer before they're back in OMA.