RngTrtl

and this ladies and gents is why I sold my n/a 996 and bought a 996TT. Porsche screwed the pooch with the M96 motor design.

allcool

Don't know if this is a question for you or Mr Raby..?

We all know now thanks to you guys and others about the structual problems of the 996 blocks, the way way out of round by 100k in more or less all of them,some a lot less miles have bad out of round.

So, my question to you, knowing you don't sell this option, and its a much more attractive option price wise, if a block is not damaged, just out of round beyond specs,
can a quality re-nik job by MT or US Chrome after they prep and round out the cyl again, then apply their great real nik plate job, can this reconditioned block last for another 50k..? 75k..? 100k miles, before going out of round again, or will it stay round with the new nik job...? We already know with a good set of Mahle/JE/etc. pistons and a MT real nik job, bore score is not a problem any longer.

You never answered my question fully in the last thread about this. I'll repeat, does the out of round occur from actual bore wear like most every other engine, or does the block actually warp out of round even with the head clamped down (torqued) correctly..?

Charles Navarro

I personally would not use US Chrome. I have had several talks with them and have tried using them and the results have not been good. We have also had to repair M96 blocks that have been done by them and have even seen some that were damaged beyond our ability to repair them.

The only blocks I would trust a direct plate job is a 2.5 (as long as it has enough time on it that a slipped sleeve isn't an issue), 2.7, and 3.2. All 3.4, 3.6, and 3.8 models can and do crack, so direct plating doesn't address this.

I'll also add that the surface finish you get from us will be different that if you send your block to Millennium direct.

The other issue is that the dissimilar materials in the bores compound these issues (the Lokasil portion with silicon particles is about .250" thick and the rest of the block's parent metal is plain 'ol aluminum). That's why we remove all the existing cylinder liner with our process, with exception of the parent metal on the crankcase side which we use to support and locate the new sleeve.

For reference, the factory Lokasil block when new was perfectly round in free air with no ovality or taper in the bores. The ovality and taper is from wear and also from degradation of the material, similar to what we see on aircooled Porsche cylinders.

As direct plating of the stock bores isn't really a viable option, I can't give you any feedback on longevity of a direct plated block, but from what I can tell you on aircooled cylinders if they are beyond the wear limit, the bores do not stay round even after reconditioning. From what I have been told by engine builders, you can expect about half the service life of a reconditioned factory aluminum cylinder compared to a new one. If you check the hardness of a used cylinder, especially closer to the cylinder head, you'll find that a used cylinder that has been in service for an extended period will be much lower than a new cylinder. This goes for any aluminum cylinder, Mahle included. In fact, we won't recondition a stock cylinder or even ours if they are over the acceptable wear limit or if they have been subject to overheating, detonation, or any other condition that has compromised the integrity of the cylinder. I believe this all to some extend is applicable to the Lokasil block. I would presume if you could do a hardness test on the parent metal that supports the Lokasil portion of the bore compared to a new block you'd find the hardness will have dropped. I'll go further on a limb and say that the further a bore is out of round, probably the softer the aluminum has become.

I hope this answers your questions.

Porschetech3

I would just like to add while on the subject of Locasil that all the blame should not be placed on Porsche for the as reported "screwed the pooch" Locasil process in the m96 engine.

Locasil is a process from Kolbenschmidt ( the big Kahuna in aluminum blocks/pistons, hard parts,ect. for over 100 years) ..I'm sure it took quite a lot of convincing to get Porsche to decide to use their process in the "new watercooled m96 engine"....and has been the only engine that has used this process...

And I'm sure Kolbenschmidt did all the testing necessary to convince Porsche of all the benefits of this process , and Porsche, like customary, was willing to push the boundaries for increased performance ( and why we love the Brand, they are not afraid to push the boundaries) ...So what went wrong with Locasil and who is to blame? Well we have seen and documented what does/can go wrong. I think both Porsche and Kolbenschmidt share the blame equally......

Chris(MA)

My theory is the silica particles that are embedded in the cylinder wall have poor bonding to the main aluminum of the casting. So the higher the % of silica the weaker the aluminum. Over many hot/cold heat cycles and pressure from combustion the aluminum is too thin to resist warping.
They probably did static tension strength measurements on hot and cold lokasil and used those values to calculate the wall thickness of the cylinders.
if they had used thicker walls or formed the silica just in the surface where needed not thru the entire cylinder wall the problem probably wouldn't happen

TT Oversteer

Dryslick I’m afraid your mechanic, while well intentioned, is out of his depth with respect to rebuilding your M96. Even with my limited knowledge it’s obvious that putting new pistons and rings in your old bores is an epic fail. Going forward with this will only lead to disappointment IMHO. You are in a bit of a bind here as you’re already in pretty deep. Only you know what your budget and patience for this project will allow. If I were in your situation I’d be looking at the Porsche factory long block option. That way you could use your existing short block as a core, send out the heads for rebuild, hopefully use some of the parts you’ve already paid for, and perhaps your mechanic will credit you for some of the time already spent leading you down the wrong path. It’s probable your mechanic has the skills to assemble the top end and reinstall your engine. The other option would be to go the LN Nickies route and have your guy do the entire assembly but I can’t believe you’ll get away for under $25k if it’s done correctly. Last resort would be to install a “good used” engine or just pull the plug and sell the entire mess as a project. I would not, however, continue the path you are on. This is the M96 dilemma…..there are no “good, cheap” options. Good luck with whatever you decide and please keep us posted on how it all turns out…

pdxmotorhead

FWIW,, Subaru's share many similar issues when tweeked up to higher power levels,
Bore score and oval-ing is pretty common in some bikes and boat motors..

Coincidentally if you take your current estimate, and add the charge for nickies,
You right at the price LN has for a complete motor...

You can also go through Hartech's affiliate shop in Canada and get their engine treatment, which I believe is close to the same price..

My 03 996 had expected bore oval, and cracks in 2 cylinders that we think were related to a associated AOS failure over pressuring the 2 cylinders.

I feel the pain man.. Good Luck

TheChunkNorris

Slakker is the US’ affiliate shop.

Dryslick13

Here are a few pics of the case.

Chris(MA)

118k on those case parts?

Dryslick13

Engine did have that at expiration. Not sure if he replaced the sleeves or not. Looks like they might have been. His English is not great as he moved here from Italy recently.

Chris(MA)

The light regions look like the area swept by the rings so appears to be untouched, blocks dip cleaned perhaps

pdxmotorhead

Based on playing with carts and dirt bikes, those cylinders have "just" enough wear to make me wonder.. Awful deep in the engine rabbit hole to turn back now..

ltusler

Looks to me like they have been painted.

pdxmotorhead

'Vapour Blasting/Cleaning" leaves a semi Matt Chiny clean surface that looks like good silver paint was used..

If the post cleaning cleanup is not done well, bad things happen.