Porsche 996 engine rebuild

Hey guys! Not sure how many of you work on your own cars here and or have experience working on them, but need help from someone who knows what they�re talking about. I got a 1999 Porsche 911 that I had a main bearing due on me and luckily didn�t do too much damage so most of the engine is rebuildable, which I�m doing myself. But, before I got on, was wondering if some could tell me if my block for Cylinders 4-6 is still any good? Got a little bit of scoring but not much and it�s all still smooth and round. Was wondering if an expert (hopefully in this group) can help me out a little. Will I need to replace the block or am I good to just throw on a new set of rings? Btw also replacing pistons with either JE or Wossner. Thanks again in advance ps. Also images are market with the cylinder number to help identify to culprit. Thanks again

I'm not an "expert" but my opinion is if you were to rebuild the engine using the block as-is, you will have wasted your time and money, and be disappointed in the long term. I think your best direction would be to have the cylinders sleeved with new Nikasil sleeves, however you certainly could proceed as you see fit. Jake Raby with FSI (Flat Six Innovations) has been very generous with his experience and knowledge; you might want to view some videos on YouTube that he has provided related to bore scoring. LN engineering provides the Nikasil sleeves.

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As PaulD stated, your best path forward is to consult with Jake Raby. It looks to my uneducated eye that you are well on your way to future bore scoring failure.

Yep, several bores are scored, and will require attention. #6 is at Stage 3 scoring, and will progress quickly from this point. Be very careful deciding which way to go with this, component compatibility is essential. Factory Lokasil cylinders do not play well with high silicon content forgings like JE, and others. I see people cut corners on this all the time. It doesn't end well, but it works okay if doing something twice doesn't bother you, and you have to learn things yourself.

Sorry but if you are looking at that last bore and are thinking you may be able to just throw in some new pistons, are you really sure you want to tackle this build?

OP - Is your polling intent to gauge opinion on ‘replaced’ or ‘resleeved and rebuilt’? ‘Replaced’ is relatively simple. ‘Rebuilt’ is just a a smidge more involved. Ask yourself, since you already have the sucker torn down, and can see the bore wear; “Do I invest the time to research all the rebuild threads (hell yes). Do I decide not to repeat the costly mistakes others have made to gamble on, maybe, saving a G or two on what will be an expensive, lengthy repair process (double hell yes)? Do I properly assess my skills/knowledge/equipment sets to ascertain if I have the capability to eventually insert the pins and fish scale the rings perfectly (hat trick hell yes)?” If you tackle the project yourself, I’ve heard there’s a DVD series and companion workbook available that you might want to seriously consider procuring. That same vendor has a plethora of YouTube vids on their channel to help guide you through your rebuild project matrices. From your post I gather you haven’t made yourself familiar with this forum. Please do so. 10 hours of thread research on RL, 6 speed, 911uk and Rennlist will save you countless frustrating days in the garage. Lots and lots of resources. Some more recent thread starters like Ahsai, Jengah, Scott at Harco, etc, have some fantastic lessons-learned from rebuilds for you to increase your awareness. You might want to start with looking through Ahsai’s threads on his engine rebuilds and other projects. The man knew what he was doing. However you proceed, I hope you find the right path to success the first time. Bon chance !

If I was going to attempt to rebuild my own engine, I would spend some time looking and reading posts on this site to get a somewhat grounded baseline as well as checking out a host of Rennvision videos to expand that knowledge. However, my very first purchase would be Jake's Focus On: M9X Engine Assembly Educational Video Series. Nothing kills a project faster than misjudgment and a lack of technical resources. I would also check out some of the latest goodies from the many vendors that have created products and services to rectify issues, support, and actually pay for the privilege to post on this site. The good news is that you are in good company as people on this site tend to appreciate machinery and are willing to share their knowledge, challenges, and successes.

Like all others have said, your cylinders are done/junk. Since you had to ask for opinions on this I will assume this is your first Rodeo, tread carefully my friend. There have been many an able bodied person fail to get an M96 up to snuff. You have two major components failures to deal with first. the crankshaft ( you said you spun a bearing) and the cylinders/cases.Both are manufactured using special processes not common to most engines, and require special repair/restore processes that are also not common. Then there is all the little things that will need to be addressed that can trip up a good intent.. If you do decide to tackle it, Jakes DVD would be invaluable to you..