beetleything

I simply don't understand why Porsche put the offset for bank 1 into Bank 2 - why did they not have an opposite one for that side?

tomcat

Porschetech3

The simple answer is that it would cost more to make another piston to fit bank 2 correctly. I'm sure the decision was made by the accounting dept. and not the engineering dept.

OutNSpace

So I finally managed to get some time to take a look at with an endoscope and concluded that this is due to cylinder scoring (Cylnder #6 video below).


Sooooooooo....after some crying I've decided to rebuild the engine.

I'm an engineer and am comfortable taking this on, and I'm lucky to treat this as a project and not fixing my daily driver - although it will be my daily when I'm done. I'm also hoping that a few on this forum that have done this before are generous in their advice and sharing knowledge if/when asked.

I have read the posts from Ahsai, Logray, redneck rebuild, and a few others at least three times and will re-read them again (and again probably). I can't start this until the springtime anyways so I have a little while to prep and research it.

I would love to take the Flat6 hands-on rebuild course but unfortunately that is beyond my budget. The online courses look interesting, and I do plan on taking one of those, but still trying to figure out which one I should take.

At this point I'm not sure if I should get the full LN Kit (https://lnengineering.com/products/w...ins-clips.html) or send it out for repair, for example to Millenium Technologies (http://www.millennium-tech.net/serviceInfo.php?id=7) and buy the JE Pistons, etc. There looks to be a significant cost difference between the two. I don't plan on tracking my car, and obviously want to keep costs down as much as possible, but also want to do this right, so any thoughts on options appreciated.

I'm hoping to give back and be able to document all this but will depend largely on my schedule.

OutNSpace

By the way, for anyone that want to look at their cylinders, you can get a really affordable ($37) endoscope here:

Then just pull your plugs and take a peek. (Make sure someone is nearby in case you need a hug)

Ahsai

Sorry to hear that man. Thanks for sharing the great video. I use the exact endoscope btw. Excellent video quality.
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Regarding the cylinder repair, I would highly recommend going with LN because they have figured out a package (combination) that works well. Their JE pistons are also custom made. Not to mention their expert experience and how great Charles and their staff are. They just go beyond in customer service.

Also definitely go with a 3.8 or even 4.0

Jake's class will guarantee the knowledge you need to be successful on your first try. If you can't attend the hands on class, you will have to do a lot more homework and accept the fact that it may cost you more time, effort and frustration (e.g., redo something if you missed something 50 steps before).

Can't wait to see your future update on this rebuild.

Porschetech3

That sucks about your cylinder scoring. Great clarity from your borescope, thanks for sharing.

Ahsai

One more thing. Are you sure the price you got from Millenium includes the new billet aluminum cylinders themselves? The NSC plating is just the plating and honing part. The LN nickies process includes removing the whole cylinder down to the deep part of the engine case. That removes most of the parent material before inserting the stepped nickies cylinder.

http://support.lnengineering.com/201...er-cayman-911/

I think even iron sleeves are like $500 per cylinder.

OutNSpace

Thanks, I'm interested in going to the 3.8 or even 4.0, but only if there aren't cascading costs for other things that would need upgrading, like the cams, chains, etc. Any idea if that is the case?

I wouldn't go the iron sleeves route - doesn't seem right to me.

Ahsai

My understanding is the 4.0 will require new rods. Other than that, most of the stock components such as cams and intake lifters can be reused on both a 3.8 and 4.0 builds.

Charles Navarro

Typically I will advise that if going larger than a 99mm bore, that the rods be upgraded, due to the increased piston mass. That said, plenty of people have just put ARP bolts on the stock rods. If you never will autocross or track the car, you'll be fine. If you change your mind or someone later on tracks the car, that's a different story. I've seen too many stock rods break at the beams on track to not advise replacing them for that purpose

We are working on a cheaper option through JE's sister company, K1, but we are still quite some time off from those rods being tested and ready. Goal is to be well under $1k so that we have a price point for a quality rod to our specs that are less money than a Carrillo.

OutNSpace

After thinking some more on this I'm concerned with putting the higher combustion loads on the existing head and crank.

I will have my heads pressure checked but even if I stay with the 99mm bore (3.6L) should I be concerned about this?

Remember, daily driver, not destined for the track.

Charles Navarro

The stock bore size on a 3.6 is 96mm. When sleeving the block, 99mm Nickies take the displacement to 3.8 liters. This is the same bore size as a stock 3.8. That's why we say that's the limit for street with the stock 3.8 rod, as we don't want to go bigger (heavier) than the original pistons.

Even at 96mm, I would recommend installing a set of ARP rod bolts. Cheap insurance.

Don't be concerned about load on the heads or crankshaft, even with increased displacement. That's a non-issue. Just make sure you have both properly checked by experts familiar with the M96 engine.

Lastly, make sure to put a new dual mass flywheel. No single masses with a stock crankshaft. If you use a billet crank, that's a different story :-)

OutNSpace

Thanks, given your response I'm back on with the 3.8L displacement and I'll do the ARP bolts.

For anyone reading this thread in the Northeast area (North of Boston) - can anyone refer me to a shop around here that has build experience with M96 engines?

AWDGuy

That sucks. Sorry to hear the news.