My crankshaft is making me cranky...

Recently I was having a semi-spirited "therapy drive" which was rudely interrupted by a very short CEL followed by an equally short flashing oil pressure light. Car hesitated slightly and not less than 1/8 mile later, the engine died and I knew right away I had serious trouble on my hands. I had the car flatbedded to my mech right away. We dropped the pan and found copper colored, non-ferrous metals in the sump and oil. Droped engine, split the case and discovered that cylinder 6 rod bearing spun, and had started to take out the nearby mains... The car is still relatively new to me and during the PPI/buying process I had them drain and change the oil (drained through a 100 micron strainer) as part of the deal. I also handed the mechanic an LN spin on filter adapter and Bosch filter along with the the oil I brought along. One of the PPI write ups was that there was a visible bead of RTV around the sump plate which the mechanic felt was a little too much. Wondering now if there could have been some momentary oil starvation caused by a chunk of RTV having broken loose and plugging a narrow oil path, but close examination of the crankshaft also shows some pitting, which I guess is from oxidation due to car having sat for long periods of time undriven. Carfax did show that the car was only driven 150 total miles in the last three years leading up to my purchase, and receipts show only 3000 miles since major service for IMSB/RMS/Clutch/Tranny mount swaps were done in 2011. The receipt for that work showed that IMSB swap was done at customer request and not out of need. My car now has 90k miles, so it looks like it went from daily driver to garage queen in short order back in 2011. The good news is that no dirty oil made it's way into the combustion chambers or the cylinder heads, so no head work needed and the cylinder walls look fine. I added some close ups of the worst area where the damage started... as well as the main journal at the other end of the crank and the basket. I know it will need to be mic'd and magnafluxed to see if it truly is still useable, but I'm wondering if the pitting is a deal killer from the get-go. And with the apparent lack of oversized bearings available for the 996 motor (according to reading here) should I even bother with trying to have this crank fluxed and polished, or should I be shopping for a suitable replacement instead? Prices for just the crank on ebay are insane, and buying one like that without seeing it first seems just as risky as having mine worked... I'd prefer to have this one ground/polised and refitted. Some of the related threads I looked at here are a few years old and I'm hoping things may have changed a bit for the positive in that time... Is it really true that oversized bearings are not available for these?

1) That sucks. 2) How much metal in the sump? Any chance you have a photo?

Photos of the sump drop are on my phone and I can't upload them right now, but there was hardly any metal in the sump at all, only tiny pieces and grains. The bearings were not yet fully destroyed... Here is a pic showing what's left of the two halves of Cyl #1 rod bearing.

Does this help? http://www.design911.co.uk/fu/prod12...e-99610120904/ https://www.europeanpartssolution.co...sized-bearings

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YES! That may help very much... Are the 3.4L bearings the same size as the 3.6L bearings?

For the RTV to plug up the oil galley it would have to make it through the oil filter, this seems unlikely. If you have bad pitting on the crank bearing surfaces it could be the cause, the pits would grind away at the soft white metal shells and spin them, once the white metal was thin enough the oil pressure would drop and your warning light came on. As far as I know, the crank is only hardened a few thousands deep, so a re-grind and thicker bearings won't work. Trying to re-harden the crank after grinding is also risky, as it can warp or develop cracks. I think your best option is a replacement crank, also you'll need to do some serious cleaning to get all those metal particles out of everything before re-assemble.

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Maybe. This is probably something you should ask an expert, rather than random strangers on the internet support@europeanpartssolution

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Wait, what? I thought everyone here was an expert.

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LOL! Me too... Experts will be consulted, for sure.... but this forum is such a wealth of info that I felt it prudent to start here.

Good Crankshafts for this engine are hard to find. BTDT I found and used a local ,ultra specialist repair place that repairs some(subject to pre-qualification) crankshafts.But I had a specialized Porsche machinist check their work.It was perfect. http://www.marinecrankshaftinc.com/ Maybe someone similar in your area would know ? This is a question for experts,not amateurs (like me) Good Luck saving the c/s

if you do "fix" this motor .......sell the car............quickly

I was in the same boat, I ended up buying a used motor and stripping that down and rebuilding it, I sold off all the good bits from my old engine , heads and good pistons get good money, case halves also , you could probably recoup a fair bit !

There was a crank in the member classifieds for $1,500 some time ago. Undersized bearings will cost you and non-Porsche bearings are a gamble. Call Shaftech if you want weld. Grind and use Subaru bearings - call SSI in MD.

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That's not my style or intent. We are not just slapping this motor back together as cheap as possible. If I could afford a Raby rebuild, that's what I'd do... but in place of that it will be properly cleaned and put back to good specs with some prudent upgrades along the way. I will be taking lots of photos and keeping all receipts. Afterwards, I plan to drive the car well long enough to prove it is reliable. Note to self.... don't buy my next car from extanker. LOL!

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I will definitely call them. Thank you!

I'm in a similar position to you, went through the pros and cons of welding, oversized bearings etc etc. My issue is with the thrust faces on the crankshaft. I'm approx 20 thou over, magnafluxed ok, polished and looked like new. But still seems like the consensus is to replace the crank. I think Jake Raby chimed in as much. I was tempted by welding etc, but shipping to California and reimporting is a PITA from Canada. (As I found out with my LN Nickies). Eventually found a crankshaft available from these guys, their service has been very good so far. I paid $1200 US for the replacement plus shipping etc (to Canada). http://www.dcauto.com/ Regards 3.4>3.6 as I understand the crankshaft dimensions are the same. Bore size went up for the extra capacity and switch over to cam drive for IMS rather than Chain. Hope this helps.

What's available isn't proven. It was haphazardly created, and thrown on the market without in depth evaluation. In every instance where I have tried to regrind these cranks, I have experienced a compromise. The heat treat is not deep enough for the surface to be ground effectively. Usually wear like what I see in these pics will also lead to a crankshaft that fails the magnaflux test for cracks. For many years I've been working with this challenge. We've even fitted Chevrolet rod bearings to these engines, and tried to make others work as well. I have a couple of test engines still going with these, but to date the longest we've had positive results was 14,000 miles. Thats about 10X less than I'd be willing to accept at minimum.

I had my crank welded and regrinded in 2011, have done 57k miles after that. So it can be done. Company that did the repair has good reputation for these kind of repairs.

How much does this cost in comparison to looking for a good used crank?

I had a similar failure. I spun number 1 and popped out my thrust washers. I was lucky enough to find a partial motor that had suffered a cracked head. It yielded a good crank and some other parts I added to my rebuild or sold. I struggled the whole time I had it apart with the "sell it immediately" mentality. You know what? At the end of the day it's just another motor. If you take your time and pay attention to the details it will run just fine. I have 1500 miles on my budget rebuild and my 996 is NOT FOR SALE.

My crank, block-halves, heads and all related short-block guts were delivered to Engine Lab of Tampa today, and a meaningful decision as to how we move forward will be made after the crank has been magnafluxed and measured. The block halves were already in a tank getting cleaned up for a proper eval as we were on our way out the door. http://enginelaboftampa.com/ Schnell Gelb will appreciate that when we spoke about the availability and repairablity of cranks, the owner of the shop mentioned Marine Crankshaft in California as a resource. Apparently they have done business with them several times. Feeling optimistic of good things to come, even if the crank is beyond use... Thanks to you all for your info and positive vibes!

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That's a pretty good test of endurance for this repair, are you easy on the motor? or do you track the car / redline frequently? If you could mention the name of the shop I would be interested if they did any nitrideing or any other hardening procedure after the weld and regrind. AFWIW if you have a 3.4 engine, the crank from a 2.7 or 3.2 from 2000-2003 Boxster will work as long as the IMS drive is the same, ie both dual row chain or both toothed chain.

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Just passing on some hard-won knowledge. As these engines age, we are going to have to pool our contacts to keep the best M96 repair shops in business.With Boxsters becoming so cheap ,they are getting a throw-away-when-broken reputation .That causes the best Indies and repair shops to look elsewhere for business. The "I bought it because it was as cheap as a Miata" guys will be the death knell of the older 2.5 Boxsters. So let's help keep the best guys in business.

If you want to weld, I'd highly recommend Shaftech. If you have one journal, about $750 plus you shipping to them. More journals, more cost. Crank will be checked, welded, ground, balanced, and nitrided. They do business for a reputable Porsche builder in CA and are used by one of he best machine shops in the DC area. Do a search. The two places in CA have done good work, but there are complaints. If you are getting work done for yourself, a little different than through an engine builder that does lots of business with said shop. Everything is a gamble and there are a lot of opportunity for gotchas if you gamble wrong.

I had the crank fixed here in Finland, cost was 350€ for rod 5 journal only. I have tracked the car and use it as a daily car at summer time.

So..... I found out my crank had 0.002" of rollout, which basically means its bent. That explains the horrendous clearances that can be seen in the photo below. My engine must have been fighting itself with every RPM! Due to this discovery, the rebuild shop I'm dealing with does not trust the old crankcase/basket either... Luckily, I was able to source a replacement crank & basket that came from the same car, with only 24k miles on it from QualityPorscheParts out of New Mexico. There's no visible pitting on the journal and the crank looks practically new. The pricing was very competitive and I've bought parts from them with much success in the past. So, while those parts are en route, I'm awaiting rebuild quotes for either a standard build staying at 3.4L using the original pistons and just new rings, or a 3.6 rebuild that involves steel sleeves and new pistons. I know all about nickies and what a great reputation that product has, but they would push this build well beyond my budget and they are not an option for me at this point.

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If I'm not mistaken, this is Jaetee's car... 2000 Cab with 93K+ miles.

Almost, B3... I sold my Cabriolet on BaT back in March/April timeframe after the full engine-out refresh and 99k miles on it. I replaced that car with a 2000 Millennium Edition coupe with 90k. Thread: https://rennlist.com/forums/996-foru...ion-coupe.html

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This is an interesting example to justify why I let my Machinist deal with the crankshaft restorer(Marine Crankshaft in Santa Ana). That way the Machinist examines the work and he does lots of business with them.If I had gone direct and there was a problem ..... not good. This si a subject that requires huge amounts of skill and experience to be proficient and to develop a reputation in.Well worth the extra $ imho.

Saaaawwweet man... I don't remember this transition for you, but do you regret given your current situation?

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I'll let you know after I pay for this engine build... LOL! Nina (the black Cab) was my first, and will likely ever be my only convertible and I figured out in that time that I'm not a convertible guy. My family could care less, too. Had a great winter in the car and drove it top down quite a bit, but my son and wife were more of the "can we put the top up" types. And in the summer, it's actually too flippin' hot here to drive with top down too much. It was good while it lasted, and I'm satisfied with the money I got for it when I sold it on BaT. I got the replacement car for considerably less than I sold the cab for, so this build isn't hurting "TOO" much... (still hurting though). I really wanted a coupe all along and I love the paint/interior and feature rich appointment of the Millennium edition. If I pony up to punch it out to a 3.6 and get some extra oompf out of the engine to make my C4 match the performance of my prior C2, then I'll definitely not regret it. The Black convertible was noticeably faster off the line than the Millenium edition.

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I completely understand where you're coming from, and if I were attempting to re-use my old crankshaft, I'd let engine lab handle it. But I've bought from the seller before, and they have a very fair return policy. Engine Lab will magnaflux and check all the necessary C/Shaft specs before we spend any time installing a bad shaft. Shaft & basket are coming from a wrecked car, and with the miles and visual condition apparent from the photos, I feel really good about this purchase. Beyond magnaflux and measuring, this crank should need nothing more than a routine cleanup and maybe a light polish.

Hi guys, this is my �99 3.4L Main journal with particle break out. How bad is this? crank. It�s straight and crack free but surface particles are breaking out at 4 main journals. I�m not sure if I should should: - build it back up with new bearings. - get it polished. - get it ground and re-nitrided and fit undersized bearings. Any advice would really be appreciated!

Crankshaft hardness is not deep enough for a hard surface after re-grind. Crankshafts can be ground and nitride but nitriding adds a small amount to the diameter (usually 0.00025 to 0.0004) and leaves a dull slightly bumpy surface that has to be polished afterwards. We have done this and they have run perfectly for years ever since but up to now managed to find enough used ones to cope and a bit worried about the consequences of the re-hardening and re-grinding process if it did go wrong and we were held responsible and had to pay for a whole rebuild again - so do not now offer the solution (may have to re-think as good used crankshafts are becoming less available). We have made new cranks with deeper hardness that would allow regrinds but they are a bit more expensive than a new original Porsche crankshaft - so for most - they would prefer the standard replacement. When "new bottom ends" were cheap it was a source of pistons and crankshafts but as the price went up and Porsche insisted on associated engine numbers that too has become uninteresting. Run out of 0.002 to 0.004" is common and probably more to do with stress relieving than anything else. The Cayman S, 3.6 and 3.8 engines have bigger main bearings than the previous smaller capacity examples. Baz

Wow... four years since I posted this thread and I've been quite absent from here.... This is deserving of an update... My rebuild took a lot longer than it should have, due to really slow work from my mechanic and my life forcing the car rebuild to the back seat... Mechanic had to move his shop twice while we were rebuilding and it took over a year to get it running properly again. I had full intention of writing up and documenting a rebuild thread here, but since this went all down I have been laid off from my job of 19 years, got divorced, and moved into a different home. No sorrow here, so please don't reply with a bunch of "sorry to hear that" comments. Life happens and we define ourselves by how we handle moments of adversity. The divorce was lawyer-free and we are on very amicable terms, my kid is not screwed up over it and I now live in a nice townhome where I don't have to maintain a pool or do any exterior maintenance. Onward and upward! Best of all, I still have my M.E. 996, and boy does she run and sound great! I had Engine Lab do the machine work to the heads and reassemble the rotating assembly/block, and my mechanic (mostly him) and I put it all back together and made her go again... Here's the list of what has been done to the engine since: The crank and basket from the 3.2L Boxster S with same part number was practically pristine and saved the day... Engine is now somewhere between a 3.5L~3.6L with Darton ductile iron sleeves, New pistons & rings from Woessner for those new sleeves LN Dual row IMSB bearing installed Heads rebuilt and gasket-match porting performed on the exhaust side I bought two additional IMS Shafts to have them all spun, so I could use the one with the least amount of rollout. (.002) All moving parts of the rotating assembly have been dynamically balanced prior to reassembly. Installed a lightweight flywheel Installed Agency Power underdrive pulley Added 200 cell sport cats to the Agency Power headers & sport mufflers (sounds fantastic) Installed Tarret Engineering Oil Sump baffle Basic ECU tune from innovation motorsports. Engine runs smooth as silk, and the car went from "quick" to "wow, this thing is quite fast" I've put maybe 12k miles on her since then... Engine is reliable. Happy motoring!

Yes.......,What comes out of engineering is rather different than what comes out of marketing