M96 Engine Rebuild time

Hello All, You may have seen the thread I started on removing the engine and gearbox from my 996 C2: http://911uk.com/viewtopic.php?t=126372 The reason for doing it, I didn't go into at the time. Long story short, I do my own servicing, (which is a whole other thread with some very good arguments either way) and after a year and 5000 miles of running Millers Nano 10W50 I decided that I should change the oil and filter. I had dropped the filter 1500 miles before to get an oil sample for analysis as I'd thought that fuel was getting in the oil. (It hadn't, and the report came back very positive with less than 10 parts per million of copper and otherwise good clean oil 'indicative of an engine in good condition") When I dropped the filter, I had a good look through it and there were no undue bits stuck there. Anyway, when checking the filer this time there was a slight increase in non-ferrous tiny silver particles. That didn't worry me as the oil hadn't been changed last time. What was concerning though, was 2 small flattened flakes of bronzy coloured non-ferrous metal I found in the filter housing. The hot idle oil pressure wasn't great either, creeping down to slightly less than 1 bar. I was very worried to put it mildly. I was now sure there was a problem with a bearing. This is the third 996 C2 I've owned. The first two were sold as I just felt too paranoid about the whole M96 engine thing, though both had been operating fine. I bought a Lotus Elise S1. Enjoyed it for 3 months, but it wasn't anywhere near the experience and sold it for a small profit. I thought about an old school Impreza Turbo, or Renault Clio Trophy. There just wasn't anything else that interested me enough. I considered a Cayman, but they have engine issues as well, there values are dipping still and it's not the same rear engine 'thing'. Then bought this car. It's a 1998 C2 manual. Aero kit from the factory, Cable throttle, LSD, Mo30 and Sports seats, sunroof delete and had the 996.2 GT3 alloys. (Though mine appear to be Porsche Tequipment supplied – Thanks Colin separate thread) I've spent a fair bit on rebuilding the suspension and brakes, cleaning painting and fettling. And a new clutch and dual-mass flywheel. As you can imagine, the money I've spent, I'm not going to get back just yet! ......... and the engine appears it maybe borked........ Disbelief/anger/bargaining/pleading/acceptance. Yep all of those and several times through too. So, what to do? The thought of selling it on to some other punter was never really an option. It would be someone like me or you, who knows their cars, and their 996's and wants a car with this spec. Probably sink hard earned money and maybe a loan into it. Traders would give be a lot less cash and do they deserve to be lumped with it either? I have decided to rebuild it, and as it's a keeper, the engine has been posted off to Hartech. I spoke to Grant at Hartech yesterday and I will fill you in on the result of the strip down and inspection in the next post. Regards James

All very interesting, best of luck with it. MC

Aye, best of luck there chum. Interesting story too, keep this thread updated :thumb:

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We'll all be there some time, most likely! :thumb: Once Hartech do their thing, hopefully all that anxiety about the donk will be lifted and you will get to enjoy the (very nice) car to the max. Going 3.7L or anything?

3.7! 3.7! 3.7! Everybody chant together!!

:stay: All the best with the rebuild :thumb:

Hope everything goes well and not to painful on the old wallet. Would be good if you can update with progress.

Hope I'm a long way off a rebuild but I'll be following this thread with interest.

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Thank you all for your comments. Much appreciated. I understand that there will be some readers of this that will think spending close to 10 K on a rebuild is nuts, but equally there are people on here that will see the opportunity that this affords. If you are prepared to keep the car to drive and enjoy. I myself am not totally convinced I'm doing the right thing as far as sound economic sense is concerned, but as a friend said to me "Hey, its your hobby, it doesn't have to make financial sense" Asterix_the_gaul and EGTE - Ha ha, of course its in for discussion. More on that below... I have not had the written report yet, and won't receive one for a week or so due to leave commitments at Hartech, However speaking to Grant, he tells me: 1.) I stopped driving the car just in time to save the crankshaft - gulp! Car is on 92,000 miles by the way. 2.) The main bearing at the front pulley end was shot, and down to copper. Though the journal on the crankshaft is not scored. 3.) He believes this is down to wear not due to any failure. Otherwise things are in usable condition, with only light marking on the bores. So, I have a week or so to consider options, and then a chat with Hartech to finalise what I want to rebuild. The car will be used almost exclusively on the road. I might do a track-day, but I doubt it. (Done before in other stuff including hillclimbs and sprints) It will have to sometimes do motorway commutes and long distance touring, as well as B roads blasts, and fast A road stuff. 3.7 - I did ask, but this apparently is only an option for cars that are left at Hartech as the engine would need a remap before being given back to the customer. As I have removed my own engine and will be refitting it again, this is a non-starter at the moment. - Shame I have thought about getting the whole rotating mass front pulley/Crank/Rods/Pistons/flywheel and clutch cover balanced and a single mass lightweight flywheel. But various comments from M96 engine owners, on the noise vibration and harshness at idle and low rpm does put me off. Also I have done a bit of internet research on torsional stresses and resonance within the crankshaft. It makes interesting reading. In summary, you can consider the internal combustion engine as an impact drill driver. bang bang bang bang bang...... The drivetrain is subjected to lots of individual accelerations as the crank turns reciprocating motion into rotational. A dual-mass flywheel (And the high moment of inertia of a heavy flywheel) helps to smooth the rotation which benefits smoother running of course, but also less snatch and strain on the timing chains (driven by the crank) and valve train, and gearbox. This will of course promote engine and gearbox longevity. But, I'd like a more responsive engine......! I have found a firm that can make a "Rattler" or a torsional absorber flywheel and they may even have a Rattler clutch cover already designed for these engines. I will find out on Monday or Tuesday when I have a chance to talk to them. This may allow a single mass flywheel to be fitted without the penalty's listed above. Other than that, I want to make the engine long lasting, reliable and powerful. I imagine that most of Hartech's upgrades may be fitted. i.e. Cylinders, possibly new pistons, as the old ones can only be reused with new piston rings to suit the nikasil liners. Timing chains and tensioners, new bearings (of course) and cylinder head overhaul. IMS - there is the option of the bigger bearing, or remain with the existing smaller one (New) and flip the dust shields off to allow adequate lubrication from the engine oil rather than grease. Any comments on what to fit are of course welcome. I know that there are some members here with lots of personal experience and knowledge in this field. Also any thoughts on things that should be done whist the engine and gearbox is out are again welcome. I do have a finite budget so this will not be a money no object build, but more one with some thoughtful additions and modifications that enhance the characteristics and retain reliability. Cheers James

If it were me in your situation now, I'd be getting the car trailered up to Hartech and let them refit & remap with the 3.7 option.

Interesting read, Is it the original engine? Only I thought the 98 cars came with the larger IMS as standard. Hope all goes to plan for you 👍

Nearly all 3.4 engines had the original dual row design.

If it were my car, I'd fit new bearings and chain guides, anything that isn't worn would stay, but then I'm an "if it ain't broke" guy and I really like the performance of the car as it is. I wonder what a simple OE build would cost, sounds like you saved your crank so just 'consumables' and labour. I'd probably buy a banger daily drive and do it myself over a few months. I'm going to continue cutting open my filter at oil change every 6k and millers oil analysis every 12k. Mines on 133k atm. Did you get a pic of your "flakes"?