Who has had a Hartech Rebuild?

Hi all, Just wondering how many 996 owners have had a rebuild by Hartech and what miles you have clocked up on said rebuild so far? I have a 1998 996 3.4 that had a Hartech rebuild 40,000 miles ago prior to my ownership, just trying to ascertain how long I have to save up before it needs another one! Rebuild was sadly not a 100% rebuild of all cylinders but did consist of: All bottom end bearings (big end, mains and thrust) crank shaft oil jets New IMS New RMS New timimg chains and guides 1x new cylinder line (No.6 I believe) All other cylinders fitted with retaining rings to help prevent them going oval

Hopefully Baz of Hartech will comment as he is the authority on this subject. IMO, given others have run these engines to 200,000+ miles on the original crank bearings (though the received wisdom is that the bearings should be replaced by around 110,000 miles to preserve the crank journal surfaces), I would have thought that you're likely to be good for another 60,000 miles at least. Crank wear is the killer of early engines rather than IMS bearing or bore score, so as long as the next (preventative)rebuild is within the mileage recommended by Hartech then I'm sure the bill will be relatively small.

Blimey Paul , I had a Hartech rebuild on my 997 gen2 last year and 7k miles ago . I would like to think that the cars now good for another 100k minimum and would expect yours to be the same :thumb: :thumb:

A rebuild on a 997.2! I thought those engine were supposed to be bomb proof compared to our shitty M96s. What happened?

:floor: :floor: They are a much better engine regarding the known flaws of the M96/97 but I do prefer the M97 engine overall . mine failed due to human error and not a flaw in the engine. The car had been fitted with cheap Chinese 200 cell cats which broke up and due to the fact the cats are so close to the engine on the gen2 on overrun metal fragments of cat material were sucked into the engine . The car now has Cargraphic trimetal 200 cell cats fitted. It took sending it to Hartech and having the fragments analysed to find what the issue was . They were then able rebuild the engine and they did do a fantastic job :thumb: :thumb:

Funny you say about the early engines being better in terms of bore score.... mine is a 98, about the earliest you can get. It had the engine rebuilt by Hartech at approx 70k due to bore score!!!!

There's different types of bore score. What you 98 car had isn't the generic flaw in the 3.6 onwards engines. The 3.4 is most deffo the most robust, just like the 2.7 in the Boxster - smaller is stronger.

I've had a few things worked on for my engine by Hartech, I was one of the first to have the regular single row bearing fitted (seals removed) and I had them fit another new IMS bearing the next time it needed rebuilding. All the cylinders have had top hats on them and re-rounded (as mush as is possible) I also have had a couple of liners fitted but I don't remember what I actually got done it was so long ago. I did the rebuilds myself so I also fitted a billet oil pump drive and have had new chains, guides, crank bearings and anything else that was required at the time. I am thinking of another preventative rebuild in the near future as I guess I have piled the miles on since it was last opened up.

Different types of bore score? Enlighten me on this one please? Scores on a bore are scores on a bore surely? my 98 3.4 had to have a complete new engine form Porsche at 90k due to d chunk, the replacement short block 3.4 direct from Porsche then failed 70k later due to bore score. So that's 2x 3.4 engines that have failed to make it to 100,000 miles. Wondering if I can expect any better from the Hartech rebuild. What gets me most about all of this is that the engines are not even part particularly powerful for their displacement. Bmw were getting more out of a 3.2 during same era (e36 m3 evo 320bhp)

Scoring on a 3.4 vs. 3.6 isn't the same failure mode. Different cylinder liners and piston coatings on both engines. Don't know the full details off hand but Baz has posted about it on here somewhere.

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Early 3.4's had weaker vylinders (that can crack or "D" chunk") but hard coated pistons that rarely fail. The last 3.4's (and any replacement engines) had the later plastic coated pistons that are not so resilient and can score. We understand that the change in piston coating resulted from E-U legislation banning the chemicals used in the original hard piston coating process - although I am sure the screen printed later piston coating is less expensive! Bank 1 original bores seem to last about twice as long as bank 2 - but it is too long an explanation to complete here - so if you want to find out why contact [email removed] and ask for the technical report on t he main failures. if you don't like long technical reads - however - I would just accept the above. Baz

Just about to tick over 100k miles since my 996.2 was Hartech'd - all still going strong.

Now there's a car that gets driven 8) How long has it taken you to clock up those miles Rob?

Unfortunately, my 98 was diagnosed with bore scoring in 2018, but I am planning a full rebuild with Nine Excellence in Horley. Don't do much mileage as it's weekend car mostly but has done a 2000 mile round trip to Austria last year. So far so good!