Riccardog

hello,

I have a question regarding the 3.6 engine. As background, I am looking at purchasing an 04 997 C2 3.6 with 47k miles on it (UK model, so registered in 04 but 2005 MY).

The car had an engine rebuild under warranty in Sep 2010 by an OPC (Official Porsche Center). When I phoned them up to confirm the work they said that the crankcase was replaced along with cylinders 4 and 6 only.

The vendor, an independent dealer specialising in Porsche and with trained Porsche technicians on the shop floor (he left the OPC network last year) says that they can see that the crankcase was replaced and, therefore, by the nature of this work, both banks of cylinders and an updated IMS would have been installed.

So, my question is, what is likely to be the correct story? To be fair, the guy at OPC seeemd a bit 'dozy' and was just reading off his screen looking at parts, so I am not sure he has the full story.

Hella-Buggin'

Can you ask for a copy of the work order & / or invoice for the rebuild? That should have a detailed list of what was used.

cibergypsy

If I am not mistaken, the cylinders are in one piece with the crankcase so, by replacing the crankcase (assuming both sides were replaced) then all the cylinders are new. He may have referred to the pistons in cylinders 4 and 6 themselves but, as Hella-Buggin' wrote, ask for a copy of the work order/invoice and see what was done.

Riccardog

Thanks for the replies. Unfortunately its not possible to get the invoice here in the UK due to data protection rules...

Cibergypsy, what you mention fits with what the mechanic at the vendor said. Sorry for the basic question, are there two crackcases? Can these be seen from underneath the car?

Macster

The engine has its block split into two halves. A left and right half. AFAIK you can't replace just one half, both are machined as a set and are not replaceable separately.

As another poster noted the cylinders are part of the engine block -- each half has 3 cylinders -- and are not replaceable. Likely the block (both halves) was replaced and the old engine's servicable parts moved to the new block but the pistons and other hardware for cylinders 4 and 6 were replaced with new parts.

Does the engine still have any warranty?

How does the engine sound? How does it run?

Or if you're worried, walk away. There are plenty of cars out there without an engine 'rebuild' to fret over this car.

Sincerely,

Macster.

Riccardog

Hi Macster,

Thanks for your reply, very useful to understand how these engines are put together. I seem to know all the potential issues with these engines but don't actually know so much about how they are built.

Given the not uncommon issue of cylinder scoring in these engines I consider the car in question, with its recently rebuilt engine by an OPC, as a bonus, which is why I am trying to obtain more information to confirm that this view is correct. I don't think that I should walk away and find another car, possibly still on its original engine, which could come up with the problems which were already addressed on 'my' car.

There is no warranty on the engine itself as it expired in Sep 2011, however, there is a comprehensive warranty from the vendor and I also plan to put the Official Porsche warranty on the car once I have owned it for 90 days (which is the minimum ownership eligibility period).

The car drove fantastically, strong through the rev range, and the clutch and gearbox where also a pleasure to use, so no concerns in that sense, I just want to make sure that I have a good picture on what work was done on that engine.

Macster

If the engine that was rebuilt was of a sound foundation and this is where the experience of the engine rebuilder comes in -- he should know how to eliminate engines that should not be rebuilt simply because they are a poor candidate for the longevity one expects from a rebuilt engine -- and the rebuild was good then the engine should be as good as factory and may even be better.

That you have driven the car I hope enough and can report the engine sounds fine from cold start and idling up to near operating temperature and runs good under all reasonable driving scenarios and still remains quiet and fluid tight afterwards suggests the engine is healthy and should deliver the experience you want from it and the car.

I see the rebuild was done at an OPC and you can get a warranty on the car, and the engine, so this removes almost all of the risk. Just an aside, the warranty only has real value if you drive the car. No engine, new, used, rebuilt, ever 'died' from just sitting around not being used. Problems, if there are any problems, only come to light from use. If you get the car and the warranty and let the warranty expire on time and not miles, the warranty will not be as much value to you as it would otherwise.

(I bought a used 03 Turbo with just 10K miles and in pristine condition. The car with a 2 year, 100K mile CPO warranty. I drove the car. Alot. And at around 35K miles and again at around 50K miles issues appeared that were covered by the warranty. These issues would have almost certainly appeared had the first owner driven the car more. While I didn't put 100K miles on the car when the warranty did expire on time I have put over 50K miles on the car.)

Sincerely,

Macster.

cibergypsy

How common is the cylinder scoring issue on these cars? Is it, in any way, as common as the IMS issue is? What years are mostly affected?

gpjli2

Hartech.org buyers guide section 5 addresses these issues. Remember the #'s are small and higher with the '05's. But it happens

Riccardog

From the Hartech research it would seem that cylinder scoring is quite common, whereas the IMS is generally seen as being an issue on only around 5% of engines and even then if within a certain mileage (~50k mi) it hasn't happened it becomes even less likely. The 06 MY (ie: cars produced after Aug 2006) had an update to the IMS design which makes it less likely to be a problem, whereas the Gen 2 model with the DFI engines gets rid of it all together, although its too early to tell whether there will be other issues with this engine as well.

Sometimes when you read Baz's (the owner) posts on other forums (pistonheads.com or 911uk.) it even seems that he suggests that 100% of cars will be affected as its a cooling design issue. Having said that, keep in mind that, by the nature of his work, he only sees the bad engines. As he offers a maintenance/guarantee plan himself one could also potentially question his motivation to have people a bit more worried and therefore signup to this plan. Not saying I do, but you can see a potential for conflict of interest.

Whats the view in the US? I think LN Engineering is one of the leading experts on these engines, right, what do they say?

Sometimes if you read too much on forums etc you can end up being just paranoid and give up on your dream car, keep this in mind.