vwrado

Just curious to see if anyone out there have rebuilt their own 996's engine? It seem that every engine related problem everyone suggust buying a new engine.

I have rebuilt a couple of the top end of bmw's engine in the past as well as replaced the head gasket and I can't see how porsche's engine would be impossible to rebuild. To replace an engine with just a blown head gasket is rediculous.

I'd like to know that if an engine fails, would it be a better idea to have it rebuilt? (Assuming I am going to dismantle the engine in my garage, take it to the machine shop, replace all necessary parts such as rod bearings, head gasket, pistons rings, etc, then reassemble it myself) In my mind, this will only cost a few grand at most plus my many hours of labor. Plus I think its fun and a good experience where I can learn about the flat 6.

Also, upon quick research I have found this...

http://catalog.worldpac.com/zygmunt/...ine+Gasket+Set

And they have many other engine related products here:

http://catalog.worldpac.com/zygmunt/...Children=false

jury_ca

You'd be hard pressed to find parts because Porsche recommends replacing engines.

Doug Donsbach

I believe the parts are available. Examples:

http://www.pelicanparts.com/PartsLoo...-10-Frame3.htm

http://www.pelicanparts.com/PartsLoo...-00-Frame3.htm

http://www.pelicanparts.com/PartsLoo...-05-Frame3.htm

juankimalo

If you are able to rebuild an engine by yourself, you are a lucky man.
The main handicap to pay for a rebuild engine in a mechanic dealer is the labour cost. A good friend of mine is an independent Porsche specialist and he told that It's cheaper to buy a new remanufactured engine than rebuilding it in his garage.
Too many hours of labour...

If you save this money in labour cost, you could do it cheaper

vwrado

Does your friend have any info on where is the best places to get parts?

I am not too worried about labour hours as I will be taking my time to have it completed. Also, I think this may be a good learning experience.

Chads996

FWIW - I was told that the Boxster 2.5 & 2.7L engines have been released from Porsche's hold and will be no longer available as replacement motors in August this year. I am sure the 3.4L for the 996's are not far behind. Look for more and more aftermarket groups making upgraded items in the near future.

C.

juankimalo

He usually purchases them in a Porsche dealer, www.fvd.de , http://www.design911.co.uk/ , pelicanparts ,

PTEC

Why would you be rebuilding this engine? All parts are available directly from Porsche.

vwrado

My engine is making a knocking sound like a loose coin in the dryer. The sound is very inconsistant and appears to be coming from near the IMS area. The car still runs 100% normal but I havent driven it much.

Worst case is that I will rebuild the engine. I will find out soon enough but I sure hope this is not the case.

Also, I was told that Porsche does not sell parts to rebuild engines. Is this true or are the shops bsing to me?

manny_g

not sure about the na engines, but according to some well tuners you will need to spent at least $4k to $5k just in special tools to re-built the tt engines.. that's a big investment right there...

PTEC

Sounds like the IMS failed and the nut is rattling around in the bell housing, if thats where the noise is really coming from. If you want to have a rebuildable engine don't run the engine any more than is absolutely necessary. I would drop the oil filter and inspect for metal. If the engine is rebuildable, ie no damage to the case halfs/cylinder walls, the only real obstacle to doing it yourself is not having the special tools. You need a special set up to install the piston wrist pin cir-clips for the bank 1 pistons, IRC(Its either bank 1 or bank 2, I dont remember which side it is for sure). You would have to get really inventive in order to install the wrist pins without the factory tools. There are a lot of other tools which the book calls for but most things can be done without them but if you blow putting in a cir-clip itll fall into the case and you'll have to split the case again and fish it out then start all over.

vwrado

Thanks for the response and that is very informative.

I have a few questions. If the IMS fail, would the engine still be running as good as it is now? When I rev up the engine slightly to about 1100rpm, the rattling goes away. Any ideas?

htny

I'm not speaking from experience on these motors, but should the intermediate shaft fail completely I would think your whole valvetrain would stop moving

PTEC

The term "IMS failure" is a really a very broad term. The term "failure" is kind of an exaggeration. The intermediate shaft runs parallel with crankshaft right? At the front (crank pulley side) it drives the oil pump and has the sprocket for the timing chain for bank 2. At the rear (bell housing end) theres the sprocket for the timing chain of bank 1 and a bearing for support. The bearing center section has a M8 stud that protrudes through the support and is held with nut. You may have seen pictures of M96 engines with the transmission/flywheel removed and you'll see the nut below the crankshaft/rear main seal. Well, when you hear the phrase intermediate shaft failure it would lead you to think the intermediate shaft snaps in half. What actually happens is the M8 stud shears off and the nut falls off backwards into the bell housing. This will sometimes cause an oil leak and sometimes a nasty noise as the nut bounces around inside the bell housing but in some cases the engine can run as if nothing at all is wrong because the main portion of the IMS is still spinning and driving both timing chains. Eventually what happens is the IMS runs without support and able to walk around and results in all kinds of metal dropping into the oil pan which eventually gets sucked up by the oil pump and you can imagine the rest. But to answer you're question, an engine can for a period of time with an "IMS failure" and you wouldn't even notice.

I would say you need to inspect the oil filter for metal however before we start to make any conclusions on what may be broken.

htny

That's the first time I've seen the IMS "failure" described technically, thank you!

So is it something external like torsion to the motor or internal like say vibration of the shaft itself over time which causes the m8 to lose its head?

Is the design (one sprocket on either end) the same for 3.4L & 3.6L? For some reason I remember seeing a sprocket with two sets of teeth on the same end (which I assumed drove the two banks from the same end) in pictures of the IMS I had seen when initially researching my purchase.