Imo000

This happened to my engine except it bent the valves. The cause was a piece of the vario cam yensioner pad breakng off and getting between the chain and the sprocket. Since you have 170K on it and happened to mine at 200K, my bet is you have the same thing happening except no bent valves yet. I would not start this engine untill you find out why the chain skipped. The valve covers are remvable with the engine in the car. I'm planning to do that in a few months. You will need to buy or make some tools to lock and hold the cams in place. They are fairly easy to make. Look for my thread on my engine repair and you'll find the link to the entire project. At the second half my thread is are the pictures of what my version of the cam tools are.

speed rII

Here's how to set the timing on the 4-6 cyl.
You need to remove the two other plugs from the front side of the cyl.head. Check allso the 1-3 head.

There is something seriously wrong in the engine, I suggest that you drop it and take of atleast the valvecovers.
It's much cheaper to rebuild it now, that it's still running.

I have taken the valve covers of when the engine is in the car, but can't recommend it when doing so first time.

This could be simple as the variocam pad's/guides.
Allso if the 4-6 chain tensioner was replaced wrong way. etc...
IMS will also make the timing go off, so be carefull what you deside to do.

tokyopav

^^ I have to agree. Cheap labor now will save you thousands later. You will end up with the cheapest 996 ever. Just take the time to sort it out. Jumped teeth easy to fix. Bent valves and bent gudgeon pins not so cheap.

Vasir

Gah... All the time I'm taking away from projects to mess with this, I'm losing money doing it myself.... But it's the only way; I won't know the car otherwise.

I'll take the time to clean/reorganize the garage, roll the car to a new position and re-evaluate the situation. 2 days in a row I'm operating with a fried brain. I can work with one hand tied behind my back on my V12s, but this I'm falling apart

Imo000

You'll be fine just take it easy and read up as much as you can. Like you, the 996 engine was alien to me too. The more you work on it the easier it gets. I'm a DIY gearhead too so the basics were there to know how engines work. They are all more or less the same and so is this one too.

alpine003

+996. People have to realize this is just an internal combustion engine with the same basic principles. Variable valve timing has been around since the 80s in production cars so nothing new there either. Like with most German and Italian machines, there maybe some special tools needed to do certain things but not really a deal breaker IMO. Glad you've decided to take the plunge and get your feet wet.

Vasir

Im throwing in the towel. Im taking it to my mechanic tomorrow or the day after, after I button it back up. We'll see what happens. I've lost 3-4 days of my life/work and possibly got a cold as result- I'm in real estate, not in the business of crawling under cars... Hah

I have a general idea of what going on and I'll be able to relay it to my mechanic. Sadly hes not a porsche guy, but a merc guy like myself- but I'm sure he knows what hes doing. He is a mechanic afterall!

After talking with my girlfriend about it and watching Inglorious Basterds at the same time, Ive come up with a name for the carrera: Bridget von Hammersmark.
A gorgeous head turner that attracts a tad too much attention, which is okay; but her story just doesnt add up... My mechanic may end up killing her.
Works out since the car prior to my current SL was Fraulein Maria and my current one is just "The Mistress".

Yeah I name my cars... Hah.

The following picture pretty much sums me up at this moment:

Kalashnikov

Vasir, I would really advise you to take it to the local Porsche mechanic at this point. These cars are very particular, so I don't want you wasting your $$$ paying for the labor to the Mercedes mechanic to try to diagnose the car. Get the Porsche Independent shop to do a full PPI and give you their low down on the car, this way you have a complete picture and good sense of how much $$$ it will cost to get it functional.

Ahsai

+1 Most likely your merc mechanic doesn't even have the proper diagnostic tool like Durametric. As you saw the info mentioned in this thread, he will have to learn all that no different than you. If he's a friend and does the work for you for free, that's a different story.

Imo000

If you want to sell it as is, let me know. A buddy of mine is in the market for a 996 exactly like this. I'm not kidding.

Vasir

Thanks, but I'm gonna get it fixed one way or another.

Imo000

Sounds like it is going to be the "other way" then.

Vasir

We'll see... I really want to take a car to thunder hill this spring/summer that isn't a boat like my 600. Sloshing around the corners isn't such a good time; the Porsche needs to be fixed. Also; too many people know about it now, can't bail on it now.

alpine003

After all that tough talkin, no you can't.

Imo000

The 996 handles extremly weird when compared to a "normal car" that has a front engine. It is downright scarry. You might not like how it handles in turns if you are used to driving the SL. Once you drive it, you'll understand why having an engine behind the rear axle is a design flaw.