Prelude Guy

Yes, I am not mad because it failed, Had it not failed, I would not be into 996s. I like restoring cars. I like cars that are left for dead and I can possibly fix it, or even make it better!

So I bought the car this engine came out of 2 years ago. It was a 2002 cabriolet with 107K miles. Previous owner was a member of this forum. I didn't know it at the time. I bought it off Craigslist for $8000. I bought it mainly to learn more about the car. I rarely buy running cars.

Anyway, I finally have been able to tear into the engine. I wasn't sure about why the timing chains failed. Sadly, several ways these fail. IMS bearing, the timing chain itself, or the scavenge pump. I knew the IMS bearing had been replaced already so I was pretty confident that wasn't it. I still don't know the condition of the IMS bearing so I will check on that as well.

I am hoping to rebuild this engine but my main purpose is to learn about these engines when time permits.

I just read a great thread on tearing down M96 engines. I am pretty sure I will need to at least take off one half of the block to replace the timing chain, as well as find all of the debris from the cam gear, timing chains, and scavenge pump. I found three small pieces in the oil pan already. I will check the oil filter next. I will update this thread as I get deeper into the teardown.

Anyway, my first question is what's the bare minimum I need to teardown the engine to replace the timing chain, assuming I get out all of the debris and everything else is fine?

Let's see if we can save this engine! I will not be able to do this without help, that's for sure!

Here are a few pics from my InstaGram. Subscribe if you can!
https://www.instagram.com/leftfordeadcars/

808Bill

Subscribed! I too have a motor I'd love to tear into but I just don't have the time or space...

Prelude Guy

Any ideas on what this debris found in the oil pan might be? Hoping these pics work from my InstaGram:

*EDIT*
Didn't work. Pics can be found here:
https://www.instagram.com/leftfordeadcars/

OutNSpace

Hard to tell from your photos. Cylinder maybe a wrist pin? Can you photo it with something other object to show the relative size?

TexSquirrel

Yeah, looks like a wrist pin to me.

Chris(MA)

Looks like timing chain parts to me (there is nothing in the photo to add scale). I believe around 2002 the timing chains were quite weak.

TexSquirrel

Yes, a proper scale is necessary.

Prelude Guy

All three pieces are the size of the tip of an index finger or smaller.

TexSquirrel

Ha, then definitely NOT a wrist pin.

Prelude Guy

Hoping to have the head off by this weekend.

Trying to get an idea of what all I should look at that could be damaged from this type of failure. Obviously once I get the head off, I will check the valves and pistons. I will check the chain guide as well.

Chris(MA)

If the chain snapped good chance one of the pistons hit the valves, so bent valves, damaged piston etc

Prelude Guy

I literally just posted pics of the head off. Got the head off today. Was pretty simple actually.

Valves and pistons look fine!!

Please pay close attention to Cylinder 2. See the wet sludge on the head and in the combustion chamber?

Cogito_Ergo_Zoom

Subscribed

Chris(MA)

Just looked at your pics, you may want to post them here. IG shrinks them down to low res and crops them.

Anyway the cylinders look odd, like they are scored or have a lot of rust in them? hard to tell from the photos.

The company that made that chain should be ashamed, they should never fail like that.

I think you have an LN engineering IMS in there, post the serial number or call LN and check

Can't see your RMS, IG is really chopping your pics down.

Noz1974

I think there's definitely a snapped chain maybe the ims chain and the small metal collar looks like the collar which goes inside the ims tensioner paddle ??