Scavenge pump failed and ruined my engine. Nope, not mad!

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/

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

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/

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

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Yeah, looks like a wrist pin to me.

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.

Yes, a proper scale is necessary.

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

Ha, then definitely NOT a wrist pin.

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.

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

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?

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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.

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 ??

Chris I don't think that's rust just looks like combustion crud , you can get a ring of it around the top of the bore above where the piston ring doesn't reach like you get on the combustion chamber

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^^Bingo!^^

Just to reiterate, the timing chain only failed because the scavenge pump failed. The chain didn't fail on its own. As for the cylinders looking odd, I agree. They aren't scored, at least 1 and 3. I need to check #2. What is odd is all 3 cylinders have this weird rusty dust in them. You can see the dust piled up at the 6 0'clock position. I left it there so you can see it. I can vacuum it out. But the cylinder walls look fine. Cylinder 2 is definitely questionable. The moist sludge in it is concerning. I'm going to check the engine again this weekend and report back.

Those pieces look like parts of the timing chain rollers. The rounded one for sure, the flat one looks to be the same except flat from possibly going through the scavenge pump. And yes i have seen this before, the piece of chain can and will lock up the scavenge pump causing the chain to totally snap, or the scavenge pump lock, snap the pump drive or the IMS gears to slip on the shaft. That's the reason I recommend installing magnets to catch any ferrous debris before it can enter the scavenge pump, there are threads on this..

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By the very nature of what a oil pump is designed to do, (circulate oil) they rarely fail without something else causing it to fail. Something entered the pump other than oil, that's what caused the pump to fail.

Just a quick update. When I try to turn the crank, I can rotate around 3/4 of a turn and then it stops. While I am turning the crank, the sprocket for the broken timing chain is not rotating at all. Might this mean the intermediate shaft is broken?

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The chains are much longer starting in 2002 allowing more opportunities for excessive slack.

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That would be my guess the sprocket has spun?

The whole engine needs to be completely disassembled. Why? Do you think metal can hide inside the crankcase? Absolutely it can.. you are shooting yourself in the foot if you don�t throughly clean everything out, including the oil galleries. It�s a struggle to get it all cleaned out even with everything apart. The parts for this engine are expensive enough. No reason you should do it twice. -Pete Koepfgen