What are these black chunks I found in my engine?

Jay Zollinger · 08-12-2006, 01:13 PM

I found the big chunks in the timing chain housing behind the chain tensioner and the other chunks on the engine side of the oil sump screen. As you can see, the largest piece is uniformly and smoothly curved on one side--as if it formed on the inside of a cylinder wall.

My car started making a significant knocking noise on the passenger's side of the engine last Tuesday. I had run three DE sessions that morning, and the car was running too hot (up to 250). The car made the drive home just fine, however, cooled down, and then made it another 20 miles out to a party just fine. After the party, it started fine and drove without any noise, but when I got home, the knocking noise had started. It made the same noise after sitting over night and hasn't stopped making it since. It happens hot or cold and (if I'm hearing it correctly) across the rev band.

The rocker arms and shafts on the noisy bank are fine and the tensioners appear to be working correctly. I'm concerned about the rod bearing, but I'm wondering if I didn't knock some carbon loose on the track and that is what I'm hearing. These chunks, however, are a lot bigger than I ever would have expected.

Any ideas? If this is carbon, what can I do about it short of a tear down?

discovery2 · 08-12-2006, 01:14 PM

chain ramp guide.

MotoSook · 01:19 PM

The picture on my screen is hard to make out details of the pieces, but I might guess that they are pieces of a broken chain rail.

Edit: If it is the chain rail/guide (can't imagine of any other plastice pices that would end up where you found them), the chin would be slapping around int he chain box...hence the noise you heard. Take the chain box covers off and inspect.

ruf-porsche · ruf-porsche's Garage

Chain rail ramp and a quarter. I'll be more concern with the quarter.

LMAO

MXMARK · 08-12-2006, 01:24 PM

Quote:

Originally posted by ruf-porsche
Chain rail ramp and a quarter. I'll be more concern with the quarter.

LMAO

I needed that. LMAO too. Thanks Mark

Jay Zollinger · 08-12-2006, 01:26 PM

The chain ramps were my first guess as well, but they are all there and in the right places. Other ideas?

Bill Verburg · Bill Verburg's Garage

My money is on chain ramps too, hard to believe that the original rubber type are still in there(they were notorious for that sort of failure.

Use 5 updated black ramps 911.105.222.06 and 1 brown ramp 911.105.222.05, brown goes on the lower right side. Long end to the nearest sprocket.

the difference between the 2 is heightblack are 12.7mm and brown are10.7mm

I would update both the tensioners and idler arms wuait. But at least the idler arms 930.105.509.00 left and 930.105.510.00 right

ruf-porsche · ruf-porsche's Garage

Ramps ever repaired or replaced? Could be the remnant of an old ramp. Did you remove the chain housing to inspect all the ramps? I think therre is one ramp that is not visible but you can feel it behind the aluminum housing.

Jay Zollinger · 08-12-2006, 02:21 PM

You're probably right about this just being part of an old ramp. I replaced them a few years ago when I upgraded the tensioners, and haven't had any trouble with them.

rnln · 08-12-2006, 05:17 PM

Don't stop. dig more in there. You might find more coins.

Jay Zollinger · 08-12-2006, 05:43 PM

Here I am with serious engine trouble and all you guys can do is mock me for trying to give some perspective--where's the love, man?

randywebb · 08-12-2006, 07:36 PM

The love got cut up with a hot knife... instead of a soldering iron. Luckily, there was no static.

I would search hard for any more broken chain ramp pieces before running the car.

Nickatnyt · 08-12-2006, 10:01 PM

Looks like stuff that came out of Mt. St. Helens.....either that or black diamonds, both of which would be worth more than the quarter.

911pcars · 08-12-2006, 11:03 PM

If the rubber chain ramps had lasted this long (doubtful) and they disintegrated, there's a good chance the timing chain would have jumped a tooth. Doesn't sound like the valves touched the pistons.

However, since you reported they were replaced, the black rubber pieces are probably remnants of the original chain ramps that happened to appear. My guess; the rattling sounds you hear are probably the tensioners starting to give up.

Do not run the engine any more. Open up the chain boxes and check the tensioners for slack.

Sherwood

darkbeer · 08-13-2006, 12:55 AM

with all the money we sink in these damn engines...it's nice to know we get a little back !!!

bkreigsr · 08-13-2006, 04:50 AM

b4 fore you install new ramps. do a search. they have a tapered end and a blunt end. in addition to getting the brown one in the correct location, you need to orientate it correctly towards or away from the nearest sprocket. same for the black ones.
good luck

Jay Zollinger · 08-13-2006, 07:43 AM

Porsche diety and all-around great guy Steve Weiner (www.rennsportsystems.com) looked at my chunks and confirmed that they're from an old chain ramp. So, that mystery's solved.

As for the knock, the mystery remains. My updated chain ramps are all intact and properly positioned. The tensioners are tight and the rocker arms and shafts are all where they should be. I would be inclined to suspect a rod bearing, but I don't hear any change in the knock when I pull the plug wires one-by-one. I may be able to get Gordon Leadbetter to listen to the engine later this week and diagnose the sound. Otherwise, I'm at a loss. If anyone solves this for me I'll send them the quarter and any other coins I pull out of the engine.

Plecostomus · 08-13-2006, 08:40 AM

Those quarters can really be expensive sometimes.