Found this in my engine - what is it?

andster · 04-17-2010, 08:34 PM

I had the sump plate off of my 3.0 and as I looked inside I found this steel clip looking thing at the rear of the opening, near the chain housing. Does anyone know what it is? I figure I better find out before I put it back together, in case I need to replace it.

Also, I found a piece of my chain ramp near the sump as well. Its part of the clip that holds the ramp to the steel pin as the ramp snaps in place. I have the chain covers sealed up and the hydraulic chain tensioners in place and I didn't really want to open it back up to replace the ramps. If a ramp is missing this clip, is it an issue? I was hoping the chain cover (outer ramps) and bolts (inner ramps) hold the ramps without the use of the clip. I appreciate any help on these issues.

4sd911 · 04-17-2010, 10:14 PM

The top picture looks like a broken piece of one of the chain ramps. I'd inspect the ramps with a mirror look at the clips that hold them to the case. The metal C clip looks to be a piston wrist pin retainer, can't see how that would work it's way out maybe the engine was rebuilt and one was lost into the engine and not retrieved? How many miles have you put on this car and was it rebuilt in the past?

OldTee · 04-18-2010, 05:20 AM

4sd911 is dead on.

Here is what I would do.

Have the cylinders bore scoped, looking for marks that would show a piston pin floating. If nothing found, go drive.

This can be done with the engine in the car.

If you find a bad cylinder, pull the engine and fix the bad one. You can fix the chain ramp at the same time.

The chain ramp can be fixed by lowering the engine a little then removing one chain cover. You have a 50-50 chance of getting the right one. An audio check with engine running may tell you if a chain is slapping on one side. That could reduce the 50-50 to 60-40.

Good luck.

PS. Nice young hands, long life line!

lucittm · lucittm's Garage

Only in the 911 Engine Rebuilding Forum can you get good advice, knowledgeable answers to questions, and a palm reading...

Mark

Eagledriver · 04-18-2010, 06:23 AM

I would replace the ramp. It's not that hard and can be done without removing the engine. You will need to remove the muffler and engine mount to have easy access.

-Andy

prschmn · 04-18-2010, 09:42 AM

If your engine has original tensioners that ring is likely a retaining ring from one of em.
Id think if you'd lost a wrist pin clip you'd be hearing bad noises.

Flieger · Flieger's Garage

Aren't there clips like that on the oil return tubes?

prschmn · 04-18-2010, 09:57 AM

Nope

4sd911 · 04-18-2010, 10:07 AM

Yep, the spring loaded tensioner's does have the same C clip as the piston's. You look to have a failed tensioner and broken ramp. Don't drive this car until this is addressed.

andster · 04-18-2010, 12:43 PM

Great advice guys, and thanks for the palm read OldTee. The engine was rebuilt about 5,000 miles ago by a previous guy and Im hoping it was a spare clip that fell during the rebuild because I really don't want to rebuild a cylinder. Prschmn, I followed up on your theory and compared the clip with the ones on the top of the spring tensioners I took out. It appears that the previous guy had rebuilt spring tensioners installed from the looks of the bright metal on them. The clips are on both tensioners, so I hope its a clip off of one of the old tensioners. Im not convinced though that this is a tensioner clip because it appears smaller that the ones from the tensioners that I took off (see pic where the loose clip is setting on the tensioner for comparison).

I need to research the wrist pin clip a little more, maybe get my hands on one and compare side by side and hopefully conclude that it is off of an old tensioner. By the way, the engine is out of the car, so this is the time to figure it out.....

You guys are extremely helpful, thanks a million!

Andy

prschmn · 04-18-2010, 01:22 PM

I had hoped my guess was right but------
Those wrist pin clips do have a way of escaping on occasion so maybe we can hope it's an "extra" that fell in the case. Kinda hard to believe you havent heard noise if it really did leave its proper home.

Flat6pac · 04-18-2010, 05:22 PM

You wont hear a bad noise until you find no compression in the cylinder because a floating pin tearing up the side of the cylinder. That should ruin your day....
Bruce

4sd911 · 04-18-2010, 07:42 PM

I grabbed an old tensioner and a piston C clip my photo looks just like yours. So I'd say that is a piston C clip. Now the tough job of finding where it came from. There is a little room between the cylinder and wrist pin, just maybe a good bore scope can get a look in?

LeakProof · 04-19-2010, 01:35 PM

I agree, that's a piston c-clip. Those buggers are really tough to get out, I could see, how one could easily end up in the case. One of my clips, ended up across the garage.

When I changed all my chain ramp's out, I had several broken pieces, end up, in my sump, that looked just like that.

I stuck my hand in the sump, and retrieved every one, that I could account for breaking.

The old ramps were pretty brittle.

The new one's, I removed recently, did not break like that upon removal.

Leakproof.

OldTee · 04-19-2010, 05:51 PM

I will reiterate. Find a qualified Porsche mechanic with one of these

http://www1.snapon.com/display/231/ToolNews/PressReleases/2009/BK6000.pdf

I would think it would be about one hour labor to pull the plugs and give it a look see. Then for the hour of labor you can get a good nights sleep.

Tea reading is extra.

Walt Fricke · 04-19-2010, 08:06 PM

On the wrist pin clip: I'd take Old Tee's advice, and use a borescope down each spark plug hole. Turn each piston in turn to BDC, so you can inspect the fore and aft sides of the cylinder walls. If a clip is missing, I'd anticipate seeing some scoring. If it wasn't put in solidly, it will come out, and the wrist pin. You probably don't have a boresocpe, so you will have to take it to a shop (or buddy) which does.

It is possible that this clip was lost (fell in) on installing a piston, and the mechanic simply got another one for that piston, reasoning (sort of correctly) that the clip will end up by the oil pump screen where it is out of harm's way. I stuff a rag around the connecting rod when installing these buggers, just in case. Wayne's book, I see, recommends clear plastic sandwich wrap. Dropping and leaving a clip is hardly professional.

I am wracking my brains for the construction of the stock 3.0 pistons. Some 911 pistons are not "slipper skirt" - they don't have a cutaway below the wrist pin slot. Such a piston can't lose a wrist pin retainer into the sump, because it can't get there. Instead it will bounce around in the slot, abrading the cylinder wall. If SC pistons are of that construction, and these are original, then the odds favor a fumble fingered mechanic. But I don't think they are.

I'd be less concerned about the broken clip from one of the chain ramps. The ramps really can't go anywhere. However, it indicates a problem. I've broken these clips trying to remove ramps, so I suppose it could happen installing them. These plastic ramps otherwise I think are pretty durable. None of mine have ever been worn so much that they really needed replacing, though usually I do anyway.

However, you need to inspect all of them in case more is broken, and when you go to that trouble you might as well replace the one which has a broken clip and thus a bit looser side to side than the others. You will have to lift the chain up a bit to see which one is loose. Removing the tensioner would give you the slack you need for that. It isn't hard to keep the chain on its teeth so you don't lose timing. Just be careful.

If it is a ramp which is in the chain box, easy. If it is one of the four in the case, you will need to unscrew the pins whose bolt heads are external. Be careful not to drop it deeper into the case, though you can probably fish one out easily enough with one of those cable grabber tools.

Good luck.

andster · 04-19-2010, 10:09 PM

Well....that was not really the news I wanted to hear. But I really appreciate all of your help with trouble shooting this one. I will research the piston configuration that I have and see if there is a gap between the cylinder and wrist pin, or an opportunity for the clip to pop off when the piston is at BDC. I may be able to see this with the sump plate off, I hope. If the gap doesn't exist - I will look into the scope.

Ironically, I picked up my 101 Projects book and found the piston configuration that I hope I have with the piston and wrist pit against the cylinder. Funny thing is they warn about clips poping off into the engine.

OldTee, can you tell me which cylinder the clip came from.....I'll pay the extra.

Andy

euro911sc · euro911sc's Garage

Sorry to say, but my '82 Euro pistons had more than enough space for the clip to fall out. I'm pretty sure all the SC malhe pistons were similar in shape, but I have been wrong before.

Have you pulled the engine yet? or are you trying for an in-car diagnosis/fix? A missing piston pin clip would essentially require you to tear the engine down to the short block to fix. Though much of the valve train can remain intact.

A bore scope would be good to have. You may be able to borrow one locally or there are several for sale from $3-500... not cheap, but if all is well it will save you that much or more in tear down inspection costs. Then if you find the wall is ruined you still have to tear it down... but only the one side.

Best regards,

Michael

OldTee · 04-23-2010, 12:51 PM

Use a professional. They know what they are looking at.

Not a time to be penny wise, pound foolish.

andster · 04-26-2010, 10:18 PM

I took a close look up a couple of the cylinders through the sump opening with my mirror yesterday and it appears that there is not a gap between the piston and cylinder where the wrist pin inserts. This sounds similar to the "slipper skirt" configuration that Walt mentioned above and appears to be good news for me, but Im confused at the fact that these do not seem to be typical pistons for a 3.0. While checking for 3.0 pistons on this site I didn't see any that fit the cylinder snug around the bottom of the piston.

Any thoughts from those of you with piston experience is appreciated.

Michael, the engine is out and on my stand.

Thanks
Andy