Failing '85 Carrera Tensioner? Mysterious Goo?

[PcarPhil]

This weekend I was able to spend some time in my workshop diagnosing a chain noise I was hearing at low RPM's on my 3.2 engine in my Carrera parts car.

The chain noise I was hearing sounded like it was coming from the right chain housing so I proceeded to remove the muffler, A/C bracket, rear tin, etc. to get to the right chain housing. When I removed the right cover I didn't really see anything that looked out of place. I tried to compress the tensioner and the very first time I did this it did compress (semi-easily) about 1/16" or so. After that there was no easy movement - I really couldn't even compress is using a screwdriver for leverage. I also checked the non-tensioned side of the chain for slack. There was a little there but not what I would consider excessive.

So then I proceeded to the left housing. This is where it got interesting. First I checked the non-tensioned side of the chain and found a good 1/4" - 5/16" of slack. If I lifted the chain and let it go it would make the noise that I was hearing at low RPM's. It seems the chain was slapping against the ramp that's located just to the right of my finger in the pic below.

Then I checked the left tensioner. I couldn't really move it with just my hand so I tried with a screwdriver. I could compress the tensioner using a screwdiver for leverage. It wasn't exactly easy but I could do it. I also noticed when I did this that oil was coming out of the main piston.

Then I used the screwdriver to extend the left tensioner. When the tensioner was extended I checked the chain slack on the non-tensioned left side and there really wasn't any slack. Hmm....looks like the left tensioner is failing.

Then I noticed something weird. There is something leaking out of the left tensioner. The more I extended and compressed the tensioner the more 'stuff' oozed out. Do you guys have any idea what this 'stuff' is?

So I have questions:
1. What is this 'stuff' coming out of the tensioner?

2. Should I replace both tensioners?

3. When I have both tensioners extended so the chain is tight do I have enough clearance between the chain tensioner arm and housing on the left side and the chain tensioner sprocket and housing on the right side? In other words - is my timing chain still ok or does it look too stretched out and need to be replaced along with all new sprockets etc? Basically requiring splittling the case to replace all the sprockets? The engine has 158k miles.

Now for the pics:
1. The first pic shows the position of the left tensioner as I found it after removing the left chain cover:


2. This is the slack I found after removing the left cover:


3. This pic shows the position the tensioner should be in to eliminate chain slack. This pic also shows the mysterious goo eminating from the tensioner!? Also shown is the proximity of the tensioner arm to the housing when the tensioner is in the position that eliminates chain slack. Is this too close to the housing?


4. Sorry for the blurry pic. This shows the chain with no slack in it after I extended the left tensioner with a screwdriver. Also another view of the goo coming out of the tensioner.


5. Here's a pic of the right side. Everything looks pretty normal on this side but I wanted to point out the proximity of the tensioner wheel to the housing. Is this too close to the housing? This pic was taken after I had extended the left tensioner resulting in no slack in the chain.


Thanks for the help folks!

[Rick V]

Check your e-mail

[2.7RACER]

Scott,
Here is a picture of a new timing chain on the left side.
Looks to me like its time for new chains.
The visible sprockets look ok. I'd get a light and check the intermediate sprockets.
Maybe soak and clean the tensioners.

[Walt Fricke]

The motorcycle guys tell me the test for a worn chain is to try to move the links while they are on a gear. If links (other than the ones at the last tooth on the gear on each side) can be lifted up, the chain has worn. I don't claim to have a feel for this.

If it is loose, you can replace the chain without splitting the case. I did that once, though I suspect it was with the heads off, in which case it is simple. But I know it can be done with cams and rockers in place, just trickier as you rotate the cams while turning the crank and feeding the new chaing through following the old.

You could also replace the idler wheels, though wear on them ought not to matter much in the grand scheme of things. The two that do the work matter, but your cam gear looks pretty good on the side one can see (suggesting parallelism is good), so the IS shaft gears are probably as good.

Don't know what to say about the snot running out of that tensioner. When you compress the tensioner you can expect oil to run out. That happens (have a rag underneath) when you put a tensioner in a vice so you can compress it and insert the pull pin, preparatory to putting a used one back in the engine. But my recollection is that it comes out in the joint between the tip of the plunger shaft and the shaft body, up top and visible - you can see the "hole" in the pictures. And not out of the installation pin hole. And not all yellow. Did you get some of that when draining the oil?

I'd take that tensioner apart. I think if you compress it in a vice and put the pin in (a nail will do), you can then pry the wire clip out of the top, using the slot, and pull it apart. I've not done that, though. The one that failed on me did so for other reasons (the relief valve blew off).

And I don't recall seeing mention of rebuilding kits or spare parts. So maybe a new one is in order. For that matter, a pair just to be safe. Lots of good miles on that engine, and just replacing the tensioners is by far the simplest thing you can do. While at it you might replace the idler wheels. Easy to do, and wear on them just maybe accounts for their seeming to be close to the housing. Though what I see in your pictures doesn't bother me. The only time I have had that get too close was because the idler wheel holder cracked! But all I know are my own several engines.

Maybe a better gooologist will chime in. That stuff would catch anyone's attention.

Walt Fricke

[SP2]

I have seen that goo in other photos. There was a thread recently on Rennlist. The goo is coming out of the oil intakes to the tensioners. Peter Zimmerman said the goo was condensation in the oil. I am not an expert by any means, but I would think that goo is bad news. Do you use Castrol oil? That goo comes from an oil line that also feeds the camshaft and rocker spray bars, and the holes in the spray bar are tiny. The tiny sprays are responsible for squirting the cam lobes and rockers and some larger holes spray the large bearings on the camshafts. I would ask a professional Porsche mechanic. I would think at the very least you need to clean out your tensioners and then take off your valve covers and inspect your camshafts. If they are super black or pitted you might have a problem. Also, you can't see the rocker faces that contact the cam lobes.

Looks like it was very good that you didn't just blow off that chain sound!

[Walt Fricke]

Now that SP2 mentions it, the goo does look like what I occasionally wipe off of my oil filler cap in the winter. Oil emulsified with water (which condensed out of the air in the system due to the cold). It has that yellow hue. I guess I figured that crap sort of floated on top of the oil in the tank and wasn't circulated through the engine. This suggests it doesn't.

I'd be more worried about its film strength (and thus its effect on wear on parts that move on each other) than its ability to clog up small holes, though.

Maybe it is more compressible than uncontaminated oil?

Can't see off hand why it would sequester itself there. Each time the chain tries to push the tensioner down I think a little oil comes out, replaced by the pressure feed, so you'd think that stuff would work its way through the system, eventually to have its water boiled off when you got the oil hot enough in the summer.

But there it is.

Walt

[Zef]

Scott...if you want to change the chain with a master link equipped one, the job is shown on the technical articles section...

[PcarPhil]

Thanks for the replies folks.

I also think the mysterious goo is condensation in the oil that was sitting in the tensioner. The engine has been sitting for the past 6 months - only running every once in awhile to move the wrecked car out of the way. I think what I'm seeing is condensation that was in the tensioner. Similar to what you see in the oil filler tube if a car has seen a bunch of short trips and hasn't warmed up enough to burn off the condensation.

The left tensioner is leaking oil. The right tensioner seems to be ok. I'm going to replace both. I think I'm going to replace both tensioner sprockets as well. The left tensioner sprocket has some wear on the sprocket while the right side looks ok. Again, replacing the items in pairs (tensioners and tensioner sprockets).

I've read mixed reviews about replacing a chain without replacing all the sprockets and ramps as well. Should I replace the chain as well as the tensioners and tensioner sprockets?

Ideally I'd like to get another 30-50k miles out of this engine before doing a complete rebuild. Do you guys think I can do this by just replacing the tensioners and tensioner sprockets?

[Gunter]

Kaefer:
New Chain on old chain sprockets makes no sense.

New chains without new sprockets? Read this!

The chain sprockets on the I-shaft are the important ones because they are the "Drivers".
Just looking at them from the top will not tell you their condition.
If the engine has over 100k, they are worn.
The cam sprockets, and idler sprockets, are "driven", less problematic and can be reached without splitting the case.
After many rotations, the wear-pattern of the stretched chain matches the wear-pattern of the sprockets. A new chain will have the same pitch but, no wear yet meaning: The new chain will not sit in the valley of the sprocket-teeth, it'll ride higher on the teeth and eventually break the tops.

Your pictures show some chain-stretch but, there is still room left for the tensioners to expand a little more with the old chain provided you renew the tensioners.
That's what I would do: New tensioners, nothing else.
Run for another 40k and then do a complete rebuild.
The goo is emulsion: A mix between moisture and oil. Clean out the small lines to the tensioners.