Wednesday, February 3, 2016

The Triangle of Death

The Triangle, weeping oil. Image borrowed from the Web.
This is not a high-power technical article that the Pros will get excited about, but rather it is aimed at the do-it-yourself mechanic who is trying for the first time to solve some common problems.

You always need a scapegoat. On old air-cooled Porsche 911 engines, the so-called "Triangle of Death" gets blamed, mostly with very good reason, for the oil leakage that frustrated owners too often see wetting the bottoms of their engines. As a bonus a generous percentage of that oil winds up on their garage floors. Some consider this to be almost normal, because the adage is, "If you're not leaking oil, you are out of oil." They leak a lot, but my engine was leaking more than it usually does, so I imagined that the Triangle was doing its thing.

In the winter when the car is up on blocks, I take the oil out of my engine, which greatly reduces the leakage, but in a fascinating perversity this does not stop the leaking; this is a wonderful mystery and joy to ponder. In any case, the Triangle is an area on the top of the crankcase, adjacent to the engine's built-in oil cooler. The three parts of the triangle are the oil thermostat, the oil pressure sensor switch (for the idiot light on the dashboard), and the crankcase breather or vent (and/or the hose attached to the breather housing). If a person is lucky, all three of these locations will be leaking simultaneously and causing a lavish slick that spreads to every nook and cranny and happily drips off the bottom of the engine, from one end to the other. I counted a dozen drip locations, spread out everywhere.

An unambiguous photo of a Triangle mess. Web photo.

My own triangle. Innocent and dry. I have to look elsewhere for my oil seepage.

Okay, the oil loss situation on my car needs attention. First, where is it coming from, and second, how do I stop it? And third, should I bother? Well, yes I should bother, it's a Porsche and everybody knows that they are perfect - as long as you put enough work and money into them. I ordered some parts.

These are the areas you need to fix, if they are bad. Web image.
Actually, a special kink for me is the fact that there is leakage coming from my transmission, and this is totally new. In my post called, "Spring Cleaning" (April, 2015) I discuss that I removed a plate on the bottom of my transmission "Transmission Cover Plate for Shift Rod Support Fork", in order to inspect the workings of the interior. The gasket for this plate is a simple piece of paper. I cleaned the mating surfaces, installed the part with its new gasket, and torqued the fasteners to the specified tightness. It leaks like a sieve. This time I ordered a 'Genuine Porsche' gasket, which may or may not be any better than the paper one that's on there now. We'll see. Maybe I'll use some gasket glop to ensure sealing. So, I have oil on the engine, as well as the trans. 

At this point I believe that the Triangle of Death is uncharacteristically innocent. You can't just stick your head into the engine compartment to have a look at the Triangle, because it is way back there behind the CIS fuel system (in my case), but behind fuel supply gadgetry in any case. With a mirror in your hand and two elbows in your arm, plus a strong light, you can see the triangle, partially. I made this awkward inspection and the area seemed dry. So, I stuffed my camera back there to try to take some pictures. I got some photos, and the Triangle is indeed dry!

On the one hand this is good, because I don't have to drop the engine to address the infamous Triangle. On the other hand, where is the miserable oil coming from? Finally, the car is 42 years old, and so I forgive it some seepage, but why did it increase? I believe that that gasket on the transmission is the evil part, because the oil released by it drips in front of the engine and then is blown back to coat various under areas of the engine. That's my newest theory, anyway.

My wet transmission bottom after wiping most of the oil off. Click = enlarge.
My attempt to blame the Triangle didn't work this time. I have to go shopping locally for some transmission oil, as well as engine oil, and a filter, etc.

Okay, right here I was going to say that this post would be continued at a later time, when some of the parts I ordered online showed up. Some showed up. They have nothing to do with oil leaks or the Triangle of Death, but I'll mention them anyway as a diversion until the rest of the parts show up.

The distributor cap and rotor needed changing, so I ordered new Bosch pieces for this. Previously I used Bremi, but looking at the two of them, side by side, I believe I prefer the Bosch, because it (the distributor cap) seems to fit more snugly and exactly.

New bits, including washers.
So, I put it together with new stuff. Good thing I did, because I noticed that there was considerable erosion on the contacts in the cap. I guess that the cap has been on there for 15,000 miles (24,000+ kms) and on a car of this vintage it should have been changed at 10,000 miles. Well, there are new parts on there now, plus the points had been replaced with a Pertronix unit when I had Jerry Woods rebuild the distributor. I'm glad about the Pertronix, because that unit may not make the car run better, but it will make it run consistently forever, without adjustment. Cool.

The washers are for the engine mounts. The old ones are corroded and tired, and have lost some of their curvature that is necessary to hold the rubber part of the engine mount firmly in place.

Those new bits going in.
Then I put the air cleaner back together, and all of that.

Now I can say legitimately that this post will be continued when the rest of the parts show up.

The parts finally showed up. The story continues below the oily distributor cap picture.

Hey! Why is this oily?!? There is no obvious leakage nearby. . .

There was a delay in procuring some of the parts that I wanted, but all of the gaskets, and fuses (which were the missing pieces causing the delay, although the smallest and cheapest), and other random bits at last arrived.

Okay, back to the theme of this post concerning oil leakage. I at first accused the Triangle of Death, because it is one of the main usual suspects, but I was wrong and my triangle has been exonerated. Looking at the whole thing for a longer time as a result of the parts delay has me convinced beyond question that the main part of the oil did indeed come from the "Transmission Cover Plate for Shift Rod Support Fork". After taking the cover off in order to change its gasket I discovered some interesting markings that may have nothing to do with the present leakage, but they tell something cryptic about the transmission's distant past. The photo I included here shows an area that suggests  something was whirling around and beating against the plate for an extended period of time. As well, there are other scratches which go over the area that was whirled upon, but I believe that these were caused at a later time, when a scraper was used to remove gasket material, probably. This would have been done when I had the transmission rebuilt, about five years ago.

The shift fork plate, from inside.
Never mind, those mysteries will never be solved. At last I installed the new Genuine Porsche gasket (which looks to be made of the exact same type of paper that the after-market gasket I used last time was made of), but this time I applied some Permatex gasket-maker material to the joint, in the hope that this will truly prevent another gush of oil all over the place.   

As we look more closely, for no good reason, at the above mentioned perplexing scrape marks, for your abstract thought exercise today, please imagine what could have made the more thoroughly abraded large curved scuff that we see up-close below.

Scuff - as if the previous photo wasn't obvious enough. Click

The plate attached with some fussing, and the gasket maker goop oozed out reassuringly. I followed the instructions on that stuff to the letter and it has worked before. Just to make everything as redundant, and maybe boring, as possible, I'll post some pictures of the final assembly below.

Everything reassembled, and prayers dutifully said.

Oozing gasket sealer; it can't leak past that, can it?

So much for the oil leak business. I'll let you know what happens after I've refilled the transmission (using the same, but filtered, oil since it only has 5,000 kms (3,000 mi.) on it and it is as clear as crystal). Waste not, want not. I'll run it a while before passing judgement.

A partial epilogue:

The transmission no longer leaks. The engine still leaks. The triangle is dry, therefore, the engine's oil leakage is a more difficult issue and will require dropping the engine, probably. I'll get back to you when I decide how to proceed with this.

Okay, I dropped the engine and I'm taking things apart. I'll write more later.

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