IF ONE HOLE IS GOOD, TWO MUST BE BETTER
Copyright 1997, by Harry Pellow, All Rights Reserved.

For some 30 years, the Maestro's been IM-pressed with Porsche Engines. Very Nice Design. Clever. Damn Good Engineering (mostly).

.....But one of the main reason why the Maestro likes 'em so much is that The Factory improved something every year. (Of course, some things NEEDED to be improved every year!)

.....Take for example the Third Piece Turmoil In the Late Fifties. From 1955 to mid-1957, the first "1600" engines the Factory built used the "5-Bolt Seal Ring", with the Pulley Seal held inside a separate Aluminum ring that bolted to the Third Piece via five 6mm nuts.

.....In mid-1957, the Factory replaced the old "5-Bolt Seal Ring" Engine having the single, small, Oil Pressure Relief Valve with a "Better" Engine having TWO Oil Control Valves and a Wondrous New "Oil Thermostat" that was designed to divert the oil to the Oil Cooler only when it was hot enough to benefit from the trip.

.....Unfortunately the Wondrous new Thermostatic Oil Control Valve didn't work out as designed, (Like it would stick "closed" every now and then, resulting in Overheating, Bad News and Expensive Repairs.)

.....So in 1958, the Factory pulled OUT the TOCV and popped on a Cover. Leaving behind a rather large hole to be filled up with oil by the oil pump each time the engine was started.

.....That was not a very good fix, so in 1959 they redesigned the Third Piece again to eliminate the Large Bulge & Hole where the TOCV used to be but 'twas no more.

.....Finally, in 1960 the Factory got smart- and increased the size of the Oil Pump Gears, which increased oil pumping capacity by about a factor of three! THAT was a Major, Needed Improvement. Now, the Oil Pump Gears were larger than a Chevroley 350 V-8. And that meant yet another redesign of the Third Piece of the Case!

.....And that STILL wasn't the last of the changes in the Engine Case. As the '60's progressed, the reinforcing webs in the Case got longer, thicker, bigger and went to many more places.

.....Evolution is a Wonderful thing.

.....Another interesting Fact about the extra capacity of the Large Oil Pump. With the Large Oil Pump came an "oil slinger washer" that sits inside the Pulley Seal of all post-1960 engines. The Factory's first design used an oil "slinger" with such a large Outside Diameter (O.D.) that it blocked half of the oil return hole in the Case.

.....Turned out this was not such a good idea, so very quickly, the oil slinger shim was quickly changed to one of smaller O.D. that would NOT block off half the oil return hole. Pulley Seal leak warranty claims mustave dropped dramatically.

.....Like I said, Porsche really tried to improve things- that's why the Maestro likes 'em. They tried to Improve the Breed, and succeeded. Usually.

.....But one thing the Maestro's always wondered about is the location of that little Oil Return Hole in the Case at the Flywheel Seal Area of the Case. Y'know- the hole by the Flywheel Main that drains oil from the Flywheel Seal back to the sump after it comes out of the Flywheel Main Bearing. This gives the Flywheel Seal less oil to deal with.

.....But the Oil Return Hole is NOT at the "6-O'clock" position at the Bottom of the Case like you'd expect. No, it's off at almost the 8 O'clock position- quite a way away from Bottom Dead Center.

.....But that's the way the Factory did it.

.....Then, one day in the Ides of September, 1997, an engine arrived via UPS (no longer on Strike) from a Man from Virginia.

.....The engine was a rather rare 1965 European SC, with an interesting combination of an almost Original Lower End, and a messed-with Top End and Flywheel.

.....The sad part was the messed-up Flywheel. The Flywheel Nut had come loose, and the dowel pins of the crank had Murphy-machined the Flywheel.

.....Of course, the Flywheel retaliated by elongating the dowel pins in the crankshaft.

.....This necessitated a repair attempt that failed. Didn't work.

.....Sigh. It was one of those.

.....The Maestro hates Crankshafts with elongated dowel pins. Because, ifin you must put larger dowel pins into the Crank, then that all-important Sealing Surface between the outside of the Dowel Pin in the crank and the outside surface of the crank is reduced. (This is where the equally all-important Soft Iron Gasket seals!)

.....The inside of the Flywheel Hub that mates with the Soft Iron Gasket is special too- for it has a One Degree, 30 minute Taper on it. The taper is designed so that the outer circumference of the Flywheel touches the Soft Iron Gasket FIRST, and compresses that all-important annular ring FIRST, thereby making a Perfect Oil Seal.

.....That small annular ring of surface from the dowel pins to the edge of the crank is all that keeps the oil away from your Clutch Disk. And ifin there's any defect or "tunnel" through that surface, oil will find a way through, suck past the flywheel dowel pin holes by capillary action, out past the Flywheel Nut Washer, and onto the Flywheel's Friction Surface. And onto your Clutch Disk too.

.....With elongated Dowel Pin holes in the Crank, there is a Very High Probability that "oil tunnels" will form through this area.

.....And ifin the end of the crank had been HAND FILED, like this one had been then it would have had myriads of radial scratches- like this one had. Then, there would be a WHOLE ARRAY of tunnels- like MARTIAN CANALS to hot 30 weight! (But, say, ifin one were to remove the dowel pins from the crank, then MACHINE flat the Crankshaft end, note how much had been machined, and reinstall the Dowel Pins, one might actually have a chance of achieving a leak-free seal again. Maybe. But first, Magnafluxing.)

.....The Camshaft showed many many miles, with worn lobes and an Oil Pump Drive Slot worn more than 45 degrees. Likewise worn halfway through was the tang of the oil pump drive gear. That lower end saw lotsa miles.

.....And as always, there was another boring set of ATE 3900 cam followers. I say "Boring" because hardly anything EVER goes wrong with Ate Cam Followers. They're the most reliable parts of the engine.

.....The SC heads show Signs of the same guy who screwed up the Flywheel Nut.

.....For what was covering the Intake Ports of the Cylinder Head but a Normal/Super Intake Manifold Gasket! On an SC head!

.....The Normal/Super gasket has SMALL, timid holes to go with the small timid ports of the Normal/Super head.

.....But the SC head has LARGE, Manly Ports.

.....So, putting a Normal/Super Intake Manifold Gasket onto an SC Head effectively puts a Ralph Nader-like restrictor right at a critical point in the Air Supply System and GUARANTEES that you'll trap ALL the droplets put in by the Accelerator Pump and have a TREMENDOUS BOG on take-off and blame the Perfectly Good Webers for your problem!

.....Such are the ways of the Turkeys.

.....The Case looked like it had never been cleaned in its life. Which is good, actually, 'cause a Greasy, oily case is a well-preserved Case. Oil/Grease is not unlike Cosmoline.

.....This one cleaned up and sparkled. Hadda wear sunglasses when the Case reflected Rays from that warm California Sun.

.....But as the Maestro was cleaning the Case Halves in preparation for Torquing the Case together and measuring the Bearing Bores, he noticed Three Interesting Things.

.....Two were expected.

.....Expected because when the Flywheel Nut comes off (or the Crank brakes in half), the Crankshaft End Play is no longer constrained. And the Crank moves axially back a forth, a LOT! Enough for the "cheek" of the Middle Main part of the crank to HIT the Case at the Middle Main Bearing area.

.....When the spinning crank touches the stationary Case, it raises case material up around the Middle Main. Sometimes this raised material is razor-sharp too, so be careful. Too much "raised area" and there you are, needing a Mandatory Align Bore.

.....Secondly- with a "free" crank, the "End Thrust", like from the Clutch being pressed "down", forces the Crank against the Middle Main Bearings, which transfer the Thrust to the bearing "tangs" in the case.

.....The little "tangs" in the case were NEVER designed to handle lotsa end thrust, so they CRACK or BREAK OFF the area of the Case where the "tang" is machined.

.....Then you gotta weld-repair and recut the tang. Maybe Align Bore the Case too. It can be Lotsa fun when the Flywheel Nut come off.

.....This engine had a mild case of both problems. There was a small razor-thin (and razor-sharp) section of Case raised up at the middle main. But that raised area could be easily scraped off with a 1930's bearing scraper.

.....And two tangs were cracked, but not broken off.

.....But the Third Strange Thing was Really Strange!

.....One of the Two Long Case Studs at the Flywheel Main had a funny little "Gouge" cut out of it.

.....And it was a "Gouge" too. No other way to describe it. About an eighth of an inch deep, cut into the side of the Case Stud, about an inch above the Case mating surface. The "Gouge" was smooth though, almost like it had been "machined" into the Stud. "Hummmmh," thought the Maestro. "That's an Interesting gouge. It's almost like a "test notch" machined into a tensile sample to induce cracking.

.....Wonder if someone did this to SABOTAGE The engine?

.....Say, maybe the Rebuilder didn't get paid or was mad at the owner, took a drill or a tool and cut this notch, figuring that the notch would cause the All-important Flywheel Main Bearing stud to FAIL! Break!

.....And with the Case held together by only the one stud on the other side, Great Leaks/Damage may result.

.....But the guy miscalculated- the Case Stud though nicked, was still intact. In one piece.

.....Insidious Plot though, thought the Maestro.

.....Hollywood, are you Listening? Jerry? Hello?

.....Anyhow the Maestro finished his preparational foreplay with the Mating Surfaces, and Torqued the Case halves together with the Through Bolt and all 6 Acorn Nuts to 29 foot-pounds.

.....Then he got out his Dial Bore Gauge from the NBS Constant Temperature Bath and inserted it into the #3 Main Bearing Bore. It checked out as a Nice Standard.

.....Then he tried the Middle Main. Not too bad, about a half thou out.

.....Then he got to the Flywheel Main Bearing Bore. And as he was about to insert his Instrument, he noticed Something Unusual about the Main Bearing Bore Area.

.....It had not one, but TWO Oil Return Holes!

.....Strange.

.....There was the Factory's Oil Return Hole- out at the usual 8 O'clock position. And there was ANOTHER hole drilled through the Case- about halfway between the Factory's Hole and Bottom Dead Center!

.....How about THAT! Thought the Maestro. The previous rebuilder drilled a SECOND oil return Hole in the CASE, probably because they thought the Flywheel Seal was leaking and getting oil onto the Clutch.

.....But the oil was getting to the Clutch through the badly "fixed" crank dowel pins, NOT through the Flywheel Seal.

.....So even TWO OIL Return holes in the Case wasn't a-gonna help things any!

.....WOW! thought the Maestro, So, maybe when the guy was drilling the hole in the Case, his drill slipped and hit the Case Stud. Maybe THAT explains the funny groove in the Flywheel Case Stud!

.....But then the Maestro took a closer look at the second oil return hole. In fact, he looked DOWN the second Oil Return Hole.

.....And what did he see?

.....I repeat. What did he see?

.....Yes, that's Right- he saw the new, intact STUD. The one he had just inserted! The Stud was protruding about halfway down from the top, inside the second, recently drilled oil return hole.

.....Which is why there was that gouge on the OLD stud!

.....When the Turkey, thinking if one is good, then a second one over here would be better, and drilled the second oil hole!

.....And when he drilled the second oil hole, he drilled it: RIGHT THROUGH THE CASE STUD that happened to be IN THE WAY! Which is why the Factory DIDN'T DRILL ITS OIL HOLE THERE!

.....And why they drilled the hole it where they did- because ifin you drill the Return Hole any closer to Bottom Dead Center,

.....THE CASE STUD IS IN THE WAY!

.....The Previous Turkeys didn't know that- and plowed right on through (They must be great Lovers too), drilling a nicely machined GOUGE, a goodly STRESS RISER in the Lower Case Stud.

.....It's a damn good thing that this "repair" never worked too! Or the Case Stud might have broken!

.....But because the engine leaked like a sieve all over the Clutch, the Owner got fed up and got another engine. And sold this one to the Man From Virginia. Who shipped it to the Maestro. Who now has to deal with all the itty-bitty problems.

.....Ifin the engine hadn't constantly leaked oil on its clutch, we might've found out what happens to an SC when one case Flywheel Main Case stud fails!

.....Maybe it IS a great Sabotage technique!

.....For now though, we'll just have to wait until someone else drills a Second Oil Return hole in the Case at the Flywheel Main, hits the Case Stud and machines another Gouge. Only Time and Murphy will tell. ifin you

Keep The 356 Faith

Maestro
 

 

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