The Turkey Day Quiz:

The Maestro has seen some Porsche Engines go over 200,000 miles on an Overhaul.

That's Good.

He's also seen Porsche Engines that have gone fewer miles than you can count on your fingers and toes and various other appendeges!

That's Bad.

One of the latter was experienced by one of the Maestro's new Customers who should have come to the Maestro's Shop one overhaul sooner. But, hey- better late than never.

(Actually, you see, the Maestro's prices were just a tad too high for the Customer-to-be, so the Customer-to-be went to one of the competitors who does a lot of VW engines. Close enough thought the Customer-to-be.)

Thilly boy.

To save money, the Customer even assembled the engine himself, using the Maestro's Books and Tapes, of course- and even asking the Maestro for Copious Quantities of free advice and buying only a few, low-cost Porsche parts that only the Maestro had.

And Lo, the Customer-to-be's Engine doth run!

For 50 miles. As the Customer-to-be watched the oil pressure drop lower and lower, faster than Gov Davis's Popularity Polls in a Power Crisis.

Finally, the Customer-to-be called the Maestro, to became a REAL Customer.

He brought his newly-rebuilt but now-disassembled engine over to the Maestro's Shop for a Post Mortem Inspection, (OK, an Autopsy). Surely, thought the Customer, surely the VW shop had made some big bad boo-boo. Why else would the oil pressure go to hell so quickly?

The Maestro just LOVES engine Disasters- especially on engines someone ELSE has built. On his own (very, very few) Disasters he feels Betrayed Big Time by the gods and wails forlornly heavenward.

This one proved to be Interesting.

Why WOULD the oil pressure drop from around 50 psi to 10-15 psi, and this, a 356SC Engine with the Big 36mm Oil Pump?

THAT is the Question. Keep the 356 Faith Maestro The Maestro's Turkey Day Quiz, Part 2: And Lo, the Customer-assembled Engine doth run... for 50 miles, until the Customer watched the oil pressure drop lower and lower- from 50psi down to 10-15 psi.

So, Why WOULD the oil pressure drop from around 50 psi to 10-15 psi, and this, a 356SC Engine with the Big 36mm Oil Pump?

THAT is the Question. Oh, yes, it COULD be that the competitor, a VW shop, supplied the WRONG size Rod or Main Bearings- that's always a possibility. And just such an event is responsible for a significant fraction of "low oil pressure syndrome" engines. Another large fraction is the 1950-1959 356A's that inherently have low oil pressure, but even they can still eke out 45 psi at cruise! But that wasn't the Cause this time.

The Maestro searched for an answer in the parts spread out before him in the back of the Band New SUV, with wifey-poo in the passenger side.

Present and accounted for were the uncleaned Case with its Third Piece, the set of C/912 "01" Rods, the Crank, and Cam and the Bearings.

The Maestro began by measuring the crank with his Trusty Micrometer. Three of the four rods were down about a thou and a half below Low Limit at Second Undersize (0.5mm).

But the Rod Journal nearest the Flywheel was down over FOUR thousandths of an inch! "Wow- said the Maestro- this Rod journal is down over FOUR thou!! You don't usually see that for 200,000 miles. How many miles did you say this engine went again?

"50." "Fifty? Only Fifty Thousand Mlles?" "No- only FIFTY MILES!" "Oh, " said the Maestro. And went back to measuring. "What did that awful shop do to my engine?" Asked the now VERY repentant Customer impatiently, now terribly sorry financially for having strayed from The Faith. "Did they grind my Crankshaft too small?" Well, did they? So, What's the problem here? Good question, said the Maestro. Maybe we can tell.

So the Maestro measured the Crank Rod Journals at 90 degrees to where he measured before. (Where he measured before is at the Diameter of Greatest Wear, which is usually in line with the Piston at Top Dead Center. Conversely, the Diameter of Least Wear and an indicator of what the Crankshaft size was Originally is 90 degrees away from the Diameter of Greatest wear- or perpendicular if you prefer.)

Measured 90 degrees off, the Maestro found the Crank to be almost within Tolerance at the Undersize.

"So, said the Customer, "What did that shop DO? Did they grind the Crank oval-shaped?" "No," said the Maestro. "I don't think so. Grinding an OVAL-shaped Journal is pretty hard to do on a Crankshaft Grinder. After all, they're made to grind a pretty good circle.

"No, what we have here is a case of is WEAR, not a bad crank grind." "But HOW did it wear THAT MUCH in only FIFTY MILES???", asked the Customer, practically standing beside himself.

So, how DID it wear THAT much in 50 miles?? Keep the 356 Faith Maestro The Maestro's Turkey Day Quiz, Part 3 So, Why WOULD the oil pressure of a newly-assembled engine drop from around 50 psi to 10-15 psi, and this, a 356SC Engine with the Big 36mm Oil Pump? "What we have here is a case of is WEAR, not a bad crank grind." "But HOW did it wear THAT MUCH in only FIFTY MILES???", asked the Customer, practically standing beside himself. Just out of Curiosity, asked the Maestro, "was there a lot of "hair" on the Magnet?"

Why, that's AMAZING, Maestro. You're Right- there WAS quite a bit of "hair" on the drain plate's magnet! And it sure did look like hair too, heh, heh." "No," said the Maestro. "That was your CRANKSHAFT! Or at least that part of your crank that is MISSING from the Journals. Being Magnetic, it ends up on the Magnet." (Note too, that being ON the Magnet means that the crankshaft pieces were small enough to get THROUGH the SCREEN that's AROUND the Magnet.)

The Maestro then checked the Case. The Case Bores didn't look too bad, but you can't really tell without a Dial Bore Gauge.

The Maestro ran his hand along the Cam Bore to feel the wear ridge near the Flywheel Main journal of the camshaft. And his finger felt funny. Funny Curious, not funny ha-ha. Funny like Rough.

So he eyeballed his finger, and felt "stuff" on his finger. Further inspection of the Case revealed lots of this "stuff".

So, what do YOU think the "stuff" was?

The Maestro thought he knew.

Do you?

The Maestro ran his hand along the Cam Bore to feel the wear ridge near the Flywheel Main journal of the camshaft. And his finger felt funny. Funny Curious, not funny ha-ha. Funny like Rough.

So he eyeballed his finger, and felt "stuff" on his finger. (And no wise guy, it wasn't THAT kind of stuff!) Further inspection of the Case revealed lots of this "stuff".

So, what do YOU think the "stuff" was?

The Maestro thought he knew. "Well," said the Maestro. "Just out of Curiosity, did you happen to have the engine sheet metal powder painted?" "Why, that's AMAZING Maestro! YES, I did have the engine sheet metal Powder Painted. But what has that got to do with the price of tea in China. Or my Crank?" "Because, said the Maestro, savoring the Victory, "I bet ifin you take off the Oil Breather Can from the Generator Stand it's probably on, and stick your finger up the oval end and play proctologist, I bet you'll find lots of "crud" on your finger. Some of that crud will be the rough stuff we found in the Case. "But, but," sputtered the Customer. "My Powder Painter told me he only bead blasted the OUTSIDE of the Oil Breather Can!" "That's not a good thing to do either- there are 30 year old Stalactites and Stalagmites growing inside, made of RUST that are just waiting to fall down inside your new engine- into the cam gears and... Beyond.

You've gotta DEAL with it. Clean the Can in Carb Cleaner. Brush out madly. Rinse in Safety Kleen Tank. Let dry in California Sun for a couple of days. Place in GE Nuclear Toaster Oven, on "Broil" for at LEAST an HOUR or until no more smoke emerges. Whichever occurs last. Now there ain't nothin' left inside the Breather Can but fluffy carbon and dry rust that's easily removed by a good bead blaster, so bead blast the INSIDE Of the Oil Breather Can while still HOT! (Re-heat if necessary.)

Blow out the Can with dry air VERY well and Powder Paint the INSIDE too, to A. Prevent more rust from forming in the future, and B. Imprison forever any stray beads that may have escaped the Hurricane/Tornado you induced before.

That's how you deal with the Breather can.

But I bet your Powder Painter didn't know that. And you have sand or glass beads inside your Oil Breather Can! said the Maestro. And that's what did your engine in!

The Customer took off immediately to check.

And a few hours later called to say that:

"Maestro you were ABSOLUTELY RIGHT again! There WERE beads in my Breather! I stuck my finger up and there they were- the same rough stuff we found inside the engine. I'm gonna have a talk with my Powder Painter about this!

Yes, said the Maestro, and the next time maybe you oughta CHECK the Breather Can to see what's inside BEFORE you put it on.

Look up through the C/912 Breather Can to a light source (the Sun works well in California). Marvel at the massive deposits inside, on the side(s) of most any 356C/SC/912 Oil Breather Can.

Think of the Horrible Things this stuff could do if it gets inside your engine.

Have nightmares about it- because if this is YOUR Breather Can, the stuff is ALREADY INSIDE your engine, and you'd better:

Keep the 356 Faith

Maestro
 

 

© © 2012 The MAESTRO, Maestro's Library