Pay attention to the gauges, subtlety matters.
Posted: Tue Aug 14, 2012 7:29 amAfter the phone call, with the diagnosis confirming a complete engine tear-down and reconstruction with (mostly) original parts, I called the cardiologist, then the paramedics, then the loan officer at the bank.
Why the elevated blood pressure and sucking sound from both my circulatory system and my wallet? A slight variation on one of the gauges on my 911 dash: the oil pressure gauge to be specific.
Here's the story: after some extensive re-working to get the car tight and right for legitimate smogging and registering, I got the car back running great. All systems were "go" and I've been planning and prepping for the upcoming TT at WSIR in September, to be followed by a stint to Laguna Seca and Buttonwillow. I've been acquiring goodies to help keep me in the running with a certain red and yellow 911SC co-driven by a couple of hot shoes, and was planning on dancing in the mirrors of a certain silver 911SC piloted by a driver who until now has driven a Porsche with the engine in the wrong place. Well, as Jackson Browne will tell you, "all good things... gotta come to an end."
I noticed a small, almost eccentric little change on one of my gauges shortly after re-fitting my car for smog: the oil pressure light came on at idle and the pressure dropped to about 0.8 bar at idle. If I rev'ed the engine just 100-rpm the light went out and the oil pressure raised to about 1.0 to 1.1 bar. At running speed (2500-rpm to 4500 rpm on the street) the oil pressure was "normal" at around 4 to 4.5-bar - 5 bar above 4000-rpm. Normal for most Porsches, but slightly different from what I was used to with the 3.6 conversion ("perversion"??) under my decklid. My pressure used to read about 20% to 30% higher on the gauge because of the difference between the 3.0 vs 3.6 engines (a gross simplification of the difference. There's too much to mention in this long post).
So I thought "Huh, maybe something in the recently changed vacuum / tubing plumbing has caused a change in the way the pressure sender reads the pressure." When I mentioned the drop the tech expert that prepped the car for smogging he said "Yeah, I noticed that, too. Replace your pressure sending unit (under the intake) and see if that isn't it." So, I thought "Great: a quick sender change-out and I'm back in business." My initial thought was; "This engine is only 2 years old; fresh-built by one of the best in the business - it's a bullet-proof 3.6 - I got nothing to worry about. This engine has another 8 to 10 years of street/track life left in it. It's barely broken in."
Well, after the sending unit was changed the pressure still read low. The mechanic/tech that I talked with (different one now) said, "Not good. There might be something wrong that could lead to real problems. We should drain the oil and look for bits of metal in the bottom of the case. You could have lost a piston oil-squirter, or it could be something worse. Best not to drive the car hard or rev it high until things get looked at." At this statement, my vision blurred and I had an epiphany of 100-dollar bills sprouting wings and flying out of my wallet in a mass migration toward ... infinity. The dream of chasing down a red or silvered 911SC at the track started to become the nightmare of chasing fleeting revenue and long weekends of side-jobs and Top-Ramen Gourmet dinners. "But, it's just a tiny drop in pressure! How bad could it be?"
Draining the oil and finding the tell-tale bits of metal told the story. The phone call from the shop came waaaay tooooo early; I knew I had to be sitting down. There was a glimmer of hope; the shop couldn't tell if it was a squirter - a less-extensive (read: less-expensive) tear-down or a crank plug; a complete tear-down. The afternoon phone call; that's when all the color ran from my face. My head pounded, my ears buzzed with the sound of small rectangular slips of paper - colored green - fluttering into the intake manifold of my 3.6, and being burned like the 100-octane on the front straight of WSIR. My engine had been laid bare on the shop's bench for all to see. The culprit: a crankshaft plug dropped from the crank and resting in pieces in the bottom of the crankcase. Luckily, no severe damage to crank, case or related parts.
There is sunshine to this gloomy story. I'm actually very lucky in one respect: had I ignored the slight drop in pressure and assumed everything was tight and right with my re-built, 2-year old engine, I most certainly would have "grenaded" the engine into itty-bitty parts either on the mountain roads of East County, or most certainly at WSIR in September. My "A-R" tendencies toward having a perfectly running engine / car saved me from making a critical error in judgement and destroying the parts that make up my engine. The cost of replacing the entire engine would be much more than the cost of the "tear-down and rebuild with same parts" fix that I will ultimately have to deal with. Just about everything that came off the engine will go back in.
"It was just a very small, slight reduction in pressure." Wrong. It was a tell-tale warning sign that something was seriously wrong and needed to be addressed before catastrophic damage occurred.
So, next time you look at your gauges and something seems to be amiss, park it! Get it checked out... thoroughly. What seems like a tiny change from the norm could be the difference between pulse ... and no pulse ... for your air-cooled Porsche engine.
Trust your gut.
Why the elevated blood pressure and sucking sound from both my circulatory system and my wallet? A slight variation on one of the gauges on my 911 dash: the oil pressure gauge to be specific.
Here's the story: after some extensive re-working to get the car tight and right for legitimate smogging and registering, I got the car back running great. All systems were "go" and I've been planning and prepping for the upcoming TT at WSIR in September, to be followed by a stint to Laguna Seca and Buttonwillow. I've been acquiring goodies to help keep me in the running with a certain red and yellow 911SC co-driven by a couple of hot shoes, and was planning on dancing in the mirrors of a certain silver 911SC piloted by a driver who until now has driven a Porsche with the engine in the wrong place. Well, as Jackson Browne will tell you, "all good things... gotta come to an end."
I noticed a small, almost eccentric little change on one of my gauges shortly after re-fitting my car for smog: the oil pressure light came on at idle and the pressure dropped to about 0.8 bar at idle. If I rev'ed the engine just 100-rpm the light went out and the oil pressure raised to about 1.0 to 1.1 bar. At running speed (2500-rpm to 4500 rpm on the street) the oil pressure was "normal" at around 4 to 4.5-bar - 5 bar above 4000-rpm. Normal for most Porsches, but slightly different from what I was used to with the 3.6 conversion ("perversion"??) under my decklid. My pressure used to read about 20% to 30% higher on the gauge because of the difference between the 3.0 vs 3.6 engines (a gross simplification of the difference. There's too much to mention in this long post).
So I thought "Huh, maybe something in the recently changed vacuum / tubing plumbing has caused a change in the way the pressure sender reads the pressure." When I mentioned the drop the tech expert that prepped the car for smogging he said "Yeah, I noticed that, too. Replace your pressure sending unit (under the intake) and see if that isn't it." So, I thought "Great: a quick sender change-out and I'm back in business." My initial thought was; "This engine is only 2 years old; fresh-built by one of the best in the business - it's a bullet-proof 3.6 - I got nothing to worry about. This engine has another 8 to 10 years of street/track life left in it. It's barely broken in."
Well, after the sending unit was changed the pressure still read low. The mechanic/tech that I talked with (different one now) said, "Not good. There might be something wrong that could lead to real problems. We should drain the oil and look for bits of metal in the bottom of the case. You could have lost a piston oil-squirter, or it could be something worse. Best not to drive the car hard or rev it high until things get looked at." At this statement, my vision blurred and I had an epiphany of 100-dollar bills sprouting wings and flying out of my wallet in a mass migration toward ... infinity. The dream of chasing down a red or silvered 911SC at the track started to become the nightmare of chasing fleeting revenue and long weekends of side-jobs and Top-Ramen Gourmet dinners. "But, it's just a tiny drop in pressure! How bad could it be?"
Draining the oil and finding the tell-tale bits of metal told the story. The phone call from the shop came waaaay tooooo early; I knew I had to be sitting down. There was a glimmer of hope; the shop couldn't tell if it was a squirter - a less-extensive (read: less-expensive) tear-down or a crank plug; a complete tear-down. The afternoon phone call; that's when all the color ran from my face. My head pounded, my ears buzzed with the sound of small rectangular slips of paper - colored green - fluttering into the intake manifold of my 3.6, and being burned like the 100-octane on the front straight of WSIR. My engine had been laid bare on the shop's bench for all to see. The culprit: a crankshaft plug dropped from the crank and resting in pieces in the bottom of the crankcase. Luckily, no severe damage to crank, case or related parts.
There is sunshine to this gloomy story. I'm actually very lucky in one respect: had I ignored the slight drop in pressure and assumed everything was tight and right with my re-built, 2-year old engine, I most certainly would have "grenaded" the engine into itty-bitty parts either on the mountain roads of East County, or most certainly at WSIR in September. My "A-R" tendencies toward having a perfectly running engine / car saved me from making a critical error in judgement and destroying the parts that make up my engine. The cost of replacing the entire engine would be much more than the cost of the "tear-down and rebuild with same parts" fix that I will ultimately have to deal with. Just about everything that came off the engine will go back in.
"It was just a very small, slight reduction in pressure." Wrong. It was a tell-tale warning sign that something was seriously wrong and needed to be addressed before catastrophic damage occurred.
So, next time you look at your gauges and something seems to be amiss, park it! Get it checked out... thoroughly. What seems like a tiny change from the norm could be the difference between pulse ... and no pulse ... for your air-cooled Porsche engine.
Trust your gut.
Case, pistons/cylinders/rings, heads/valves, intermediate shaft/oil pump, timing chains and gears, etc., etc., - all 
OK! Phew! dodged a $-bullet there! Now on to even better news:
Old crank and rods are fine for resale to a street-car home (not advised for a racer 
).
