Total Destruction

Mr9146 · 04-15-2005, 02:48 PM

The other day I took apart a core motor that was just laying around the shop - you know, to see what it was. I could see the broken #6 intake valve through the port, so the question was how bad had the motor been damaged. Check out these pictures:

The case was also hosed where one of the bearings started to spin and literally melted away the main. Pretty cool stuff....

Sonic dB · Sonic dB's Garage

The question I always have when I see something like this here...is how did it get that way? What led to that destruction? What could have been done to avoid it?

dd74 · 04-15-2005, 02:55 PM

Marco! What's up, Chief? Tony lets you play with his tools? Did he put my old calipers on his 356 yet?

Vipergrün · 04-15-2005, 03:06 PM

Looks just like the piston head I keep on my desk as a paperweight.........and a reminder to ALWAYS turn the motor over by hand BEFORE using the starter

-B

CarreraCab · 04-15-2005, 03:18 PM

Nothing a little Marvel Mystery Oil couldn't handle, ahem ! Doug

Mr9146 · 04-15-2005, 03:28 PM

David, yes, the car is about done. Here's a picture from most people's perspective.

dd74 · 04-15-2005, 04:12 PM

Looking good. Tell Pops I said "Howdy!"

Tyson Schmidt · 04-15-2005, 04:21 PM

Quote:

Originally posted by Sonic dB
The question I always have when I see something like this here...is how did it get that way? What led to that destruction? What could have been done to avoid it?

Valve guides wear out, valves now lose their ability to conduct heat away from the head through the stem and out through the cylinder head. This causes the valve head to heat-fatigue and break off from the stem and the mayhem ensues.

Sonic dB · Sonic dB's Garage

Quote:

Valve guides wear out, valves now lose their ability to conduct heat away from the head through the stem and out through the cylinder head. This causes the valve head to heat-fatigue and break off from the stem and the mayhem ensues.

OH. This is why we should rebuild our Carrera (or SC) engines once the oil consumption gets down to 1 quart for every 500 miles or less etc. I get it now...

BTW...Tyson, is your shop good at rebuilding 915 trannys? My car is getting to the point of needing it.

Mr9146 · 04-15-2005, 04:40 PM

Hey, Tyson, I don't even get a hello? Thanks for nothing ...

You headed up north at the end of the month?

Oldporsche · 04-15-2005, 05:16 PM

The last one I too apart that looked like that was shoved into second gear at about 75 mph. What was left of the exhaust valve was bent into an "S" shape!

DAvid Duffield

Tyson Schmidt · 04-15-2005, 07:33 PM

Quote:

Originally posted by Mr9146
Hey, Tyson, I don't even get a hello? Thanks for nothing ...

You headed up north at the end of the month?

Hello Marco!

Sorry Bro'.

Yeah, I'll be there. Driving my new car with lots of new upgrades. I'm looking forward to this year's event. I'll be an official member soon.

See you there!

Tyson Schmidt · 04-15-2005, 07:36 PM

Quote:

Originally posted by Sonic dB
OH. This is why we should rebuild our Carrera (or SC) engines once the oil consumption gets down to 1 quart for every 500 miles or less etc. I get it now...

BTW...Tyson, is your shop good at rebuilding 915 trannys? My car is getting to the point of needing it.

Yes, I rebuild a lot of them. From stock to race, whatever you need.

The 356 boxes we send to Marco's papa.

(Tony @ TLG)

Mr9146 · 04-15-2005, 08:04 PM

Good, good Tyson. Looking forward to bench racing with you.

I can't wait to see what you've done with the new toy, too.

VaSteve · 04-16-2005, 07:01 AM

Quote:

Originally posted by bb80sc
Looks just like the piston head I keep on my desk as a paperweight.........and a reminder to ALWAYS turn the motor over by hand BEFORE using the starter

-B

What does this mean? With a wrench before each time you drive it?

speeder · speeder's Garage

Quote:

Originally posted by Sonic dB
OH. This is why we should rebuild our Carrera (or SC) engines once the oil consumption gets down to 1 quart for every 500 miles or less etc. I get it now...

One quart of oil consumed every 500 miles would be acceptable for an SC or Carrera when they were brand new, and that is according to the factory and printed in the owners manual. You either mis-typed or you have your information confused.

Some motors consume less, of course, but my "rebuilt to brand new" SC motor w/ better valve guides than original consumed ~1 qt. per 500 miles.

dd74 · 04-16-2005, 10:01 AM

Quote:

Originally posted by speeder
One quart of oil consumed every 500 miles would be acceptable for an SC or Carrera when they were brand new, and that is according to the factory and printed in the owners manual. You either mis-typed or you have your information confused.

Some motors consume less, of course, but my "rebuilt to brand new" SC motor w/ better valve guides than original consumed ~1 qt. per 500 miles.

Denis - great information, since I don't have an owner's manual. I always thought excessive smoking and loss of power would be a good indication of a rebuild. There's too many variables with oil consumption IMHO - especially when the days get warmer - i.e., the engine consumes more oil with higher ambient air temperatures. What are your thoughts?

speeder · speeder's Garage

I just thought that it was important to correct that statement right below it for the whole *Pelican data base* thing here.

Once again: 1 quart of oil consumed every 500 miles in an air-cooled 911 does not equate to rebuild time. It equates to brand-new, properly broken-in car/motor.

That sounds like a Motor Meister ad: "911 burning a quart every 500m ? Bring it in for our spring special, the KY jelly rebuild....."

The cliche w/ a 911, was that the factory recommended oil changes @ 6000 mile intervals, but that the customer had "changed" the oil once in between. (Get it? 1 qt. every 500 for 6000 miles = 12 new quarts in between).

speeder · speeder's Garage

Quote:

Originally posted by dd74
Denis - great information, since I don't have an owner's manual. I always thought excessive smoking and loss of power would be a good indication of a rebuild. There's too many variables with oil consumption IMHO - especially when the days get warmer - i.e., the engine consumes more oil with higher ambient air temperatures. What are your thoughts?

911s, like a lot of good motors, have a ratio of bottom-to-top end longevity that works out to 2 or more top end jobs per bottom, at least w/ the stronger cases that they made. My 911 SC needed a complete going through w/ only ~100k miles because of the dreaded broken head studs, but the bearings were like new. Broken parts, unacceptable leakage whether compression/vacuum or oil, generally worn-out, etc.. would be the indication for rebuild time. Or the situation pictured above.