Diagnostic process - Page 2

'78 SC · '78 SC's Garage

Thanks for the warning. Not obvious it would travel there.

I wonder how much fine stuff get blown through the crankcase vent to the oil tank. I imagine it's just a tornado of oil mist and pulverized metal.

'78 SC · '78 SC's Garage

Take a look at at these main bearings. Surprisingly little embedded metal, it seems.

Flat6pac · 01-15-2016, 04:05 PM

Yes the mains actually look descent, not scratched through the rotation.
Bruce

'78 SC · '78 SC's Garage

Are the mains good enough to reuse?

Flat6pac · 01-16-2016, 01:06 AM

There is 2 thought processes here. One to fix the fault and the other is to rebuild because you're there. The nice thing about the Porsche design is you can fix the fault.
You ll need a rod, P/C, head, rocker. Check the oil line in the carrier for damage from the rocker.
Remove the mains and mark exactly where they came from in the case to be reused.
Cleaning will be the biggest problems. Oil galleys in the case, galleys in the crank, how scratched up inside is the oil pump?
Etc, etc
Bruce

Tom '74 911 · 01-16-2016, 05:40 AM

Quote:

Originally Posted by '78 SC

Oh my.

I think Bruce is correct. Cleaning is going to be at, or near, the top of the "difficult steps" list.

'78 SC · '78 SC's Garage

You said it, Tom. It's going to be a nightmare.

The old race cars had a filter called a "grenade" to keep debris from the external oil system. It's a magnesium casting with a stack of fine mesh filters inside that attached to the motor in place of the internal cooler. I think the name was partly due to its shape but mostly due to it role when an engine "grenaded".

Here's one on a 906 (just aft of #6).

'78 SC · '78 SC's Garage

Spun bearing, right?

Flat6pac · 01-16-2016, 02:02 PM

That's what they look like
Bruce

'78 SC · '78 SC's Garage

I'm sure there was a cheaper way to learn that. Wikipedia, maybe.

'78 SC · '78 SC's Garage

Here's the rod journal. No grooving I can detect with fingernail. Not glassy smooth like the others but not rough. Mikes out near low end of wear limit.

Flat6pac · 03:30 PM

Oh, I could have showed you several pictures but you asked after the fact...
Polish out the journal and see if you can straighten it out making it usable then get coated bearings to build up the thickness.
Mike on three different angles to check for oval
Bruce

'78 SC · '78 SC's Garage

Someone suggested the crankcase spigot can be welded to build it up and machined back to standard height. Is that feasible? The damage is shallow (about 1mm at deepest) and extends about 1.5 inch.

Flat6pac · 10:10 AM

A machine shop will heliarc the low spot and flycut it up to standard.
At that point you might consider using the thicker fiber base gaskets to fill in better.
Bruce

'78 SC · '78 SC's Garage

OK, I've been slowly working my way through the process of assessing damage, locating replacement parts and cleaning, cleaning, cleaning.

Here's the crankcase after repairs. The repair inside the spigot is obvious, there were also small repairs to the top of the spigot.

'78 SC · '78 SC's Garage

Quote:

Originally Posted by Flat6pac

You ll have shrapnel in the FI intake too on both sides and the airbox because the junk was blowing up from the pressure in the engine and sucking in on the good cylinders.
Bruce

Right again, Bruce. Here's the bottom end of the #5 intake runner and the breather line from the case to the oil tank.

puddy · puddy's Garage

The horror! So sorry to see this misfortune, best of luck getting her back in track shape!

'78 SC · '78 SC's Garage

Quote:

Originally Posted by puddy

The horror! So sorry to see this misfortune, best of luck getting her back in track shape!

Thanks, Chris.

The clean up has been an enormous task. The whole oil cooling and circulation system had to come out to be flushed, swabbed and ultrasonically cleaned.

In the process, I explored areas I've never seen - here's the inside of the air box.

Note the metal flakes still present after flushing with carb cleaner and flooding twice with solvent. I had to open it up to really clean it.

The good news is I found my air leak.

That's the o-ring that seals the throttle body to the air box protruding.

Flat6pac · 03-10-2016, 08:24 AM

You found your air leak, so it's all been worth it......in the end
Bruce

'78 SC · '78 SC's Garage

Yep, finding the air leak is a plus. I'm also having the crank drilled for better oiling and installing a 964 oil pump. Not sure I can stand this much fun again - at least not soon.