Whats this ????? Please help feel like I'm going backwards.

[Sharkbitemarky]

1976 911 2.7 . So I have taken air box getting ready for delivery of the new air box install.

Remembering before taking the engine out of the car 4 years ago it run ok with a slight misfire, as the spark plug on #4 cylinder looked like it had not been firing and compression was good, I guessed it needed either new injector &/or a new spark plug/spark, which it now has however, the backfire stopped play ! for what few seconds the car run before the air box busting backfire, I could not detect a misfire.

So now being able to look in to the inlet ports I see this white sludge around the port #4 !

Could this be running long term without spark or fuel and condensation residue building up over time ? any other ideas ? all other ports are clean.

[bkreigsr]

One of the benefits of listing your location in your signature line is, we would be able to rule out a salt-based electrolysis-type corrosion problem, or whether your car might have been involved in a flood.
List your location, and give us any clues that might help ID the problem.

The guide, valve, and seat look fine from here.
If you get it running right again, you might be able to get rid of the deposits with a product like Seafoam.
Or not.

Bill k

[Sharkbitemarky]

Originally Posted by bkreigsr

One of the benefits of listing your location in your signature line is, we would be able to rule out a salt-based electrolysis-type corrosion problem, or whether your car might have been involved in a flood.
List your location, and give us any clues that might help ID the problem.

The guide, valve, and seat look fine from here.
If you get it running right again, you might be able to get rid of the deposits with a product like Seafoam.
Or not.

Bill k

. UK. Its only #4 inlet, does not look like corrosion, looks like a deposit very much like the white sludge you get on a oil filler cap when doing lots of short trips.

[Sharkbitemarky]

No body seen this before ?

[proporsche]

from what i see something has fallen into your chamber and burned..or just melted...
Ivan

[Dpmulvan]

Originally Posted by bkreigsr

One of the benefits of listing your location in your signature line is, we would be able to rule out a salt-based electrolysis-type corrosion problem, or whether your car might have been involved in a flood.
List your location, and give us any clues that might help ID the problem.

The guide, valve, and seat look fine from here.
If you get it running right again, you might be able to get rid of the deposits with a product like Seafoam.
Or not.

Bill k

I wouldn't run that motor, tear down the head inspect valve, valve guide et. That valve is covered in crust. Looks like a pile of oil, un burnt fuel and moisture all mixed together just my opinion.

[porsche930dude]

I wouldnt worry too much about it as long as it cleans up. Get a boreoscope and look in the cylenders aswell. I bet its old fuel it does nasty stuff when it sits a long time. I had a 3 wheeler that had brown sludge everywhere there was fuel it actually locked up the engine I had to pull the head and clean it out. Though it did rot the valve and seat

[Tom '74 911]

Can you tell if the built-up stuff is hard (crystalline) or soft (sludge)? In either case, remember that when you get the motor running, it will be going right through the combustion chamber on its way out...

[Sharkbitemarky]

Stuff was soft like a paste, 95% came out with vac hose, the rest cloth on wooden stick, looks like new now.

I think this was a long time blocked injector, as, if the injector was working the fuel would have flushed the stuff away, I think condensation/stuff built up because of temp differentials e.g. non firing piston next to firing. Possible WDYT ?

Bore scope every thing looks normal.

Engine was rebuilt 14k ago by Charles Ivy of London.

Valve guides are good, no smoke, very clean exhaust.

Originally Posted by Sharkbitemarky

Stuff was soft like a paste, 95% came out with vac hose, the rest cloth on wooden stick, looks like new now.

I think this was a long time blocked injector, as, if the injector was working the fuel would have flushed the stuff away, I think condensation/stuff built up because of temp differentials e.g. non firing piston next to firing. Possible WDYT ?

Bore scope every thing looks normal.

Engine was rebuilt 14k ago by Charles Ivy of London.

Valve guides are good, no smoke, very clean exhaust.

I think your theory is correct. Goo like that gets created when water and oil mix--think about what the coolant and oil looks like in an engine with a blown head gasket. Flat sixes tend to build up oil in the cylinders when they sit, and I'll bet that plus the water from condensation caused the stuff to mix like that.

Have you changed the oil? If so, what did it look like?

[wayner]

Decomposed mouse?

(Upon closer inspection I change my answer to fish :-)

[Sharkbitemarky]

Originally Posted by madcorgi

I think your theory is correct. Goo like that gets created when water and oil mix--think about what the coolant and oil looks like in an engine with a blown head gasket. Flat sixes tend to build up oil in the cylinders when they sit, and I'll bet that plus the water from condensation caused the stuff to mix like that.

Have you changed the oil? If so, what did it look like?

Oil that came out was good. New oil put in before cranking.

[stlrj]

Originally Posted by wayner

Decomposed mouse?

(Upon closer inspection I change my answer to fish :-)

Maybe a yeast infection. There might be an antibiotic for that.

[patkeefe]

What is the relative position of the deposit with respect to gravity? ie, is that junk on the bottom of the port?

[Sharkbitemarky]

Originally Posted by patkeefe

What is the relative position of the deposit with respect to gravity? ie, is that junk on the bottom of the port?

The engine is in its normal attitude.