Engine damage running on WVO... see pics...

Or Turbo Diesel · December 24th, 2007, 16:01

I just removed the head on a car I bought- 96 Passat TDI, 300k, crank only turns about 30 degrees.

I have never seen a piston just dissapear!

(See pictures under members, OR turbo diesel)

I have only drained the water (coolant must be overrated); I am going to drain the oil and see if parts of the piston are there.

Anyone care to explain what may have happened? I bought it this way, prev. owner said he was coming back from a trip, overheated on the fwy., never would run again. He was running WVO, veggie.

Could an overfuel cause this (only 1 cyl. though), or a wvo problem?
Thanks...

concours · December 24th, 2007, 16:08

Woooowwwwwwww... lot's of corrosion as well. Did it sit out in the weather?

aNUT · December 24th, 2007, 18:33

Thought putting the pictures in the thread would make things easier...

I cry for that poor TDI...

whitedog · December 24th, 2007, 19:41

Holy Mother of God!

Time for a long block. since it's just one cylinder, the most likely cause would be the injector but it doens't look bad in this picture:

It could have been just dribbling fuel in with zero atomization.

How long did it sit?

TurbineWhine · December 24th, 2007, 20:03

I have a friend that was running WVO and his engine died after about 50K miles. The engine was trash and had to be replaced completely. His pistons were still there but the cylinder walls were so badly damaged it could not be repaired. I would suspect that engine is not repairable either. Hope you got the car real cheap.

TW

Or Turbo Diesel · December 24th, 2007, 22:22

Is there such thing as a cheap TDI? It's ok, I have more parts to make a wagon swap happen. All the "corrosion" you see is actually metal left from the piston- it actually melted onto the cyl. wall, and I got a chunk out that was resting on the small end of the rod. Some tranferred to the head to, but it just fell off when I touched it. The rod scored the wall more than the piston!

Dimitri16V · December 24th, 2007, 22:24

can you say meltdown ?

Franko6 · December 25th, 2007, 05:39

That appears to be an injector that wasn't ever shutting off. I've seen them like that. Instead of popping, they just spray and spray and spray.

But let's face it... that took determined driving to get that hole so completely cleaned out of aluminum.

The engine that turbowhine is talking about is DuluthRoosters. It's been bored out .5mm oversized and it's running quite happily in another car as we speak.

But where did the rod go? It doesn't hardly look like it touched the cylinder walls.

Also, despite the heating that the piston took, That cylinder head looks retrievable. I wouldn't use those two valves...

mijbo11 · December 25th, 2007, 06:36

WOW.
im not surprised. The Injection components just cant handle the wvo.
Ive seen larger engines just cut holes through forged pistons and cut cylinder liners like you were using a plasma cutter.

Drivbiwire · December 25th, 2007, 07:41

The cause is referred to as "streaming" where the nozzles become plugged and are no longer able to atomize the fuel. This becomes a bigger issue with higher viscosity fuels which is why WVO is perhaps the stupidist thing anybody can do to a diesel.

Larger injector holes ie "Pintle" design are the ideal nozzle for WVO applications where more viscous fluids are used.

What occured was the fuel streamed, the jet of fuel rather than atomizing came in contact with the aluminum of the piston. In normal combustion the fuel NEVER comes in contact with the surface of the piston! The swirl within the chamber mixes the droplets of fuel during the "ignition Delay phase" then autoignition occurs without any contact with the piston bowl.

Streaming and use of WVO or thicker oils causes fuel to fail to mix with the "swirl" in the bowl, the slower mixing results in increased contact and burning of the piston as evidenced by the high levels of black soot on the surfaces.

DB

Or Turbo Diesel · December 25th, 2007, 10:26

The rod appears fine- wrist pin scored the walls, but I see no rod contact. Sounds like that one injector has a big problem. They may not have been serviced in a long time (if ever).

I let a head rebuilder look at the head, and he said no problem. Of course the 2 valves are junk.

Perfect example of what can go wrong with "free" fuel!

WB9K · December 25th, 2007, 19:09

Quote:

Originally Posted by Or Turbo Diesel

Perfect example of what can go wrong with "free" fuel!

Yeah....in the hands of an idiot. Like Franko6 said, it took some real effort to get to this point. Anyone who ignores the symptoms that had to be visible leading up to a failure like this deserves what they get. These people don't need experimental fuel to destroy what they touch, but it can sure help. Was that 300k miles or kilometers? How many on WVO? That poor engine....

WB9K · December 25th, 2007, 19:21

Quote:

Originally Posted by Franko6

That appears to be an injector that wasn't ever shutting off. I've seen them like that. Instead of popping, they just spray and spray and spray.

My first thought was major leakage from the injector. In either case, would the ultimate failure mode be hydrolock? What causes an injector to stick open like that (not pop off), other than total neglect?

Did the piston melt down or break apart, or both? What's with all that rust--blown head gasket?

ninedee_golf_tdi · December 26th, 2007, 05:34

A novel way to transform a 1.9 into a 1.4.

WB9K · December 26th, 2007, 06:13

Quote:

Originally Posted by ninedee_golf_tdi

A novel way to transform a 1.9 into a 1.4.

And a 100% fuel savings! ZERO emissions!