Mystery oil leak (finally) solved

[Chuck]

Rosie has had a little seep on the left jug since I got her. Thought, oh.. valve cover gasket. Replaced that. Still leaking. Put one of the nice thick green ones on there and filed the bottom of the valve cover flat. Fixing the wrong thing.  Decided it must be the blanking plug o ring. Put a new one on there. No cigar. Cleaned it up and dusted baby powder all around, and it looked like it was coming from a valve cover screw. The Distinguished Previous Owner had dropped her on the left side, so I cleaned that up, put aviation Permatex on the screw, and called it fixed.

Ran 700 miles to NW Arkansas on back roads in 40s weather, and saw just a little oil again. Thought, WTF? Ran twistys at 6000 + rpm for about 70 miles, and had oil clear back to the pork chop. Not a lot, mind you.. but certainly aggravating. 

This time, I cleaned it up really well and sprayed this aviation leak detector on it. Let her idle a bit.. didn't see a thing.

The light comes on.. "Must need to be really hot to leak" so took her for a blast of hard running.

Well well. I've never seen this one..

Yep, it's a pin hole in the valve cover flange all right. A pin will go right into it. Cleaned it up with thinner, etc. made up some JB Weld, and tried to squeegee it in.

Time will tell...   

 

[docc]

Unequivocal evidence that, from time to time, we might all need a dose a NAD Developer . . .

[Chuck]

True.. true..

[Lucky Phil]

Not that unusual really, its just porosity. I have seen it many times over the years mainly on Ducati crankcases but a friend also had porosity on the crankcase around the r/h cylinder base gasket area on his Mk4 lemans. 

My V11 also had a porous r/h cylinder head from the drain galleries which the previous owner had repaired with sleeves.

Every pair of Ducati Corse crankcases I purchased new I would inspect for porosity before i acceped as probably 40% had issues of one form or another.

BTW Locktite "wick in" would be the way to go in my opinion or if its a cleanish defined hole then what you have mentioned of Araldite works well. 

Ciao

[Kiwi_Roy]

Great detective work Chuck

 

I had a manifold made for distributing Methanol, nice shiney stainless steel 150# fittings all welded together.

On testing with water we found beads of sweat building up on the surface of the tees, sure enouch cheap Chinese fittings were rough as guts on the inside, polished like chrome on the outside. I was told later by a Chineese client never to use their 150# fittings.

[guzzimeister]

Hi fellow masochists

 

just a postscript to this discussion, but alu porosity is a well-known curse of the casting industry, especially die castings. I used to be involved in such stuff, and porosity usually occurs where there is a sharp change of cross-sectional area, or in very thick pieces. Standard cure is to avoid such features if possible, but where it is not, foundries use vacuum impregnation to fill it (like the sound of that). Basically the casting is put into a vacuum chamber filled with resin which fills the holes. Guzzi at one time even sold a two pack resin to fix such issues, I think there is a number for it in the V11 spares list. I also have Royal Enfields, and the standard procedure was to paint the inside of all crankcases with a paint called Glyptol, which did much the same thing at a surface level.

 

Thanks for letting me empty my over-crowded brain of a little useless trivia; now to fill it with some more.....

 

Cheers

 

Guzz