Tuesday's Engine Rebuild Teaser Pic...

[Wayne 962]

Due to the unforeseen injury inflicted on my hand last night, I have limited progress to display. However, here is an interesting pic showing how to detect a crack using the Magnafluxing process. The crack shows up under UV light. This is a VW type-IV oil pump gear with an axial crack...

-Wayne

[old_skul]

Cool, Wayne - very shagadelic! What'd you do to your hand?

[ebrownson]

It makes me think of Jimmy Hendrix and "Purple Haze". Now if you can put in a little left to right trails, we can all have a flashback! Great pics Wayne. Please do tell us about your hand.

Eric
83SC

[Wayne 962]

Hand photos coming later on today when I remove the bandages. Right now, it's tough to type with my left hand...

-Wayne

[aseem]

Can you shed some light on the Magnafluxing process, or is this common knowledge to all?

[Wayne 962]

From the new book:

Magnafluxing - The most common task associated with crankshaft inspection is the process of ‘magnafluxing’ it. This process exposes the crankshaft and is able to detect microscopic cracks that are contained in the surface. You should have your crank magnafluxed, if you are planning on reusing it again.
The process of magnafluxing is relatively simple. The crankshaft is initially magnetized using a large circular magnet. The magnetic field is applied to the crankshaft at a 45° angle so that the process will detect cracks that run both parallel and perpendicular to the length of the crankshaft.

The crankshaft is sprayed with a special liquid that has a magnetic powder dissolved within the solution. The crankshaft is then examined under a ultra-violet black light in total darkness. The powder in the liquid will become trapped in any cracks that are present in the crankshaft. Under the black light, the cracks will clearly show as bright lines in the surface. 911 crankshafts do not typically crack, however, when they do they typically show failures at the point where the journal bearing meets a center flange.

After the crankshaft is tested, it is demagnetized and then washed again in solvent to remove any of the magnaflux material. It’s very important to make sure that the crankshaft is demagnetized, otherwise you will have the tiny bits of metal that are in your engine oil sticking to the crankshaft bearing journals.

-Wayne

[Joeaksa]

Wayne,

Just working with a friend who is having to re-overhaul his airplane motor. The PO overhauled the motor and did not demagnetize the wrist pins... they collected bits of metal from all over the motor, came loose in the rods and scored the cylinders...

Its very important to check each and every part and make positive that its not magnetic after being tested and before assembly. Sometimes even aircraft mechanics mess up...

Joe

[Wayne 962]

Very true - people are only human!

-Wayne