Archive for March, 2013

Magna-Whats? Magnaflux!

Posted: March 11, 2013 in Uncategorized

Finding myself heading to the Boston area for a long weekend (without the Phaeton), it seemed like a good time to stop in and meet with John Gulbankian of  J&M Machine Co in Southborough Mass ( to get a tour of his facilities and an education about engines and their restoration.  John is one of those guys that seem to love what he does.  The J&M Shop, while restoring engines of all types, specializes in antique engines and has a focus on Model T, A, and V-8s.  From what I could tell, his shop came about as an offshoot from his family’s transportation related business and their need for engines to be serviced and rebuilt correctly. 

The collection of large machines in this “machine shop” immediately demands the respect and attention of anyone visiting.  John  has tools for grinding, balancing, boring, honing, lathing, baking, blasting, measuring, welding, and so on and so on and so on.  John took the time to tell me about each machine and why they were each important to the restoration process.  The depth of his knowledge was impressive.  I would have never imagined that something as “simple” as honing or balancing could have such an impact on performance and was such an artform. 

Throughout the morning John kept talking about the importance of mangafluxing parts.  I confessed to him that I had heard of it many times, knew it had to do with cracks, but had no idea what it was or how it worked.  He then took me to one of the magnaflux stations to show me on an old crank.  The following is the video of his demonstration.  This was the first time I saw someone magnafluxing anything.


Magnafluxing (magnetic partical inspection) is based on the idea that a crack in a piece of metal will attract particles more so than an uncracked surface.   The inspector takes the parts and “dyes” them with a fluorescent compound that is magnetic – this is typically a dust or liquid. The part is then magnetized and the “dye” aligns itself with any cracks in the part.  The inspector now can see the cracks more readily and decide what to do.

John was also kind enough to show me how he balances cranks and the changes in load on the crank when you go from “per spec” balancing to greater tolerances.  He equated the load on the crank to flexing a paper clip.  The more you flex it the sooner it will break.   He then showed me a 10,000 RPM stress test on a crank and how the load dropped from 116lbs (before additional balancing) to 3lbs of pressure (after balancing).

I am hoping NOT to have to rebuild my engine anytime soon (although I am certain it needs work).  If the time comes when a rebuild is needed, John is the type of guy I am going to call.