Yamaha and Mercury four stroke cylinder repair.
Yamaha /Mercury cylinder head showing serious corrosion from salt and high mineral content water. Although the head appears to be beyond repair, Baltimore head Works machine shop can  repair it and return it to service.
First step in reconditioning the head is to clean the metal, and remove all corrosion. This is accomplished in our state of the art ultra-sonic cleaning process that removes all grease, coolant and dirt.  The head is then glass beaded to remove surface corrosion on all internal and external surfaces. Compressed air is used to blast small glass pellets at the aluminum surfaces, this results in a surface ready to be welded with an inert gas welding process. Inert gas welding is used to build up the eroded areas on the head surface.

To the right is a photo of a head that has been cleaned and  glass beaded and ready for the next process.
  The head is further machined in preparation for welding with our TIG welding machine. TIG welding  aka Tungsten inert gas welding  results in a clean flux free weld that bonds perfectly to the original metal casting. 

Inert gas welding (TIG or MIG) produces a weld without any oxidation, because the process is preformed in a non oxygen atmosphere. This results in a perfect buildup of new aluminum melted into the original aluminum alloy.

To the Right is photo of head that has been welded and ready for the resurfacing process.   

Now the water passages in the cylinder head are ready to be coated with an anti-corrosive strontium chromate coating. It provides an excellent barrier to reduce pitting of the metal from galvanic corrosion. The head originally had no protective coating from the manufacturer, so this will greatly improve the corrosion characteristics of the head in the future.

To the left is a photograph showing the head after coating.

The head is now resurfaced, and this was accomplished with a “DCM” mill utilizing “CBN” cutters. This machine imparts a surface finish below an Ra of 20. That’s smooth! With the introduction of “MLS” gaskets, multi layered steel, smooth is not only better it is necessary. All valve jobs get milled to not only flatten the surface but also to give the head gasket a better environment in which to seal.

To the right is a photograph showing the resurfaced cylinder head ready to be returned to you and extending the live of your engine.
Next the valve seats and valves are dressed in our valve dressing machine. This returns the head back to factory specifications, and assures excellent compression to return your engine to its original running condition. 

on the left is a photo showing valve seats being dressed in our Newen CNC valve machine
Baltimore Head Works is a state of the art machine shop specializing in the repair and remanufacture of cylinder heads for both automotive and marine.
Please call for pricing @ 410-781-7272 Baltimore Headworks
6340 S. Carrol Park Dr. Suite 400 Eldersburg, MD 21784

page last update Feb. 13th, 2014