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General Discussion => How To's => Topic started by: elagache on November 20, 2016, 04:10:29 PM

Title: Sealing cylinder heads by Vacuum Casting Impregnation
Post by: elagache on November 20, 2016, 04:10:29 PM

Dear mid-60s Buick caregivers,

My trusty wagon had developed some small leaks in the cylinder heads, so I called Mike Tomaszewski at TA-Performance to get some advice on how to seal them.  In the end, he suggested first trying some high-temperature silicone sealant and that was good enough to plug the leaks.  However, Mike mentioned a more comprehensive procedure to seal cylinder heads that I wasn't aware of: Vacuum Casting Impregnation.  Like so many other things, here is an article on Wikipedia that describes how this is done:

https://en.wikipedia.org/wiki/Porosity_sealing (https://en.wikipedia.org/wiki/Porosity_sealing)

Quoting from the Wikipedia article:

Porosity sealing is a four-step process:

• Air within the pores is expanded under reduced pressure (vacuum).
• Pressure reversal (adding pressure outside the part) saturates pores with monomer.
• Excess monomer is rinsed from the exterior surfaces of the part.
• The liquid monomer within the porosity is polymerized into a solid to seal the passage.

According to Mike, the Federal government requires all Aluminum heads to be impregnated before being used in government applications.  Mike has an outfit in Phoenix that can impregnate heads and he has even had success sealing up some cast iron nailhead heads.

So if you were like me and didn't know about this process, here is another option to get heads to stop leaking short of replacing them.  To learn more, get in touch with Mike at TA-Performance:

http://www.taperformance.com/ (http://www.taperformance.com/)

Cheers, Edouard