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General Help- Ask the Experts... / Re: 1971-73 2.0 motor mounts
« Last post by Wittsend on Today at 10:27:00 AM »Interesting..., I have just been going through this with my Corvair Station Wagon. The trans/differential has two mounts roughly 2" x 2-1/2" circular. They are $170 for the pair!!! After investigating the Polyurethane method I came to find that it comes in many hardness's and within the hardness factor there are numerous scales that they are measured on. Shore Hardness A seems to be the appropriate scale.
Shore Hardness A as it applies to factory motor mounts can be anywhere from 40-50. 60 is commonly sold as stiffer upgrade. Then you get these people who go all the way to 94 which is like solid steel. Smooth On is one of the big suppliers of the Poly and they have a chart that helps you understand. https://www.smooth-on.com/page/durometer-shore-hardness-scale/
Because most motor mounts are primarily compressible (downward, at an angle) the 2 part Poly should do well. In the case of my Corvair they are vertical and housed in a 2" tube with a center bolt. Because adhesion was paramount I opted for another product. The regular Poly can shrink and I would lose bond in the tube. Thus I opted to use 3M Windo-Weld 08609. This had adhesion properties to strongly bind a windshield to the car but is still a Poly product with a Shore A hardness of 55-60. The only down side is that it is a 1 part moisture cured product. I had to put it in in 1/8" thick layers (that would we 12 layers) two hours apart and it was a 24 hour all night affair. While cheaper than buying new mounts the stuff isn't as inexpensive as many state. They are often sold in "Starter Kits" otherwise you are buying gallons. Tax and shipping pushes the kits into the $40 range. My Window-Weld was 10.5 Oz. and was $33 with tax (free Amazon shipping). I used two thirds of the tube on my two mounts.
Anyway, sorry I don't have any 2.0 mounts for you to test with but hopefully the Poly information is helpful. I've included a before/after picture of my Corvair mounts as inspiration.