Engine Mount

Troy Scott · Post by **Troy Scott** » Jan 29th, '06, 23:26

Folks,

Thanks for all the interesting possibilities for solving my engine mount corrosion problem.

I spoke with Tom Fake at Robinhood. Interestingly, he suggested duplicating the original mount in type 316 stainless steel.

tartansailor · Post by **tartansailor** » Jan 30th, '06, 05:42

Do what the Navy does, Cadmium plate your originals, then bake in an oven to eliminate hydrogen embrittlement, then the mount will outlast your boat.
Dick

Mike C · Post by **Mike C** » Feb 18th, '06, 17:23

how long did you have the original motor mounts. Mine are are in teen years and I wondering if there is some recommendation as to when they should be changed

Tom Blanchard · Post by **Tom Blanchard** » Feb 18th, '06, 17:59

Troy, my engine mounts were not removed from the boat. There was some heavy rust at the aft ends where the base rods were bonded into the hull.
These were cleaned and sealed. New flex mounts were installed and the new engine installed.
The remaining gaps were sealed with an epoxy paste coating.
The steel plate that held the original muffler was cut out and a new larger platform bonded to the hull further aft.
The Yanmar requires a 3" exhaust, larger than the Perkins 2".
Tom

Troy Scott · Post by **Troy Scott** » Feb 18th, '06, 19:30

Mike,

My mounts are probably original, which would make them 18 years old. They are still servicable. There is, as far as I know, no recommended time period after which the mounts should be replaced. I'm sure it's just an "on condition" thing. I just don't like the idea of all that rust, and I prefer to make all repairs and/or changes better than the original.

Mark Yashinsky · Post by **Mark Yashinsky** » Feb 19th, '06, 16:27

Rusty mounts, why? Is this normal rust after decades in a marine environment, or is something dripping on the mount(s)? Just one mount rusty or are all about the same? Next, engine mounts have rubber bits in them, that can degrade and take a set. After 18 years, might be time to replace them and anything else rubber.

Stainless steel corrosion, ever try Zoop Seal.

Mild steel, would be careful trying to weld caps on closed tubes. What about a rust converter, or a rust dissolver then use a rust encapsulator. I am not talking about Rustolem here, but stuff that automotive restorers use.

Oswego John · Post by **Oswego John** » Feb 19th, '06, 17:15

After wire brushing, power brushing or spot sand blasting, try Rust Arrest RA 30. Hard rust turns black chemically and becomes acceptable to prime and finish coats.

O J

Andy Denmark · Post by **Andy Denmark** » Feb 19th, '06, 21:27

I resolved this problem on Rhiannon's Westerbeke 13 by removing the engine from the mount and having the mount hot dip galvanized. Since the engine mount alone was far under the weight for their minimum price, I also galvanized my neighbor's 45 lb. CQR, a bunch of anchor chain and a piece I welded up for the Moore 24 trailer. I think it cost $100 for all of it. The biggest drawback was the several hours of driving to the contractor and the long cooling off time. All said and done it took an entire day.

Prior to the hot dipping the contractor "pickled" the mount for several hours and every speck of rust came off leaving only base metal. (I don't know what the pickling is.) They waited until I could inspect the mount to see if there was any serious degradation of the base metal --- there wasn't so they went ahead and galvanized it.

This seems to be a rather simple solution to much of what's been said above.
________
Frontenac (automobile)

Troy Scott · Post by **Troy Scott** » Feb 20th, '06, 00:45

Andy,

This seems like a very reasonable solution, especially since my CD36's original Spartan anchor could use an update on the coating.

Do you (or does anyone here) know what anti corrosion treatment was originally provided on these mounts? I wonder in it was galvanized, cadmium plated, painted, or some combination of the above.

Andy Denmark · Post by **Andy Denmark** » Feb 20th, '06, 08:16

Troy,

As I recall the original mount was painted over some unknown primer coat, probably zinc chromate by the color of it. Most of the rust was under the raw water pump where there was some sporadic dripping around the seal.

In an effort to make the mount look like the rest of the engine I painted it with the same red as the engine (Ford Motor Red) but the paint didn't stick very well to the galvanized surface. If I were doing it over I wouldn't paint it.

Hope this helps.
________
Honda S500 specifications

Oswego John · Post by **Oswego John** » Feb 20th, '06, 21:29

Hi Andy,

I have to agree with you than hot dip galvanizing is a good way to treat them. After reading your post, I wondered if you had spot primed that area on the motor mount where the galvanizing showed through, maybe the Ford Engine Red might have adhered better to the zinc surface, and maybe not. I guess that after the galvanizing job you had done, the point is now moot.

In the past, I have had pretty good luck by using iron oxide prime paint on ferrous metal and zinc chromate primer on non ferrous metal.
For those who are thinking about hot dip galvanizing or would like to know more about the process, there is an excellent web site on the subject. It is written clearly in layman's language.

For those who have some rust but not enough to warrant grinding the mounts out and removing them, this web site has links to how to remove rust, how to prevent rust, how to treat rust, etc, etc.

http://www.wisegeek.com/what-is-galvanized-steel.htm

Just a suggestion for those who are, or will be going through a motor mount upgrade, don't forget to check the inside bore of the mounts for rust or any degradation.

Good luck to all.
Think spring,

O J

The Cape Dory Board

Engine Mount

engine mount

Why Spend The $$ ?

motor mounts

engine mounts

Oxidation and other things,

Rust

Hot dip galvanizing

Original Finish

Engine Mounts