Hi I'm looking for some advice on replacing engine mounts - seriously not good vibrations led me to discover the rear port engine mount was snapped and the front starboard mount attachment needed replacing. I've removed engine and am aiming to replace the mounts myself but the current mounts don't look like any i've seen and I'd appreciate any input on recommendations for replacement.

The one's I've taken out had a few stainless washers on top and a piece of steel over the rubber and looked pretty DIY. I've posted a longer update on this topic over at the tophat website www.tophatyachts.com but thought I'd throw it out to as many opinions/experts/theorists as possible.

The mounts were held in place with simple coach screws a couple of which snapped when i tried to remove them.. are coach screws a common method of securing engine mounts down?

I'd rather not replace any engine mount beds if i don't have to..

All opinions welcome - it's a tophat 25ft. Engine is a 13hp Sole diesel.

Cheers
Shea

Starboard front mount


Broken rear port side mount







Front port side mount















Engine before removal - the rear of the engine is suspended by a cross-bar that sits on the mounts + threaded rod welded to the back of the transmission


Current state of the bilge

Hi Billy

Just replaced the engine mounts on my cav. Some of the bolts snapped so the mechanic used slightly larger mount bases so the holes for the coach screws were in different places. We considered drilling them out but concluded it was easier to replace the mounts all together.

Just match the mounts with engine size / weight. The poly guys up in Bris will help you.

You could possibly rotate the bases so you don't have to drill out old bolts.

It was an expensive exercise but I'm happy I did not DIY as I don't have the time and the post engine alignment concerned me.

Happy to discuss more if required
Ed

On the basis of my recent experience I would suggest you avoid IsoFlex mounts if at all possible. 18 months ago I replaced all four mounts on a Beta 35 with IsoFlex M55 mounts using the Yellow insert. The yellow Co-Polymer inserts have now shrunk to the stage that they no long carry any weight and the mount stud is bearing directly on the engine mount bed. They are now effectively solid mounts with no damping what so ever. Total cost was about $600 including freight.
The first photo shows the amount of shrinkage between the top washer and the weight bearing insert. The second photo shows the mount inverted and the amount of protrusion of the mount stud below the fixing plate

Awesome, thanks for the info, I'll follow it up with poly flex.

skedaddle - that sucks! does that mean the mounts are too soft for the weight of the engine?

cheers

The mounts shown in the pictures are just normal industrial engine mounts. I would suggest doing some research for the correct size mounts for that engine. It's a real marine engine with a heavy flywheel on the right end and you should have different rated mounts at the front compared to the rear. If you can't find Sole specs then use something like Volvo MB7b spec mounts.

Billy, see my post on the Top Hat Site

Get on to the Mackay Consolidated web site and have a look at their "vibration Isolators". I saved a fortune on my new engine mounts for a Cav 32, exactly the same mount, size and load rating. May be useful, may not.
Mike

Select to expand quote

billybones said..
Awesome, thanks for the info, I'll follow it up with poly flex.

skedaddle - that sucks! does that mean the mounts are too soft for the weight of the engine?

cheers

I can understand why you would ask that. However the weight bearing yellow "Co-Polymer" insert has shrunk way past the point of being compressed by the engine weight. All the engine weight is now being transferred directly to the engine beds thru the adjusting studs and the Yellow material is still shrinking.

Cheers
Mike

As a final comment on this thread - here is what the mighty Sole 12hp and engine mounts in all her glory should look like - with the mounts in the picture nothing like what i have..










I can source these original mounts.. but that will involve modifying the engine beds to make it look like the photo above.. it's been modified in the past so the back now looks like this




Any thoughts on the current aft end of the engine?

Think I just talked myself out of modifying back to the original. Likely to cost too much cash. I'll go with replacing the engine mounts that were there with similar but better ones. Wonder why the engine was modified like that?

Thanks for the input

Original setup