Author Topic: Engine mounting shore hardness  (Read 165 times)

daantjie

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Engine mounting shore hardness
« on: 30 April 2021, 08:28 AM »
Hi guys

This topic is kind of intriguing to me to be honest, as I recently swapped out engine mountings.  I ended up using the W123 diesel mounts - 1232411613, they felt firmer than the 1232413013 ones which you can get Lemforder still and they are plentiful and cheap. 

The old mounts actually did not feel too bad, slightly compressed but not bad (they were replaced in the late 90's BTW by previous owner).

But I got my hands on the 116 ones for which you get LHS and RHS ones.  Part # 116 241 2913 which is LHS.  I imagine they have different shore hardness then, and that 116 241 2813 (RHS) will be harder.  However the one I got - 116 241 2913 is extremely hard, like hockey puck hard, hmm, is this normal?

Any insights appreciated.

Cheers
Daniel
1977 450 SEL 6.9 - Astralsilber

raueda1

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Re: Engine mounting shore hardness
« Reply #1 on: 30 April 2021, 04:07 PM »
Daniel, there was a similar thread on this some time back.  I'm going from memory here, always dangerous, but this is my recollection.   At the time the 6.9 mounts were NLA.  As I recall, the consensus was to go ahead and use 450sel mounts anyway, which I did.  Then, by a nice coincidence, the Classic Center announced that the 6.9 mounts were back. I got them and replaced the 450 mounts.  The 6.9 mounts actually were very much harder, along the lines of hockey puck.  As I recall the 450 mounts could be squished a little by hand.  Hope this helps.   :o  Cheers,
-Dave
Now:  '76 6.9 Euro
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

daantjie

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Re: Engine mounting shore hardness
« Reply #2 on: 30 April 2021, 04:17 PM »
Thanks Dave yup I scoped out that thread as well, however it does not really speak to the "scientific" nature of these mounts.  I am really interested to know if a softer mount is perhaps better as it will then dampen the vibrations better?  If you think about it, a solid steel mount for example will be useless as effectively you might as well mount the engine directly on the frame, so it will rattle your fillings out your head.
On the flipside if the mount is too soft then it will collapse and of course you will get the same result of heavy vibration.  Thus to my mind the answer (as usual) lies somewhere in between :D
The old mounts I took out, which had the correct part number, Benz and Phoenix rubber stamps on them, were still quite nice, but not nearly as hard as the 116 numbered one I scored off ebay, I just got one NOS one for kicks as it was cheap and I wanted to get it in my hand to check.
So I guess the real question is, are the 6.9 mounts, when new also rock hard, and they soften up over time?  Does not make sense to me.  Or maybe they used a softer compound back in the day, and the repop ones you now get from the Classic Centre are of crappier rubber quality.  Hmmm, interesting, at least to me 8)
Daniel
1977 450 SEL 6.9 - Astralsilber