Surprise: Solid Motor Mounts not really Solid
05-02-2006, 10:59 AM
#1
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Surprise: Solid Motor Mounts not really Solid
I recently bought a set of 928 motor mounts from Rock Auto and heard sloshing in them so traded/sold them to another Rennlister who didn't mind. I then ordered the "solid" mounts that 928 Motorsports sells (non-Porsche). The build quality looked better than the Rock Auto units but the 928 Motorsports motor mounts "sloshed" also when shook. On checking with Carl, below is his response. Based on this, "solid" motor mounts does not mean "Solid." I had found that confusing. Carl didn't mind if I shared his note on this with you.
My question would be this...air, oil or water..if mounts have one of these inside them and the filler leaks out...it would seem to make sense that the motor mount would collapse, whereas a truly "solid" rubber mount would not sag...but admittedly, as Carl points out, a truly solid rubber mount may transfer more vibrations.
The MM changeout is supposed to be such a nasty job, I only want to do this once before I die.
Harvey
==========
This is the message:
All the solid mounts will slosh when you shake them.
In order to have the correct vibration-absorption in a solid (non-hydraulic)
mount, the interior of the mount has a hollow chamber. An air-pocket, if you will.
During the rubber molding process, the manufacturer uses light oil or water to
keep the hollow space as the rubber is cast.
The sloshing you hear is the left-over water within the mount left from the
manufacturing process. That is a solid mount (non-hydraulic)
The hydraulic mounts do not slosh when shook, they are filled completely with
oil, and rely on the oil within to hold their shape and height. That's why, when
the oil leaks out, the hydraulic mounts collapse. The solid mounts are made
differently, and support the weight of the engine without any assistance from an internal fluid.
A few people have been confused and figured that "solid mount" means a solid
block of hard rubber. That would be a terrible mount, and shake the car like
crazy and tear itself apart. The term "solid mount" in the industry means
non-hydraulic. Rubber-only, but not solid rubber.
If you are displeased in any way, return them for a full refund. I think you can
see, because you had the same results from the mounts from Rock Auto, that this is the second set of solid mounts you've tried, and they all "slosh" when
shaken.
But - I'd rather make you happy than anything else, so please just return them
(including the hardware we supplied) for a refund if that is your wish.
I hope we will have an opportunity to serve you again soon.
928 Motorsports
My question would be this...air, oil or water..if mounts have one of these inside them and the filler leaks out...it would seem to make sense that the motor mount would collapse, whereas a truly "solid" rubber mount would not sag...but admittedly, as Carl points out, a truly solid rubber mount may transfer more vibrations.
The MM changeout is supposed to be such a nasty job, I only want to do this once before I die.
Harvey
==========
This is the message:
All the solid mounts will slosh when you shake them.
In order to have the correct vibration-absorption in a solid (non-hydraulic)
mount, the interior of the mount has a hollow chamber. An air-pocket, if you will.
During the rubber molding process, the manufacturer uses light oil or water to
keep the hollow space as the rubber is cast.
The sloshing you hear is the left-over water within the mount left from the
manufacturing process. That is a solid mount (non-hydraulic)
The hydraulic mounts do not slosh when shook, they are filled completely with
oil, and rely on the oil within to hold their shape and height. That's why, when
the oil leaks out, the hydraulic mounts collapse. The solid mounts are made
differently, and support the weight of the engine without any assistance from an internal fluid.
A few people have been confused and figured that "solid mount" means a solid
block of hard rubber. That would be a terrible mount, and shake the car like
crazy and tear itself apart. The term "solid mount" in the industry means
non-hydraulic. Rubber-only, but not solid rubber.
If you are displeased in any way, return them for a full refund. I think you can
see, because you had the same results from the mounts from Rock Auto, that this is the second set of solid mounts you've tried, and they all "slosh" when
shaken.
But - I'd rather make you happy than anything else, so please just return them
(including the hardware we supplied) for a refund if that is your wish.
I hope we will have an opportunity to serve you again soon.
928 Motorsports
05-02-2006, 11:07 AM
#2
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Totally contary to what the manufactures say - I will continue with what I know and stick with it.
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
05-02-2006, 11:48 AM
#3
Developer
The only thing I'd change in my response to Harvey is
"All the solid mounts will slosh when you shake them..." I would change that to " Many solid mounts will slosh when you shake them. "
I stand by everything else.
A quick dig into our accounting software reveals that we have sold 80 pairs of our solid mounts since we introduced them in 12/21/04 and have had only 2 returned. No failures in the field, many happy 928 owners. The two that were returned were sent back before they were installed because they "sloshed" when shook and that made the buyer think they were defective or hydraulic, so they sent them back.
"All the solid mounts will slosh when you shake them..." I would change that to " Many solid mounts will slosh when you shake them. "
I stand by everything else.
A quick dig into our accounting software reveals that we have sold 80 pairs of our solid mounts since we introduced them in 12/21/04 and have had only 2 returned. No failures in the field, many happy 928 owners. The two that were returned were sent back before they were installed because they "sloshed" when shook and that made the buyer think they were defective or hydraulic, so they sent them back.
05-02-2006, 12:31 PM
#5
Banned
That's why I buy the majority of my Performance parts from Carl @ 928 Motorsports. Another excellent "customer service" vendor is D.Lomas @Motrorsports Inc.
You wont go wrong with these guy's.
RDS
You wont go wrong with these guy's.
RDS
05-02-2006, 12:41 PM
#6
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Carl,
Check with Schocki, I think he has sold about 200 sets so far.
It may be worth asking him some feedback from our German counterparts.
I have fitted about 12 sets and so far no problems with any of them.
My GTS was first and after about 15k miles and 2.5 years.
Still to change them out is fairly straight forward when you have done it a few times.
Roger
Check with Schocki, I think he has sold about 200 sets so far.
It may be worth asking him some feedback from our German counterparts.
I have fitted about 12 sets and so far no problems with any of them.
My GTS was first and after about 15k miles and 2.5 years.
Still to change them out is fairly straight forward when you have done it a few times.
Roger
05-02-2006, 02:04 PM
#7
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Perhaps a non-hydraulic mount should be called a 'pnuematic' MM? There are millions of cars running around the world with solid rubber mounts in them. As long as the material has the specified elasticity for the service, there's nothing wrong with solid rubber mounts. When the hydraulic fluid leaks out of a hydraulic mount, you now have a solid rubber MM. None of those cars has shaken themselves apart AFAIK. It does make for more vibration when running, but it's not catastrophic by any means.
The 928 prolly came with hydro mounts because it was deemed 'better' at the time. Maybe they are better initially when installed, but over time, the solid rubber mount will retain it's shape better.
Doc
The 928 prolly came with hydro mounts because it was deemed 'better' at the time. Maybe they are better initially when installed, but over time, the solid rubber mount will retain it's shape better.
Doc
