After market engine mounts and polymer mounts

[Rustic Charm]

As everyone knows, original engine mounts are expensive. I'm looking at $180 each Aust for my Volvo Penta 2003 T. I'm considering getting aftermarket ones such as the following

Home - Poly Flex Group - Advanced Polymer Technology for Vibration Control

Or these,

http://www.mackayrubber.com.au

Has anyone had any experience in using after market mounts?
Are they cheaper?
What are the polymer ones like?
How tight does the rubber need to be for something like a 38hp engine?

[DougR]

Hello Rustic Charm,

The term "aftermarket" is a little misleading in this sense, as many suppliers of flex mounts sell mounts loose, but also are suppliers to engine manufacturers as well. For example companies like Yanmar, Westerbeke and Volvo Penta dont build flex mounts, they source them from outside vendors. The advantage that the engine builder has over the individual customer is that the engine builder, when doing the design and testing on a new engine, goes to the flex mount builder and says " We have this new engine with such and such characteristics and we need mounts for it". The mount supplier might suggest four or five or more mount combinations and send them to the engine guys for testing. After testing mounts, perhaps from several suppliers, the engine builder decides on the best combination of isolation, cost, durability, etc.

You, the individual consumer typically only get one shot at getting it right. Even with help from the supplier this can be a crap shoot.

Take a look at the existing mounts on your 2003. They are designed to be stiffer in the fore/aft plane to absorb the propshaft thrust while being soft in the side to side and up/down direction to absorb the heavy vibrations usually found in three cylinder engines. (Look at Yanmar mounts....same thing)

The mounts which are shown on the web site of your first supplier, Polyflex, seem to be omnidirestional mounts. In the marine world, this type of mount is usually found on gasoline engines like V6 or V8s where there are not severe side to side forces and the mount is mostly absorbing thrust. The mounts shown on the second site, Mackayrubber, seem more in tune with what is used on propulsion engines today. The mounts with the rectangular shaped steel cover usually have the rubber placed in the fore and back of the cover which places the rubber in compression to handle the prop thrust, but in shear to handle the side to side vibration.

Something else to consider is the transmission which is used on your engine. Straight output shaft transmissions impart only horizontal thrust to the mounts, while down angle gears tend to lift the rear of the engine somewhat, and V drive transmissions impart a lot of lift into the gear and require a completely different mount selection.

Talk to the mount suppliers. They will want to know engine weight, power, etc before making a recommendation. Ask if they have ever installed their mounts on your model engine. Because of the mount orientation, it could be difficult to find something to install on the front of the 2003 engine.

Good Luck,
DougR

[NoTies]

Go Poly Flex. I've had nothing but great experience with them and their service back up.

[Rustic Charm]

Originally Posted by DougR

Hello Rustic Charm,

The term "aftermarket" is a little misleading in this sense, as many suppliers of flex mounts sell mounts loose, but also are suppliers to engine manufacturers as well. For example companies like Yanmar, Westerbeke and Volvo Penta dont build flex mounts, they source them from outside vendors. The advantage that the engine builder has over the individual customer is that the engine builder, when doing the design and testing on a new engine, goes to the flex mount builder and says " We have this new engine with such and such characteristics and we need mounts for it". The mount supplier might suggest four or five or more mount combinations and send them to the engine guys for testing. After testing mounts, perhaps from several suppliers, the engine builder decides on the best combination of isolation, cost, durability, etc.

You, the individual consumer typically only get one shot at getting it right. Even with help from the supplier this can be a crap shoot.

Take a look at the existing mounts on your 2003. They are designed to be stiffer in the fore/aft plane to absorb the propshaft thrust while being soft in the side to side and up/down direction to absorb the heavy vibrations usually found in three cylinder engines. (Look at Yanmar mounts....same thing)

The mounts which are shown on the web site of your first supplier, Polyflex, seem to be omnidirestional mounts. In the marine world, this type of mount is usually found on gasoline engines like V6 or V8s where there are not severe side to side forces and the mount is mostly absorbing thrust. The mounts shown on the second site, Mackayrubber, seem more in tune with what is used on propulsion engines today. The mounts with the rectangular shaped steel cover usually have the rubber placed in the fore and back of the cover which places the rubber in compression to handle the prop thrust, but in shear to handle the side to side vibration.

Something else to consider is the transmission which is used on your engine. Straight output shaft transmissions impart only horizontal thrust to the mounts, while down angle gears tend to lift the rear of the engine somewhat, and V drive transmissions impart a lot of lift into the gear and require a completely different mount selection.

Talk to the mount suppliers. They will want to know engine weight, power, etc before making a recommendation. Ask if they have ever installed their mounts on your model engine. Because of the mount orientation, it could be difficult to find something to install on the front of the 2003 engine.

Good Luck,
DougR

Thanks for this. It's a lot of considerations I had not thought about at all. I know at the back of my engine there is thrust 'down' onto the mount on the port side. Whereas on the starboard side, the thrust is 'up'. I have no idea what the front ones do.

[Rustic Charm]

Originally Posted by NoTies

Go Poly Flex. I've had nothing but great experience with them and their service back up.

What sort of engine do you have?

How did you sort out what you needed?

[Snowpetrel]

Ive got polyflex mounts. They are pretty firm, seeming to be much more rigid than the old rubber ones. I did notice slightly more vibration after the change, but also much less engine movement.

I have been very sceptical of the plastic feet, but since snowpetrel 1 had the steel engine feet fail, and the plastic polyflex mounts survive I've had to eat my words. I still do have concerns about the loads on the plastic in a rollover but the polyflex engineers are adamant that they are up to the job. I am Hopeful I wont be able to test them for inverted strength... Anyway Ive just fitted polyflex mounts to the nanni in Snowpetrel II due to minimal stern tube clearances and a need to limit engine movement. They seem to work well. All the mounts are the same type.

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[Nicholson58]

Originally Posted by DougR

Hello Rustic Charm,

The term "aftermarket" is a little misleading in this sense, as many suppliers of flex mounts sell mounts loose, but also are suppliers to engine manufacturers as well. For example companies like Yanmar, Westerbeke and Volvo Penta dont build flex mounts, they source them from outside vendors. The advantage that the engine builder has over the individual customer is that the engine builder, when doing the design and testing on a new engine, goes to the flex mount builder and says " We have this new engine with such and such characteristics and we need mounts for it". The mount supplier might suggest four or five or more mount combinations and send them to the engine guys for testing. After testing mounts, perhaps from several suppliers, the engine builder decides on the best combination of isolation, cost, durability, etc.

You, the individual consumer typically only get one shot at getting it right. Even with help from the supplier this can be a crap shoot.

Take a look at the existing mounts on your 2003. They are designed to be stiffer in the fore/aft plane to absorb the propshaft thrust while being soft in the side to side and up/down direction to absorb the heavy vibrations usually found in three cylinder engines. (Look at Yanmar mounts....same thing)

The mounts which are shown on the web site of your first supplier, Polyflex, seem to be omnidirestional mounts. In the marine world, this type of mount is usually found on gasoline engines like V6 or V8s where there are not severe side to side forces and the mount is mostly absorbing thrust. The mounts shown on the second site, Mackayrubber, seem more in tune with what is used on propulsion engines today. The mounts with the rectangular shaped steel cover usually have the rubber placed in the fore and back of the cover which places the rubber in compression to handle the prop thrust, but in shear to handle the side to side vibration.

Something else to consider is the transmission which is used on your engine. Straight output shaft transmissions impart only horizontal thrust to the mounts, while down angle gears tend to lift the rear of the engine somewhat, and V drive transmissions impart a lot of lift into the gear and require a completely different mount selection.

Talk to the mount suppliers. They will want to know engine weight, power, etc before making a recommendation. Ask if they have ever installed their mounts on your model engine. Because of the mount orientation, it could be difficult to find something to install on the front of the 2003 engine.

Good Luck,
DougR

Spot on Doug,
We build custom machinery and deal with vibration isolation mounts daily for small machines up to 5000 HP windmill generators weighing 35 tons. There are many suppliers out there. You may even find the original maker of the mounts Volvo is reselling & marked up.

Berry mounts. McMaster Carr. are two easy vendors to deal with. Reid tool is a re-seller of many mounts. My 115 HP Westerbeke is re-mounted by the PO on Paulstra glycol filled heavy engine mounts. These have multiple chambers with porting for the fluid through orifice plates. Very effective but expensive. They also make standard type mounts. You could work through the bins at NAPA. Most automotive mounts are about the same capacity as your engine regarding weight and RPM.

[Rustic Charm]

Originally Posted by Nicholson58

Spot on Doug,
We build custom machinery and deal with vibration isolation mounts daily for small machines up to 5000 HP windmill generators weighing 35 tons. There are many suppliers out there. You may even find the original maker of the mounts Volvo is reselling & marked up.

Berry mounts. McMaster Carr. are two easy vendors to deal with. Reid tool is a re-seller of many mounts. My 115 HP Westerbeke is re-mounted by the PO on Paulstra glycol filled heavy engine mounts. These have multiple chambers with porting for the fluid through orifice plates. Very effective but expensive. They also make standard type mounts. You could work through the bins at NAPA. Most automotive mounts are about the same capacity as your engine regarding weight and RPM.

Thank you for those suggestions, but I'm in Tasmania, Australia. Land of the Tassie Devil.

[Snowpetrel]

Also have a look at the isoflex mounts. Good website, and based in aussie.

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[GILow]

Vetus is another manufacturer that might have what you need. Fenquin in Sydney can supply them.


Matt

[Nicholson58]

Originally Posted by Rustic Charm

Thank you for those suggestions, but I'm in Tasmania, Australia. Land of the Tassie Devil.

suggestions still hold. Most of the engine mount people are international. We have auto producing customers in Australia too. Sleuthing standard motor mounts at the auto parts shop works anywhere.

[Rustic Charm]

Originally Posted by Snowpetrel

Also have a look at the isoflex mounts. Good website, and based in aussie.

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Snowpetrel, how much did your mounts cost?

I've just got back from a three day sail and had to motor today and it's clear by the vibration my engine alignment has moved. So I think I have to speed up replacing my mounts.

[Snowpetrel]

That's no good Ted, I think they were about $150 each. That's for a light 30 hp engine. Main reason I went for the polyflex was needing a very firm mount to limit movement due to the small clearance in the stern tube.

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[Rustic Charm]

Originally Posted by Snowpetrel

That's no good Ted, I think they were about $150 each. That's for a light 30 hp engine. Main reason I went for the polyflex was needing a very firm mount to limit movement due to the small clearance in the stern tube.

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Thanks. The vovlo originals for mine are $186@ so a bit of a saving.

Last year I had a second stern tube bearing made up. So I have one just where the prop is, or the cutlets bearing and another on the inside where the stern tube seal is. But this means my engine has to be lined up perfectly. So time for new mounts I think. (Along with new turbo, exhaust elbow, list goes on).

[GILow]

The Vetus mounts to suit our 460kg 96HP Nissan ED33 were only $92 each. And much to my surprise, they seem pretty robust and well designed. And they sure soak up the vibration.

Early days yet, I'll let you know how they look after ten years.

Matt