Durability of aftermarket motor mounts

[jimmy p.]

As I posted earlier, after complete frustration with the available mounts, I went in for a set of Conrad's Grp A mounts, and they are really well done.
I hazard to say even nicer than the real ones I have in the Prodrive car, probably benefitting from 22 years of mfg. advances.

I do really like the mounts that Mike B found.
That might be the best S14 alternative yet from a cost / performance standpoint.
I'm bummed that I just bought a brand new set of stock mounts for my street car.
If I had seen that post only a week earlier, I would have bought a set of those to try.

[conrod]

Hi Ken,

thank you for the compliment! No I have not seen inside a Gp.N mount. But I am sure that the quality is very good!

best regards
Conrad

[ken garchow]

those are indeed very nice looking and look to be one of the best mounts i have seen so far
conrad did you ever see inside a group n mount by chance?
thanks

[conrod]

Hi all,

I have just found this thread and have been reading with much interest, (notwithstanding the fact that my name has popped up a few times!)

There is a whole discussion thread on my mounts here:

http://www.s14.net/forums/showthread.php?t=46247&highlight=gp.a+engine+mounts

so I will try not to repeat any of it here.

Anyway, a couple of points I would like to make regarding the discussion so far.

a) using urethane as an isolating medium. Urethane is quite a useful material to damp out vibration from an engine. It is impervious to oil, will withstand a reasonable degree of heat, is easy to pour into moulds, and can be had in a wide range of hardnesses ("shore" hardness) The big downside is that its adhesive or "peel" strength is rubbish. Poured on to a bolt or washer, and with no other mechanical attachment method other than its own adhesive strength then it will fail, as can bee seen by the number of pics posted in this thread already.

b)

Engine mounts that consist of a compliant material and solid thru-bolt are flawed in design. They are total nonsense. Either the mount is solid, either it is somewhat soft. If it is somewhat soft, then the top and the bottom parts of the mounts should be decoupled.

true, but only to a point. If the bolt is isolated from the aluminium arm that is attached to the engine, via rubber or urethane then it can be made to work successfully. here are a couple of pictures showing how my engine mounts work:





The urethane bush is actually two half bushes, and you may just be able to see from the photos that the bush is tapered, the aluminium arm is machined with exactly the same taper into it, and this locates the whole assembly. The steel spacer tube fits inside the urethane bush so that the bolt can be tightened properly without deforming the urethane bush. The washer under the M10 bolt head is 5mm steel, and it can be seen the even if the whole urethane bush were to somehow disappear, then the mount would "fail safe" meaning the engine would still be captive within the mount. By design the urethane bush is very cheap and replacements are available readily, although I will say that although I have sold many many sets of these engine mounts nobody has asked me for a replacement set of bushes yet! This mounting system is virtually indestructible by design.

The only downside is that they do not come cheap, it was a particularly expensive project to undertake insofar as tooling patterns and machining jigs go, but they are still considerably less than what most vendors are charging for a set of BMW Gp.N mounts.


cheers Conrad

[ken garchow]

good point do we need to compare compressed heights too, i bet they dont all compress the same amount
how much play would you say there is in height any so as not mess with things such as fan clearance, intake elbow pressure, u joint angle and other items related to motor location?

[UweM3]

That's them. These would likely fit on an E30 as they are just over 72mm in
length and use metric HW. (Stock mount 80mm / 5 Series 65mm).

Mike

from my trials and measurements I came up with an mount height of 76mm. They sink in a little with weight on them. Could be I had worn mounts though, but I had a few sets to play with.

[ken garchow]

thanks
another cool option
do you see any problem adding washers to make the 72mm height 80 mm?

still would like to see if the group n have this interlocking feature

[Az in Oz]

I like the look of them. My only concern is that they look like SS and that may not be the ideal material for the threaded section.

[booker]

I'm guessing these are the pics you've posted:

http://www.hinsonsupercars.com/p-128...5c6gtorx7.aspx

That's them. These would likely fit on an E30 as they are just over 72mm in
length and use metric HW. (Stock mount 80mm / 5 Series 65mm).

Mike

[UweM3]

That's exactly the intent I'm going for Mike, just done slightly different. I like that way better actually. Who's selling them?





Jake

I bloody give up! Everytime when I think I have a good idea and get stonking rich somebody else has already made it [peace]

[The///MadCircle]

I'm guessing these are the pics you've posted:

http://www.hinsonsupercars.com/p-1285-hms-urethane-mounts-c5c6gtorx7.aspx

[Jake]

That's exactly the intent I'm going for Mike, just done slightly different. I like that way better actually. Who's selling them?





Jake

[booker]

Something like this?

http://www.s14.net/photopost/showphoto.php?photo=9783&cat=500

Mike

[Jake]

Swap the big and small washers around.

- Bolt
- Small washer
- 1" spacer
- Big washer

Bolt head and small washer submerged, big washer as top and bottom plates, and the extra threads sticking out the bottom and top.

Jake

[UweM3]

I have (as usual) something a little bit complicated in mind.

I would physically limit the travel of upper and lower metal part to avoid them to come apart when the poly stuff may split. i.e. 10-20mm of "poly" travel allowed
and then hit the internal "rebound limiter" to avoid the mount to rip apart.

does this make some sense?