Tim K

A little while ago I read an article preaching the hazards of using solid motor mounts (specifically in the 911). It also stated that to contrary to popular belief, they were actually a power robbing nuisance. For the life of me I can't remember where I read this. Any first-hand experience with these?

Tim

BER

I also read an article recently about the perils of solid mounts, especially using them for the engine mounts.

I do not have any first hand experience with solid mounts. I installed Club Sport mounts (both engine and tranny) on my '84 Carrera about a year ago. Very satisfied with the results.

Bruce

Bill Gregory

There was an ad in Pano or Excellence a month or two ago preaching the evils of solid mounts. Ensuing discussion on racing forum.

JackOlsen

I've never heard anything about power being robbed by solid mounts. Somebody should warn the factory about that, I guess. But the solid mounts could be seen as hazardous for 911's that aren't regularly checked for the effects of increased stress and vibration. It could be very bad if they rattle a fuel line fitting loose, or start to crack a tired old crossmember.

Of course, the same thing can be said for anyone using tires that exceed the specs of the ones the cars were designed for. Most of us are seriously overstressing our suspensions and chassis, especially with r-compound tires.

Sport mounts are probably a good compromise. And if you want extra quiet and comfort (with performance in the same ballpark as sport mounts all around), go with stock mounts by the transaxle, and sport mounts in back.

Cookie Porsche

Hello,
I have solid mounts fitted in several cars, and have never noticed any loss of power, on road or dyna. As with any mod it is important to check relevant and associated parts for wear, that also goes for engine, chassis, suspension and similar upgrades. As said above a good compromise is to fit solid mounts on the engine and retain rubber (sports) mounts on the transmission – this reduces noise dramatically.

Benefits include less engine movement for better feedback, stiffer chassis and improved gearshift. On the power issue the solid mounts definitely improves launches.

I believe that road or intermediate tires reduces the major vibrations enough for this upgrade to be safe to use on ordinary cars. As always just triple check and use new fasteners everywhere. Lastly check the engine cross-member for cracks, as this item is prone to breaking.

Regards Tom

classic911

I believe the ad was in Pano and the short article was written by Richard of PMO. Interesting article.

Tim K

Thanks for the info. guys. I'm a recent PCA member, and June was my first Pano issue. I didn't see it. Maybe it was the May issue?

I was thinking of using solid mounts in my 83SC which will be used as a track/street car. I am interested in the increased shifting accuracy. I am always so paranoid about miss shifting or grazing reverse.

I just found the thread on the Racing Forum (Panaroma PSA against solid motor mounts). Interesting. I guess for my cars application and my priorities, they may work for me. It's a relatively cheap experiment.

Thanks again.
Tim

GeorgeM

I put club sport mounts on and noticed more engine vibrations. They look the same as the stock mounts, but they don't act the same.

If you don't want to feel the engine in your butt, steering, and pedals, then stick with the stock mounts.

JackOlsen

Tim, if your worry is about missing a shift (a very legitimate worry, by the way), I'd suggest the Seine Systems Gate Shift Kit. It will dramatically reduce the liklihood of a missed shift, and also improve the feel of the shifter.

I have solid mounts, and the Wevo internal gate, and the (more expensive, and inferior) Robotek Gate Shift Kit, and the Gate Shift Kit is the thing I recommend to others. (The Seine versions wasn't available when I bought the Robotek).

Other than that, replacing your bushings and linkage, as well as adjusting your shifter properly, can make a 915 a joy to shift.

Tim K

George, does your car sport lumpy cams or other that might make engine vibration more noticeable? For the time being I am using 2.7CIS (which obviously necessitates a pretty tame cam profile) and putting my money into suspension upgrades and safety equipment. But the day will come...

Jack, that looks pretty good. I found more info here: http://members.rennlist.org/911pcars...iftStory-1.htm
Have you noticed any effects of the constant torsion in the shifter linkage when in 1st and 2nd gear (since the Robotek system doesn't mirror the factory's 'rest tabs' for 5th and Reverse?) BTW Do you salivate every time YOU see your car (very nice)?

Tim

GeorgeM

Tim,

Nothing non-stock internally that would cause the vibrations.

It's not annoying, I can just feel more motor at any RPM, especially in the pedals.

JackOlsen

Yes, the car never gets old to me. I'm lucky to have it.

mm86911

Sport mounts on the trans - solid at rear crossmember - increased vibration but much improved shifting. If you're tracking a 915 I would recommend this setup.

an6drew

I put solid mounts at the rear & sport mounts at the transmission on my '82 SC. It has definitely increased the engine noise a little & added some vibration (the sunroof motor access panel started rattling because it was missing a screw, something I hadn't noticed w/ the stock mounts. The oise is not objectionable though, actually sounds a bit more like an early car which I like. There was a small improvement in shifting, though my transmission never used to grind or anything like that before.

Andrew