Reproducing the Stock 914/6 Engine Mount, and comparison to alternatives Options

[McMark]

UPDATE: maddog is producing my mount for sale. Contact him directly to see about ordering.

I just got a 2.4 six and it's got me thinking about all the various aspects of a conversion. One that I haven't heard much about is using a stock 914/6 style engine mount instead of the aftermarket alternatives.

I have access to a couple real sixes and I was thinking of making a reproduction of the stock mount. The only major alteration would be using a single 911 sport mount instead of the NLA 914/6 rubber mount.

What have you heard about real sixes running bigger engines with factory mounts? How much HP did the factory race cars put out?

[Elliot Cannon]

I just got a 2.4 six and it's got me thinking about all the various aspects of a conversion. One that I haven't heard much about is using a stock 914/6 style engine mount instead of the aftermarket alternatives.

I have access to a couple real sixes and I was thinking of making a reproduction of the stock mount. The only major alteration would be using a single 911 sport mount instead of the NLA 914/6 rubber mount.

What have you heard about real sixes running bigger engines with factory mounts? How much HP did the factory race cars put out?

Wait a minute! Aren't YOU supposed to know all this shit? (IMG:style_emoticons/default/happy11.gif) (IMG:style_emoticons/default/poke.gif)

[Steve]

As far as I know it was only the 2.0 220 hp GT motors and I heard they braced the sides of the single mount. I am also curious what the 908 motor used for a front mount in the 914.

[McMark]

Googled the 914/8 for awhile and then it dawned on me that likely the 914/8 used the same mount as the 908 the motor came from. In which case it would look like this piece which is mounted on the front of the engine. The mount bolt is sideways.

[carr914]

FWIW I would use an Aftermarket mount - all the different ones have double mounts to the firewall. A High HP motor will try to twist in place and spread out the mounting area will help

[McMark]

I agree for 3.6s and maybe 3.2s. But if the factory was running 220hp through a factory mount, that seems like a good referral to me.

Plus, we're actually talking torque there. HP doesn't twist mounts, torque does.

Based on my research, I think I'm going to build one for my car. An interesting project regardless. I like the idea of an OE style setup (surprise, surprise).

[Luke M]

A friend of mine ran a 3.2 in his Org. 914-6 with the stock motor mount in place for a good 6 years. He ran the car hard and did many track/auto x events with it.
I now own that same car but has a 2.4 w/ 2.2S p/c's with it.
I recently removed the motor and found no issues with the factory engine mount.
The firewall mount is fine and doesn't have the gussets on the side like the GT cars had. I would say a 3.2 would be the max on the factory mount. I'm working with my brother on his 6 conversion and it's getting a RJ mount for his 3.0 engine.
I took some pics of the under side of the 914-8 when I was at the Porsche museum last year. I'll check to see if I have a good photo that shows that mount.

[Larry.Hubby]

I have had a '78 SC 3.0 motor in my car for 30 years with a stock 914/6 mount with no problems. My car was not an original 6, however. When I did the conversion, 1982-3, all the parts were still available from the factory, so I bought the lower part of a 914/6 firewall that had the motor mount bracket attached and all the other front mount parts, removed the bracket, and welded it onto my 1970 914-4. I also changed the transmission mounts to the 914/6 parts. I've examined the mount and it's attachment to the firewall many times and have never seen any sign of stress, let alone failure.

One additional data point: In 1983 I talked to George Vellios, who set up a 916 side shift kit on my 915 transmission for me, and he claimed to have briefly worked on the factory Peter Gregg 916 that AA now has. He said at that time that the factory had apparently been concerned about this very issue and had added a torque arm to one side of the motor that was anchored to a small rubber mount on the firewall. No idea as to whether or not this is true.

[carr914]

I agree for 3.6s and maybe 3.2s. But if the factory was running 220hp through a factory mount, that seems like a good referral to me.

Plus, we're actually talking torque there. HP doesn't twist mounts, torque does.

Based on my research, I think I'm going to build one for my car. An interesting project regardless. I like the idea of an OE style setup (surprise, surprise).

But remember at the time, the Factory was experimenting with things with No Computers, Wind Tunnels or Shakers. The Factory Stiffening Kits were Trial & Error.

The Fact that a 4 Cyl 914 or a 911 has Duel Mounting is good enough for me

[brant]

I like the large foot print of the aftermarket also.

look at the stock 911 motor bar
it spans the width of the engine bay

I think looking at the 911 chassis over the years of development is a better indicator than 16 one off race cars that were expected to last 24 hours each and then be discarded...

the 911 had ongoing improvements and ongoing engineering put into it.

[McMark]

I certainly can't complain about the available aftermarket mounts, and I have no intention of trying to detract from those mounts.

That being said, and in the interest of friendly debate...

The aftermarket mounts aren't exactly widespread mounts. I mean, if you want 911 style, make a mount that's 911 width. (IMG:style_emoticons/default/wink.gif)

Also the 908 engine mount above is a single mount. Also, here's a 99-05 996 engine.

(IMG:http://www.914world.com/bbs2/uploads_offsite/hitecauto.us-419-1367986340.1.jpg)

[brant]

...

[McMark]

Touché. (IMG:style_emoticons/default/laugh.gif)

[Luke M]

Here's some pics of a factory 914-8. I recall the front being like/if not a oem 914-6 mount but you can see another mount by the L/R shock/rear trunk.
(IMG:style_emoticons/default/idea.gif)

[sixnotfour]

Great pics Luke, The mid mount increases rigididy and provides the torque arm effect Torque plate for v8 guys.
Makes the motor and trans kind of a stressed member..




The six mount has 2 plates top and bottom to control rotation and prevent drop out. I don't think a single 911 mount is sufficient.
The 910 908 design is great.

[iamchappy]

I know they reinforced the GT cars mounts with minor plates welded
to the sides of the plate, but i have never heard of a 6 mount failure ever.
My car was originally a club PCA racer with a 3.2 and i am running the turbo engine in it, the rubber insulator must do a good job of absorbing the torque and think the factory 6 mount must be pretty sound.

[Jeff Hail]

Engines that use block mounted transaxles don't have the torque windup that a vehicle would have with a conventional driveshaft. Even ones with torque tubes dont have that much engine lift compared to a good old muscle car. Torque is still present but its transfered differently where huge mounts with large footprints are not required.

Every mounting system I have ever seen Porsche devise is thought out for ease of service. Ever seen the front motor mount on a 917? Its has 1 single big ass bolt, actually its not even that big.

911 mounts are spread wide apart because the rear body panel sheet metal was not designed for that kind of weight.

[McMark]

Cool pics, Luke. Thanks for sharing. (IMG:style_emoticons/default/thumb3d.gif)

911 mounts are spread wide apart because the rear body panel sheet metal was not designed for that kind of weight.

Interesting idea. Makes a lot of sense. The mounts would need to be out to the sides. That cross-member under the 911 engine lid latch isn't strong at all.

I don't think a single 911 mount is sufficient.

I'll have to do some research on this. I'm actually thinking about using a 996 engine mount in my personal car. These are modern fluid filled hydraulic mounts. Probably going to grab one off eBay for trial fitting.
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.sierramadrecollection.com-419-1368123838.1.jpg)

[Cap'n Krusty]

As a shop owner, I really liked the fluid filled mounts. HUGE profit center ................

The Cap'n

[McMark]

(IMG:style_emoticons/default/lol2.gif)

Actually, that's exactly the response I suspected I was going to get from you Cap'n. I guess I'll stick with the 911 Sport Mount.