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?

Wait a minute! Aren't YOU supposed to know all this shit?

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.

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.

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

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).

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.

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.

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

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.

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.

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

...

Touché.

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.

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.

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.

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.

Cool pics, Luke. Thanks for sharing.

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'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.

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

The Cap'n

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.

OK maybe you are better at the mental gym than I am, but I have a hard time determining whether a lot of torque actually gets passed to the engine mount. My idea is that the bell housing handles a torque argument between the crank and the diff and the torque ends up mostly squatting the rear and lifting the nose. In real terms are we dealing with more weight or twist? My guess is weight.

You rev a torque monster real fast with a load on it you can bet that engine is trying to twist out of it's mounts. Look at trucks that do tractor pulls, they back up the mount with a hefty chunk of chain just in case.

But Mark, as was mentioned by some else earlier, isn't most of the 'american muscle' chassis twist because of the long driveline and the fact the the source of the torque is so far away from the recipient of the torque? I'm off to YouTube in search of high HP 911 engines revving. We'll see if the motor moves...

I think this is a perfect video. Solid/stable camera mount, accelerating under load, and you can't see a bit of engine twist. Even stock 911 mounts have some give. BTW, this is 303hp.


https://www.youtube.com/watch?v=wySSMKNsC6M

This one shows some engine twist, but it's not like those tractor pull trucks you're talking about where the whole chassis twists. And this is a 3.6 Turbo.


https://www.youtube.com/watch?v=cYmlhLjeLOE

I agree with this more and more as I think about it.

I twisted the chassis of my first 914 V8 drag racing in front of the police station. Front left wheel came off the ground. The engine cradle transferred all the torque into the chassis...

BTW, I won

I can kind of see where you are going with this

The one thing that the mount must do is limit engine movement, mainly for the shifter rod.

I do know from my bug experience that I would try to make the mounts as stiff as possible, without transferring extra noise. In the bugs it's not so much twist, the engine actually tries to hop up and down. In bugs this is a main cause of wheel hop and will literally bend the the frame yoke.
I would make a bar so I had two 914/4 mounts at the front (nose) of the trans, as the stock single mount was not good enough for a HP application. I would keep the rubber (real VW HD) trans mounts at the bellhousing and I would add a crossbar with a pad on the tail of the engine or I would build a kafercup style mount.
My 901 and type 4 in bug set up has a crossbar with 914/4 mounts at the front, stock bug mounts at the bell houseing and I will be fabing a rear bar to use the stock 914/4 mounts.

Might be a month or more but I'm going to be fabing up my own mount soon. I was thinking of fabing an RJ style mount as I have blueprints and parts templates that were given to me. Also was thinking about a Patrick style, but I don't like the fact it has no backup to a (however unlikely) a bolt failure.

Maybe I should dig out that dummy engine and stick it and a tranny in there and start thinking as well. MrHyde is dropping off my DW tank this weekend.... maybe I'll get the itch and stick something in there sooner.

Mark any ideas you may have you would be welcome to bounce them off me, other than making my own mount I have no interest in becoming a mount retailer.

Wait, was it an open diff in your transmission?

Despite the nay-sayers, I'm moving forward with this project. Finished the drawings for the chassis section and made a template. I tried to fit a stock 996 motor mount and they're just too big. So I'll be making an adapter to utilize a 911 sport mount, which means it could also use a Wevo mount to reduce flex. The pieces will be made from thicker steel than the factory mount to increase rigidity, probably 1/8" plate.

Mark,

Looooooks very interesting. When your done, I'm interested in a unit. Pm me when done.

Oh I like add that I have an OEM engine one...,so if you can adapt the one your making to hook up with oem engine mount- the better

Thanks

in the 914-4 power train mounts you have a 3 point design, the wide spaced points at the tranny and at the front the single mount at the engine bar.

with the 914-6 besides hanging more weight from the front mount the is no difference in the stress on the chassis.

front engine/tranny config with a live axle uses the same 3-point mounting and they do have torsional twisting of the chassis because the drive shaft is transferring torque to a lever [the rear solid axle] that is acting against the ground on one end and the engine/tranny mounts on the other, and this force is causing the chassis to "twist".

the forces that a engine/transaxle transmit to the chassis are a axial rotation [in relation to the transaxle outputs] on the fore/after axis of the chassis [engine will try to lift the chassis at the front of the engine under acceleration and pull it down under braking. because it is now the wheels that are acting against the ground in torsional force.

the key to this is that the engine and transaxle are a solid unit and the side to side torque force is nulled as the torque is transferred to the halfshaft outputs.

I run solid mounts in the Alien. Rubber mounts are designed for family cars and the critics from the magazines that want performance from their Lazyboy Recliner. I have no noticeable engine vibration and when I hit the loud peddle the front of the car lifts. Because of the half shaft arrangement the car stays flat and level during lift off. Twist is not part of the equation or a limited part. And torque is abundant with over 350 hp.

Mark, your mount pattern is very nice.

Mark already knows this because we had this conversation 1:1, I had a conversation with Jim Patrick about mounts. He asked what I was using and I told him vaguely, that we were reproducing a beefed up factory six mount. His concern was that because of the geometry of the narrow triangle formed by the front mount and the transaxle mounts, the engine / transaxle unit twists and "can cause shifting problems."

One has to remember that Jim Patrick puts food on the table selling engine mounts. That isn't a criticism. In any research you must identify possible bias.

Best I can tell from what I've read, the mount isn't the area that should be the focus for the solution to the shifting problem. Cable shifter?

One of the 'spurts explain to me that if there is no torsional twist with the 914 set up, why do you hear a thump when you have a broken drivers' side mount on the later cars?

The only mount I have seen broke was the little rubber front one from hard launches from a standing start....

Well there's one way to definitively solve this armchair-engineering debate.

As for my addition to the speculation, I figure if the factory race cars (908 engine for example) used a single center mount and if the boxsters use a single center mount, I can't see it being a problem.

Porsche also used a dampener (basically a gas-shock) from the engine to the chassis.

Any idea where this would mount (on the 908)? I looked through a bunch of pictures (including these) and can't see any brace nor any location that would support a torsional brace.

I would love to see how this was done on any of the center mount Porsche race engines.

The yellow zonker had a narrow mount and seemed to work OK. Kind of hard to see in this pic.

as for solid mounts - i think when using them - it is important to remove engine and trans evenly - cause if you start to lower engine or trans, first, you run the risk of twisting the opposite mount bracket or worse - i'd think.

were as rubber would give some and provide some play.

ps - that is one kick ass bell crank on zonker !!!

I've seen pictures but it's been a while. I thought they were still doing this on (at least some of) the newer cars.

Mark,

In the For What It's Worth dept. I've been running the 993 engine in the Rocket now for 4 years, and about 4000 miles. It's sitting on the stock 914/6 frame mount, rubber mount, and -6 engine mount.
The driving experience is pure torque and adrenaline. I love thrashing it.

I've noticed no issues so far.

The trans is using a Guard LSD, and the transmission mounts I got are the Wevo Blue urethane units.
I don't know if these help keep things in check, but nothings broke so far.

my 84 carerra uses a hydraulic damper in the rear and from what I read its required after the 3.2 for vibration more than torque..

The motors hit a harmonic balance that can make things shake to much...

For the front mount on a 2.4 motor....go for it.
I will buy one if you figure it out.

rich

Ron. That's a big no-no in racer circles to mount a fuel gauge on the motor. A fire waiting to happen. I've seen a 911 light up at the track from exactly that mistake.

Elliot and Ron, thanks for the real work experiences! Glad to hear positive impressions.

Is your '84 a cab? Mine is, and I've only seen the shock on cab cross-members, not on coupes or targa's. There wasn't one on my 993 cross-member when I got that engine either. Can't speak to the 964's... Don't run across them very often.

~Ron

I'm pretty sure this is beaten to death at this point. But I checked out the Porsche online parts catalogs, and found the Carrera GT PET. Center engine mount and no additional support braces. I'm done looking.

Mine is a cabriolet

That might have been it. My memory is a bit foggy.

So the dampener on the cabriolets is for engine vibration, not torque?