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Posted by: Not_A_Six Dec 1 2018, 12:18 PM

Hi All-

New member here. I have the engine out of my '73 2.0 to address some fluid leaks and noticed that the engine mounts were unusual. Going through old paperwork, I found that a PO had installed "Club/Sport" engine mounts 15 years ago.

The car is a '73 with stock side-shift trans and cross bar with the hole in it for the trans linkage. But the engine is mounted to the crossbar with solid aluminum blocks and the crossbar is mounted to the chassis with rubber -- similar to the older style tail shift factory mounts -- instead of the inboard rubber+outboard solid mount expected.

I'm inclined to return it to stock, but I'm trying to understand the purpose of the "Sport" mounts. Online searches suggest that 911 "Sport Mounts" are used somehow for /6 conversions, but I don't know why PO changed from the stock mount with the factory 2L engine/trans.

Thanks for your help.

FWIW, pic of my baby is attached.

Posted by: mepstein Dec 1 2018, 12:22 PM

Posted by: SirAndy Dec 1 2018, 12:26 PM

The 911 "sport mounts" are often used as replacements for 914 transmission (!) mounts.

You really should go back to the correct solid outer mounts on your engine bar and rubber mounts on the front of the engine.
The engine flexes enough under torque that it could very well hit the shift-rod with your current setup.

Posted by: ndfrigi Dec 1 2018, 12:28 PM

here is a sample of 911 sports mounts.

Posted by: Not_A_Six Dec 1 2018, 12:33 PM

Thanks, all.

The mounts in the pic look like the ones on my car, but they're on the *engine*, not the trans. Weird.

Was this maybe a track mod back in the day?

Posted by: SirAndy Dec 1 2018, 12:42 PM

No, see my post above. Your setup makes things worse, especially on the track.

Posted by: Not_A_Six Dec 1 2018, 01:17 PM

Thanks. So, are you saying that the engine would move more with the rubber at the ends of the crossbar than it would with the rubber inboard? On which axis? (Pitch? Roll? Yaw?)

I'd guess that it would flex less due to the longer moment arm between the rubber points (unless the outboard rubber is more flexy than the inboard rubber...)

Thanks again. I think I'm gonna return it to stock as you suggested. But, I'm just trying to understand why this mod was ever made in the first place.

Posted by: SirAndy Dec 1 2018, 01:24 PM

No, i'm saying that with the correct setup (solid outer mounts, rubber engine mounts) the movement of the engine does *not* affect your cross-bar, which is where your shift rod goes through.

With your current setup, the cross-bar moves with the engine under torque load and since the clearances are already tight on the hole for the shift rod, you will have the engine bar hitting the shift rod.

When the shift rod hits the engine bar it makes it very difficult or impossible to shift. This usually happens when you combine g-force with torque. For example, when hitting the gas coming out of a tight corner.

Posted by: SirAndy Dec 1 2018, 01:25 PM

Ignorance?

Posted by: ndfrigi Dec 1 2018, 02:13 PM

still the better mount for street car.

Posted by: Not_A_Six Dec 1 2018, 04:04 PM

Ahhh! That makes sense. Thanks.

Posted by: Not_A_Six Dec 1 2018, 04:06 PM

That looks like a nice setup. Where did you get those rubber bushings? They don't look like the stock parts.

Posted by: rhodyguy Dec 1 2018, 04:16 PM

They're the stock ones for a SS. Outboard mounts are the solid variety.

Posted by: SirAndy Dec 1 2018, 05:04 PM

They are the stock rubber mounts for all sideshift 914s.

Posted by: Not_A_Six Dec 1 2018, 05:10 PM

Thanks. The mold seam in the original pic made it look like it was a two-piece setup. I'm on it if that's just the stock SS part.

Thanks, all.

Posted by: Bruce @ 914 Rubber.com Dec 1 2018, 05:11 PM

I agree you should go back to stock. I wonder how they used the early style mounts at the end of the bar. It will drop the engine down. I had a car where they made it work by cutting the height of the engine bar.

Posted by: Not_A_Six Dec 1 2018, 05:37 PM

I dunno. I hope the bar wasn't cut.

Here's a pic of the mount itself. (The bar is buried and I can't get a pic at the moment.)

Posted by: ndfrigi Dec 1 2018, 06:14 PM

914-4 side shift engine mount on the side should be like this. no rubber mount on the side for the engine mount bar to body mount.

Posted by: Not_A_Six Dec 1 2018, 06:19 PM

Yep. Thanks. We're on the same page.

Posted by: porschetub Dec 2 2018, 02:08 AM

Ditch any crap that's not original,it was well designed system if your rubber mounts are replaced with new stay with that,good luck.

Posted by: DRPHIL914 Dec 2 2018, 07:29 AM

you can see the correct solid bracket and mounting bolts in this picture, they can be obtained feom Mr bdstone @bdstone here. he probably has some original ones and has some new remanufactured ones. very reasonable prices.
Several vendors have the inner rubber mounts. I think i got mine from Automobile Atlanta. Yes there is a seam and they are bonded together the upper and lower bolt that comes out of them it is not a solid bolt that goes thru. When i pulled my motor bar fell because the mount had split in two! the motor was just sitting on the bar and was not actually bolted to the bar anymore. now all new correct parts ans its nice and solid.
One never knows what you might find that the DAPO did!


Attached thumbnail(s)

Posted by: DRPHIL914 Dec 2 2018, 07:31 AM

here are the correct new inner mounts on the brackets.


Attached thumbnail(s)

Posted by: Not_A_Six Dec 2 2018, 10:56 AM

Very nice pics. Thanks!

Posted by: bbrock Mar 6 2021, 11:38 AM

Anyone know the torque spec for the nuts securing the rubber mounts? Don't see it in the factory shop manual.

Posted by: Superhawk996 Mar 6 2021, 12:59 PM

@http://www.914world.com/bbs2/index.php?showuser=20845

I believe it is 21.7 Nm per Hanes manual (Engine support nuts - Body).

As a 2nd rationaltiy check here is the standard torque table for black oxide fasteners.



26 Nm for an M8 grade 8.8. I'd go with the Haynes spec.

Posted by: bbrock Mar 6 2021, 03:11 PM

That torque spec in Haynes is for the outer bolts that attached the steel support to the body. And if they say Nm, they are wrong. The factory manual clearly specs those bolts as M10 and 21.7 ft.-lbs. Way too much for an M8 bolt.

I wound up using that exact same torque chart you found (almost). The table you reverenced is for untreated screws (black finish). If you scroll down to the table for zinc plated fasteners, it speces 17.7 ft.-lbs. I was guessing 18 ft.-lbs. so pretty much spot on. I didn't know if there would be adjustment for the rubber mount factor but as I thought about how they are made, there shouldn't be. Anyway, I went with 18 ft.-lbs. which I think should be fine.

Posted by: Superhawk996 Mar 6 2021, 04:45 PM

@http://www.914world.com/bbs2/index.php?showuser=20845

You are correct Haynes is 21.7 ft-lb and you are correct, that is a bit high for an M8. I had assumed the units to be Nm. That is why I did the standard torque check as quick 2nd check for sanity. Yup, 26 Nm for a M8 black oxide fastener -- plausible.

Agree, plated fastener is slightly lower torque than black oxide but now you're splitting hairs for this application.

Honestly, I've never used torque wrench on those rubber isolator bolts. Torque spec is Good N' Tight. They are a reasonably rigid metal to metal joint. If you were actually torquing against rubber in the joint, you would never get anywhere near 20+ Nm of torque.

Bottom line - you got it done!

And for the record 21.7 Nm = 16 ft-lb. What's 2 ft-lbs amonst friends in a non-critical application.

Posted by: Dave_Darling Mar 7 2021, 05:41 PM

One thing to note is that the earlier tail-shift cars had the same type of mounts both on the transmission and on the outboard ends of the motor mount bar. It could be that the car's previous owner knew of that and didn't realize that the solid outer mounts were the correct way to mount the side-shifter mount bar.

--DD