Transmission mount lead weight

AL MEREDITH · AL MEREDITH's Garage

I have a 912E (1976) When I removed the transmission I removed a large heavy lead? weight ,12LBS , from the Yoke. Part #923 375 303 0 and GW in a circle. What is the purpose of this weight? is it only on the 912E for some kind of weight compensation devise ? Is it necessary? Al

johnsjmc · 12-25-2005, 07:13 AM

Weights hung on rubber mounts are to offset some vibration .usually at some particular speed.The 4 cyl in the 912 would have a rougher character than a 6 in a 911.

Britain Smith · 12-25-2005, 02:42 PM

I have seen a couple of those, I actually think I might have one or two. I am not really sure of there purpose...I have heard it was for weight balance or vibration like it was said above. I would leave it off it I were you.

-Britain

jluetjen · jluetjen's Garage

Britain;
So your presumption is that the engineers put that there for no reason and so the car would be better without it. A lead weight? The same engineers who designed some of the largest magnesium castings (for the crank case as well as the gear box) in order to save 5 to 10 lbs???

Al; if it is there, it is there for a reason -- even if we may not understand at this moment what it is. If it is easy to take off/put on, sure -- try driving without it for a week and then put it back on. I doubt that it would make a night/day sort of change, so don't expect your car to suddenly perform like a 2.7RS without it. I wouldn't be surprised if you might find that there is a buzz or vibration at a certain engine speed without it which is much weaker when it is there.

randywebb · 12-26-2005, 10:51 AM

John, Maybe he just meant that a more performance oriented driver would be willing to suffer more NVH for better performance. But, it is best if advice explicitly points things like that out.

I'd also check this out on the PET to see if it is a P AG part or something a PO added. Also examine for a p/n... P AG put lead wts. in the bumpers for a while, but later found ways to get improved handling w/o that. So if it is factory check later years and see if they modified things somehow as the engineering evolved.

jluetjen · jluetjen's Garage

Touche' Randy -- I didn't mean to come across so harshly. The problem here is that the 912E is a one-year model, Porsche never made another 4 cylinder in the 911 body. I agree that a more "performance oriented driver" may be willing to suffer a vibration then someone who is not as concerned with that. It might be worth while to search the 914 forums, both here and at other sites. They've got essentially the same drive line and so I would expect that the same question would have come up.

If it is easy to put on and take off -- do a test and make up your own mind as the owner of the car.

randywebb · 12-27-2005, 10:30 AM

Ah, I didn't realize which 912 we were on...

Not that you _were_ harsh, but that it might be mispercieved in the limited communications environment of a bbs post...

And, BTW, thanks for all your quality posts - both recently and over time.

I agree re saving the peice and just trying it both on and off for a while. If there is no difference over various road surfaces & speeds then put it up for sale on eBay as a rare Porsch piece for $600 starting bids....