VehiGAZ

Could be the case - when David Lloyd "met" my car, he remarked that the oil fill tube was sitting about an inch or so below the strut brace. I'll have the shop check everything over before they change the oil (another part of the job). Wouldn't make sense to change the oil just to pull the pan off afterward.

Thanks for the analysis!!

Landseer

Its gotta be an expensive job for a shop to do.

dr bob

I'm a big fan of hydraulic mounts, especially after working with Ford on some severe NVH issues that were eventually solved with them. I also have some sympathy for folks who may not be able to swallow the expense involved with the original mounts and their short lifespan relative to the aftermarket solid options.

I bought Porsche mounts before the Anchor option was shared, and installed them several years ago now. No apparent problems so far. If I needed mounts today, I'd be looking at aftermarket hydraulics first, though, just for cost comparison. The solids might not be my second choice. The money for the mounts themselves is only part of the issue. I'll speculate that Porsche changed from the early solids-with-the-outboard-damper to the later hydraulic mounts for some good reason. It may be that for battle-worn cars, the NVH related to solid mounts is literally lost in the noise. Hard suspension on worn-out bushings, in concert with RMB exhaust noise, probably masks almost completely the NVH differences with solid mounts vs. hydraulics. For many owners, just the improvement with solids over collapsed is large enough to impress. I'm still thinking that if I need to spend a (long) day under the car doing what may arguably qualify as one of the dirtiest projects, I darn well want to make sure that the results are as good as possible.

Roger-- Got a line on some quality aftermarket hydraulic mounts? I'd buy those, I think.

Mrmerlin

Wildwest for your question, i would suggest that you have changed the front end geometry by removing the lower control arm securing bolts and clamp. This would indicate that a front or 4 wheel alignment should be performed this will re center the steering wheel.

Schocki

wag,
WYAIT replace the oil pan gasket too. Roger has a silicone replacement gasket, no leaks forever

Landseer

Mine are battleworn, that's for sure. Great points, Dr. Bob, as usual!

hopwood

I think Paul makes a really good point. Don't forget that most folks reporting "success" with the solid mounts will have been driving around with collapsed mounts for a while before doing the job. Maybe a long while. Installing the solid mounts will give a great improvement on collapsed, but that is not to say that they wouldn't have seen an even greater improvement with hydraulics.

Joel
ex S2 auto - put solids in, great improvement
S4 manual - put solids in, great improvement
79 - not gone there yet :-)

mj1pate

I only had the intro mechanical engineering courses, sufficient just to invite experts to intervene when I make an opinion about statics/dynamics. So, here I go anyway: The real danger of cyclic engine movement is the possible open-loop amplification of the movement (i.e. heavy vibrations/oscillations) of the type that were renown for shaking bolts loose in Triumph motorcycles and old supercharged muscle-cars. I suspect that if the engine vibration is satisfactorily isolated from the chassis, that the motor mounts are doing their job as being sacrificial energy absorbers. There may be more subtle arguments for vibration dampening with the 928, but I haven't heard them, as of yet.

It seems to me that its irrelevant what material is used in the motor mount. Manufacturers have used piston-type, solid rubber and fluid filled, just to name some. In the end they must do a good job of dampening, hopefully for as long a period of time as possible.

From my experience, the solids worked out very satisfactorily, acknowledging that this an experience of one. An application of a broader driving dynamic or placing myself in the mindset that "this is a $60k car" might produce somewhat less satisfaction. I should mention that one reason I bought the solids from Roger, was testimony that they were reliable and at a decent price. There has been testimony concerning some aftermarket hydraulics that suggests real caution in choosing anything but OEM hydraulics.

lastly from my own testimony: There are plenty of ways to shove $600.00 into one of these cars, choose those avenues carefully ;-)

dr bob

Mike, you have a good point. The solids from Roger are almost always a huge improvement. But I do drive a used-to-be-$80k car, and feel that it's part of the ownership responsibility to do no harm. And yes, the hydraulic mounts are noticeably smoother -in my car- that solids are in another local's S4. Of course he has different tires and wheels, RMB, kickdown bypass, and likes to hear his car rev and shft harder than I do. Probably not a fair comparison. Bottom line for anybody is if they are satisfied with the results they get in their cars, we'll call that a success. I also appreciate when another 928 owner rides in my car and the first comment is how quiet it is. Whoooda thunk?


That said, I was thinking about aftermarket hydraulics from someone other than the cheapest sources. The stated application for the solids that are commonly substituted is a Ford truck. I'll speculate that there are more than a few sources for hydraulic mounts for those trucks, starting at the cheapest imports and going all the way to the ones I can buy at the Ford parts counter. In between are the Rock Auto, the Pep Boys specials, and the perhaps better ones that NAPA stores sell. Somewhere in that range there's a mount that lasts longer than the few years (maybe) that the imported Anchor products are reported to last in the best case. Last I heard, the major car mfrs were outsourcing all of their motor mounts, so it's just a matter of sleuthing some to find one that does the job for longer than a month or three. I don't sell motor mounts-- I'm just another victim here. But I would look hard at a reputable mfr's hydraulic offereing, given the chance.

Shark_gts

I would think that solids won't have the low temp performance of the hydraulics. But once they warm up they should be about the same.

We went to a mid durometer molded urethane for our jager speed mount and it is silky sweet from cold right to hot. the properties of urethane blow away rubbers, but it is expensive.

Mrmerlin

What exactly does the speed mount do???
If the mounts are collapsed then there will be other issues with the drive line that can only be corrected with the engine, TT in its correct position the oil pan should be flush with the bottom of the crossmember

ROG100

Long before I started to sell MM's I was amazed at how expensive the Porsche hydraulic units were.
Luckily for us some other 928 owners (Ray Wach) had found the solution in the Ford MM.

Having both types fitted to my cars (hydraulic & solid) and feeling absolutly no difference what so ever, convinced me that solid rubber was the way to go.

My engineering logic does agree that attenutation via water versus rubber could be better for some frequencies. How much of a difference and wether it is detectable via the foot or the *** is a discussion point only. Throw into the mix the other parameters and the whole argument is lost in conjecture.

What is more important to me is that the early cars were fitted with solid rubber MM's and they are still good today. My 78 (both extra engine shocks are shot for the record) that I am driving at the moment is as vibration free as my 93 GTS and both are super smooth. In my book the proof is in the pudding.

Hydraulics fail prematurly and collapse once the water leaks out. So if there is no tangible benefit to the water filled units why take the risk and in the case of the Porsche units why pay the high cost.

I can sell hydraulic units for the same price I sell solids so if you want them let me know.

Mrmerlin

I have fitted both types of aftermarket Hydro and solids, I wouldnt be able to tell you what car had what kind of motormount by driving it, much less looking at it.

The mounts are made to isolate the engine driveline from the chassis and hold the powerplant in a predetermined position. So if your oil pans is level with the bottom of the crossmember with the mounts you have you should be good to go.. Solid or hydro thats the question??? I have found that virtually all of the hydro mounts I have replaced have been empty, I would stick with the solid mounts as there are less things that will fail and the the difference in aftermarket hydro VS soild vib dampening is almost a moot point. Pick your favorite, It cost the same amount of time/ money to replace the motormounts so then you now have a choice do it once every 5 years (est) or once till the soilids collapse

Shark_gts

i believe they are oil filled. like a balloon in a coffee mug. the balloon deflates and the isolation is lost.

the jager speed mount uses the bottom of the engine and the cross member as support to raise the engine back up to spec. advantage is that the mount installs with a few minutes of work and will keep your oil pan bolts from loosening off! we are running a 1990 here with the new urethane and it is sooo smooth.

we also installled the low-cost solid mounts into a 85 car since we had the engine out and it drove fine.

on my gts i installed hydraulic and also run the speed mount as a back-up to take some of the stress off the two mounts.

Tom in Austin

I can vouch for the new Jaeger urethane mount as I've been running one in my car for past several months. It will be interesting when I finally get time to do the actual mount replacement job to see how it compares.

Based on what some others have said here, it may actually be more time/money effective in the near term to do the transmission mounts next in combination with the Jaeger solution in front.