merchauser

is it possible to have collapsed motor mount(s) and yet visually, rev the engine and it appears rock solid??

Rob Edwards

Rock solid engines when revved are congruent with collapsed motor mounts, so yes. Not only possible, but likely.

SeanR

The Forgotten On

Unless you own a 78-82

GregBBRD

Pretty sure that "congruent" is that stick/tree thing in Guardians of the Galaxy....or perhaps what they call the people that hang out with it....can't remember.

Anyway, what does that thing have to do with motor mounts?

Rob Edwards

The symptom is no rocking, the disease is dead motor mounts. The symptoms are congruent with the disease.

Otto Mechanic

Regardless of geometry or popular film, yes. A motor that doesn't move is either equipped with solid or "semi-solid" motor mounts, or the stock liquid filled mounts have failed. It's pretty common. The factory mounts are only good for a few years.

Otto Mechanic

PS: I recently replaced my factory mounts with what I call "semi-solid", meaning they have solid rubber isolators between upper and lower metal parts. I mention the distinction because there's been an ongoing debate over terminology as it applies to motor mounts. It's my belief there are three types of mount:

- Solid. This is a solid metal mount. It provides no isolation between the engine and the chassis.
- Semi-Solid. Upper and lower metal parts with a hard rubber isolator sandwiched between.
- Liquid. A thick walled rubber capsule filled with gel. The stock Porsche engine mounts are liquid.

I noticed no difference going from failed liquid mounts to semi-solid. I've never really tried liquid mounts since the stock mounts in my car were long dead when I bought it.

Strosek Ultra

Here Paul!
https://members.rennlist.com/pirtle/svc_mm.html
https://rennlist.com/forums/928-foru...-pictures.html
Volvo motor mounts (models 740, 940, 960 and 980) are commonly used, Volvo part no. 62 438 657
Åke

merchauser

well the joke is certainly on me! had a neighbor come by the other day, who prides himself on being "all knowing" especially
with cars. he blips the throttle hard, and proclaims: "you're motor mounts are perfect. you could put a glass of champagne on
that motor, and not spill a drop. you don't need motor mounts." lol

can someone post some photos of the relationship between the manifold and crossbar, and/or the oil filler and crossbar?
I can put 2 fat fingers between the crossbar and oil filler.

I am guessing that the intake should stand proud of the crossbar? by about how much?? any photos?? thanks

Rob Edwards

Tons of them in the archives-

https://rennlist.com/forums/928-foru...sbar-test.html

https://rennlist.com/forums/928-foru...t-options.html

Here's Dr. Bob's '89 with factory mounts, 1 year post-install:



And my GTS, factory mounts, nearly exactly 1 year post-install:

Wisconsin Joe

You can also tell by looking underneath.

MMs in good shape will hold the bottom of the oil pan level with the bottom of the crossmember.

Squished ones will allow the bottom of the pan to be below the crossmember.
If you see the bottom of the oil pan below the rest of the underneath stuff, then the MMs are shot.

Otto Mechanic

Ooops. I just realized I was in the wrong forum. I've never replaced the mounts on my 928. Probably should, but never have.

Wisconsin Joe

To take my "look underneath" comment a step further, post 7 of this thread:

https://rennlist.com/forums/928-foru...l#post15177406

shows what the oil pan/crossmember heights should look like.

dr bob