motor mount washers - which way round?

[DCred911SC]

Hi,
Can someone tell me which way round the motor mount, and transmission mount washers should be ?
Took the engine out so long ago that I can't remember. I seem to think that I left washers on the bolts so that I could remember which way they were installed, but if this is the case, the transmission mount washers a oriented different to the engine. i.e. on engine the washers were convex side toward mount rubber, but transmission was concave side toward rubber mount.

Which is correct ?

Thanks in advance

David

[Christien]

Convex side to the rubber is how I've always done it, based on how they were when I first dropped my engine. If you think about it, it only makes sense. If you had the concave side facing the rubber, you only be putting pressure on the outer rim of the rubber, which means there will loads of room for the bolt to travel up and down, stretching the rubber, and therefore bouncing your motor and tranny around.

[RWebb]

Steve W. recently answered this on Rennlist

[jonbot]

I searched on Rennlist and couldn't find the post you're talking about, any chance you could post a link?

Originally Posted by RWebb

Steve W. recently answered this on Rennlist

[RWebb]

here is the gist of it:

placing the washers with concave sides facing away from each other,
like this: ()
- results in better shift quality but more vibration.

placing the washers, concave sides facing inwards, like this: )(-
- gives the smoothest configuration but the shifting under load is not
as nice.
__________________
Steve Weiner

[dshepp806]

saw this pic:


Best,

Doyle

[Christien]

Originally Posted by RWebb

here is the gist of it:

placing the washers with concave sides facing away from each other,
like this: ()
- results in better shift quality but more vibration.

placing the washers, concave sides facing inwards, like this: )(-
- gives the smoothest configuration but the shifting under load is not
as nice.
__________________
Steve Weiner

That post could cause a lot of confusion - I'm glad the parentheses are there to clarify, because the terms are backwards. Concave means bent or curved inwards. Convex means curved outwards. Think of it as "caving in" to remember.

[RWebb]

he is referring to the washer itself - better reread the post...

[Christien]

I just re-read it - maybe my brain is tired (it *has* been a long day and I've been breathing far more gas fumes than I should be!), but I still think it's backwards. If the concave sides of the washers are facing each other, they'd look like this: ( ) whereas if the convex sides are facing each other, they'd look like this: ) (

Please correct me if I'm wrong - I hate seeing threads with discrepancies when I'm looking for a definite answer to something, so I'd hate to leave this up in the air.

[techweenie]

Christien is reading what Steve posted correctly. The description and relationship of the parentheses are in direct contradiction.

[FPB111]

1con·cave
Pronunciation: \kän-ˈkāv, ˈkän-ˌ\
Function: adjective
Etymology: Middle English, from Latin concavus, from com- + cavus hollow — more at cave
Date: 15th century
1 : hollowed or rounded inward like the inside of a bowl

convex (comparative more convex, superlative most convex)
1 : curved or bowed outward like the outside of a bowl

[DCred911SC]

Seems to be a bit of debate about this, there seems to be mixed opinions....and no right or wrong !

How did the factory do it, anyone know ?

David

[kodioneill]

factory mount

[jwetering]

OK - so to cut to the chase...which configuration gives the crispier shifts?

This = ()-

or

This )(-

[x98boardwell]

The picture above is correct. We have soft mounts in our cars. When they are installed properly it allows our mounts to move somewhat as intended by Porsche.

jwetering, () is crispier shifts, )( is normal and smoother... the way they are suppose to be mounted.

If you are wanting a solid mount feel then go with Wevo, but I wouldn't recommend turning these washers around. It is not the correct way to install them.

Bryan

[don gilbert]

this was addressed in an excellence tech article a while back, factory put out a TSB telling shops they can go either way, depending on the customer drivability problems

[JFairman]

All the ones I've seen were like this ( )

Seems to work fine and the other way doesn't even make sense.
Just use little washers, or flat washers if you don't want the big washers to cup the rubber part, if the rubber flexes beyond a certain point.

I guess you could say or hope the big washers won't go through the mount if the rubber completely dry rots and breaks out of there while they are installed ) (

[RWebb]

yes on the TSB - either way is ok

next step stiffer is the factory sport mounts

then the Wevo - 2 stiffnesses (blue or black)

[RWebb]

he must have been thinking about the entire configuration when he posted - I agree it is not the clearest

[JFairman]

fwiw, factory sport mounts are origonal equipment on a 930

Originally Posted by RWebb

yes on the TSB - either way is ok

next step stiffer is the factory sport mounts

then the Wevo - 2 stiffnesses (blue or black)