[harsh_ride]

So it turns out my balance belt is intact, it's evidently an engine mount that's gone south (symptoms -- very rough idle, smooths itself out at 1200 rpm, starts vibrating again nastily at ~3000+ rpm, and a nasty rattle that's the exhaust shield, which fits, given (a) the car has 90+K on it, (<img src="/forum/images/smilies/968/cool.gif" class="smilie" alt="" /> there's no documentation of the engine mounts ever being replaced, © the engine mounts are known to wear out, and (d) the right engine mount, by the exhaust, is usually the first to go -- as I understand it, from talking with BHP, etc.)



So --



How tough a job is this? Shadetree mech, or more involved?



Are there better-than-OEM replacements, or should I just get the updated 951 part from the factory?

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[flash]

wow - that is a different set of symptoms than others have described with broken mounts - that was my first thought though, but when it was vibrating all the way up (and i didn't notice any smoothing anywhere) i thought balance belt - since we couldn't get the front cover off to be sure, and you definitely needed belts anyway, it was an easy conclusion - sorry about that



bummer - it is more than a shadetree job, unless you have a hoist - the engine needs to be lifted to do it - dave did his, but he has a hoist



last i heard, the aftermarket mounts were not as strong as the oem

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[Ryan]

I changed mounts without a lift. If your car is on stands, you jack the engine with your floor-jack at the oil pan. (with a wood block) It is a pain job though.



However, bad engine mounts show up at idle only and not at 3000 rpm. I would guess there is another problem besides mounts.

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[Greimann]

Replacing motor mounts falls into the category of advanced wrenching. When I did mine, I lifted the engine ever so gently with a jack under the oil pan and big block of wood to cushion it. You have to drop the crossmember as well. I did mine one side at a time so as not to booger up the alignment too badly, and to keep the engine supported at least by one side while I was removing the other.



That requires a lot of muscle and prying to get the mounts in and out. Certainly dropping the cross member all together makes it much easier, but the engine should be supported by a hoist at that point.



Get the OEM replacements. There are super duper ones out there, but they are more rigid than stock and more expensive too.

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[flash]

dave - does that mean you just used the hoist to hold the weight of the engine while you lowered the crossmember? (oh joy, another alignment too)



chris - i meant to ask - how did you manage to get the cover off? the nuts were spinning in the plastic - did you actually get it off to verify the belt was intact?

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[harsh_ride]

[quote name='flash' date='Jul 21 2005, 07:32 AM']dave - does that mean you just used the hoist to hold the weight of the engine while you lowered the crossmember? (oh joy, another alignment too)



chris - i meant to ask - how did you manage to get the cover off?  the nuts were spinning in the plastic - did you actually get it off to verify the belt was intact?

[right][post="7624"]<{POST_SNAPBACK}>[/post][/right][/quote]



It's at the stealer... I'm at the point now where opportunity costs outweigh the interest rate on my credit card... <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />



Looks like they'll be doing the engine mount, too... If it falls under the category of "advanced wrenching," I'll have a pro do it.



Will the labor of the belt swap be reduced by the labor of the mount replace?



(Should I have them do both mounts, as long as they're in there?)



Water pump -- 951 part, or something else?



Re: Symptoms --

Going by this: "If you have excessive vibration at idle, and the vibration disappears around 1200 RPM, one or more of your motor mounts may be bad." http://www.rennlist.com/944values/9685.htm



Was exactly what I experienced, so BHP's "haven't torn it apart yet, but it 'feels like' ..." diagnosis seems spot on.



I may have other things going on...



Seems my car always does.



"Personality," they call it. <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />

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[Greimann]

No I didn't use my hoist, Just the jack. I only unbolted one side of the crossmember at a time to help preserve alignment. It worked well, but you have to pry and swear a lot to get the mounts out. I got lucky and the alignment wasn't affected. I agree that you really should have it checked after doing this.

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[Greimann]

(Should I have them do both mounts, as long as they're in there?)

Definitely! Both will be worn out.

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[flash]

ok - feeling senile now - what job did you use the hoist on? we had a whole conversation about something you were doing where you used the hoist, and i thought that was the job



chris - given that your pump is probably as old as everythig else in there, yes, i would change it - the 968 pump is the safe route (marked 2.7, as opposed to 2.5) - i currently have a 2.5 pump in mine (don;t get me started on how that happened), but have not had the opportunity to put them side by side to see which one is actually better for this car



also, you might save yourself some labor later by either replacing the crossmember with the lindsey racing 3 piece removeable one, or by attacking now leaks that would require dropping the crossmember again

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[Eric_K]

You can also fab something like the below pics to hold the engine while you remove the cross member & mounts.







These pics are from tech-session.com's rod bearing replacement procedure.



Eric

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[flash]

lol - it's not often you get to use a table saw when working on a porsche



danged creative

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[Tom in Austin]

Hoist? When I did my mounts, just used my floor jack and some hefty wood blocks to support the engine under the oil pan (after lifting it just slightly), then dropped the crossmember down and out.



Not sure what type of alignment people are thinking of. The control arm forward mounting points go through the outer portion of the crossmember, but that's trivial - at most, your toe might change by a half a degree or something. As I remember, the four crossmember-to-body bolts don't allow it to move very much (a few mm at most) in any direction, so can't see how it would throw anything off.



The crazy part of this job is getting hold of the 4-13 mm bolts that fasten the mounts to the engine. I bought several wrenches of different types to finally get hold of the last of these and get it to come loose.



Oh, and something I wish I'd done - while the crossmember is out, you can easily reach the PS hoses and it's a great time to change them out with easy access to the back of the steering rack. Also to change the rack mounting bushings.

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[flash]

alignment is EXTREMELY sensitive and critical on these cars - 1/4 degree is the world - you would be stunned at how little it takes to throw it off - i am at the point of making 1/10 degree adjustments to get the maximum handling



as an example, by installing a strut tower brace to hold things in place, and from stock, adding just 1/4 degree of negative camber and reducing the toe by 1/4 degree, you can double your tire life and seriously increase the front end cornering ability



absolutely get the alignment checked and/or reset after doing this job



chris - your rear ride height was WAY off anyway - you absolutely need a 4 wheel alignment with ride height

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[apex]

erik_k thanks for those pics! <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" /> That is exactly the thing I've been looking for!

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