87 - Help with removing and replacing engine mounts

[Sajan]

Original Post:
Got two new engine mounts. Figured...this can't be that hard. Well..haven't gotten a single bolt off.
How the heck did you guys remove the two M8 bolts while holding the nut on the bottom? I even have a 13mm offset wrench..but I can't seem to get that thing on the nut.
I gave up. Back to quarantine.

SUMMARY EDIT:

I figured I update everyone on how things turned out in case someone ever searches for this information.

As it turns out my 1 hour project of replacing engine mounts turned into a multi day event. I was able to get the 13mm offset wrench under the mount to hold the nut to undo the M8 bolts.
Then things went south as my driver side mount M12 bolt was seized up. This bent the bar pretty bad which meant I had to get a new bar (Rennline). To get the old bar out, I tried lowering the engine a little bit but that didn't work.

I ended up removing the crossover pipe + muffler + rear tin to get the bar out and slip the new bar in.
The engine needs to be lower than its typical resting position (by 2 inches or so) to get the rear tin out. So if someone just wanted to take the rear tin out, you would still need to unbolt the M12 engine mount bolts and lower the engine a little bit to take the tin out.

Then I figured I powder coat the rear and side tins (not too hard to remove, 5 x M6 bolts for each) while I am at it. That turned out well. Cost me about $125.

I replaced all the nuts and bolts with new hardware and used nickel anti seize on the M12 bolts and the muffler bolts.

Thanks to everyone who responded in this thread.

[salayc]

It's tricky, but you're on the right track. You can cut a wrench down to get it to fit or I used a mini 1/4" ratchet.
You should drop the engine a couple of inches by removing the center bolts for more clearance.

[Sajan]

Originally Posted by salayc

It's tricky, but you're on the right track. You can cut a wrench down to get it to fit or I used a mini 1/4" ratchet.
You should drop the engine a couple of inches by removing the center bolts for more clearance.

Wait...I should do the M12 bolt first? maybe that explains why i can't get my hands in there. The crossmount is in the way. Doh

[Snitzler]

Just wait until you have to install the nuts onto the M8 bolts with the new mounts. I taped a magnet onto my finger to hold the nut and washer, still took hours. I had to walk away, it was making me crazy....

[911obgyn]

I think I removed the engine tin at the back, cleaned it up while I was at it. I broke the crossbar and had to reinforce and re weld it!

[Sajan]

Good news: I was able to wiggle the offset wrench in there to get the M8 bolts off.

Bad news: I have gotten myself into a sticky situation. While undoing the big M12 bolt on the driver's side mount, the crossmember bent a little bit on that side. The passenger side bolt came off much easier.

I unbolted the crossmember from the engine bracket thinking I can somehow wiggle the crossmember out the top. Nope, that was a dumb idea.

Next idea was to remove the rear engine tin but the muffler is right up against it. Bolts are rusted so I sprayed some PB blaster and I am going to let it sit overnight before unbolt the muffler.

Any advice would be appreciated.
How can I get the crossmember out without doing an engine drop? The damn engine bracket gives no wiggle room. Heeeelppppppppppp.

Assuming I am able to get it out, should I unbend the OEM one? Order a replacement OEM? Order a Rennline?

[mo-mon]

Don't worry about bending it. It's flexible. In fact, I had to bend mine slightly for the drivers side M12 to fit in the hole.

[Arlo911]

Have you tried lowering the engine a small bit with your jack? Should give you some more space to work.

[ab1752]

I did my '89 and it was a it of a pain but not too bad, getting them out was no problem. The car is up on jackstands? Just support the engine with your floor jack and let it drop down about 2" or so. The biggest pita was the nuts for the mounting bolts. I taped it to the end of my finger and then used a small wrench to hold in place for torquing down. 65ft/lbs for the centre bolt and 18ft/lbs for the outters...antiseize for the cente.

https://www.pelicanparts.com/techarticles/101_Projects_Porsche_911/27-Motor_Tranny_Mounts/27-Motor_Tranny_Mounts.htm

[Lyle O]

Don't forget that when you install, leave all nuts and bolts loose. Tighten/torque the large main bolts first, then tighten the small retaining nuts/bolts last. This allows any pre-loads in the system to be eliminated.

[Sajan]

I was hoping I can drop the engine 2 inches to get old bar out but engine doesn't want to go down easily. There's a bolt coming out of the AC compressor that will get stuck over the right engine mount area.

I am also not sure if I need to follow a different set of instructions if I proceed in the direction of lowering engine. Treat me like an idiot. Don't assume anything :-)

[Lyle O]

Originally Posted by Sajan

I was hoping I can drop the engine 2 inches to get old bar out but engine doesn't want to go down easily. There's a bolt coming out of the AC compressor that will get stuck over the right engine mount area.

I am also not sure if I need to follow a different set of instructions if I proceed in the direction of lowering engine. Treat me like an idiot. Don't assume anything :-)

Just remove the bolt that is sticking out from the AC compressor, and put it back in when you are all done. It is for adjusting the tension on the AC compressor drive belt; your belt will just be loose while you do this. But don't forget to re-tighten the belt when finished.

To lower the engine, put a good jack under the center of the engine (to the rear), with a block of wood or similar to help distribute the load. Jack it up a little, remove the two main engine mount bolts, then lower the 2-3". Check carefully around the rear so there is no interference.

[Sajan]

Update 3. Got a chance to work on it some more today.

crosspipe came off easily.

in preparation of taking off muffler bolts, i have been spraying them with "Liquid wrench" over the last few days. it worked. got the 3 muffler bolts + 2 strap bolts without any major issues. one of the strap bolts was slightly seized up but it eventually gave away.

with crosspipe and muffler out of the way, the rear engine tin easily out (this was my 2nd fear..if this tin didn't come out, i would need to resort to lowering the engine). with the tin out, BAR IS OUT!

that's where I stopped since I need to get new hardware. don't want to reuse any of the nuts and bolts.

question: the muffler strap nut has some rust, should I order new straps (obviously not new OEM since they are 4 million dollars each)?



Rennline bar left vs. oem bar. notice how much the end is twisted. very close to snapping at weld point.


what was removed so far:


seized up bolt!


left to right: Engine mount bolts, enginer carrier bolt, engine tin bolt, muffler bolt, muffler strap hex bolt

[911pcars]

Due to a lack of any counterholding surfaces when tightening/loosening the bolt, the engine mount or cross bar (proper factory name = bracket) may eventually fail from metal fatigue - that corner of the engine will drop as far as gravity takes it, and if not caught in time, the other corner as well, then bigger problems.

The long term solution is to remove the internal threads from each end so the existing M12-1.5 x 95 bolt slides through the motor mount and bar end opening, then clamp together using a new M12 nut and washer (#s 11 and 13) - the same connection as in early 911 bars. You now have two hex shapes to rotate and counterhold to relieve stress on the engine mount bar. BTW, apply anti-seize onto threads and friction surfaces to reduce material corrosion and for more accurate tightening.



Reinforcing the bar is an option as well. I've seen 964 engine mounts fail as well, but unsure of the cause of that.


Sherwood

[Sajan]

Originally Posted by 911pcars

Due to a lack of any counterholding surfaces when tightening/loosening the bolt, the engine mount or cross bar (proper factory name = bracket) may eventually fail from metal fatigue - that corner of the engine will drop as far as gravity takes it, and if not caught in time, the other corner as well, then bigger problems.

The long term solution is to remove the internal threads from each end so the existing M12-1.5 x 95 bolt slides through the motor mount and bar end opening, then clamp together using a new M12 nut and washer (#s 11 and 13) - the same connection as in early 911 bars. You now have two hex shapes to rotate and counterhold to relieve stress on the engine mount bar. BTW, apply anti-seize onto threads and friction surfaces to reduce material corrosion and for more accurate tightening.



Reinforcing the bar is an option as well. I've seen 964 engine mounts fail as well, but unsure of the cause of that.


Sherwood

Ya it's definitely a poor design. Nothing to counteract the heavy torque needed to undo a seized bolt.

I bought the rennline bar which seems to be much better made and fixes both issues you brought up. There's a nut (welded in) on the bottom and I forget the exact term, but reinforcement on the other side of the bar to avoid bending.

[sugarwood]

I thought about trying this job 6 years ago.
Chickened out and never tried it.
Looks like I made the right decision
Questions about a possible motor mount DIY

[salayc]

Originally Posted by sugarwood

I thought about trying this job 6 years ago.
Chickened out and never tried it.
Looks like I made the right decision
Questions about a possible motor mount DIY

On a 1-5 difficulty scale it's a 2. Took me all of 20 minutes for the motor mounts. Put a jack under the engine, loosen two bolts, lower engine 1-2 inches, remove mounts, reverse.

[sugarwood]

You're the same guy who was talking about fabricating wrenches and dropping the engine for this job? LMAO.

If it were a 2, OP would not be making a thread about how FUBAR his project is.
It is so confusing that I don't even know what went wrong.

Multiple posters are talking about fabricating wrenches, taking hours to install a bolt,
dropping the ****ing engine, removing engine tin (whatever that is), removing the exhaust, breaking crossbars, welding, etc.

So, no, it's not a 2 when you're taking half the car apart

[sugarwood]

Originally Posted by Sajan

Good news: I was able to wiggle the offset wrench in there to get the M8 bolts off.

Bad news: I have gotten myself into a sticky situation. While undoing the big M12 bolt on the driver's side mount, the crossmember bent a little bit on that side. The passenger side bolt came off much easier.

I unbolted the crossmember from the engine bracket thinking I can somehow wiggle the crossmember out the top. Nope, that was a dumb idea.

Next idea was to remove the rear engine tin but the muffler is right up against it. Bolts are rusted so I sprayed some PB blaster and I am going to let it sit overnight before unbolt the muffler.

Can you explain to clueless idiots like me exactly what went wrong
on such a simple "20 minute repair"?

You removed the small bolts.
Then you tried to remove the large center bolt?
It ended up bending the pointy end of the diamond shaped engine bracket?
How hard was the M12 bolt to remove? Were you using a breaker bar? It's not easy to bend metal.

Why did you try to remove the bracket? To be able to bend it back?
What is the cross member? Why are you removing it?
What is the cross pipe? Why are you removing it?

[sugarwood]

Would using an impact wrench on the big center bolt help prevent bending the engine bracket sleeve?