How-to Swap the Motor Mounts?

[VetteMed]

I have been wondering if the lack of clearance between the #1 header tube and the steering shaft is due to sagging mounts, being that my car has a lot of miles on it.

I should have changed the mounts when the headers were off, but I didn't -- so now I'm left with wondering if I'm going to need to pull the headers off in order to change out the mounts or not. Does anyone know if it's doable with the headers (Jeal) in place?

Edit:
It's not doable. Pulling the headers is really not that bad of a job, and it gave the access needed to do this job properly. See later in thread for pics of mounts and more commentary.

[VetteMed]

Yeah, I just looked at the driver's side, might be doable. Can't tell on the passenger side just from looking from above. Might take some creative use of extensions and wrenches.

[A26B]

Don't forget the C-beam is attached, making the whole driveline one rigid unit. Jacking up the engine with the c-beam still secured could damage the c-beam or trans. When I tried jacking the engine with all attached, it acted like the motor mounts were still bolted to the frame. I suggest removing the c-beam before trying to jack the engine up. Does the service manual mention anything about that?

[VetteMed]

Yep, I figured the c-beam would have to come off the trans... thanks Jerry!

[VetteMed]

I pulled the headers off today, and removed the motor mounts. Here's what the original 20 year old mounts look like, next to the aftermarket new mounts:

http://i680.photobucket.com/albums/vv163/agchoset/IMG_0334.jpg

As you can see, the mount is cleanly cracked right through the rubber.

http://i680.photobucket.com/albums/vv163/agchoset/IMG_0335.jpg

You may also notice that the aftermarket mount is a few mm taller than the OEM mount, which in my case may be helpful, to help with header clearance near the steering shaft.

The OEM mounts are made in Japan, the aftermarket mounts are made in India. Quality seems OK, but on the mount I used for the passenger side, a little massaging with Mr. Angle Grinder was necessary for proper fit. The tube which slides into the bracket on the block, was a few mm too long, requiring some trimming.

[VetteMed]

Couple of pics of the motor mount area, without mount, for reference purposes:

http://i680.photobucket.com/albums/vv163/agchoset/IMG_0338.jpg

With new mount installed:
http://i680.photobucket.com/albums/vv163/agchoset/IMG_0344.jpg

[VetteMed]

Anchor 2902. I ordered a private label and a regular inventory closeout, they were the same part but one had a made in india sticker, the other did not, but had INDIA stamped debossed on the rubber portion of the mount.

[VetteMed]

hmm the one im trying to order is going up as a 2713 mount?


Yes, the rockauto catalog is wrong - it lists the L98 mount as the right part for the 90-91 ZR-1, but you need to look up the PN for the LT1 or the later ZR-1 to find the right 2902 part.

[VetteMed]

Here is a Pioneer engine mount at Oreilly's ;)
http://www.oreillyauto.com/site/c/detail/PIO0/601125.oap?keyword=motor+mount&pt=02327&ppt=C0019

Pioneer engine mount at Summit Racing ;)
http://www.summitracing.com/parts/PIO-A2902/


Good to know -- looks like the same part as the Anchor unit, but who knows.

[Ccmano]

Andrew,

Now that the mounts are in have you noticed any less engine/drive train noise inside the car? I've beed wanting to do this for a while on mine as I get an unusual amount of drivetrain noise inside the car. I'm thinking the mounts are collapsed and there is metal to metal contact somewhere.
Did the header to steering shaft clearance get any better?
H

[VetteMed]

Andrew,

Now that the mounts are in have you noticed any less engine/drive train noise inside the car? I've beed wanting to do this for a while on mine as I get an unusual amount of drivetrain noise inside the car. I'm thinking the mounts are collapsed and there is metal to metal contact somewhere.
Did the header to steering shaft clearance get any better?
H

Hans, I just got the header gaskets in from Jerry yesterday, so I haven't been able to get everything buttoned back up yet. Also, I'm redoing the pinion seal on the rear diff yet again (maybe the third time will be the charm), so that's adding to the delay. I'll post up as soon as I get the chance to get things re-assembled!

Andrew

[GOLDCYLON]

Andrew thanks for the tip. I ordered a couple of mounts from Rockauto. I figured while the block is being pulled what the hell. Daryll

[VetteMed]

Andrew thanks for the tip. I ordered a couple of mounts from Rockauto. I figured while the block is being pulled what the hell. Daryll

Yep, I wish I hadn't been so cheap when I had everything disassembled months ago. Makes sense to do it when they are easily accessible!

[VetteMed]

Andrew,

Now that the mounts are in have you noticed any less engine/drive train noise inside the car? I've beed wanting to do this for a while on mine as I get an unusual amount of drivetrain noise inside the car. I'm thinking the mounts are collapsed and there is metal to metal contact somewhere.
Did the header to steering shaft clearance get any better?
H

Hans, I drove the car today, I can't say I noticed any appreciable difference in the sound or vibration inside the car - but admittedly it's been over a month since I drove it so I'm not sure if it helped. It did NOT help with my header clearance issue, so I'm rather frustrated about that. My #1 primary tube is still just a hair away from the steering shaft. Perhaps I need to try to shim up the motor mount with some large washers to gain some clearance.

-Andrew

[Ccmano]

Good to know, I went ahead and ordered a pair from RockAuto as well. Good price too, paid $89 delivered. I figure if nothing else it's time they get changed out on my 21yr old car!

Let us know how the shimming goes. I have the same issue as you, the steering shaft is like 1mm away from the header pipe. Everytime I turn right I can hear the engine touching the shaft.
H
:fahne:

[LGAFF]

Hans,

Pull the motor and put some cams in there

[Ccmano]

Are you kidding, between the new job and the new house I barely have time to drive the thing. I have 3 Z projects lined up, parts are sitting here. This will make 4.
H
:fahne:

[LGAFF]

What are the three project?

[Ccmano]

Power coat the topend, the clear coat paint we used is yellowing (badly in some places).
Replace the shocks, found a set of original Bilsteins with only 200 miles on them.
Install the forced air intake I bought (like yours)
Now the engine mounts.


Thought about you yesterday, A buddy and I were checking out a 123K 91 Z for sale locally for $9995. He was thinking of getting it for his GF (he has a 94' with a Haibeck 415) Decent car, ran real good, but needed most of the usual C4 items repaired plus brakes and tires. Seller (used car dealer) wouldn't come off the price a dime. He passed.
H
:fahne:

[VetteMed]

Hans, an update for you... today I unbolted the lower nuts from the motor mounts, and jacked up the driver's side of the motor. I slipped 2 body/alignment shims in around the stud (I chose 1/8 inch each, for a total of 1/4 inch), and lowered the motor back down, and tightened the nuts once again. I gained approximately 3/16 to 1/4 inch of clearance between the #1 primary and the steering shaft.

I'd like to find a shim with a larger surface area, but I suppose this has got to be better than the interference that was present before.

[VetteMed]

Update: After taking the car for a drive, the mount settled a little, leaving about 1/16" or so of clearance -- which was enough to make me notice just how much vibration was being transmitted through the car due to the interference. It's much quieter and smoother now.

[Ccmano]

Update: After taking the car for a drive, the mount settled a little, leaving about 1/16" or so of clearance -- which was enough to make me notice just how much vibration was being transmitted through the car due to the interference. It's much quieter and smoother now.

Cool, my mounts are on their way... now I just need some time to install them.
H
:dancing

[Ccmano]

BTW Andrew... did you have to remove or at least loosen the C-Beam?
H
:cheers:

[VetteMed]

BTW Andrew... did you have to remove or at least loosen the C-Beam?
H
:cheers:

When I initially did the job, yes, I removed the headers, h-pipe, and the rest of the exhaust, and removed the c-beam so that I could have as much freedom as possible to jack up the motor. When I later shimmed the driver's side mount, I did not have to re-loosen the C-beam.

[Hog]

Update: After taking the car for a drive, the mount settled a little, leaving about 1/16" or so of clearance -- which was enough to make me notice just how much vibration was being transmitted through the car due to the interference. It's much quieter and smoother now.
Whats the NVH like at WOT with the new mount? I did up some custom rubberized miunts for the Caddy and they did transfer a bit more NVH into the cabin but only under WOT conditions.


NVH=Noise Vibration Harshness
peace
Hog

[VetteMed]

Whats the NVH like at WOT with the new mount? I did up some custom rubberized miunts for the Caddy and they did transfer a bit more NVH into the cabin but only under WOT conditions.


NVH=Noise Vibration Harshness
peace
Hog

Well, it's much less, BUT that's comparing to the prior situation where the #1 primary tube was sitting on the steering shaft. So it's not applicable to most people's situations.The OEM mounts were hard as a rock, aside from being cracked, so I can't imagine they were dampening too much NVH anymore.

-Andrew

[Dynomite]

A question regarding Motor Mounts came up and I refreshed an old thread with some additional information regarding Motor Mounts :thumbsup:

Oreilly Auto 2902 (http://www.oreillyauto.com/site/c/detail/ANR0/2902.oap?year=1991&make=Chevrolet&model=Corvette&vi=1041297&ck=Search_2902_1041297_-1&keyword=2902)

Summit Racing 2902 (http://www.summitracing.com/parts/PIO-A2902/)

Ecklers Motor Mounts (http://www.ecklerscorvette.com/corvette-motor-mount-side-1992-1996.html)

Good to know -- looks like the same part as the Anchor unit, but who knows.

Anchor 2902, I ordered a private label and a regular inventory closeout, they were the same part but one had a made in india sticker, the other did not, but had INDIA stamped debossed on the rubber portion of the mount.

If buying from Rockauto , the Rockauto catalog is wrong - it lists the L98 mount as the right part for the 90-91 ZR-1, but you need to look up the PN for the LT1 or the later ZR-1 to find the right 2902 part.


I pulled the headers off today, and removed the motor mounts. Here's what the original 20 year old mounts look like, next to the aftermarket new mounts. Anchor 2902. I ordered a private label and a regular inventory closeout, they were the same part but one had a made in india sticker, the other did not, but had INDIA stamped debossed on the rubber portion of the mount.

http://i680.photobucket.com/albums/vv163/agchoset/IMG_0334.jpg

The OEM mounts are made in Japan, the aftermarket mounts are made in India. Quality seems OK, but on the mount I used for the passenger side, a little massaging with Mr. Angle Grinder was necessary for proper fit. The tube which slides into the bracket on the block, was a few mm too long, requiring some trimming.

[VetteMed]

A blast from the past...

[Blue Flame Restorations]

Hey there, Andrew! good to see you posting. Hope all is well! :cheers:

[VetteMed]

Hey guys, yeah, I still pop in every now and then, waiting to see if my old Z ever turns up...

[GOLDCYLON]

Andrew come back to the fold and get another car