Motor mount swap questions

[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

[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]

Originally Posted by 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.

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

[Ccmano]

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

[VetteMed]

Originally Posted by Ccmano

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

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]

Originally Posted by 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.

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]

Originally Posted by Hog

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

Oreilly Auto 2902

Summit Racing 2902

Ecklers Motor Mounts

Originally Posted by VetteMed

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.

Originally Posted by 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. 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.



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...