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Old 08-25-2019   #1
efnfast
 
Join Date: Nov 2011
Location: Dunbarton NH
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Default Motor mounts?

I've noticed my shifter seems to lift noticeably when I drop the hammer on Bertha. Motor mounts?
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Old 08-25-2019   #2
Ccmano
 
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Default Re: Motor mounts?

Possibly or loose C frame (Beam) bolts at the trans or both...
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Old 08-25-2019   #3
Young1
 
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Default Re: Motor mounts?

Quote:
Originally Posted by efnfast View Post
I've noticed my shifter seems to lift noticeably when I drop the hammer on Bertha. Motor mounts?
C beam bolts. The C beam ties the trans to the differential and the torque lifts the tranny if they are loose. Others will comment I am sure.
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Old 08-26-2019   #4
secondchance
 
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Default Re: Motor mounts?

Steve,
I would check the C beam bolts first.
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Old 08-26-2019   #5
efnfast
 
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Default Re: Motor mounts?

I'll put it up on the lift and check it out. Anything special about tightening them?
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Old 08-26-2019   #6
secondchance
 
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Default Re: Motor mounts?

Quote:
Originally Posted by efnfast View Post
I'll put it up on the lift and check it out. Anything special about tightening them?
I believe fronts are 40 lb-ft and rears are 60. Do not over tighten. Could result in ovaling the housing relative to shaft.

It is possible to use torque wrench without removing the exhaust. I can't remember if I used "U"joint extension to get around the exhaust or crow feet open end. If using crow feet, I would stay a shade below 40 lb-ft since you will be eccentric relative to the extension.
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Old 08-26-2019   #7
Dynomite
 
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Default Re: Motor mounts?

You should install C4 Beam Plates from ZFdoc as described here ........Post 39 - C4 Beam Plates and Installation

www.zfdoc.com

Last edited by Dynomite; 08-26-2019 at 02:03 PM.
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Old 08-26-2019   #8
Ccmano
 
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Default Re: Motor mounts?

While the C Beam bolts are the most likely culprit and the ZFDoc beam plates the best solution (wouldn’t drive a C4 without them) don’t assume your engine mounts are good. They need to be inspected. 30yr old oil filled rubber right next to the exhaust manifolds is a bad combination. Every single C4 I’ve owned and many I’ve inspected have had at least a bad right mount if not both. If they are original, dollars to donuts at least one is bad.
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Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold
08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold
05 C6 Z51 Red/Black Sold
90'ZR-1 #1723 Black/Gray Sold but not forgotten
91' Z51 L98 White Vert. My First, you always remember your first. Sold.
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Old 08-26-2019   #9
efnfast
 
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Default Re: Motor mounts?

Thanks for all the input.
Bill C Beam plates have already been installed.
I'll check the motor mounts, Pete had the engine out last year, I would have thought he would have noticed.
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Old 08-26-2019   #10
efnfast
 
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Default Re: Motor mounts?

C Beam is not obviously loose, but I did not put a socket to them.
Motor mounts? Floor jack and 2x4 under the oil pan?
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