Install Solid Motor Mounts?
Thread Starter
Burning Brakes
Joined: Mar 2012
Posts: 877
Likes: 6
From: Cherry Hill NJ
Install Solid Motor Mounts?
Will have my C5 FRC up on the lift for a bit, installing an LS6 top end and some other stuff. I might pull the motor, not sure yet. At the very least I'm going to do new motor mounts, should I do stock, poly, or solid? Car is gutted and track only. No street use.
Thanks
Thanks
Race Director
Joined: Sep 1999
Posts: 12,437
Likes: 919
From: CONCORD NC
race car, I just cut a piece of aluminum, drill a hole throught it, and mount it solid to the cradle. Yoiu need either front or rear to NOT be solid however (diff).
You can't run knock sensors with solid mounts, it will cause you to pull timing and run in low-octane mode
You can't run knock sensors with solid mounts, it will cause you to pull timing and run in low-octane mode
Thread Starter
Burning Brakes
Joined: Mar 2012
Posts: 877
Likes: 6
From: Cherry Hill NJ
Thanks Dave. Can you elaborate on the knock sensors? I'm running on 93 pump gas, do I need them? When I get the car tuned after I'm all done will they take care of that? I found solid mounts for $100. I have a lathe and I could easily make them, just use a stock mount to measure off of?
Thanks!
Thanks!
Melting Slicks
Joined: Sep 2007
Posts: 3,155
Likes: 45
From: Merced California
race car, I just cut a piece of aluminum, drill a hole throught it, and mount it solid to the cradle. Yoiu need either front or rear to NOT be solid however (diff).
You can't run knock sensors with solid mounts, it will cause you to pull timing and run in low-octane mode
You can't run knock sensors with solid mounts, it will cause you to pull timing and run in low-octane mode
Thread Starter
Burning Brakes
Joined: Mar 2012
Posts: 877
Likes: 6
From: Cherry Hill NJ
The ebay seller who is selling the solid mounts has advised me to get poly instead. I'm sorry, I'm completely ignorant on this whole issue. So what do I want, poly all around or solid front/poly or stock rear? Noise and vibration are not an issue, the car has no interior...
Safety Car
Joined: Jan 2005
Posts: 3,781
Likes: 14
From: Phoenixville, PA
I had poly-poly and had a leak at the diff/trans junction. Could have been a faulty install (pinched o-ring) - not sure as I swapped out the rear poly a little later (due to a bad trans). I couldn't tell the difference between the poly and OEM trans mount and I am not sure if there is any benefit to going stiffer. I don't think that having compliance back there hurts anything, and making everything solid/very stiff does not seem to be a great idea (no performance advantage and harder on parts, but I could be wrong on this).
Le Mans Master
Joined: Oct 2005
Posts: 9,429
Likes: 44
From: Macon, GA
Before I went with poly engine mounts, I could move my engine side to side by hand a huge amount (150k mile stock mounts). That has to have an affect on handling when there's 400lbs flopping around like that.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Racer
Joined: Jan 2010
Posts: 266
Likes: 1
From: Seattle Washington
Ok... Let's get to the bottom of the knock sensor with solid motor mounts. I had Pfadt solid motor mounts on my car. I spun a bearing and bought a Dailey dry sump. I have to have a custom motor mount on the passenger side fabricated. My engine is at the shop right now getting rebuilt and set up for the dry sump. My question is do have them install knock sensors or not. Track only car, so it won't be driven as a daily driver.
Race Director
Joined: Sep 1999
Posts: 12,437
Likes: 919
From: CONCORD NC
GM Engineering told me the vibration of the engine, normally dampened by the balancer/flywheel/engine mounts would just get overloaded and register false knock. You can either have the low spark table copied over with the high spark table, disconnect the sensors, etc.
I followed GM's advice, so I never actually had the problems they warned me of.
I followed GM's advice, so I never actually had the problems they warned me of.
Instructor
Joined: Aug 2009
Posts: 211
Likes: 7
From: Portage IN
GM Engineering told me the vibration of the engine, normally dampened by the balancer/flywheel/engine mounts would just get overloaded and register false knock. You can either have the low spark table copied over with the high spark table, disconnect the sensors, etc.
I followed GM's advice, so I never actually had the problems they warned me of.
I followed GM's advice, so I never actually had the problems they warned me of.
Jim M.
Melting Slicks
Joined: Sep 2007
Posts: 3,155
Likes: 45
From: Merced California
I also noticed zero difference between stock rear diff mount and solid mount except that my diff stopped cracking and leaking. The driveline needs some flexibility and ability to expand/contract with temperature fluctuations. It's nice having the engine mounts stiffer and I think most of the the "solid" mounts have some compliance (ie. not 100% aluminum). Mine have a layer of poly sandwiched between 2 pieces of aluminum.
Regarding the knock sensors, I don't have any issues with knock with my motor mounts. I also have my low octane table equal to the high octane. It would be better to leave them connected and deal with false knock in the tune if it's a problem, which it shouldn't be.
Regarding the knock sensors, I don't have any issues with knock with my motor mounts. I also have my low octane table equal to the high octane. It would be better to leave them connected and deal with false knock in the tune if it's a problem, which it shouldn't be.
Melting Slicks
Joined: Sep 2007
Posts: 3,155
Likes: 45
From: Merced California
.
Team Owner
Joined: Jul 1999
Posts: 50,808
Likes: 9
From: Buy USA products! Check the label! Employ Americans
Melting Slicks
Joined: Sep 2007
Posts: 3,155
Likes: 45
From: Merced California
.
Thread Starter
Burning Brakes
Joined: Mar 2012
Posts: 877
Likes: 6
From: Cherry Hill NJ
Jeez them VBP's ain't cheap! I might go with Pfadts in the front, and stock in the rear. It's hard for me to swallow these prices when I have a mill and lathe sitting here, I could make half this crap. For some reason I'm scared to do it on the car, even though I've been doing it on bikes for years. I guess it's just more $ at stake if I screw something up! That VBP unit would be an easy afternoon if I had one in my hand to copy, and about $20 in materials.