SAAC Forum

The Cars => 1966 Shelby GT350/GT350H => Topic started by: EdwardGT350 on May 28, 2020, 07:05:04 PM

Title: motor mounts
Post by: EdwardGT350 on May 28, 2020, 07:05:04 PM
how can one determine if a motor mount is cracked or bad?
what are the signs?
will engine vibrate excessively?
how hard is it to change them?
which brand is a good quality?
are the hipo ones more robust?
im getting severe shuttering under load from a stand still and its particularly bad on an incline.
tia
Title: Re: motor mounts
Post by: gt350hr on May 29, 2020, 04:43:52 PM
   Early multi piece or later one piece mount?
Title: Re: motor mounts
Post by: EdwardGT350 on May 29, 2020, 05:04:55 PM
for april 66 build.
Title: Re: motor mounts
Post by: gt350hr on June 01, 2020, 10:50:33 AM
   Your car "should" have later "standard production" '66 mounts. They are one piece and easily inspected for cracks in the almost 3/4" thick rubber that bonds the upper and lower halves together. There are several "improved designs" but they are obvious if you are trying to keep it looking "stock" . They are not too difficult to replace. Jack stands and a floor jack are a must have.
    The shudder you describe sounds more like a clutch/flywheel issue.
Title: Re: motor mounts
Post by: 67350#1242 on June 01, 2020, 01:53:27 PM
The driver's side usually the one to go first because is stretched by torque.
A good indicator with a 4spd is the shifter will tilt excessively to the right during acceleration.
Title: Re: motor mounts
Post by: kjspeed on June 01, 2020, 02:15:36 PM
Easy to check with a friend (or if you can see your motor from the driver's seat with the hood up). Put car in drive (auto trans) and slowly press the gas pedal as you keep your foot on the brake to keep the car from moving. If the driver's side motor mount is shot you'll see the engine lift up. Put the car in reverse and repeat to check the passenger side. With a good emergency brake you can do this with a stick also. If your E brake won't hold the car, then it's a bit trickier. Either way, make sure that there's nothing in front or behind you when you do this.
Title: Re: motor mounts
Post by: S7MS427 on June 01, 2020, 09:03:39 PM
Quote from: kjspeed on June 01, 2020, 02:15:36 PM
Put the car in reverse and repeat to check the passenger side.

I don't understand how this will check for a bad mount on the passenger side.  The engine only rotates in one direction regardless of whether the transmission is in forward, neutral, or reverse.  Am I missing something?
Title: Re: motor mounts
Post by: SFM5S000 on June 01, 2020, 10:39:14 PM
Martin,
The best stock looking OEM type to me are the Lakewood "muscle mounts". They look like the stock ford pieces, but are interlocked.
Cheers
~Earl J
Title: Re: motor mounts
Post by: 427hunter on June 01, 2020, 11:01:34 PM
Quote from: EdwardGT350 on May 28, 2020, 07:05:04 PM
how can one determine if a motor mount is cracked or bad?
what are the signs?
will engine vibrate excessively?
how hard is it to change them?
which brand is a good quality?
are the hipo ones more robust?
im getting severe shuttering under load from a stand still and its particularly bad on an incline.
tia



Are you sure it's not clutch chatter?
Title: Re: motor mounts
Post by: EdwardGT350 on June 01, 2020, 11:37:03 PM
same shuttering occurred before the new clutch. i thought the new clutch would solve problem.
now we think its either the flywheel or oil from a rear main seal that got onto new clutch.
advised to slip the clutch or start in 2nd gear to hopefully burn off the dried oil.
shuttering ONLY happens when starting in first gear, especially on an incline.
Title: Re: motor mounts
Post by: 427hunter on June 01, 2020, 11:56:40 PM
Quote from: EdwardGT350 on June 01, 2020, 11:37:03 PM
same shuttering occurred before the new clutch. i thought the new clutch would solve problem.
now we think its either the flywheel or oil from a rear main seal that got onto new clutch.
advised to slip the clutch or start in 2nd gear to hopefully burn off the dried oil.
shuttering ONLY happens when starting in first gear, especially on an incline.



You always have to resurface the flywheel when you change the clutch, oil will not burn off - it's the clutch and flywheel not the motor mounts.
Title: Re: motor mounts
Post by: kjspeed on June 02, 2020, 07:34:34 AM
Quote from: S7MS427 on June 01, 2020, 09:03:39 PM
Quote from: kjspeed on June 01, 2020, 02:15:36 PM
Put the car in reverse and repeat to check the passenger side.

I don't understand how this will check for a bad mount on the passenger side.  The engine only rotates in one direction regardless of whether the transmission is in forward, neutral, or reverse.  Am I missing something?

Transmission output shaft in reverse applies torque in the opposite direction. With brakes locked it will lift the passenger side if the mount is broken.

Sounds like OP's problem is clutch related though.
Title: Re: motor mounts
Post by: EdwardGT350 on June 13, 2020, 08:25:20 PM
where is the best place to jack up the motor to check or change the motor mounts?
can the jack be placed under the drivers side of the oil pan with a 2x4 piece of wood in between?
Title: Re: motor mounts
Post by: Jbarela on June 13, 2020, 11:43:56 PM
I am no expert but I experience the exact same thing in my mustang and in my bmw after clutch replacements.both times it was either the throw out bearing or the pilot bushing. I cant remember but I remember when the clutch was done one of those parts were not replaced and bam chatter..parts replaced and chatter was gone. I also went with needle bearing pilot bushing.