Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Not so Good Vibrations

  1. #1
    Senior Lancista Old Man Wattsy's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Posts
    392
    Downloads
    117
    Uploads
    4

    Not so Good Vibrations

    My series 2 coupe has always had an engine related vibration in the cabin.
    Engine mounts, subframe bushes and exhaust droppers are all in good condition, brake lines are isolated and the gearstick is clear of the body.
    The only direct connection between the subframe and the body is via the steering column which is attached directly to the underside of the dashboard.
    Looking at the TAV and my car, there is no provision for any vibration isolation other that a spice.
    Whilst this may not be the only source of the vibration, it has me thinking.
    Has anyone consider or installed some form of isolation between the steering column and the car body?
    Regards, Mick

  2. #2
    Legendary Lancista 1,6 HF's Avatar
    Join Date
    Mar 2007
    Location
    West Hollywood, CA
    Posts
    5,297
    Downloads
    42
    Uploads
    52

    Re: Not so Good Vibrations

    Where does the vibration seem to be coming from? Is it audible or just felt?
    Ed Levin
    Fulvia 1,6 HF

  3. #3
    Master Lancista
    Join Date
    Dec 2015
    Location
    Warwick UK
    Posts
    159
    Downloads
    9
    Uploads
    0

    Re: Not so Good Vibrations

    Generally,

    Vibrations through the seat are from the back of the car- out of balance wheels. If you feel them through the wheel they are more likely from the front wheels. Is the vibration speed sensitive? isolating the column from the body won't really help as the steering box is still connected to the subframe which will still be seeing what ever vibrations are being generated if they are from the front end.

  4. #4
    Senior Lancista Old Man Wattsy's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Posts
    392
    Downloads
    117
    Uploads
    4

    Re: Not so Good Vibrations

    Quote Originally Posted by 1,6 HF View Post
    Where does the vibration seem to be coming from? Is it audible or just felt?
    Ed, good question.
    And one that shows that I have been focused on the "felt" portion.

    At idle and at slow speeds I can feel it in the steering wheel (leather wrapped) and under the dash. I can stand next to the engine bay and tweak the idle screws to make the engine tick over as smoothly as the cam will allow. I'll then get in the car and wonder why the vibration seems much more noticeable.

    But now that I think about it, I have a performance exhaust system plus the cabin floor and firewall have only a thin version of dynamat. The engineered exhaust system is mildly noisy and does little to baffle the gas velocity (if you put your hand over the exhaust pipe, you can feel a strong and distinct poot, poot, poot, poot)

    Next time I take the car for a drive I'll try to feel whether the major portion of the vibration is coming from the exhaust.

    (And on a good note. Drove the car to Auto Italia in Canberra on Sunday. its a round trip of just over 600kms at mostly freeway speed. The car (and driver) enjoyed the blast).

  5. #5
    Senior Lancista Old Man Wattsy's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Posts
    392
    Downloads
    117
    Uploads
    4

    Re: Not so Good Vibrations

    Quote Originally Posted by Phil-m View Post
    Generally,

    Vibrations through the seat are from the back of the car- out of balance wheels. If you feel them through the wheel they are more likely from the front wheels. Is the vibration speed sensitive? isolating the column from the body won't really help as the steering box is still connected to the subframe which will still be seeing what ever vibrations are being generated if they are from the front end.
    Phil,
    Thanks for your comment.
    Its not speed related in the sense that it indicates an out of balance wheel or an odd harmonic.
    Seems to be more noticeable at lower speeds and idle.

    And as I noted in the reply to Ed, I'm now wondering whether its more exhaust related. The pipework is well isolated from the body however maybe the vibrations emitting from the system are being transfer/absorbed into the floor and that is what I'm mainly feeling.

  6. #6
    Legendary Lancista 1,6 HF's Avatar
    Join Date
    Mar 2007
    Location
    West Hollywood, CA
    Posts
    5,297
    Downloads
    42
    Uploads
    52

    Re: Not so Good Vibrations

    Quote Originally Posted by Old Man Wattsy View Post

    And as I noted in the reply to Ed, I'm now wondering whether its more exhaust related. The pipework is well isolated from the body however maybe the vibrations emitting from the system are being transfer/absorbed into the floor and that is what I'm mainly feeling.
    Exhaust resonance was one of my initial suspicions, which is why I asked where you felt/heard it.
    Ed Levin
    Fulvia 1,6 HF

  7. #7
    Senior Lancista Old Man Wattsy's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Posts
    392
    Downloads
    117
    Uploads
    4

    Re: Not so Good Vibrations

    Update:
    After feeling the floor and firewall above the exhaust system and getting a general sense of the vibrations in the car with windows closed and open, I believe its not the exhaust.

    So to the engine bay.
    1. Checked the balance between the front and rear carbies and found that they were slightly out of balance ('3' in the front and almost '4' rear). Now balanced. Now wondering if I accidentally tweaked the wrong screw when adjusting the idle speed.
    Vibration at idle is less but still present.

    2. When the engine was rebuilt about 6 years ago, the only item not checked was the cam profiles. Idle has always been lumpy so the cam profile might be the cause of the vibration.
    Will check when I get some time.

    Lastly, am I correct in my understanding that there is some form of vibration isolation in the steering column of a Series 1 car?

  8. #8
    Legendary Lancista 1,6 HF's Avatar
    Join Date
    Mar 2007
    Location
    West Hollywood, CA
    Posts
    5,297
    Downloads
    42
    Uploads
    52

    Re: Not so Good Vibrations

    Quote Originally Posted by Old Man Wattsy View Post
    Update:
    ....

    Lastly, am I correct in my understanding that there is some form of vibration isolation in the steering column of a Series 1 car?
    Yes -- there's a rag joint
    Ed Levin
    Fulvia 1,6 HF

  9. #9
    Experienced Lancista carcrank's Avatar
    Join Date
    Jan 2017
    Location
    Rokeby, Victoria, Australia
    Posts
    54
    Downloads
    23
    Uploads
    0

    Re: Not so Good Vibrations

    I just removed some vibrations from my car by adjusting the "Outrigger" on the RHS of the engine it was resting on the chassis rail, I gave it a couple of mm clearance and it's transformed the car, worth a look.

    Cheers

    Mark

  10. #10
    Senior Lancista Old Man Wattsy's Avatar
    Join Date
    May 2009
    Location
    Sydney
    Posts
    392
    Downloads
    117
    Uploads
    4

    Re: Not so Good Vibrations

    Quote Originally Posted by carcrank View Post
    I just removed some vibrations from my car by adjusting the "Outrigger" on the RHS of the engine it was resting on the chassis rail, I gave it a couple of mm clearance and it's transformed the car, worth a look.

    Cheers

    Mark
    Mark, good comment.
    I did the same years ago by inserting a 5mm rubber pad below the foot of the 'outrigger' and then allowed a 3mm clearance gap.
    Just checked gap and its still there.
    Slowly eliminating likely causes!
    Mick

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •