Results 1 to 23 of 23

Thread: Bad Vibrations

  1. #1
    PF's #1 soft roader advocate Captiva Fan's Avatar
    Join Date
    Nov 2001
    Location
    The Crime Zone
    Posts
    28,797

    Bad Vibrations

    Pretty much from Day One, the Volvo's been excessively harsh; lots of vibrations & (dis)harmonics.
    I initially dismissed it as Old Car, but the stock car I had was never as bad as this.
    One thing I know it isn't is the driveshaft (in isolation), as it's only a couple of years old & was balanced when installed.

    It's a Volvo B23E bottom-end (leaded Volvo SOHC 4cyl engine late 70's to early 80's) with a cam, custom exhaust manifold & exhaust, early GT25, W58 'box, TrueTrac diff-centre & MoteC M84. Oh, and lightened flywheel.
    It's definitely worse than B23E standard harsh (they're not sewing-machine smooth anyway), considerably worse, and there are definitely some fun harmonics at play as well (unfortunately coinciding with just-over-the-100km/h-speed-limit in 5th).

    One thing; when it was originally built, it was balanced, and the clutch was balanced with it. I had one of my usual FUBARs (had to drill a snapped-off adapter out of an oil line --> swarf in the oil gallery) before it was ever run, and had a local engine builder pull it apart & clean it out & put it back together again; plus I'm running a different clutch now. Is it possible to put the "balanced" engine together "wrongly" in such a way that makes vibrations worse than standard? Any chance the replacing of the clutch (pretty sure both plates were replaced so pretty sure whatever attaches to the flywheel has been replaced) unbalanced it this much?

    Is this a normal thing (in general), or does this just mean it's a shit engine & won't ever be solved?
    Is there any chance it's all in the exhaust?

    Is there a "next" I can do?
    Last edited by Captiva Fan; 17-07-17 at 11:49 AM.
    Soft roaders represent an excellent compromise between the needs of the hardcore 4x4 user and the convenience of a city hatchback. Its clear to see why they have become so popular in todays society.

  2. #2
    short fat cunt redbucket's Avatar
    Join Date
    Mar 2005
    Location
    Lockyer Valley, Qld
    Posts
    2,604
    Have you tried playing the Beach Boys on the cassette deck?

  3. #3
    PF's #1 soft roader advocate Captiva Fan's Avatar
    Join Date
    Nov 2001
    Location
    The Crime Zone
    Posts
    28,797
    No I haven't, so that can't be the cause!
    Soft roaders represent an excellent compromise between the needs of the hardcore 4x4 user and the convenience of a city hatchback. Its clear to see why they have become so popular in todays society.

  4. #4
    Registered User
    Join Date
    Sep 2010
    Location
    Adelaide, SA
    Posts
    1,385
    What engine?

  5. #5
    PF's #1 soft roader advocate Captiva Fan's Avatar
    Join Date
    Nov 2001
    Location
    The Crime Zone
    Posts
    28,797
    Sorry, I realised in describing my problem to a Volvo specific group that info that could be generally useful to someone who knows what they're doing was missing ... so description updated.
    Soft roaders represent an excellent compromise between the needs of the hardcore 4x4 user and the convenience of a city hatchback. Its clear to see why they have become so popular in todays society.

  6. #6
    Resident Oaf Jim's Avatar
    Join Date
    Nov 2001
    Location
    ACT Now!
    Posts
    26,556
    you need to isolate the engine from the driveline when testing. Does it change with revs, or with speed? Does it change when you put the clutch in? Better or worse when under accel or decel?
    Turns out, far too much has been written about great men and not nearly enough about morons


    Quote Originally Posted by seedyrom
    my neighbours called the cops...... not because of the sound of me working in the garage was too loud, but because i taped a cardboard box to my back, covered my self in vaseline and pretended i was a snail on their lawn

  7. #7
    Emissions Friendly VW Sloth's Avatar
    Join Date
    Jan 2013
    Location
    Das Valley
    Posts
    2,909
    balance/dizzy drive shaft timed up correctly
    Sloth: [Sloff] Noun, like Skompa but with euro shitboxen, a large bearded person, with a penchant for cider and garlic pizza.

    Quote Originally Posted by Rdyno View Post
    That's retardism cunt stop discriminating against me and my fellow retards.

  8. #8
    Registered User gtrboyy's Avatar
    Join Date
    Nov 2005
    Location
    sydney
    Posts
    1,774
    Engine mounts?


    I've always assumed externally balanced means flywheel or flexplate has to go back on same spot it was balanced or vibrates like a mofo so bad you'd notice on start up but they usually have a dowell or locator to not fuck it up.

    *Moo-mangs supposedly external balance...also have balance shaft & gel-filled engine mounts yet still rough as hell.
    an easy fix is get a mate to drive in front of you at 60 then 80 then 100 and mark in on your speedo with some liquid paper.

  9. #9
    Ellis Juan mizone's Avatar
    Join Date
    Jul 2003
    Location
    Western Australia
    Posts
    3,474
    Quote Originally Posted by Jim View Post
    you need to isolate the engine from the driveline when testing. Does it change with revs, or with speed? Does it change when you put the clutch in? Better or worse when under accel or decel?
    +1

    Drive shafts are mostly felt through the seat back. Are all the bolts tight on the flywheel/clutch?

  10. #10
    Resident Oaf Jim's Avatar
    Join Date
    Nov 2001
    Location
    ACT Now!
    Posts
    26,556
    could be a variety of reasons. Until more info is had it's going to be only guessing though.
    Turns out, far too much has been written about great men and not nearly enough about morons


    Quote Originally Posted by seedyrom
    my neighbours called the cops...... not because of the sound of me working in the garage was too loud, but because i taped a cardboard box to my back, covered my self in vaseline and pretended i was a snail on their lawn

  11. #11
    PF's #1 soft roader advocate Captiva Fan's Avatar
    Join Date
    Nov 2001
    Location
    The Crime Zone
    Posts
    28,797
    Quote Originally Posted by Jim View Post
    you need to isolate the engine from the driveline when testing. Does it change with revs, or with speed? Does it change when you put the clutch in? Better or worse when under accel or decel?
    I don't have completely definitive answers.
    Spac having suggested the coasting-at-worst-vibration, trying in different gears, etc, the following are true:
    (*) 105km/h seems to be about the worst, in 5th
    (*) using the clutch while coasting at that speed does make it slightly less shuddery & quieter; but not a heap
    (*) being in 4th at that speed is much the same as coasting with the clutch in
    (*) being under heavier acceleration in 3rd or 4th & moving through 100-110 sems a lot smoother than really light throttle in 5th at 105
    (*) accelerating lightly in 3rd at that speed is actually not far off the same as being in 5th
    (*) coasting in 5th at 105-ish and bringing the revs up (no load) to match what it would be doing in-gear makes an imperceptable difference compared to letting it idle, pretty much can't hear or feel the engine revving at no-load over the other noise/vibration
    Last edited by Captiva Fan; 17-07-17 at 10:04 PM.
    Soft roaders represent an excellent compromise between the needs of the hardcore 4x4 user and the convenience of a city hatchback. Its clear to see why they have become so popular in todays society.

  12. #12
    Registered User
    Join Date
    Jan 2012
    Location
    Syd-en-ey
    Posts
    400
    You don't mention the model (and I haven't extensively researched your post history... but is it a 242gt?)... anyway, does yours have a centre bearing for the tailshaft? Maybe you had a single piece made when you had it remade??

    I know from experience (740...) that the centre bearing can cause some pretty impressive vibrations in the car... including the tailshaft deflecting under load, or just wobbling all the time when not under load.

    Easy to check, get under car and check the rubber around it, it should look well used, or cracked. While under car wobble it. Centre bearing or centre uni would be my guess.

  13. #13
    PF's #1 soft roader advocate Captiva Fan's Avatar
    Join Date
    Nov 2001
    Location
    The Crime Zone
    Posts
    28,797
    Yes it's a 240 (242GT).
    The moo-mang-sourced driveshaft does have a centre bearing, but it's new so ain't worn or cracked, and the rubber etc. is fine. I guess there's the possibility of a dud-from-new centre bearing. It was also balanced before fitting, albeit in isolation (whether that means anything).
    Soft roaders represent an excellent compromise between the needs of the hardcore 4x4 user and the convenience of a city hatchback. Its clear to see why they have become so popular in todays society.

  14. #14
    Resident Oaf Jim's Avatar
    Join Date
    Nov 2001
    Location
    ACT Now!
    Posts
    26,556
    I'm inclined to suggest it's driveline and not engine. If it's still there with the clutch in, it cannot be engine.
    Driveshaft misaligned unis (unis out of phase) is a good possibility particularly with a centre bearing set up. driveshaft splines may be out a spline or 3.
    Could be wheels, such as out of balance tyres or rims not located by the centre bore. locating on studs only causes heaps of balance problems.
    Turns out, far too much has been written about great men and not nearly enough about morons


    Quote Originally Posted by seedyrom
    my neighbours called the cops...... not because of the sound of me working in the garage was too loud, but because i taped a cardboard box to my back, covered my self in vaseline and pretended i was a snail on their lawn

  15. #15
    Registered User Marlin's Avatar
    Join Date
    Nov 2005
    Location
    On the Shelf
    Posts
    5,080
    I used to catch a lift to school in one of these old shit heaps many years ago. Bloody awful bang bang bang and vibrate from somewhere at around 100klm/h. It did it for years. Always sounded and felt like the dogleg over the diff banging the floor.
    They never did fix it.

  16. #16
    Registered User
    Join Date
    Sep 2010
    Location
    Adelaide, SA
    Posts
    1,385
    What set up is it running for fan belts? I have had to rebush all the accessories on a 244 to fix shocking engine harmonics. And even then I had to fuck around with all the bracketry to get rid of the vibrations. Hopeless design.

  17. #17
    PF's #1 soft roader advocate Captiva Fan's Avatar
    Join Date
    Nov 2001
    Location
    The Crime Zone
    Posts
    28,797
    Quote Originally Posted by Jim View Post
    I'm inclined to suggest it's driveline and not engine. If it's still there with the clutch in, it cannot be engine.
    Spac also suggests maybe something is touching or rubbing against the body, gearbox or exhaust or similar ... I mean it's not at idle, but I wonder if that's possible at speed with the clutch in?
    I'm wondering whether my oil-filter & oil-cooler hoses, which I've clamped to the inside of the front frame-rails, are clamped too close to the engine & transmitting vibrations.

    Driveshaft misaligned unis (unis out of phase) is a good possibility particularly with a centre bearing set up. driveshaft splines may be out a spline or 3.
    That sounds very much like "give it to someone who knows what they're doing" to me.

    Could be wheels, such as out of balance tyres or rims not located by the centre bore. locating on studs only causes heaps of balance problems.
    I should be able to find someone else with a 240 & try my wheels on their car & vice-versa.

    Quote Originally Posted by BigJonWB
    What set up is it running for fan belts?
    Electrons.
    But there are other accessories ...

    I have had to rebush all the accessories on a 244 to fix shocking engine harmonics. And even then I had to fuck around with all the bracketry to get rid of the vibrations. Hopeless design.
    The aircon compressor is in a custom mount, hence may not be perfect; and if it's pulley's not aligned perfectly then the PS pump pulley will be affected too.
    Would this be engine-revs dependant though?
    Soft roaders represent an excellent compromise between the needs of the hardcore 4x4 user and the convenience of a city hatchback. Its clear to see why they have become so popular in todays society.

  18. #18
    Resident Oaf Jim's Avatar
    Join Date
    Nov 2001
    Location
    ACT Now!
    Posts
    26,556
    Run a piece of string from the front uni to the back uni and see if they are lined up. Not rocket surgery.
    Turns out, far too much has been written about great men and not nearly enough about morons


    Quote Originally Posted by seedyrom
    my neighbours called the cops...... not because of the sound of me working in the garage was too loud, but because i taped a cardboard box to my back, covered my self in vaseline and pretended i was a snail on their lawn

  19. #19
    PF's #1 soft roader advocate Captiva Fan's Avatar
    Join Date
    Nov 2001
    Location
    The Crime Zone
    Posts
    28,797
    Granted, but I'm not even a meat surgeon let alone a rocket surgeon.
    What needs to be lined-up with what, what's going to look wrong? In what axis/axes? Is what I'm looking for going to be obvious if I run a piece of string from the front uni to the back uni?

    The driveshaft itself is new since the vibrations started, but the angles/orientation between the front of the diff & the back of the gearbox won't have changed.
    Soft roaders represent an excellent compromise between the needs of the hardcore 4x4 user and the convenience of a city hatchback. Its clear to see why they have become so popular in todays society.

  20. #20
    Resident Oaf Jim's Avatar
    Join Date
    Nov 2001
    Location
    ACT Now!
    Posts
    26,556
    http://bfy.tw/CtQt

    Then click on images.
    Last edited by Jim; 18-07-17 at 04:21 PM.
    Turns out, far too much has been written about great men and not nearly enough about morons


    Quote Originally Posted by seedyrom
    my neighbours called the cops...... not because of the sound of me working in the garage was too loud, but because i taped a cardboard box to my back, covered my self in vaseline and pretended i was a snail on their lawn

  21. #21
    PF's #1 soft roader advocate Captiva Fan's Avatar
    Join Date
    Nov 2001
    Location
    The Crime Zone
    Posts
    28,797
    Ta! Will check out the results later (dunno if you thought you were being facetious, but I wouldn't have even known what terms to search on in order not to get mostly tripper links).
    Soft roaders represent an excellent compromise between the needs of the hardcore 4x4 user and the convenience of a city hatchback. Its clear to see why they have become so popular in todays society.

  22. #22
    Ellis Juan mizone's Avatar
    Join Date
    Jul 2003
    Location
    Western Australia
    Posts
    3,474
    You have checked the gearbox mounts yeah?

  23. #23
    Registered User
    Join Date
    Mar 2005
    Location
    wollongong
    Posts
    917
    Pull the tail shaft out and tow it with another vehicle, sounds stupid but it will isolate whether the tail shaft is the culprit. I have seen re-built tail shafts give problems like you describe and it is not uncommon to get the phasing wrong.

Posting Permissions

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