Author Topic: Terrible Engine Vibration  (Read 770 times)

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5816nick

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Terrible Engine Vibration
« on: May 25, 2019, 08:46:05 AM »
Hi Guys, I have a Terrible Vibration on my Aircooled 126 at about 1750 RPM to 2000 RPM, It is seriously  so bad you cannot drive it, I have replaced the Gearbox and Engine Mountings, The new mountings were recently Purchased and the only difference is spring is Longer and there is a Green Plastic Bush - I wasn't sure where this went as The Original set up didn't have one? 

I was reading on here about A Terrible Vibration on BIS Models with the Flywheel Being Put on Incorrectly  - Can it happen on Aircooled Models if the Flywheel has been put on Incorrectly  ?

Bar Vitelli

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Re: Terrible Engine Vibration
« Reply #1 on: May 25, 2019, 10:56:17 AM »
I’m not sure if the spring is the cause of the vibration but it sounds like you’ve put an early aircooled spring into a later model which can’t help as they must be shorter for a reason. Upload a video if you can as it might help give some clues as to the cause.
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Gadge

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Re: Terrible Engine Vibration
« Reply #2 on: May 25, 2019, 01:06:38 PM »
Could be the spigot bush that the gearbox mainshaft inserts into. I’ve had this happen before
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Gordan

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Re: Terrible Engine Vibration
« Reply #3 on: May 25, 2019, 08:58:16 PM »
Could be the spigot bush that the gearbox mainshaft inserts into. I’ve had this happen before

If I understood this correctly i had the same problem, only mine vibrated only in 1st gear….

5816nick

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Re: Terrible Engine Vibration
« Reply #4 on: May 25, 2019, 09:11:29 PM »
Hi Guys. Mine Vibrates so badly - both when stationary and when driving, between 1700-2200 RPM it is terrible, it is so bad it cannot be driven, I've driven it once round a car park so far....

I've read about flywheels being put on incorrectly on 126 BIS and am wondering  are Aircooled 126's the same in that if you put the flywheel on wrong it will make the Crank out of Balance?


Thanks Nick

Pete126

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Re: Terrible Engine Vibration
« Reply #5 on: May 25, 2019, 10:00:44 PM »
Have you checked for play in the alternator bearings? Try taking off the fan belt for a moment and see if the vibration disappears also check that the fan hasn’t started to do disintegrate, if some of the blades are broken or missing this will unbalance the engine also.
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5816nick

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Re: Terrible Engine Vibration
« Reply #6 on: May 26, 2019, 10:19:01 AM »
Thanks Pete, I Didn't think of the Fan or Alternator! I'm working on it on Monday so i'll let you know what i find.

Kind regards Nick

Minijohn

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Re: Terrible Engine Vibration
« Reply #7 on: May 26, 2019, 01:20:29 PM »
Is it actually firing on both cylinders?

5816nick

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Re: Terrible Engine Vibration
« Reply #8 on: May 26, 2019, 01:32:23 PM »
Hi, Yes it runs very well on both cylinders, goog compression on both cylinders,  ticks over fine, revs up fine both stationery and when driven but as soon as you hit 1700-2200 RPM -  this terrible vibration, the whole car shakes violently - it's so bad you can't drive it >:(

5816nick

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Re: Terrible Engine Vibration
« Reply #9 on: May 27, 2019, 08:40:19 PM »
I Took the Fan Belt off and Ran the engine for a few seconds, The Vibration is Still there and as bad as ever ..... I'm Stumped

Bar Vitelli

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Re: Terrible Engine Vibration
« Reply #10 on: May 27, 2019, 08:54:59 PM »
Does it make the noise when idling?
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Pete126

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Re: Terrible Engine Vibration
« Reply #11 on: May 27, 2019, 09:03:43 PM »
Well that's ruled that out, is this on your 1999 or 1988 126?  the only other thing it could be is the clutch as Gadge suggested, but before you check that are you sure this is not a miss fire at these rev's?
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5816nick

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Re: Terrible Engine Vibration
« Reply #12 on: May 27, 2019, 09:15:46 PM »
Hi pete, It's neither my 99 or 88 -  it is a Blitz aircooled 126 based Buggy I Purchased a few weeks ago, i'm not sure of the Year as No Plates were on it when i bought it, i think it's late 70s - I applied for a logbook through the Chassis number -  DVLA  sent me a V5 logbook last Thursday although it hasn't arrived yet.

What would be the best way of checking on a  misfire at 2000 RPM?

It Only Does the Vibration at 1700-2000 revs, Tickover is fine and 2500 RPM is fine.

Kind Regards Nick

Pete126

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Re: Terrible Engine Vibration
« Reply #13 on: May 27, 2019, 09:53:02 PM »
Arhh, if it has a conventional distributor check points/condenser then try slackening it off so it grips but you can still move it, start it when it starts vibrating move the distributor and see if by moving it slightly you can make the engine run smooth, a photo of the engine would be good
Pete.      il cavallo piccolo

5816nick

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Re: Terrible Engine Vibration
« Reply #14 on: May 27, 2019, 10:12:46 PM »
Hi Pete, i'm changing the points and condensor tomorrow, i'll upload some photos on here ASAP

i'll try moving the Dizzy when the vibration starts and see what happens.

Kind regards Nick