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excessive engine vibration at high speed
Posted: 04 Sep 2018, 22:06
by matteo
Hi,
I've a CU engine that runs well at low speeds but as soon as I get to ~80kph/50mph it starts to vibrate violently which can be felt in the cab. This occurs whether the throttle is open or not and occurs every time (i.e. a consistent speed-related symptom). Compression check suggest a healthy engine. I recently refurbished and rebalanced the carbs which has not solved the problem.
Has anyone experienced similar or can advise what might be the problem?
Cheers,
Matteo
Re: excessive engine vibration at high speed
Posted: 04 Sep 2018, 22:34
by 300CE
Could be a tracking issue - have you noticed any uneven tyre wear or had new tyres recently fitted?
Re: excessive engine vibration at high speed
Posted: 05 Sep 2018, 00:03
by 937carrera
Knock the van out of gear when this happens to eliminate engine concerns.
Vibration through the wheel, front wheel balance /steering play
Vibration through the seat, rear wheel balance
Vibration when braking, warped discs / drums
Could also be other things, but that should help the diagnosis
Re: excessive engine vibration at high speed
Posted: 05 Sep 2018, 06:17
by Mocki
cv joints?
Re: excessive engine vibration at high speed
Posted: 05 Sep 2018, 07:10
by matteo
Thanks for the suggestions all,
Same tyres as usual. I'll do a test run tonight and take it out of gear and will also inspect CV joints.
Re: excessive engine vibration at high speed
Posted: 05 Sep 2018, 09:59
by sarran1955
Hello,
Broken , cracked, or failed rubber front engine mount, ( 4 of them)..
or even nasty CV joint..
Cordialement,
Re: excessive engine vibration at high speed
Posted: 05 Sep 2018, 10:05
by clift_d
300CE wrote:...had new tyres recently fitted?
I've got the same question about new tyres, but for a different reason. If you've had new tyres fitted then I would suggest you check whether they were properly balanced at the time they were fitted - we had a similar issue with our car which kicked in at a similar speed and was down to this issue.
Re: excessive engine vibration at high speed
Posted: 05 Sep 2018, 19:51
by Sir Brixalot
Check they've been fitted properly. I nearly had a rear fall off and the other three were all loose after getting tyres swapped
Re: excessive engine vibration at high speed
Posted: 05 Sep 2018, 19:56
by 937carrera
Sir Brixalot wrote:Check they've been fitted properly. I nearly had a rear fall off and the other three were all loose after getting tyres swapped
https://club8090.co.uk/forum/viewtopic.php?f=1&t=166078
Was that you I helped in Teesside this afternoon ?
Re: excessive engine vibration at high speed
Posted: 06 Sep 2018, 06:21
by kevtherev
My van started vibrating at 50 and got steadily worse until 60 then it was undrivable.
CV Joint
Re: excessive engine vibration at high speed
Posted: 10 Sep 2018, 20:51
by matteo
Update: On a 50mph+ test run I took the van out of gear and the vibration continued. All looked/felt right on inspection of rear suspension/driveshaft so I took it into my usual garage.
Up on the lift they saw movement (30+mm) at the tyre and it turned out to be an old tyre worn unevenly. Thanks for your suggestions and I'm embarassed I missed it after the pointers
Still sorted now and I'm looking forward to a trip out for a long weekend
