So I drove back from the IVA today which included 20 miles on the M1. I kept it between 60 and 70 when on the motorway but there was a lot of
vibration through the floor/chassis. The vbration was making the vision in the mirrors blurry it was that bad.
This was the first proper drive for me so I wasn't sure if this normal for these cars? What could be done to reduce vibration?
Cheers
Could be wheels out of balance but would guess its the prop if self made.
Never mind the vibration and noise, did it pass?
Either back wheels or propshaft would be first check
Wheels I assume to be balanced when they arrived from Wheelbasealloys (all wheels have the weights on, none have fallen off). Prop is sierra modified
by MK. What should I be looking for on the prop?
The vibration isn't noticeable when going through the rev range, probably because I was busy thinking "this is awesome!" as I was
ragging it up to 11k rpm :-) It did get a bit frustrating on the motorway though.
quote:
Originally posted by ReMan
Never mind the vibration and noise, did it pass?
Nip it down to kwikfit for a free balance check, if not out there will be no charge. At least then you know its not them.
quote:
Originally posted by Sloan85
Wheels I assume to be balanced when they arrived from Wheelbasealloys (all wheels have the weights on, none have fallen off). Prop is sierra modified by MK. What should I be looking for on the prop?
The vibration isn't noticeable when going through the rev range, probably because I was busy thinking "this is awesome!" as I was ragging it up to 11k rpm :-) It did get a bit frustrating on the motorway though.
quote:
Originally posted by ReMan
Never mind the vibration and noise, did it pass?
Yup, passed no probs. Only had to tweak the power commander slightly, add a label to my reverse switch and file a sharp edge on the exhaust mounting bracket. DVLA to deal with next.
[Edited on 4/9/13 by Sloan85]
quote:
Originally posted by Sloan85
Wheels I assume to be balanced when they arrived from Wheelbasealloys (all wheels have the weights on, none have fallen off). Prop is sierra modified by MK. What should I be looking for on the prop?
The vibration isn't noticeable when going through the rev range, probably because I was busy thinking "this is awesome!" as I was ragging it up to 11k rpm :-) It did get a bit frustrating on the motorway though.
quote:
Originally posted by ReMan
Never mind the vibration and noise, did it pass?
Yup, passed no probs. Only had to tweak the power commander slightly, add a label to my reverse switch and file a sharp edge on the exhaust mounting bracket. DVLA to deal with next.
[Edited on 4/9/13 by Sloan85]
You don't get vibration in the steering wheel if its the back wheels
My first thought was 'that is how my bike feels at particular speeds', right down to the blurred wing mirrors. It has a 'reverse sweet
spot' where it's really uncomfortable to ride. Ten miles up or down and it smooths out again. It also happens in other gears at the same rev
range.
Since you have a BEC, it might be worth seeing if it is rev related, drop it down a cog and drive at the same revs.
[Edited on 4/9/13 by Slimy38]
60 mph is the normal speed for imbalanced wheels to show up, is worse in lightweight cars. Kwikfit are hopeless at getting it right btw as their machines are not calibrated well I ended up going to a specialist fitter who did it right first time.
Mine is pretty bad around 70, 5mph either side and it is Ok. A winter upgrade is a TRT and prop balance.
There is also high frequency vibration around 4000rpm, another winter mod is to rubber mount the engine cradle.
All this pails into insignificance taking into account that the gearbox is mullered
4500 miles on the bike and 1000 in the MK, but not unusual even
on a bike, apparently they are made from cheese
So an "E" or Z1000 box as another winter mod, or possibly a Mazda V6 transplant.
With wheel balancing the knowledge of the the guy working the machine is the critical thing.
Front wheels need a full dynamic balance but you can quite often get away with tatic balance.
For rear wheels a simple static balance will usually be good enough, you can use a spirit level balancer for this or weld up a simple hand spun
static balancer up using an old stub axle & wheel hub of the correct pcd. The one I made for balancing Imp wheels used the bottom an old front
strut from a Chrysler Avenger and an Imp front hub.
Essentially this is just a bracket to hold the stub axle horizontal, to reduce friction the wheel bearing should have the seals removed and the
grease washed out using WD40. The important thing is to reduce the bearing friction as much as possible so adjust the end float allow a little more
clearance than normal.
Mount the wheel and spin the wheel at a reasonable speed and wait until it naturally comes to complete rest. Mark the lowest point of the tyre with
chalk. Repeat the process if the wheel stops in approximately the same place you have found the heaviest point on the tyre.
[Edited on 5/9/13 by britishtrident]
I might have mentioned this on another post, but I have also noticed that some wheel balancing places only put weights on one edge (or even the inside flat surface of the wheel), whereas others have machines that say what weights have to go on what edge. I don't know whether there is a significant difference?
It felt like a very high frequency vibration. Would have a guess it is prop or engine related, not wheels.
quote:
Then check prop balance weight hasn't come off. I hope mk didn't just shorten prop and send back!!!
quote:
Originally posted by whitestu
quote:
Then check prop balance weight hasn't come off. I hope mk didn't just shorten prop and send back!!!
I think that is all they ever do isn't it?
I've never heard of them balancing a prop.
Stu
^^ You can get the existing one re-balanced but it maybe not much more to get a new one made by a prop-shaft supplier (MK re-use the UJ at one end of
the prop, it maybe best to start with a new one)...
Something I may look at eventually..
Interesting, who are the favoured suppliers?
I only really notice i in 5th at speed, does the collective think this really is the prop?
Thanks and sorry for the thread hijack.
David
quote:
Originally posted by DavidW
Interesting, who are the favoured suppliers?
I only really notice i in 5th at speed, does the collective think this really is the prop?
Thanks and sorry for the thread hijack.
David
Test the prop by simply taking off a rear wheel and running it in gear, any vibration must then be the prop...
Diff bolts tight?
Hi
Mine was vibrating also when crusing on and off the throttle. It was the prop phase that was wrong. I realigned it and its a different car. No vibs at
any speeds and revs right thru to over 100 mph with no issues. Going to put a cush drive in the prop over chrimbo.
quote:
Originally posted by Rogthebandit
Hi
Mine was vibrating also when crusing on and off the throttle. It was the prop phase that was wrong. I realigned it and its a different car. No vibs at any speeds and revs right thru to over 100 mph with no issues. Going to put a cush drive in the prop over chrimbo.
Hi jacko
Ya i turned the spline through 90 deg on the front section of the prop. Massive different. I am going to put a cush drive in also then rebalance.
Forgot to say also, the rear section of my prop was in phase. The front was out by 90deg. The place i had it made must have throught i was running the front section straight (which is not recommended due to bearing life). Being a bec its running about 5deg angle.