PaulYDP
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| posted on 18/8/09 at 10:47 AM |
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Vibration
Hi guys,
I'm hoping someone can help me here.
I have a Tiger B6 running a zx9r engine, with a 7" 3.62 diff.
Ever since I built my car I have had a vibration from the drivetrain. It sounded like it was coming from the diff itself - I didn't know the
history of it as I bought the car as a part build, so I picked up another one and fitted it last night. My problem is still there.
Basically if i'm going along at 55 - 60 and lift off the throttle there is a rattle, but if I touch the throttle again it goes away. Also if I
reach an up-hill it goes away without touching the throttle - it seems if there is any load at all the rattle goes away. The main problem however is
when the car reaches around 90mph (on track) the rattle becomes constant and the car actually vibrates.
The only thing I can think of now since I replaced the diff is the propshaft. I got the prop shortened and balanced when building the car.
As anyone experienced anything similar?
Thanks in advance,
Paul
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cd.thomson
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| posted on 18/8/09 at 10:59 AM |
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only need the one post, people dont just live in one area of the forum. 
Craig
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Mr Whippy
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| posted on 18/8/09 at 11:00 AM |
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Have you any play at all in the front bearing on the diff?
Have you tried greasing the prop shaft joints or are they sealed for life?
Is there a welded on tab on the prop shaft that indicates it’s really been balanced?
You should be able to jack up a rear wheel and run the car in gear so you can feel what is actually vibrating. Obviously you need to be extremely
careful doing this...
Fame is when your old car is plastered all over the internet
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PaulYDP
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| posted on 18/8/09 at 11:36 AM |
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quote:
Originally posted by cd.thomson
only need the one post, people dont just live in one area of the forum.
Some people do
Cheers for the reply Mr Whippy. There is no play in the diff at all - this is the 2nd diff now and the problem is exactly the same.
The prop has definitely been balanced as I can see the weight on it - I got the prop shortened and balanced before fitting it.
The diff end of the prop is sealed for life, however I think the new section on the front can be greased so i'll check that.
Yeah I guess I could jack the rear of the car up and see what's going on, just always thought it wasn't that safe lol
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gixermark
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| posted on 18/8/09 at 01:20 PM |
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if you decide to run it jacked up on one wheel at the back... have a video running paul - at least it it goes tits up.. you will get the £250 or
whatever it is for the TV show :-))
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rob2005
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| posted on 18/8/09 at 03:11 PM |
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I get the same high speed vibration. I thought it was at 70 mph but after calibrating my speedo it to is at about 90mph. I get it through the car.
Someone told me it was the reverse box as he had the same on his Westfield.
I live with mine but eager to see what's causing yours.
Fortune favours the brave!!
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:{THC}:YosamiteSam
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| posted on 19/8/09 at 02:52 AM |
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try tightening up the reverse box prop flange nut - big nut holding it on can come loose - or the prop bolts
make sure the gearbox flange nut too is tight. i have similar probs - turns out it was that
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PaulYDP
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| posted on 19/8/09 at 11:29 AM |
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LOL Mark I'll have the camcorder at the ready!
Going to check the harley splicers are lined up correctly, to make sure the prop is fitted exactly the same way as it was balanced. Also while doing
that i'll check that the adapter on the engine is 100% tight.
I don't have a reverse box so it's definitely not that! I could possibly live with the vibration too but i'd really rather not as it
shouldn't do it and i'm afraid it is something that could go wrong further down the line!
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gixermark
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| posted on 19/8/09 at 02:55 PM |
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you coudl leave it as is........
do track days, and charge ladies for a few laps... you coudl make a fortune :-))
I'll expect 20% of revenue for giving you the business idea though Paul
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PaulYDP
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| posted on 19/8/09 at 04:46 PM |
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Haha love it Mark - I think you are on to something, 20% profits to you it is! I could maybe even build a proper BEC Seven then! 
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Rogthebandit
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| posted on 27/7/13 at 10:08 PM |
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Hi Paul
I know it was some time ago this thred but i have exactly the same problem with my mk. Did you sus what the problem was?
Cheers
Rog
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unijacko67
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| posted on 27/7/13 at 10:49 PM |
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Just my opinion, but I would recommend making sure the diff flange and the gearbox flange are parallel to each other, they don't need to be in
line and can be offset, but need to be parallel. I've done a bit of testing and it definitely makes a massive difference.
http://www.kittenkitcar.co.uk
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Rogthebandit
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| posted on 27/7/13 at 11:20 PM |
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Hi mate, ya i have just read the same on another post. There not parrallel. I set the engine up to suit the headers so the exhuast would fit right. I
have read that the use of a cv joint at the front end would sort the issue? What do you think?
Cheers
Rog
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unijacko67
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| posted on 28/7/13 at 12:37 AM |
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You can still set the diff flange parallel to the engine/gearbox flange, just rotate the axle. I have cv front and uj rear (not ideal) , when not set
parallel I thought my diff and gearbox needed re-build, I then rotated the axle to be parallel and silence in top gear 9000rpm. I think I'm
going to re do my prop with two uj's just to be on the safe side.
http://www.kittenkitcar.co.uk
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Rogthebandit
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| posted on 28/7/13 at 08:42 AM |
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Hi
Rotating the diff isnt an opion on my chassis. I also have a starter motor reverse that needs the diff to be parrallel. If a cv joint wont do then i
would need to move the engine and mod the exhuast. Big job
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unijacko67
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| posted on 28/7/13 at 11:22 AM |
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Just a thought, but how about 2 cv joints, one each end.
The s2000 prop had a pair of cv joints as standard, but I had the prop shortened and a uj replaced the rear cv joint as I was led to believe it
would be fine and I needed to match my alfa diff flange. It is fine when all in line (parallel) but when I first fired it up and into gear (on axle
stands) with the diff pointing down 5 degrees I thought I had a major problem as it sounded like the gearbox and the diff needed a re-build.
Would a two piece prop help (not sure as might make it worse) , I realise they would be very short, but just an idea as re fitting the engine seems
like a lot of work.
http://www.kittenkitcar.co.uk
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Rogthebandit
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| posted on 28/7/13 at 12:09 PM |
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I have a 2 piece prop on the car now. I was thinking of trying a cv at the front end. I also am thinking about putting a cush drive in the front
section as well to absorb some of the clunck when selecting gear. I was looking at the engine this morning. Its about 4 deg out of parrallel with the
diff flange. Both flanges are pretty vertical. It would be a fare job to move the engine now. If i have to do that then its christmas sorted for me!
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jacko
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| posted on 28/7/13 at 01:14 PM |
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check the middle bearing in the prop
also check the prop adapter on the engine has not come loose
Jacko
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Rogthebandit
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| posted on 28/7/13 at 03:48 PM |
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Hi jacko
Ya I've checked both, everything seems ok. The rubber on the centre bearing is a little cracked so I will replace. I might go for the transit
centre bearing. The prop place I go to recommended that one last time. Cheers Rog
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