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High speed vibration - propshaft?
Twin40 - 29/4/13 at 07:02 AM

Hey guys, Need some help from team LCB...

We've been trying to get the MK ready for its next track outing, last time out the car was vibrating quite heavily at high speed. Tried to remedy the prob trackside with no success.

Got the car home and on the ramp to run it up, and it's smiulating the same type of vibration. So I've double checked the rear wheel balance, and the propshaft alignment. All seems ok in terms of angle etc etc.

The propshaft is a brand new TRT unit from AB performance, so i'd assume this is 100% ok? Anyone have any experience with this type of prop? It doesn't look to be running that "true" but difficult to tell.

We even checked the driveshafts to see if they are bent, but all seem to be ok.

Any other ideas? Something obvious i've not checked?

Appreciate any advice, desperate to get back on track!

Cheers

C.


mark chandler - 29/4/13 at 08:17 AM

You can try and balance prop shaft by attaching a jubilee clip and twisting into different positions where the balance weights sit and run the car up.

If nothing else it will help isolate this item.


cliftyhanger - 29/4/13 at 09:06 AM

2 jubilee clips are better, with the weight bits opposite so they start in balance.
Whole process is fiddly though.

If there is a propshaft place local, or indeed AB are helpful (likely) then get them to check the propshaft.
If possible can you run the car without the prop, see if the vibration goes. Then ideally connect the prop but disconnect the driveshafts. All a faff, but can isolate the problem.

Other idea is to borrow a prop that is known good.

Nothing is easy though....

[Edited on 29/4/13 by cliftyhanger]


RJK350 - 29/4/13 at 09:26 AM

Friend had the same problem.
Turned out to be a cracked engine mount


puma931 - 29/4/13 at 09:50 AM

take a look half way down this post for a prop failure

http://www.locostbuilders.co.uk/viewthread.php?tid=122181


[Edited on 29/4/13 by puma931]


amalyos - 29/4/13 at 05:58 PM

Are you running a reverse box?


britishtrident - 29/4/13 at 06:21 PM

first try unbolting the flange joint and rotating the propshaft through 180 degrees.


Twin40 - 1/5/13 at 05:52 AM

Thanks for the reply guys, we've had it up on the ramp again, can't find anything obvious. Not sure of the 'jubiliee clip' technique so my best bet is to probably hand it over to AB. I'm sure its something simple but i'll let the pro's find it!!!

Thanks again.


aeromanboeing - 7/6/13 at 02:51 PM

Did you find out what your vibraton was.?


AJR - 6/10/14 at 07:24 AM

Sorry to drag this up again but I'm having the exact same problem with a new TRT shaft from AB.
Was the problem found/rectified in the end as I'd love to know what the issue was.