Author Topic: Vibration, my nemesis  (Read 1352 times)

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Offline jbcollier

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Vibration, my nemesis
« on: Monday,July 01, 2019, 12:19:38 PM »
It’s all about vibration, vibration, vibration.

— Started losing brake fluid.  Took me a while to find the source as it was not leaking very quickly.  I use a Wilwood remote reservoir like this:

https://jbcollier.smugmug.com/Lotus-Europa/i-NLj2CTL/A

Constant vibration had caused it to crack here:

https://jbcollier.smugmug.com/Lotus-Europa/i-8js4wVV/A

I had a spare but will look for a remote reservoir that is better supported.

— Had a couple of intermittent DNFs on the AC and back-up lights.  Turned out two (2) fuses had fractured internally.  Sometimes it made contact, and sometimes it didn’t.  Thank goodness for test lights.  May switch over to blade type fuses.

— Have been working hard to reduce vibration.  Main source is out-of-balance brake drums.  This is my third set.  One drum took just a 1/2 oz of weight while the other 1.75 oz.  Made a HUGE difference.  Next is to build my own tire shaver as one tire is just a tad out of round.

Offline Clifton

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Re: Vibration, my nemesis
« Reply #1 on: Monday,July 01, 2019, 01:35:34 PM »
I'm using the same Wilwood MC's mounted above the rack where the blower was. I'll keep an eye on mine now.

Offline Grumblebuns

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Re: Vibration, my nemesis
« Reply #2 on: Monday,July 01, 2019, 02:04:14 PM »
John,

You had a posting a while back about how you balanced your drums, can't seem it find find it. Would a static balancer like the one Harbor freight sells be sensitive enough to balance our drums?

https://www.harborfreight.com/search?q=tire%20balancer

Either I have a lead bottom or I can't discern any vibration on my S2 rears. Just wondering if going to rear discs will be the solution to out of balance drums. I should add that I may not know what rear wheel imbalance feels like. On the front, you can feel the steering wheel shake. If the rears are not balanced, how does it affect the car?

Joji Tokumoto
Fallbrook, Ca



« Last Edit: Monday,July 01, 2019, 02:14:00 PM by Grumblebuns »

Offline jbcollier

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Re: Vibration, my nemesis
« Reply #3 on: Monday,July 01, 2019, 04:02:25 PM »
The first time I balanced them I used a bubble balancer like the ones Harbor Freight sell.  Improvement?  Yes.  Good?  Nope.  This time I used a motorcycle wheel balancer with the drums bolted to a rear hub.  Basically it's a ground shaft on high quality bearings (no rubber seals) with machined cones to centre the hub:

http://www.marcparnes.com/Universal_Motorcycle_Wheel_Balancer.htm

I also spooled up one of my old drums that I had cut off a huge chunk to get it balanced.  It was still heavy though there was a good 1/4 lb of material cut off!  There are some sh*t drums out there.

A rear out of balance is felt through the body.  Bit like the magic-fingers, coin-operated vibrating beds that motels had way back when.  Mine was so severe that the steering wheel also shook, but up and down.  The reason Europas are sensitive to rear imbalance is due to the chassis design.  It's like a giant tuning fork and its harmonic frequency comes on in and around 120 kph/75 mph range.  On mine it's not helped by HD engine and tranny mounts, rose-jointed lower links and rose joint poly-bushed upper links (twin link).

Should you worry?  Of course not!  If it ain't broke, don't fix it.

Offline GavinT

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Re: Vibration, my nemesis
« Reply #4 on: Monday,July 01, 2019, 07:44:10 PM »
Yeah . . that crack looks to be a “feature” of the moulding process.

But I can’t figure out the mounting arrangement.
There seems to be two holes in the bottom of the reservoir. A large hole and alongside that, a smaller hole where I presume the outlet fitting is mounted?
I’m missing something obviously.

On the tire shaver, I recall the Formula Ford guys used them all the time, so I wonder if there might be a tyre shaving service available.
Perhaps it’s different in Canada? . . but here in Oz, the FF’s were restricted to road tyres and they usually shaved most of the tread off in order to get some tyre stability.

Offline jbcollier

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Re: Vibration, my nemesis
« Reply #5 on: Monday,July 01, 2019, 07:49:05 PM »
Same here but our local track is long gone. and with it all the associated services.

I added a bulkhead fitting to supply a hydraulic clutch.  The main outlet (and mount) feeds the brakes.

Offline GavinT

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Re: Vibration, my nemesis
« Reply #6 on: Monday,July 01, 2019, 07:55:59 PM »
Ahh . . thanks - two feeds from one reservoir makes sense.

Also, off topic to this thread but I (and likely many others) would be interested to hear your thoughts on that nifty scissor lift.
Maybe a new topic?

https://jbcollier.smugmug.com/Lotus-Europa/i-T944TMM/A

Offline jbcollier

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Re: Vibration, my nemesis
« Reply #7 on: Tuesday,July 02, 2019, 05:32:49 AM »
It's a Quick Jack:

https://jbcollier.smugmug.com/Lotus-Europa/i-T944TMM

https://www.quickjack.com

Light, mobile and easy to set up.  Had to modify it to lift a Europa with all its weight towards the rear.  The wood is temporary.  I'll have some rectangular tubing cut up to suit for the long term.

Offline GavinT

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Re: Vibration, my nemesis
« Reply #8 on: Tuesday,July 02, 2019, 06:26:16 AM »
Cheers for the info, JB.
The Quick Jack looks pretty good.