Panhard rod mounting?

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Ash
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Panhard rod mounting?

Post by Ash » Thu Aug 02, 2012 2:05 pm

Could anyone please tell me if the pahard rod mounting bracket on a mk1 was welded directly to the chassis or onto a plate first which was then welded to the chassis.

I need to know if mine has had a crude repair or is it just Jensens handywork :P

Many thanks

martin172
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Post by martin172 » Thu Aug 02, 2012 7:46 pm

I can't help but if you look on Brad's Tiger thread, there are some pics that may help.
A Pm to him with a pretty please contained may do the trick.

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gvickery
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Post by gvickery » Thu Aug 02, 2012 8:02 pm

Martin

Here's the basic production finish. There was no plate even if the pro's now say the whole bang lot should be reinforced.

Image

Here's an earlier thread from Mal Graham in NZ showing how these brackets can get torn up!
http://www.sunbeamtiger.co.uk/forum/vie ... cb1413cdc6

And here's Tom Hall's (USA) solution http://www.tigerengineering.net/TECHTIP ... 20rod1.pdf

Graham
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Ash
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Post by Ash » Thu Aug 02, 2012 8:39 pm

Thanks for that chaps.

It seems the car has had a repair done "back in the day".

A very kind gentleman named Thomas from Germany has sent me the Rootes bulletin to show how the repair work should be completed. The plate on my car is very similar.

Mystery solved! :D

martin172
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Post by martin172 » Thu Aug 02, 2012 10:37 pm

Mine looks like the pic Graham has posted but with 2 small plates welded onto the bottom of the rail.
I took some pics earlier at great personal risk but my PC is being a git as per usual.
When I figure it out I'll post them so you'll have another reference.

What a Rootes Bulletin?

martin172
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Post by martin172 » Thu Aug 02, 2012 11:24 pm

Image

Image

Ash
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Post by Ash » Fri Aug 03, 2012 7:12 am

Hi Martin
Your car has had the correct repair done as per the Rootes bulletin. Note the tabs on the plate.

tigerguy2
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Post by tigerguy2 » Sun Aug 05, 2012 12:00 am

Supposedly, the best design practice is to have the panhard rod run parallel to the axle rather than upward at an angle as it does on the Tiger. I know the Tom Hall repair also provides other mounting holes to make the rod more parallel.

Other than the Tom Hall repair, does anyone know of other ways, perhaps working with the existing bracket, to get the chassis side mounting side lower? Seems like a piece square tube or channel iron could somehow be made to work with an undamaged factory mount to make a lower attachment point possible. Rather than try and reinvent the wheel, thought I would ask.

Cheers,

Gene

Mal
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Post by Mal » Tue Aug 07, 2012 2:20 am

This is what we did to replace the mount and to lower the mount point.
The chassis is also redone of a heavier gauge steel.

Image
Image

Tomaselli
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Post by Tomaselli » Tue Aug 07, 2012 5:29 pm

Excuse my ignorance, what does a Panhard rod do, and why the racing boys take them off :?:

tigerguy2
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Post by tigerguy2 » Tue Aug 07, 2012 8:09 pm

Mal, that looks absolutely beautiful. Thanks.

Mr. Tomaselli, as I understand it the panhard rod is intended to keep the body centered (more or less) over the rear axle in a turn when the rear suspension is with leaf springs. The body will try to move sideways in a turn relative to the rear axle. The axle is attached to the ground so to speak through the wheels and tyres. The body is being slung by the forces of the turning motion. Despite the fact that the spring leafs are wrapped, they will also try to slide sideways one relative to the other in a turn. Since the panhard rod is attached one end to the axle and one end to the body, it holds the body and the axle relatively stable with respect to each other in the vertical plane.

I am no racer so I cannot speak exactly as to why some take the rod off. As I understand it, the rod creates a separate roll center from that of the rear axle. That rod based roll center is higher and is located at the point the rod passes through the fore and aft centerline of the car. The two roll centers are in conflict with each other and creates an especially stiff rear end, which is not good for handling in turns. Also since the factory rod goes up and across that center line, you get different effects in right and left hand turns due to the arc it travels in as the suspension flexes up and down. Thus the ideal location of the rod would be parallel to the ground and as low/close to the axle as possible. So at least lowering the body attachment point to make it parallel to the ground to the ground is a good thing.
BTW, when the rod is removed, usually something else, like a Watts Linkage, etc. is substituted to perform the function the of the panhard rod.

Now you know everything I think I know about the subject!

Cheers,

Gene

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