Just to throw my data point into the mix, on my car when I disassembled it, both
of the fulcrum pins were installed with the bulge away from the engine. I'm
sure
this is the way it came from the factory as the PO wasn't the kind to fix things
on the car if they weren't broken.
In addition, one of the vertical links was bent so I trolled through one of the
local club members vast pile of spares. I found no fewer than 4 sets of
complete
front suspension and all 4 had the fulcrum pin bulge pointing away from the
engine. So that's 6-0 score for pointing outwards.
Rob
74.5 TR6 CF28217UO
Ottawa, ON
Pete & Aprille Chadwell wrote:
> The fulcrum pin orientation question I posted has exposed some
> controversy, I'm afraid. Funny how some of these issues seem to
> present such an obstable to finding the 'right' answer. I received
> an email from one list member who points out that there was a
> correction issued in a 1992 Practical Classics magazine where
> apparently the magazine admitted that the caption and photo on page
> 78 of the Practical Classics & Car Restorer Triumph TR6 Restoration
> book shows INCORRECT installation of the upper fulcrum pin. A few
> other responses had generally supported the instructions from the
> book, which recommends that the curved part of the fulcrum pin should
> 'bulge' toward the engine and prior to the above information, I had
> come to the conclusion that my fulcrum pins had been intentionally
> reversed at some point in order to gain some negative camber in the
> front wheels.
>
> This new information casts doubt now on the whole question
> I think
> everyone agrees that the part in question is asymmetrical, and as
> such the orientation of the fulcrum pin HAS TO affect the camber of
> the front wheels. On my TR6 the curve of the fulcrum pin bulges AWAY
> from the engine and yet the camber of the front wheels was set (at
> last alignment) at around .75 deg negative. In other words, the
> orientation of the fulcrum pins on my car has not resulted in a
> greater-than-normal amount of negative camber.
>
> Of course, the other variable in this equation is the number of
> alignment shims installed under the lower wishbone pivot brackets.
> The basic idea is that the greater the number of shims used, the more
> NEGATIVE camber will be introduced, since adding shims pushes the
> LOWER end of the vertical link AWAY from the longitudinal centerline
> of the car. Also, adding more shims behind the FRONT lower wishbone
> arm than is used in the rear tends to decrease caster and adding more
> shims in the rear than in the front tends to increase caster. All of
> this is somewhat theoretical, as I expect that on each individual
> chassis the lower wishbone support brackets are welded in SLIGHTLY
> different locations. As a result, each car will require different
> numbers of shims in different combinations to achieve the same toe,
> camber and caster specs.
>
> With all of that out of the way, I've just taken 'inventory' on the
> number of shims installed on my car for purposes of comparison. This
> is only for the front suspension, mind you. And these numbers may
> change in a couple of weeks when my suspension is back together and I
> take it in for another alignment.
>
> Right Front: 1 shim
> Right Rear: 6 shims
> Left Front: 4 shims
> Left Rear: 3 shims
>
> This combination was arrived at 12 years ago after I took it to a
> front end shop for an alignment after rebuilding the front
> suspension. (new bushings, ball joints, etc.) As I recall, this
> combination yielded about .75 deg negative camber and I think the guy
> was only able to get about 2.5 deg positive caster on both sides.
> All of this, of course, with the upper fulcrum pin installed with the
> curve pointing AWAY from the engine.
>
> --
> Pete Chadwell
> 1973 TR6
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