Personally there are many occasions when I regret not being back at square one, and being able to address - at the root ? the problems that I live with whilst DRIVING mine !
The way I went about addressing Reaction-Plate problems recently is not best-practice or particularly recommended, and I?m not proud of the result, so please be gentle with me, but it seems a pragmatic and practical solution to a problem that I am sure I am not the only one to have faced.
As soon as I started to get the motor out to do the gearbox flip, I realized just what kind of botching I was up against ? just look at those special ?wedge-ended? bolts that had been driven through the torsion-bar anchor arms ! They appeared to have been forced through the kind of misalignment that goes with leaving the shocks in place when trying to reassemble the front torsion bars and reaction plate ? see below. All the bolts had semi-stripped areas as well.
The alignment of the reaction-plate and the principal shell rails wasn?t good enough to allow the proper 1/2? bolts to be used, so someone had substituted 7/16? and had still had to bang those in.
The reaction-plate ears (the brazed-on sleeves) had fretted on the rails and begun to ovalise their holes, whilst the sheet steel of the rails was no longer flat and true any more ? seen here much later after cleaning-up and painting.
With the engine now out, once I had fitted the correct-length dummy shock-absorber bars and tried and failed to refit the torsion bars correctly I realized that I was going to have to take a more radical approach.
Once it became apparent that I could remove the rearmost pair of 3/8? bolts from the front-frame-tubes-to-chassis-rails intersection without any of the alignments changing in the slightest, I decided to try and combine the 1/2? and the 3/8? anchorages into one item, giving me a much thicker and stiffer clamp on the shell.
The first thing I did was to chivvy, flatten and generally true up (with a big hammer on a big anvil) the far-from-flat reaction-plate itself, and then refitted it clamped tight between just the 4 side-bracket bolts ? this itself required some ghastly leverages and ratchet-strap usage before the bolts would slide in cleanly.
Then I used a 400 litre nozzle on the blue-tipped precision-adjusting multiple-usage equipment, and took an area to each side up to cherry-red for a minute.
Before someone squeals about ruining the temper and strength of a highly-stressed bit of unobtanium that was hand-forged by Jaguar in the heat of Le Mans experiences etc (cont p.92) I should point out that on my car, at least, the reaction plate was dead-dull 1/4 ? MS plate from what I could judge during the anvil session.
Jaguar?s notorious parsimony regarding ingredients leads me to assert that if it had needed to be stronger it would have been made from 5/16 ? or 3/8 ? MS plate rather than anything fancy like the alloy steel used for the front tubular structures.
Thus relaxed and relieved its stresses, the plate was now aligned with the side brackets and the bolts came out easily. Progress.
I then took a deep breath and cut the tubular lugs off the reaction plate. One of those no-going-back moments ???
Relying on that essential Intellectual-But-Horny-Handed-Son-Of-Toil?s tool
known as the Veritas Optical Centre Punch,
I then spent a couple of hours measuring and making ? as accurately as possible ? a pair of 8mm slabs that would coincide perfectly with the ?? and 3/8? holes in the chassis rails ; these came out as significantly different and generally asymmetrical left-right parts, but I ended up with bits that could be fixed convincingly into place using the correct bolts and without recourse to anything more drastic than a plastic hammer.
Progress. (But don?t use my drawing, it won?t fit yours !)
Then came the tricky bit of joining them to the reaction plate, first tacking them in-situ lightly with the MIG,
then bracing them on the bench,
before gouging the interfaces
and then whacking up the current on the MIG
to really make it scream, crackle,
and penetrate.
I finished them off with a bit of curved ? gusset,
probably unnecessary but it looks more convincing and less of a botch.
Once back in the car, with just a modest amount of ratchet strap between the lower front frame rails I was able to tap all (now 8) of the reaction-plate securing bolts through their respective holes and plates, and feel that I might ? at last ? be able to set the front suspension up without blanching at the prospect.
Later, with the engine and (new JT5) gearbox in place during a dummy-run, I had to ease away slightly the areas shown (red arrows) to facilitate the entry of the rear 3/8? bolts.
The frame rails must spring apart slightly with the added load of the engine/box since the ratchet-strap needed racking up much tighter upon final assembly ? but I think I have saved the chassis rails from further damage and the car has lost many clunks and grunts whose origins I think I can now trace to incorrectly aligned/tightened/mating surfaces in the reaction-plate area. It also sits agreeably higher at the nose now the torsion bars are right, and appears square from behind for the first time in 11 years.
PS Does everyone have a cut-out in the reaction-plate to cope with the motor/gearbox LH gusset, or is this another unaddressed horror ?!
