That was a year that was..

[Bfg]

4 minutes ago, Pete Lewis said:

did you load 150lbs on each seat  as per the TR workshop manual  

or the  toe settings wont be quite right 

Pete

yes.,  68 kg., or thereabouts, in night storage heater bricks onto each seat

[Pete Lewis]

good pleased that was done  , its ignored by so many  

if you now measure what toe you have you will get the unladen result which makes 

any future checking a lot easier 

pete

[Bfg]

^ That makes sense, cheers.

[Bfg]

Yesterday was interesting, but not as productive as I hoped ..and my back now aches something rotten.   Nevertheless here we go . . .

Ignoring for a moment the ride height, which I hoped might be helped a little, with what I was about to do - the challenge was to adjust the rear wheel's positive camber. 

But firstly, I needed to ascertain where we were at.

^ eight approx 8kg night storage-heater bricks in each seat, half a tank of fuel, the spare wheel and another 15kg of weight in the boot to simulate normal load conditions.

The car is on the level having been rocked and rolled forward.

   

^ The spirit-level is standing on the floor and leaning against the wheel-arch brow, with a piece of wood leaning against it to hold it steady while I measure to the rims top and bottom.  The dimensions recorded (rear LHS) were 46.5mm top and 50.5mm bottom, so the top of the wheel was tilting out (positive camber) closer to the spirit level rather than being upright or slightly tilting in.

I did a scale drawing of this (on the computer in ACAD) and the angle equated to 0.73 degrees (positive). The TR4A workshop manual tells me it should be +/- 0.5 degrees. Personally speaking I would like to see zero to -0.5 degrees negative camber.  In any case the requirement is to alter the positive camber to negative by about 3/4 of a degree (have the wheel sitting vertically when the car is loaded or leaning in by about 3mm difference) or just a little more.   NB. the difference on the rear RHS of the car was the same 5mm / 0.73 degree positive camber.   It's reassuring when both are the same.

Now, working on the rear RHS of the car, only because that was easier in my present working environment, and with the wheel off this is what we see . . .

       

^ Taking the chassis rail as being level,  you can clearly see how the trailing-arm brackets adjust the camber of the trailing arm and therefore the wheel.  It ought, by the look of things, to be negative camber (top of the wheel tilting in) as the orientation of the brackets are correct for this car.  The camber does go to negative as the suspension is compressed. This is so.. when cornering - it's like putting the tyre at a very slight angle to stop it sliding sideways.  As it is the tyre leans outwards and the so is scrubbed further under the side wall.  This positive camber then is consistent with the car's ride height being more than it should be (the springs are not compressing enough).

Looking on Buckeye Triumph's report on adjusting the camber ;  I read this . . .

This records three different bracket shapes, 1, 2 and 3.  each marked with notches on the top edge.  

Type-1 has the trailing-arm pivot / axis bolt (where the rubber or poly-bush goes) just 3.2mm below the centre of the bracket (between the bracket's two mounting bolts). NB. This type-1 is what I have.. seen to the left of my photo (above). 

Type-2 has its pivot/axis-bolt 9.35mm above the centre of the bracket. This type of bracket is what I have (outboard by the sill) seen to the right in the photo above.

Type-3 bracket doesn't concern me because I don't have those (they're sometimes used on the TR6), but for record their pivot/axis-bolt is some 16.8mm below the centre of the bracket. 

3D-2D means Outside a type-3 bracket with notches Down, used in conjunction with an inside type 2 bracket, also with its notches Down.  In this configuration the camber between the brackets is -4.16 degrees ..which because of the trailing arm's geometry gives -3.3 degree (negative camber) of the wheel. (it say 3.61 degrees in another table). Another row starts with 2U-3U whereby the U signifies that the bracket is orientated with its notches UP.   

Katie  presently had the configuration I've highlighted in blue. 2U-1U ..that is type-2 brackets with their notches facing Up on the outside, and type-1 brackets, also with notches Up on the inside (nearer the centreline of the car).

Editing that table into what is pertinent to me at this time .. insomuch as I only have two type-1 brackets and two type-2 brackets to play with, let's clear all the other permutations away ..and so this is what we see . . .

^ The configuration Katie  has (correct according the manual) is again highlighted in blue.. Outer ; 2 with notches Up, inside type-1 bracket also with notches Up.

I want more negative camber by at least 0.73 of a degree ..and the table says to reverse & invert (in red) the brackets I have. That it says would alter the camber by 0.6 degree which is very close to what I want, and the most these particular brackets will give us.  

However to me it doesn't make sense.  Surely if you rotate the brackets 180 degrees ..the angle between them will be the same.?   (Rich - it's just like rotating a cooling fan around )     I wasn't convinced ..but at the same time I remained uncertain, as this report is reputed to be accurate.  Perhaps I was missing something.?  So., I took the brackets off and did what it suggested . . .

^ getting those brackets out is a pain-in-the-arse when you're an old fart working under a car on axle stands.  Firstly the road springs had to be removed to take the pressure off them, so driveshaft inner coupling and damper, then the spring could come out, and the trailing-arm pivot-bolts removed, and then finally the bolts holding the brackets to the chassis rail.  Thankfully the corner triangulation / gusset plates I had added didn't restrict access too much but still it was working blind to get the socket in there.

     

^  brackets off the RHS of the car.  The Left bracket with notch Up is type-1 and from the inside, and the right bracket with notches up is the type-2 (which I'm also indicating with the blue masking tape) and that was next to the sill.  on the table this was designated 2U-1U   

^^ RH piccie shows these reversed and inverted as suggested.  On the table above this designated ID-2D.   Nope., the angle didn't suddenly change as I stepped over them to take a photo from that side.  But as I say, I might have been missing something so I put the car's suspension back together again with the brackets this way around.

I then loaded the car up again and bounced, rocked and rolled it forward to the marked-level ground.  But I do admit that I haven't yet driven the car to re-settle the suspension, but for a quick check I presumed this might give us an indication.

Results ;  that side's wheel has adjusted, in part the suspension appears to have dropped by 10mm (wheel centre to wheel arch) which was much more than was predicted in the Buckeye report. This change is in part due to the pivot axis (although the same 2.08 degree angle) being of a different height (as illustrated below) relative to the chassis rail / the bolts on the brackets . . .

^ Drawn to scale, the brackets -3.2mm (type-1 bracket) or +9.35mm (type-2 bracket) offset relative to the chassis rail / the mid axis of the bolts through those brackets.  

Top is how the car's RHS trailing arm brackets were. And across the bottom is how they now are.  And yes as I thought, the pivot's axis angle is unchanged (at 2.08 degrees) and the height relative to the bolt's horizontal axis is lower (by some 6mm).  According to the report this height change should have rotated the wheel, around the spring by " 10.5"/19" or 55% of the change in the bush axis height" ..which translates as lowering the ride height by 55% of 6mm = a little more than 3mm.   For whatever reason my quick check suggests its lowered by around 10mm.   And this is with the M&T supplied replacement road-spring fitted. 

The camber angle did not change by 0.6 degrees, as the table suggests (..so I've not yet gone completely nuts !) but it does appear to altered by almost 1/4 of a degree ..from 0.73 degree of positive camber to 0.51 of positive camber.  Because the angle between brackets has not changed - I might only attribute this change to ; 1. the camber changing according to suspension compression (ride height), and 2. because each of the bracket bolts have been pinched up but not tightened yet, so they have self adjusted with the bushes now being in line and also with any slight slack in the chassis or bracket's holes.

The looseness of fastenings, until the road-spring was refitted, probably also accounts for the noted change in ride height.

- - -

So that's about it.  I think to further correct the camber, I'll need to buy two more type-2 brackets, and to swap them out for the type-1's that are fitted.  This ought to alter the angle between the brackets by almost exactly 1 degree, which will translate through the geometry (according to that report) to -0.87 degree of the wheel.  That would take the present 0.51 deg positive to -0.36 (negative) camber ..which is exactly what I want.   However the ride height will go back up again be 3 or 4mm. 

I think only shorter / lowered springs, or less than 7mm thick collars, is going to help with that.  

 

^ Interestingly, or not, from photos taken when I was first looking around under this car.., the brackets this way up (now inverted) are close to what we had before the chassis change. . . particularly evident with the inside bracket (top left in this photo) whose the bottom edge is almost parallel with the bottom of the adjacent chassis leg.

I'm particularly grateful to the gentlemen who wrote the article for Buckeye Triumph  as, although their data is in some parts wrong, they have provided a lot of useful measurements and an overall well-worthwhile insight into the geometry of these IRS components.  BIG THANK YOU to them. 

Pete.

 

[Pete Lewis]

thhere are a number of ideas on Chris witors techy downloads

whilst its not the same much of the suspn on 2000  has same parts 

worth a read/ comparison on what changes what 

https://www.chriswitor.com/technical.php

Pete

 

[Gully]

Just a thought. When you make the same adjustment to the LHS side of the car, lowering that side down by an equivalent amount should also reduce the apparent positive camber on the RHS? Assuming you're measuring only the wheel against the vertical?

Gully

[Bfg]

Good point Gully,

I was struggling to understand why the measured change in ride height and camber was not closer to that predicted in the Buckeye-Triumph reports. 

Dwelling on the issue and work the car came to a halt with my having to prepare for having a minor operation.  I live alone, so things like grocery shopping and house cleaning, bedding, car insurance and other bills, as well as positioning of furniture as zimmer-frame like aides to getting up n’ down etc., all had to be done / dealt with in advance of my being laid up thereafter. Then last Tuesday I was surprised to wake up from having open-surgery rather than key-hole as expected.  Anyway, right now I'm on the mend again, but off physical bending, stretching & lifting exertions, including jacking up the car, crawling under it, undoing and lifting off a wheel, &/or reaching and struggling to loosen half-shaft and trailing-arm bolts. 

I hope to get back on with it soon but in the meantime, when able to concentrate, I've been looking again at the Buckeye-Triumph reports.  I've found a number of errors in their figures. Their author’s thinking of what happens when adjustments are made has been really helpful, but in practice their measurements were a little off.  Tbh., not enough in themselves to make a significant difference but possibly enough to confuse the issue ..of why actual adjustments don't result according to prediction.

However, your point of my adjusting just one side and then re-measuring the effects ..on car now leaning, is inspired. Thank you.

TBh., I really didn't think it would make much difference over the full width of the car (the axle's track dimension), but I've just checked.. and just 10mm lower suspension on one side, on the TR4's track width of 48.5" (1233mm), equates to the car leaning by almost half a degree (0.465 deg).  This of course means the chassis, the trailing-arm brackets, and therefore the wheel-bearing's hub, being likewise tilted relative to the datum vertical spirit-level.  

Should anyone be looking at the same issues, of ride height &/or the rear wheel’s camber being out - In due course I’ll try to pull together a few more pointers.

Pete

[RogerH]

Hi Pete,

 don't know what surgery you have had but do take it steady. With the years ticking on recovery does take its time.

No point in putting back the recovery rate just to get the car sorted quicker than is needed.

Look after your self.

 

Roger

[AndyTV8]

3 hours ago, Mathew said:

Second that. Get yourself fit first, the car will come.

Yep - definitely make sure to give yourself time and space to heal well. The car isn’t going anywhere while you rest.

........ Andy

[Colin Lindsay]

On 20/09/2021 at 17:59, Bfg said:

     

Just a small point / thought - can you get full-length bolts for these, where the bracket rests on the collar and not the threaded section? When I was rebuilding the TR7 the kit came with bolts that were to me unsuitable, the threaded section was through the bracket itself and I was concerned about rapid wear, so I sourced longer that were a more correct-looking fit.

  

 

[Pete Lewis]

just make sure it clamps the crush tube firmly and the nut doesnt  bottom  out  the bolt should not rotate in use.

the bush should rotate around the tube firmly clamped between the ears of the bracket 

and yes get well soon     too many of us are on the ailing creak and groan listing 

Pete

[Peter Truman]

Yes Pete get well soon the car will wait whilst you recoup, keep in contact, and keep us straight 

[RogerH]

3 hours ago, Colin Lindsay said:

Just a small point / thought - can you get full-length bolts for these, where the bracket rests on the collar and not the threaded section? When I was rebuilding the TR7 the kit came with bolts that were to me unsuitable, the threaded section was through the bracket itself and I was concerned about rapid wear, so I sourced longer that were a more correct-looking fit.

  

 

Hi Colin,

I have an Aerospace background. The bolts we used had a length based on the shank.

So a 2" long bolt had a 2" long shank PLUS approx 1/2" thread.

In the Automobile world a 2" bolt includes the thread that could be 1" long. Very poor practice.

 

Roger

[Bfg]

The bolts through the bush and bracket would need to have a 3" long shank plus its threaded length.  Possibly more readily available as 4" bolts that can be cut shorter to suit the tight fit between the bracket and the rear chassis rail.  What Colin says is correct and good practice but as Peter implies ; probably unnecessary ..as when the whole assembly is bolted up tight (done while the suspension is loaded of course) then the ends of the crush tub should not move relative to the bracket and therefore neither the bracket nor the bolt's thread would wear. 

Thank you for your best health wishes and cautions.  The operation was for "a large left inguinal hernia"  which is possibly why I had a large open incision across the left groin, and then a rather tender four to five inches of Frankenstein-like sutures and a whole lot of deep bruising where no one wants it.  Naturally I would have preferred key-hole surgery, but hey.. they didn't wake me up to ask my opinion.! 

Had I known beforehand the effects of general anesthetic on my system, then most likely I would have taken stool-softener medicine before and immediately after the op  ..because five days worth of blockage pressing from within was, I feel, unnecessary and avoidable pain, distress and discomfort (..lots of each).   The sister of a close friend had the same side effects after having general anesthetic., so I'm not alone.  Indeed the post-op literature makes a big deal about avoiding constipation.  But by then it is too late, and thereafter eating only gruel and soft fruit wasn't enough to correct the issue.  Anyone facing surgery might want to heed this warning, but also to seek their doctor's advice, so as to avoid any conflict in medicine.   

Anyhow, once unblocked, I took to light exercise, as highly recommended ..and managing to walk about 3/4 mile (round trip) to a local shop on the Saturday (the op was late on Tuesday afternoon), and then four or five miles on the Sunday, another three or four miles on Monday ..by which time I felt I was hurting myself.  So Tuesday I had a day of rest.  In the meantime (Monday night, I think) we had a 3 - 4" flood on the patio where my TR is up on ramps.  Once that had subsided, there was of course a whole lot of crud to sweep up and wash out . . 

   

^ my 'light exercise' for today was to clean up this S%%t.  Perhaps it doesn't look too bad in the photos but just from this space and under where the Chrysler is parked I swept and shoveled up the best part of a wheelbarrow load of crud.  I'm now aching (both front and back !) more than would have liked ..but at least now the ground under the car has half-a-chance to dry out. 

Job done for today, I'm going to take it easy now.

Wishing you a peaceful evening.

Cheers, Pete.

 

[Bfg]

5 hours ago, Colin Lindsay said:

..

  

^ Those are amazingly skinny brackets, and the bolt thread looks coarse ..I too would share your concern.  The brackets on the Tr4A - Tr6 are made from 3/16" (4mm) plate so possibly less of a concern.   

Pete

[Colin Lindsay]

1 hour ago, Bfg said:

^ Those are amazingly skinny brackets, and the bolt thread looks coarse ..I too would share your concern.  The brackets on the Tr4A - Tr6 are made from 3/16" (4mm) plate so possibly less of a concern.   

Pete

Glad to hear that Pete; I just thought I'd stick my oar in... and pretend I know something!!   Incidentally those were rear axle pivot brackets on the TR7, thinner than the originals but stainless steel.

[Colin Lindsay]

11 minutes ago, Mathew said:

I like stainless but think its over used. It should not be used in structural points unless reinforced as it can fatigue easy and reacts with alloy badly. Nice and pretty in the right places though.

These were bump stop brackets on the rear axle; kind of a double layer with the metal axle brackets underneath and the bolt going through both.

 

[Peter Truman]

from work experience S/S fails due to vibration and fatigue

[Bfg]

11 hours ago, Mathew said:

I like stainless but think its over used. It should not be used in structural points unless reinforced as it can fatigue easy and reacts with alloy badly. Nice and pretty in the right places though.

We use Stainless steel quite a lot in the marine industry, often taking some pretty impressive structural loads. Mind you we also have aluminium masts, copper wiring, lead keels and bronze tubes through the hull.. so what might that say about us ! ?     ..and that's aside from the timber of the bulkheads and in hull framing, engine beds etc., and then foam or balsa wood for our structural laminate cores, and then sail cloth to propel the vessel.!   ..the motor industry is just so die-in-the-wool using iron and steel all the time.

[PeteH]

18 minutes ago, Mathew said:

Do you know why there are zinc blocks attached to the hulls of steel ships? (I know but would love to hear why other people would think its done).

Yes. Came as part of the Naval Architecture And ship construction needed for marine engineering certification. So we’ll see who else knows likely Dick will.

Pete

[NonMember]

I'd assume its for electrolytic reasons (I won't give details until a few other people have guessed).

[Chris A]

I'll ask Barnacle Bill when I next see him.🙄

Talking of sea food in shells, the coquilles St Jacques season has just started here in Normandy so we'll be taking a couple of days to go to the cost very soon.

[RogerH]

2 minutes ago, Chris A said:

 

, the coquilles St Jacques season has just started here in Normandy

Hmmm, yum yum

[Pete Lewis]

anodes and cathodes comes to mind 

bolt one on your triumph to take on the corrosion 

pete

[Bfg]

sacrificial anodes to the god Ferrous. 

Did you know that a particularly famous architect designed ..and had built, a ship clad in copper.  Apparently when launched in seawater the electrolysis was something to behold.

Conversely, as if there wasn't enough salt at sea.. salt blocks are used to scrub the timber of decks, and are also added to water in the bilges of vessels built in timber.

- - -

Back on the subject of Triumph suspension.  Mathew kindly shared a few images of the Triumph 2000's IRS. 

As the TR's IRS was derived from this it makes an interesting comparison . . .

^  Triumph 2000 IRS.   The sub-frame assembly onto a monocoque body shell is pretty neat. Also of note is the telescopic damper mounted directly to the body tub, whereas the TR uses lever arm dampers which are of course assembled onto the chassis.

I was particularly interested to see the angle of those sub-frames ..and their trailing-arm bush axis, relative to the axle's axis ..which from the photo appear to be 40+ degrees rather than the 32 degrees of the TR's.  I presume the 2000 required more camber change (to negative) to counter the saloon car's tendency to roll.

The 2000's inner and outer trailing arm bush brackets are different, ..as they are for the TR's,  so I guess the selection of those is likewise used to set the saloon's rear wheel camber.

 

For comparison,  my own TR4A chassis mounted IRS (below) . . .

    

I wonder how many, if any, components are interchangeable between the different models. ?

Pete