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Standard Vanguard 28% o/d box queries


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Dear Collective

As you may recall, I recently removed 3 teeth from the 1st gear portion of my layshaft.  I have since obtained the necessary parts to repair the box, including the broken 2nd gear bush that I have found after stripping.

The other night, I also bought an interesting overdrive box from a Standard Vanguard / Triumph enthusiast which I hoped to fit to the car so I could take my time rebuilding the original box.  It cost less than the spare cogs cost me, so I couldn't resist.  We tested the box using a TR4 lump mounted on a test rig, and everything worked as it should (gear selection, overdrive operation, overdrive oil pressure, etc).

However, I have a few queries relating to the box / overdrive combination, mainly concerning compatibility with my 3A.  These are listed below, including one minor issue that I have already solved. I have also inserted some photos to illustrate.

1. Clutch actuating lever: the Standard Vanguard item is a two hole lever, with different angle to the TR item.  Easily swapped so no issue.

2. Gearbox ID number: the ID number on the box starts with VF. According to both my sources of Info (How to Restore + Moss Catalogue), VF boxes should be 4 synchro, but this box is most definitely 3 synchro, with the casing an identical match to my original TS stamped box. Anyone care to explain this?  Either the books are wrong, or someone messed with the serial number?

3. The overdrive unit, as I have since discovered, is an original Standard Vanguard item, which means that it has the serial number 28 / 1327.  This of course means that it is a 28% overdrive unit, rather than the TR standard 22%  It is an A-Type overdrive, identical externally to the 3A overdrive which has serial number 22/1374. Is there any issue with using this higher ratio of overdrive? I think this will result in 3rd overdrive being lower revs than 4th, but I actually quite like the prospect of having the car geared slightly higher for more relaxed high speed cruising.

4. I need to swap the solenoid mounting plates: the Standard Vanguard solenoid is mounted horizontally, whereas the TR is vertical.  Swapping the plates would appear to be straightforward, but there are some interesting differences, e.g. the o-ring which seals the operating shaft is on the inside of the TR plate, but the outside of the Standard Vanguard plate.  The one difference that I am most interested in, though, relates to the accumulator spring behind the plate, and the backside of the plate where it presses on the spring. On my 3A overdrive, there are two springs, exactly as expected.  The Standard Vanguard has only one spring, which is fitted inside a solid brass tube, perhaps similar to the spacer tube used on later 4A overdrives with softer engagement?  In addition to the differences in the springs, the plates are also different in that the Standard Vanguard item has a small protrusion which inserts inside the accumulator spring to hold it in position, whereas the TR plate has a hole in the same location, so no spring locating protrusion.  The question is, can I safely use the TR plate given it does not have the spring guide? 

image.thumb.png.34256b6db106f3be881e99712fdb5ee9.png

 

5. Finally - the Vangaurd box has splodges of alloy where the 3A box has what looks like nice neat little ball bearings in the casing. I don't know what these are.  Are both factory, or has one been tampered with?

image.thumb.png.46eee0277cc1dbc111fee538f6068fc0.png

Hoping one of you out there is an expert on Vanguard overdrive boxes!

 

TIA
Malcolm Glover

 

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According to the manuals which I obtained from Laycock in 1972, the type (this is not a serial number, by the way) 28/1327 was fitted to the Vanguard and had a 1.125" accumulator piston.  

The early TR2, which had O/D on top gear only, used 22/1275 unit with the same size piston.

Later TR2/TR3/TR4, which had OD on 2/3/4, used 22/1374, which has 1.375" accumulator piston.

I was the club's Technical Editor from 1971 to 1986, and throughout that time, I corresponded frequently with Ian Gibson, who later became Technical Editor. Inside my Laycock manual I have found a letter from Ian Gibson, dated 3/5/75.  In his letter, Ian says that the 28/1327 was fitted to Vanguard Phase 1 and was operated by cable - the car's gearbox was 3-speed (and operated from steering column - ugh!).

Ian Cornish

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Well, I'm certainly not the Vanguard overdrive expert you are looking for although I have used components from one for a recent TR unit I built.

To get a clear & definitive answer to your questions I would recommend you call/email one of the gearbox & overdrive specialists.

Regarding the 22% v 28% change - that is what I have just done for a 'touring' box to give it longer legs & economy on a run - as long as your engine has the power that should not be a problem for you, you have already identitified that it will alter how you use the box & O/D unit due to the proximity of the new ratios, that is certainly not a game changer for me.

Reference the end plate  - I've never seen a TR one without the locating dowel for the accumulator spring so I don't see that as an issue either, but again I've only done a few units & it's got to be worth an enquiry with the experts. 

Good luck

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H Malcolm,

regarding the last two photo's.

They are both oil way 'bungs'.   The bearing is held in place and the casing metal squeezed down around it to seal it in.

The ali splodge is essentially  a rivet. It is hammered down into the hole. The rivet expands and seals the hole.

 

Roger

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4 hours ago, ianc said:

The early TR2, which had O/D on top gear only, used 22/1275 unit with the same size piston.

 

Hi Ian - that's very useful info.  I note from the Moss catalogue that the early TR2 overdrive is 'hydraulically incapable' of handling the extra torque of later cars.  Is this down to the size of the operating pistons being smaller in that overdrive?  Does this mean that there may be some slippage in the overdrive clutch if you use it in 2nd gear at full noise?  I don't mind not having overdrive in 2nd, but I'd like to have it available for 3rd gear.  I may fit the box and see how it performs in 3rd gear with the overdrive.  I assume that nothing will break... just slip a little?

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3 hours ago, RogerH said:

H Malcolm,

regarding the last two photo's.

They are both oil way 'bungs'.   The bearing is held in place and the casing metal squeezed down around it to seal it in.

The ali splodge is essentially  a rivet. It is hammered down into the hole. The rivet expands and seals the hole.

 

Roger

Thanks Roger - so both methods must have been used at different times in the factory... maybe the splodge was on earlier o/d units.

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4 hours ago, Chilliman said:

Reference the end plate  - I've never seen a TR one without the locating dowel for the accumulator spring so I don't see that as an issue either, but again I've only done a few units & it's got to be worth an enquiry with the experts. 

Thanks John - so my TR solenoid mounting plate does NOT have the locating dowel... just a hole in the plate where a dowel may once have been.  This suggests that maybe I should be looking at some way of re-inserting a dowel before I use this plate on the Vanguard o/d.  I wonder what happened to the old one?!

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Malcolm - yes, there's insufficient force available with the smaller pistons, so, because of the torque multiplication which occurs in 3rd and, even more, in 2nd gear (factor of 2), slippage is very likely to occur.

TRs fitted with type 22/1374 (i.e. from the later TR2) are, as far as I am aware, the only 4-speed production cars on which overdrive operates on 2nd, 3rd and 4th gears as standard.  Because the ratio is halfway between 2nd and 3rd, overdrive 2nd is exceedingly useful on hill climbs, the more so because there's no need to move one hand from the steering wheel when playing tunes!  Better still when logic overdrive control is fitted!

The Laycock manual lists a great number of vehicles to which overdrive was fitted, some being most unlikely candidates: Vauxhall Velox and Wyvern; and D type units to Ford 100E, Hillman Minx, Standard 10.

Ian Cornish

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The steel locating pin in your Vanguard side plate can be pulled out and should fit in your TR plate in any event you should have the locating dowel fitted to keep the springs in place. It may have fallen out and be sitting inside the spring or on top of the accumulator piston, have you looked?

 

Graham

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9 hours ago, Graham Harris said:

The steel locating pin in your Vanguard side plate can be pulled out and should fit in your TR plate in any event you should have the locating dowel fitted to keep the springs in place. It may have fallen out and be sitting inside the spring or on top of the accumulator piston, have you looked?

 

Hi Graham - no, I have not looked yet, but will definitely do that.  Only issue with pressing the Vanguard plate into the TR plate is that I would be concerned that it would just fall out again... it is also cast iron instead of Aluminium.  I have had some ideas for how I could come up with something that would be pressed in place by the spring and so no risk of falling out, so that may be a way forward.

That TR overdrive did pretty well for many years without the dowel.  I wonder if it is only necessary during assembly.... spring pressure may keep everything in one place once it's all tightened up?  I did notice that the TR springs protrude much further than the Vanguard spring... the Vanguard spring has very little pressure on it when the plate is pressed 'home'.  I wondered if that was the reason it needed the little dowel and the TR one didn't... but it looks like the TR one is just MIA!

Thanks for your input!

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Well - I've just returned from the first test of the Vanguard box. 

Overall, I think for a 300GBP box and overdrive, it did well.  Observations are:

  • car is LOUD without the tunnel or carpets and sound deadening.
  • distinct whine in all gears except 4th... could be layshaft bearings?
  • changed gear smoothly, no synchro issues that i could tell.
  • no oil leak from front end of box when I returned... could it be that the crank seal leak i had cursed since the car was built was actually coming from the front of the gearbox?
  • the early type overdrive is VERY slow to come in, compared with the lightning bolt that is the later A type overdrive.  BUT - you can use it very smoothly without the need for clutching or deft throttle adjustments, so this could be seen as a +ve. Looking fwd to seeing what difference the extra 6% makes to cruising revs.  

I think I will stick with it while I rebuild the original box... then decide which one I prefer...

 

 

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Malcolm - it could be that slow engagement is caused by the pull-in coil on the solenoid not operating, leaving just the hold-in coil to do the job.  However, could be the fact that the overdrive is not really the correct version for a TR, so is struggling.  Horses for courses!

Use of the clutch should not be necessary.  Overdrive should be engaged with the throttle open (power applied) in order to achieve a smooth change.  And when changing down, the throttle needs to be open in order to avoid a vicious jerk to the transmission.  If braking whilst changing out of overdrive, use heel & toe to achieve a smooth change.

Ian Cornish

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Hi Ian
I finally got the solenoid set up in the right spot and the o/d seems to be working very well indeed.  Honestly - for anything other than track work or very spirited road driving, the slight delay in the take up of the o/d is more than made up for by the smoothness with which it operates.  I definitely notice the increased road speed for a given engine speed, too... or at least I think I do ;)   

I've heard many times before that the later o/d shouldn't need the clutch to engage it, but mine just would not allow me to do that.  A change at any revs with any sort of +ve throttle would always result in quite a jolt, unless a dab of clutch and lift of throttle was used.  Coming out of overdrive was smooth, though, without need for the clutch.

Anyway - I'm happy enough now with the replacement box that I will put the interior back together and get the original box rebuilt.

 

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My A type overdrive is as smooth as silk when it engages but it jolts when it disengages if the car is on a trailing throttle so I tend to dip the clutch. Disengaging under power - say when climbing an incline or overtaking is fine, no clutch needed. 

Rgds Ian

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On 3/1/2020 at 8:09 AM, Ian Vincent said:

My A type overdrive is as smooth as silk when it engages but it jolts when it disengages if the car is on a trailing throttle so I tend to dip the clutch. Disengaging under power - say when climbing an incline or overtaking is fine, no clutch needed. 

Rgds Ian

You should always apply throttle when changing into or out of overdrive that way its always smooth, never change out of overdrive on a trailing throttle as you will damage the unit.Hence the thread on the TR6 forum with the broken shaft in the overdrive unit.

Stuart.

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And, on a TR2 with the early 'Lockheed' axle, you would seriously stress the half shafts were overdrive disengaged at high speed on a trailing throttle - there would be an almighty jolt as the rear wheels lock momentarily, and, if this happens too often, the poor old half shaft(s) will give up!

Even with a modified engine (say about 135 BHP), an A type overdrive should be able to handle engagement on full throttle in 2nd gear at 5500 rpm whilst ascending a hill.  Jolly useful, as it means that one can go from 20 to over 60 mph on full throttle without any need to move the gear lever.

Ian Cornish

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So you can overstress the halfshafts on a trailing-throttle down change (agreed)  but on a full throttle up-change where you are asking the car to accelerate instantaneously there is no such stress.  Obviously physics has changed since I was at school Ian. 

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No, Rob, physics hasn't changed greatly since I was at school, but as the clutch in the overdrive engages there will be a short period of slippage within the mechanism, and that gives the smooth, bump-free transition as long as power is being applied. 

View it like this: you are not really asking the car to accelerate (although it will continue to do so), but rather you are forcing a reduction in engine speed, and the gearbox and engine can cope with that.

If power is not being applied, then there will be a jerk as the overdrive engages.  When tootling through towns, I open the throttle momentarily in order to change from 3rd to OD 3rd, and this smooths the change.

Ian Cornish

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5 minutes ago, ianc said:

View it like this: you are not really asking the car to accelerate (although it will continue to do so), but rather you are forcing a reduction in engine speed, and the gearbox and engine can cope with that.

But that reaction is still being transmitted through the whole drivetrain Ian, including the half-shafts. 'Every action has an equal and opposite reaction'.

My experience seems to be the exact opposite of yours though. If the power is kept on while engaging o/d there is a distinct thump as the o/d clutch tries to speed up the car and/ or slow down the engine at the same time. If you momentarily feather the throttle a bit I find that shock is much reduced.  

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1 hour ago, RobH said:

But that reaction is still being transmitted through the whole drivetrain Ian, including the half-shafts. 'Every action has an equal and opposite reaction'.

My experience seems to be the exact opposite of yours though. If the power is kept on while engaging o/d there is a distinct thump as the o/d clutch tries to speed up the car and/ or slow down the engine at the same time. If you momentarily feather the throttle a bit I find that shock is much reduced.  

If thats what you are finding then it may well be that your cone clutch is getting very worn or you have play in your UJ`s or sliding joint on the prop. Ive been driving overdrive equipped cars for a long time and as Ian has stated to get smooth engagement when changing in or out of overdrive I always keep power applied, in fact that was pretty much beaten into me by my old guvnor a very long time ago when I used to have to drive him home from the pub in his MK2 Jag.

Stuart.

 

Edited by stuart
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39 minutes ago, stuart said:

If thats what you are finding then it may well be that your cone clutch is getting very worn or you have play in your UJ`s or sliding joint on the prop. Ive been driving overdrive equipped cars for a long time and as Ian has stated to get smooth engagement when changing in or out of overdrive I always keep power applied, in fact that was pretty much beaten into me by my old guvnor a very long time ago when I used to have to drive him home from the pub in his MK2 Jag.

Stuart.

Stuart.

So good you named it twice? :-)

Seriously though, keeping the power on when engaging the O/D is pretty simple but I find it more of a challenge to always keep the power on when I am disengaging hence I dip the clutch which I assume is protecting the unit from abuse.  I also have one of those logic boxes that disengages the overdrive when changing gear - again while the clutch is dipped.

Rgds Ian

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2 minutes ago, Ian Vincent said:

So good you named it twice? :-)

Seriously though, keeping the power on when engaging the O/D is pretty simple but I find it more of a challenge to always keep the power on when I am disengaging hence I dip the clutch which I assume is protecting the unit from abuse.  I also have one of those logic boxes that disengages the overdrive when changing gear - again while the clutch is dipped.

Rgds Ian

I have the logic box as well so obviously overdrive disengages when you change gear so thats with the dip of the clutch but if you are in overdrive  and just want to change out a prod on the throttle should be second nature and anyway most of the time when doing that the reason to change out is because your losing forward way in that gear despite having the throttle down so the engine revs will immediately rise on disengagement anyway. If your coming up to a junction in overdrive just change down slightly later with the logic box and your in the right gear. Interestingly new drivers these days are not taught to use the gearbox to slow down but just use the brakes, back when I learnt to drive you never had any brakes anyway so had to use the box especially with trucks.

Stuart.

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Thinking out loud without the benefit of any reference to hand so please feel free to put me right.......

I think that by declutching to change in or out of overdrive you may find the cone clutch locked but with slack in the uni directional clutch. This leaves scope for the slack in the udc to be taken up during the next change and impart a ballistic load into it. 
Changing with power on should keep the udc “wound up” and avoid the slack being taken up sharply. 
I haven’t got one to hand but guess that the udc has 10 to 15 degrees of slack between its extremes of operation and won’t take kindly to being snatched. 

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Stuart and I have both the same experience (over a great many years of driving TRs with overdrive units) and are offering the same advice. 

And both of us use a logic box - highly recommended!

If one can learn to heel & toe, opening the throttle whilst decelerating and dropping out of overdrive becomes possible.  However, it may necessitate an extension on the throttle pedal to bring the bottom of the pedal further to the left (hence, nearer the brake pedal) and may also require the throttle pedal to be pulled nearer to the driver (had to do that on my old TR2 in the 1960s).  If bending the throttle pedal back, take the strain on a block of wood against the bulkhead so as not to break the pin securing the mechanism.

Ian Cornish

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