Why are these Spitfire gearbox's so weak ?

[Clive]

On 23/05/2021 at 18:37, Mathew said:

Assuming you have the 1500 j type box. Drove with one of these for 20k miles no problem and the box was second hand to me! I have a lead right foot as well!

So why is yours failing? When you rebuilt it did you fully rebuild it or just change the bit that had failed? Oil used? Driving style? Do you ease up when changing gear or slam it in?

Trouble is new stuff is difficult/impossible to find if you want quality.

Just had my type 9 overhauled by the best (BGH) and they used all secondhand parts. Unless I wanted steel synchros fitted for £750ish, there are no new decent brass ones available. But they know what is good and what isn't.

For triumphs the best gearboxes are usually built with vgc used parts rather than new repro. New oe best if you can find them....

[Pete Lewis]

so its a bit of a  mincer 

by chance you have not  been towed a good distance recently  have you ???

Pete

 

[wimpus]

2 hours ago, Pete Lewis said:

so its a bit of a  mincer 

by chance you have not  been towed a good distance recently  have you ???

Pete

 

No, she always arrives home under her own power ! 😂

[Pete Lewis]

good i was talking about towing problems on paula's toyo page 

Pete

[Colin Lindsay]

7 hours ago, clive said:

For triumphs the best gearboxes are usually built with vgc used parts rather than new repro. New oe best if you can find them....

I just invested for the future, in case... £12 the lot. Now I've got to sort through it all and see what's what and what's useable...

[Clive]

48 minutes ago, Colin Lindsay said:

I just invested for the future, in case... £12 the lot. Now I've got to sort through it all and see what's what and what's useable...

My local gearbox man and good friend has a stack of gears/layshafts etc, and has a knack of being able to put a good gearbox together. Had a stroke of luck, bought a very low mileage non od box recently, stripped and provided all te parts to rebuild an OD box, plus a load of excellent condition parts for future rebuilds. Little gets wasted.....

Sadly layshaft pins are often worn, and good used rare. Sometimes he has to buy new, but it makes him nervous. Th erecord was 12 miles to knacker a new pin. No hardening at all it seemed. That was 20 years ago, most seem to be OK now, but once bitten....

[Pete Lewis]

5 minutes ago, clive said:

see what's what

you seem to have a short mainshaft . is that just the photo or its for a  new pygmy version ???

Pete

[Colin Lindsay]

2 hours ago, Pete Lewis said:

you seem to have a short mainshaft . is that just the photo or its for a  new pygmy version ???

Pete

That's for short gearchanges... need to see what's what and what isn't. Triumph, that is.

Anyway I've found out why these gearboxes are so weak... they're not well.

 

 

[68vitesse]

44 minutes ago, Colin Lindsay said:

Anyway I've found out why these gearboxes are so weak... they're not well.

Are they weak or just have a reputation for being weak, isn't the same basic design, in three rail form, used for the 2L Vitesse, GT6 and early 1850 Dolomites.

Regards

Paul

[johny]

no, think they are weak. Physically they are small compared with units used on cars with similar characteristics especially on the sixes. The original design was used on the 948cc Herald and although some improvements were made its was later installed in cars with much more power and, more importantly, torque. This was because these cars use a separate chassis, which is also of similar design on all the cars, so limiting the space available to fit a bigger gearbox. In fact this is one of the problems in trying to find a suitable substitute gearbox from either Triumph or another manufacturer...

[Pete Lewis]

10 hours ago, 68vitesse said:

used for the 2L Vitesse, GT6 and early 1850 Dolomites.

yes it certainly is   the origins come from earlier than the 948 and standard 8 and earlier form the base for the design

some better design on the chassis would have allowed the big box on the 2 ltr cars but Nah  didnt happen

when you compare the two triumph boxes they are chalk and cheese /little  and large 

the problems come  from its 40 years beyond its designed life and  core and aftermarket supplies have dried up or are poorly made  eg a few years of duff layshaft spindles and baulkrings made like thrupenny bits , soft bearings etc

so even rebuilds can be a trial.

over the years some have gone type 9 ford routes and they are less available now but spares are there

all changes need some serious rework , beyond what many want to do .

pete

 

 

[Steve P]

I was lucky in finding a single rail box with o/d in Devon on e bay a few years ago,bought unseen for £120 including the mounting bracket.

Aside from changing the oil a few times i have done nothing to it other than use the car,including finishing the 2014 RBRR in the Herald with a 1300 engine then,now in the Herald with a 1500.20k miles so far and it`s quiet,changes gear nicely and the o/d works perfectly.

Steve

[68vitesse]

People only mention when their gearbox fails, don't expect triumph expected them to last this long, problems often start from abuse, uprated and non standard engines, and neglect during the banger years.

And as Pete mentioned suppliers selling crap remanufactured parts made down to a price and probably made to last the warranty on the limited yearly mileage they expect most drivers do.

Regards

Paul

[johny]

Youre lucky as it definitely seems to be the OD boxes that fail more often although that could be because theyre more common or driven more or something...

[Peaks]

On 26/05/2021 at 09:45, clive said:

Trouble is new stuff is difficult/impossible to find if you want quality.

Just had my type 9 overhauled by the best (BGH) and they used all secondhand parts. Unless I wanted steel synchros fitted for £750ish, there are no new decent brass ones available. But they know what is good and what isn't.

For triumphs the best gearboxes are usually built with vgc used parts rather than new repro. New oe best if you can find them....

I absolutely agree with Clive. Over the years I've had several 'overhauled' gearboxes and the average life for them.has been around 40 - 45k miles (this is in a Vitesse). I like to think I'm not a hooligan and just drive the car as it was intended. Each of my failures have been down to poor modern bearings.

The latest box has been built using good used or NOS components and good quality (expensive) bearings. Only time will tell if my investment will pay off, but what I do know is that anyone selling an overhauled small chassis Triumph box for 2 or 300 quid has definitely cut corners and/or used cheap parts. I have he same view on the overhaul kits you can buy for around £125, I highly doubt those components will last. 

[Paul H]

Advice please , my Vitesse od gearbox was rebuilt by Manvers Triumph 4 years ago. The company is no longer in business as Clive Manvers has died 

Works as it should BUT don’t go from 3rd to 2nd anything above 20mph unless you want to hear a crunch. Would double de clutching help ? 
what’s the reasoning behind ? 
 

Paul

[Peaks]

Sounds like weak or failed synchromesh on 2nd to me Paul, although I've never driven a Triumph box which isn't prone to a bit of crunching when rushing a change from 3rd to 2nd. 

[Badwolf]

How many times have we fitted lovely new spares only to end up refitting the old ones as either the new ones didn't fit, were poor quality or just didn't look right?

[johny]

yes it sounds like the synchro isnt working very well which is probably because the synchro ring is worn. The result is that when you go to select second the gear isnt spun up to the correct speed by the ring so then crashes because of the difference in rotational speeds when trying to engage.

Changing up isnt nearly so difficult because the gears naturally tend have the same speeds especially if you take your time and wait for the right moment to engage. With a bit of practice double declutching helps on changing down by revving to increase the speed of 2nd gear so it matches that of the sliding sleeve for engagement...

[Mathew]

Will have to wait on price of bearings till next week. Had to goto Wakefield to pick up some kitchen units!

[Pete Lewis]

synchro relies on a number of things 

the dog teeth have a accurate chamfered tooth edge  this matches the same on the baulkring and especially on the sliding sleeves 

this  angle is what baulks the change until synchronised , any chimbled chamfer due to crashing is often terminal in the way this all works 

the difference in rotational speeds gives the sleeve the ring and the gear a 1/2 tooth rockover and untill the mainshaft has spun the gear set and clutch disc up to speed the misaligned teeth wont let you through to fully engage all this is done in the blink of an eye 

any crashing is due to the sleeve not offering enough pressure to the ring and the ring lets go halfway through a change and the sleeve then clatters on the gear dog teeth causing more damage

double de clutch will not help synchro work you are evading its operation , you may get your gears but you have by passed the synchro 

Paul when youre bore drop the box and buzz to sunny Luton we can soon sort this out 

heres a clue from a Rootes WSM  

Pete

 

[68vitesse]

Think this was the order I was told on rebuilding a 4 syncro box, best ring on third, then second, fourth and lastly first.

Have also wondered if the oil pressure of a overdrive is set for the more powerful cars it gives the gearbox a harder life when used in the lower powered models.

I have a J type which changes with a definite thump and the one currently in use, rebuilt by O R S Sheffield and set for a 2L Vitesse, is very smooth switching in and out.

Regards

Paul

[Paul H]

36 minutes ago, Pete Lewis said:

synchro relies on a number of things 

the dog teeth have a accurate chamfered tooth edge  this matches the same on the baulkring and especially on the sliding sleeves 

this  angle is what baulks the change until synchronised , any chimbled chamfer due to crashing is often terminal in the way this all works 

the difference in rotational speeds gives the sleeve the ring and the gear a 1/2 tooth rockover and untill the mainshaft has spun the gear set and clutch disc up to speed the misaligned teeth wont let you through to fully engage all this is done in the blink of an eye 

any crashing is due to the sleeve not offering enough pressure to the ring and the ring lets go halfway through a change and the sleeve then clatters on the gear dog teeth causing more damage

double de clutch will not help synchro work you are evading its operation , you may get your gears but you have by passed the synchro 

Paul when youre bore drop the box and buzz to sunny Luton we can soon sort this out 

heres a clue from a Rootes WSM  

Pete

 

Hi Pete is it a gear box / od out to sort ? 
Paul

[Pete Lewis]

yes need the gearbox not the car   Ha !!

Pete

[thescrapman]

Paul, Clive probably had the gearbox rebuild by Bob, who went to work for Mark O'Malley out at Stoke Ferry after Clive died.

one thing to try, disengage OD before changing from 4th to 3rd. Couple of my cars crunch if I hurry a change down with OD engaged. Seems to be worse with a J-Type box.