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Herald all-alloy gearbox - pros and cons?


Colin Lindsay
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I had one of these years ago as a novelty item, but sold it and regretted it ever since however when one came up on the Net last week for a silly price I made an even sillier offer (£30) and ended up buying it.

It's now arrived with me and is in surprisingly good condition, so much so that I'm even debating replacing the bearings and seals and using it in my 1200. I know the gear ratios are lower than later cars, especially second gear, but the top end is the same, and whilst it might tie me down to a coil-spring clutch - no great problem - I'm interested in hearing any views on why it wouldn't work, weaknesses compared to later boxes etc. It's only the novelty value I want it for, no other reason such as weight saving, as the intended box already has an alloy bellhousing. Any thoughts?

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chick and egg  was the cast iron introduced as a cost saving or to handle more torque or both ???

on a 1200   think it  would o be fine and the weight saving is a real performance boost 

dumping the cast iron clutch Hsg is another   Triumph  ground anchor speciality 

the combined weight save will bring the 0-60 under 3 minutes 

Pete

 

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No, Johnny - it's a very interesting setup; there's no pivot pin, the bearing release carrier is bolted to the bellhousing on a hinged bracket and in behind that there's a metal plate, held in with four bolts - once I remove the bearing arm I'll undo those and see what's in behind - the bearing and seal will be in there, and I'll see what I'm working with once it's on the bench.

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Congratulations! It's a scroll!

There's a metal plate - the cover plate assembly, part number 119223, held on with six bolts, and this incorporates the scroll seal. A little judicious sandblasting will clean that up again; I doubt if I'll find a replacement any time soon. The gasket - or as the WSM calls it, the joint washer, might be saveable.

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In behind we have the front bearing, so that's coming out, along with the rear bearings, for replacement. As you can see I've a lot of cleaning to do, but only in the bellhousing area, as the internals are excellent. It's a very interesting variation on what we're used to, especially since the release arm is bolted in, not just slotted in and pinned. As you say, Pete - was it all just cost, or a simpler design?

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You did very well there Colin, I sold an alloy Herald / Spitfire bellhousing for £90 a couple of years ago via the Triumph Spares Day @ Stoneleigh !!

Mine came with a stack of free spares that were of no use to me, having a Vitesse.

Regards.

Richard.

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interestingly Colin for a scroll seal there doesn't appear to be a drain hole in the bottom of the Bellhousing.

Why shouldn't the alloy gearbox case be strong enough it's the same material and construction as the big saloons and TR range presumably just smaller so unless it's of thinner construction should be stronger. I read somewhere Triumph went to the cast iron bellhousing to kill the noise yet they persevered with alloy in the Vitesse and all other models go figure?

Don't the boy racers like the light weight alloy gearbox's for racing ie weight saving.

I have two alloy bellhousings a Herald early one which is definitely of thinner construction and fewer strengthening ribs, and a later one which is thicker and the same molding as the standard cast iron unit.

My daughters an Aero Space Engineer and when I rebuilt her gearbox 18 years ago whilst she was in Germany working for VW/Audi I asked her which bellhousing I should fit the thinner light weight or the later thicker alloy unit, her answer surprised me, the later thicker alloy unit as it was stronger and would last better and kill the noise better, this was after she had built a carbon fiber racing bike with friends at Uni, her motto was reduce weight as much as possible, ie alloy water pump and alternator pulleys, alloy thermo/water pump housing, brackets drilled out to reduce weight (even the alt is a NOS Holden Aussie Lucas and looks shorter/smaller than the std 15ACR, but I haven't weighed them) I think we might look at alloy front and rear engine backplates just cos we can & there reasonably priced.

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Someone does - or did - an alloy SC gearbox case, probably Canleys. I imagine the weakness in the Standard-Triumph unit is the bellhousing, which is integral to the unit.

Having looked into this as I had a new 4-syncro+OD GB made up for the Atlas - the original being alloy like yours - I know that the SC boxes from the Standard 8 & 10 era had a layshaft with a sleeve bearing and a scroll on the shaft to circulate oil. When did they change that to a pukka bearing?

Cheers, Richard

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11 hours ago, Peter Truman said:

interestingly Colin for a scroll seal there doesn't appear to be a drain hole in the bottom of the Bellhousing.

There is, just not visible in the photo; I cleaned it out yesterday. 

I remember reading way back that the gearboxes suffered from cracks and so were replaced by the cast versions with the alloy bellhousing, and it was with the increased power of later 1200s that they were able to go fully cast and not adversely affect performance. This one might be going into a 39bhp 1962 Herald so should be fine for low speed low mileage ownership - curiosity value only! (Must cut a clear window in the centre tunnel so people can see it...)

It looks to be exactly the same casing and bellhousing as fitted to Standards of the period - see the Standard 8 box below; only the top remote system and rear extension are different on the outside.

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8 hours ago, Colin Lindsay said:

It looks to be exactly the same casing and bellhousing as fitted to Standards of the period - see the Standard 8 box below; only the top remote system and rear extension are different on the outside.

It is the same Colin. Only the tail extension was changed for the rear mount we all know on our cars. (Overdrive on a Standard 8, 10 or Atlas was possible but it was located to the rear of the mounting eye with a special tail piece.)

The only other thing is that if you want to mount the "tower" top cover (for a pudding bowl gear lever) then you need to machine a rebate along ... I've forgotten. It's either the bellhousing or OD adaptor or something at the front (or is it rear?) of the GB casing. But it's highly unlikely anyone here would want a pudding basin gear lever!

Cheers, Richard

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I've butchered an old speedo cable to screw onto the threads to avoid damaging those; butchered as in: it used to be a complete speedo cable but pulling on it snapped the outer cover off...

It's not moving at all, so plenty of penetrating oil and gentle tapping. I'm wary of heat on the alloy case... might end up with a shiny silver puddle....

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It's yet another chicken and egg scenario. The speedo drive is stuck, and won't budge, so I'm trying to be very gentle with it and tease it out but the rear housing won't budge until it clears the gears.

The rear housing is held in by the rear bearing clutching the shaft and won't budge as I suspect the speedo drive is also holding it in place, and I don't have a spare housing so don't want to break any of the little fins off by battering it.

If one moves, the other will too. Patience, and perseverance. What I'm desperately fighting the urge to do is to put a drift into the small oil hole on the other side of the speedo drive and push it out... NO! (I don't think that would work anyway due to the design of the drive.. but it's a thought.)

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Thanks Johnny; one of the reasons I post here is that it helps clear the mind wonderfully - a bit like thinking out loud - so extension removal it is. 

I reconditioned two 1200 gearboxes earlier in the year and darned if I could remember how I got the extension off, but I'm almost sure the drive came out first. As long as I know it'll come off over the speedo drive I'm all for it tomorrow.

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Well, I got the extension off... plenty of heat to get it moving then once I had a gap between the extension and the body it was all systems go.

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With the extension off I decided to have a go with the speedo drive which was really really stuck. I mean, really stuck. I put the end of an old cable onto it to protect the threads but nothing would move it; in the end I put a spanner around the base of the cap and whacked that gently with a hammer whereupon it flew off and was only located about two hours later. Sadly it looked a bit strange, and it was soon confirmed that the threaded part of the speedo drive had succumbed to years of corrosion and broken off. Pity, as it's one of the original early metal versions. I'll have to look into how it was constructed, and by whom, in case something can be salvaged, otherwise I'll just fall back on one of the more modern plastic versions. Who's going to see, anyway?

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2 hours ago, johny said:

hmmm it looks pretty clean but maybe theres been something going on between the steel of the pinion and the aluminium housing....

The threaded section was well away from the alloy, however from looking at it I reckon it has just rusted away through being exposed on the outside of the gearbox as even when a cable was fitted this section was left exposed. Furthermore I reckon it's just a threaded section set into the outer body and could be unscrewed again. 

If that's the case I forsee a visit to the in-laws in the next few days, it's long overdue and they just might, with enough choccy biscuits, machine me a replacement section - in fact they could probably remake the entire thing from one piece of metal. I have a complete version they can scan and replicate, if they ever get the free time. The rubber seal inside is still available, as it's probably common to the plastic versions as well. (Replacement plastic housings are only £6.40 second hand and the seal is £4.85)

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