The Triumph Dolomite Club - Discussion Forum

The only joke in there is that washers were as valuable as ten-a-penny to SU.

And the olives work. Though, clearly, I can see you would have to be first pressed to accept that.

Graham

Here's a clip from the page on disassembly of the HS carbs.

The words that go with it are as follows:
(b) Unscrew the jet tube sleeve nut from the float-chamber and withdraw the jet assembly (11). Note the gland, washer and ferrule at the end of the jet tube.

I'm sure the "jet tube sleeve nut" is what I've been calling the gland nut and the ferrule is what I called the ferrule (well I had to get something right eventually). Clearly then the ferrule is right most on the drawing of the parts listed as "gland, washer and ferrule". That makes the order from left to right, i.e. going into the float chamber, sleeve nut, gland, washer and ferrule. That means there's something they call a "gland" between the sleeve nut and washer. With no reference to what we've been calling the rubber washer, that has to be this gland.

The word on assembly are the classic, "reassemble by reversing the procedure used to dismantle the carburetter".

So the order of the parts on the outside of the jet tube, i.e. excluding the ferrule, must be metal washer, then the rubber washer or gland, then the sleeve nut, which is tightened directly against the gland. This order of metal washer first then rubber washer is exactly as shown in the previous picture of the partly disassembled float chamber.

I think the jets come with the metal and rubber gland in the reverse order just because the rubber gland keeps the metal one on the jet tube.

I've heard of this in aviation systems, where a set of parts came packed in a different order to that in which they should have been fitted - presumably for some similar reason of convenience. That was okay while someone who had been trained went and got the parts and ordered them for fitting. But when he was sick and someone who hadn't been trained got stuck with the job, the parts were put in, in the order they were packed, and all the engines failed at once - which did not go that well, and the FAA bathed in the blood of the airline management.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).

This is a pointless reply, because you will ignore it...
But for the benefit of anyone else who might read this...
You fit the parts as supplied. The correct order from outside to inside is nut, washer, rubber. That way, when the nut is tightened, the washer stays still. You end up with the rubber compressed and gripping the pipe without being twisted up by the nut... That's the point of the washer. It's a bearing surface for the rubber effectively....
Matt.

This is correct.

_________________
Vindicator Sprint, Honda Fireblade RRX 919cc, re-powered by AB Performance. Quick.

Well, I wouldn't actually ignore it. Or do I mean "couldn't"?

What I think is that you should fit the parts in the order stated in the instructions which is the order SU fitted them when they assembled the carbs in the first place: ferule, washer, gland, sleeve nut, as they go down the hole.

It would be nice to hear from others who've taken apart ones that were untouched since manufacture, but I'm sure of the order SU fitted the parts.

And the point of the story about the aircraft engine seals being packed in a different order than assembly required, is that you can't rely on it even in such safety critical applications, where failure condition severity is catastrophic.

As to the technicalities, I do wonder, if the gland goes in before the washer, what's to stop it oozing into the bottom of the chamber between the orifice wall and the tube if the rubber softens. The innermost, bottom most edge of that orifice is only a casting in zinc aluminium alloy. So control of its exact dimensions won't be great - it's a nice casting, and well good enough to hold the flange on the inner end of the ferule in the orifice, and so hold the tube back. But there could be some variation in the gap between the plastic jet tube or ferule flange and the bottom hole in the orifice, casting faults, possibly even damage from disassembly by the ham-fisted.

Whereas, the part of the orifice where the threads for the sleeve nut are cut and the ledge at the bottom of that part of the hole are machined. So their dimensions and tolerances are controlled; as are those of the metal washer and the inner face of the sleeve nut, which should be new every time you fit a new jet. So, if the washer goes in first, it bares on that machined ledge and can be guaranteed to fill the whole of the gap between it and the plastic tube, which is supported by the inner ferule. So, the washer fully holds the gland in compression against the plastic tube, and it's going nowhere unless the packing gland entirely liquifies. Even if it starts to turn to jelly, the packing gland can't easily get out of the stuffing box that is formed anew each time by the inner face of the sleeve nut and the washer.

As to whether there's a need for a washer between the face of the sleeve nut and the gland: clearly there isn't. That the gland is not damaged by the nice new inner face of the sleeve nut is shown by the simple, plain impression of its face on the gland in the previous picture of one (I'm sure) SU assembled. If it was intended that seal would be frequently dissembled and re-assembled with the old parts, that might be a different issue. But baring having to replace the float chamber, I can't see a reason to do that often.

That washer, rubber gland, sleeve nut combination does sound a better solution than the olives, in some ways. And looking at the surround to the inner hole in the orifice, it looks to me like it was meant to take an olive, and the rubber gland was a design improvement (though there may be several reasons for such changes; Microsoft change stuff just because they can). Except, I don't feel I can predict what's going to happen with fuel compositions in the next 10 years or so. In which case, choosing a rubber gland that will be good for that long is a guess - and someone else's to boot.

Whereas, if the olives seal without the sleeve nuts stripping, as they have, I reckon they will be set for life (mine at least). And not in the sense of the wristwatch with the lifetime guarantee - when the mainspring breaks, it slashes your wrist. Though I admit I was worried that they wouldn't seal and wouldn't have tried if I didn't have a spare set of float chambers. So I was a bit concerned when the first attempt failed. But that was carelessness on my part in the assembly, not a fault in the implementation.


But the bottom line is this: The instructions say take note of the ferule, washer, gland, and sleeve nut - I assume meaning take note of the order they come out - and put the new ones back the same way. So if you are replacing an original jet tube seal set that was fitted by SU and you follow that simple rule, you won't have a problem or be confused by what's been written here. But if you are replacing a replacement, be aware of what it says in the instructions about that order they go down the hole - ferule, washer, (rubber) gland, sleeve nut.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).

Oh, just one more thing:

The packing gland that was supplied is cylindrical and clearly meant to fit between two flat faces, i.e. the inner face of the sleeve nut and the metal washer.

As the gland is cylindrical, not conical in any way, to get a lasting seal with it in first, you have to tighten the sleeve nut till the gland is squashed all the way to the bottom of the curved conical part of the orifice and meets the flange on the ferule. Otherwise, it is liable to creep over time, loose compression, and leak. But squashing it to fill all that hole is going to take much more force than squashing it between two flat faces. And I'm not sure that there's enough volume of rubber for it to fill that space anyway. So I think, if it was meant to fit to that curved taper face between the outer and inner holes of the orifice, one of the two faces of the gland would have a complementary shape.

It will depend on how the rubber changes with time and exposure to fuel. So it is possible that with the rubber only filling part of the conical part of the hole, you still get a seal. But will it last as long as brass?

So I think that curved taper face was designed for an olive, and the rubber gland is a change to the design. But rather than change the casting or supply a gland shaped to fit the hole, SU saw that it was cheaper to fit a washer on the back side of it, to turn the taper into a flat face.

By the way, looking down several holes, not all the machined holes have a machined face at the top of the taper. But as long as the washer sits reasonably square on the top of that taper, as it must, that won't matter to forming the stuffing box the packing gland is compressed into.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).

Sorry, really cannot read and digest that level of waffle.
The question has been answered - you can assemble it any way you wish, but the correct way has been stated by Jeroen, Jod, me, and SU who probably ought to know best.

Where's the answer from SU, other than the one I listed that says "gland, washer and ferrule" following inwards from the sleeve nut?

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).

Any parts list, diagram, order a new jet and that's how it comes preassembled, take your pick really....

Well that's half hour of my life I won't get back but never mind - the man needs evidence.

Sooooo.....

Exhibit A - One new old stock, never fitted to a car, sat on a dusty shelf for years SU carb. Guess what! gland in first, then washer, then nut.





Exhibit B - 2018 SU (Burlen) catalogue. Exploded view of HS6 and also actual picture of jets - guess what! nut, washer gland !






Exhibit C - fresh from 1969 (less it is thought someone tampered with exhibits A & B) BMC SU Carburetters (note spelling!) service parts list. Again nut, washer, gland.











Finally Exhibits D, E and F. 3 new old stock jets, still sealed in packets. One unknown manufacture, one Unipart and one SU Butec. ALL have nut, washer, gland AND they ALL have a retaining cap over the end to prevent said items coming adrift and getting mixed up and also I suspect to prevent dirt entering the tube.









Enjoy or ignore as is your want.

I would add that there is nothing wrong with olives on plastic pipes provided the pipe has a reinforcing insert - the plumbing industry have used them for years, BUT the fittings must be designed for olives - think plumbing compression fittings. Just because it "squashes in ok" and "doesn't appear to leak" does not in my opinion make it OK. Also as pointed out by Steve, there are plenty or cars that have or had fuel pipes secured with olives and nuts, but again they were designed that way. I am certain the SU float chamber was not.

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1975 Sprint Man O/D in Honeysuckle Yellow
1971 Stag Auto White

Too many cars, too little time!

Yes, but....

Here's Exhibit G if allowed from the SU manual:

Jeroen

_________________
Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com

Graham, everything you have posted shows the washer behind the rubber, which is correct and what we've all been telling you was correct from the start....
I give up.

Well, finally counter evidence, not just re-statement of opinion and denigration of any questioning of that.

So where it says in the disassembly/assembly instructions at Burlen, "sleeve nut... gland, washer and ferrule" that must be wrong or at least rather misleading, and the four chambers I looked at must have been assembled wrong. Since this new evidence all shows sleeve nut, washer, and gland as the order.

But "washer behind the rubber" is not exactly definitive Matt, without having the sleeve nut in the list. The picture I showed has the rubber in front of the washer, hence the washer is behind the rubber. And that's as you say it, but opposite to the order you mean.

But it still don't matter to me anyway - I've got the brass olives.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).

Well it wasn't a totally useless discussion after all.

As a Dutch I never had heard of the word gland before.

Jeroen

_________________
Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com

Well you liver and learn.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).