Not that familiar with SU carbs.
What I believe in the factory manual are called the overflow pipes - on mine, there are no hoses fitted to what is a short nipple at the bottom of the carbs.
Should I have hoses on them and do they empty on the ground?
Could it cause a problem if no hoses were fitted?

Also in the owners manual it says you shouldn't coast in gear with your foot on the clutch.
Is it imperative that I follow that instruction?

 

You're riding the clutch when you do that, and in Jaguars, the bearing is this sort of bake-lite substance that will heat up if you do that.
Why would you want your foot on the clutch at any time except to change gears ?
If you want to coast down hill, take the trans out of gear and and put it neutral. This will enable you to take your foot off the clutch.

There are 2 breather pipes on top of the float bowls and 2 at the bottom of the plenum chamber _ all vent out into the atmosphere.

The hoses are just to direct the fuel away from the car in case the carbs over flow from a pump that may not shut off if the due to a failed or failing float valve.

Yes, they empty onto the ground in case of fuel over flow _ and that is called the plenum chamber, it's part of the intake, and not actually part of the carb system.

 

@JeffR1 Ok thanks much.

So I live in the city and lotsa stop-start action your foot ends up in the clutch a lot with it in gear. Will try not to do that!
That kind of action wouldn't happen at speed for sure.

Thanks again ~ Dave

 

Listen to Jeff re the carbon thrust bearing. You would accelerate wear ~ Don't ride the clutch ~ take the car out of gear. The nipples on the bottom of the carb Plenum Chamber should have plastic/nylon hoses connected to them that dumps excess fuel on the ground. Failure to do this puts you at risk of an under bonnet/hood fire.

 

I've said before, Bill Heynes' regarded the clutch as a minimum use item; you only put your foot on the pedal when you absolutely have to and then you depress it to the maximum and release it as soon and as as quickly as possible. That may be why our engines have such heavy flywheels. I regret not asking him for some clarification when I had the chance.

 

https://www.scparts.co.uk/sc_en/clut...g-1-22518.html

There is a roller type upgrade for the diaphragm spring clutch. I don't know if it is any good or worth the extra cost. Perhaps in the unlikely situation of someone who uses their car every day for commuting.

 

These Roller thrust bearings are a sensible and substantial upgrade to the carbon bearing. I have one waiting at the Southern tip of Africa should I experience any trouble with my new carbon thrust bearing. In many ways I'm sorry I did not fit it but was going for originality. Probably a dumb decision. At least my car will seldom spend time in any heavy traffic. It is a sealed for life bearing. I have even had the Donaldson workshop that is duly equipped unseal it and repack it with our Polyurea Synthetic, long life grease for such bearings that we sell to all the Japanese sealed for life bearing manufacturers where every bearing produced is noise tested as do the bearing manufacturers in Ningbo, Zhejiang province, China. Their QC and materials are top notch. Just as good as any SKF, *** etc. bearing.

 

... another item for my drive train shopping list.

 

Annnd you answered my next question if there was an upgrade.
Fortunately I've made contact with they guy who put the engine & trans together which was two owners ago. Will have to ask if he upgraded.

The clutch as a "minimal use item"??? Am I the only one who thinks that's insanely ridiculous? haha
Like telling a guitar player those six tuners are minimal use only! Another tax for being the coolest kid on the block I guess.

 

At one time all old cars used carbon thrust bearings.

It's like our Polyurea Synthetic, long life grease for such sealed for life Japanese & Chinese bearings. It is a product we have a total monopoly on ~ We know how to make silent extremely high performance greases. As an example it is the only product approved for Voestalpine AG, Austria continuous casters. Yes it will handle those temperatures. Much as ExxonMobil have a monopoly on Nuclear. There is only space for one oilco to specialise in that area. We don't waste our time there.

 

You have to keep in mind that back in the day, even if we hadn't started to use the word, we were much more into 'sustainability' than in more recent years. Changing a clutch isn't a small job on any RWD car and especially not on one of ours. And a long clutch life is possible; my Mk2 covered more than 100,000 miles without a swap. The owners manual gives the same advice as Jeff perhaps a little more strongly. I don't know where I read it, but I'm sure I've seen that Heynes even instructed his racing team not to double de-clutch.
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@Peter3442 Right. Back when we were required to do actual maintenance on cars.
Had a lot of std. trans cars over the decades, and have yet to completely wear down a clutch on any of them. The absolute bare minimal slippage at all times being the best way to achieve that of course.