clutch lightening servo

[QBee]

Engineer1949 said:

absolutely right peter is the man, and as to getting vacuum before starting the engine only way would be an electric pump as even with the alternator pump still needs to be rotating just that it would supply constant vacuum not dependant on the butterfly being shut or little opening to produce vacuum, seriously considering it for nicks blown chim as like yours now anthony as its turboed much less chance for vacuum to be produced as you are forcing air into the plenum.


john

I have noticed no change in the vacuum since turbocharging. Thinking about it, when I change gear I take my hoof off the loud pedal, which dumps the turbo pressure out of the dump valve, then press the clutch, so I am guessing that at the exact point of clutch pressing I have a vacuum in the right place, even though there is only a fraction of a second between the two actions. What do you think, John?

Peter, do you need to know where my vacuum take off is located on the inlet manifold? I seem to have three vacuum take off points. If I am reading it right, my clutch servo comes off the middle one, but I have a spare to the rear of the power steering reservoir.

[phazed]

You can just see the small copper spigot that comes off the plenum base to the left of the brake servo take off.

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[QBee]

You don’t seem to have one to the right of the brake hose, unlike in my photo?

[phazed]

That is because it is an especially made larger trumpet base to fit the triple throttlebody plenum.

[QBee]

phazed said:

That is because it is an especially made larger trumpet base to fit the triple throttlebody plenum.

Aha, gotcha. Could you drill another hole and fit a suitable fitting?

[phazed]

I could, that would involve stripping off the plane and bass to drill and tap it.

I’m not convinced that this is the best solution as I have tried the clutch servo hose direct on the brake servo nipple and it isn’t an improvement. It is not too bad after 10 seconds or so, (not actually counting).

I am wondering if the triple platinum doesn’t develop as much vacuum as the single plenum. If this is the case then I wonder whether I should use an electric vacuum pump?

For instance:

https://www.ebay.co.uk/itm/Brake-Vacuum-Pump-31317...

I could wire this in to the power steering circuit so that it only runs when the engine is switched on but surely the pump isn’t designed to run all the time or is there some sort of built-in microswitch which switches the electric motor off when not required?

I really could do with some help as I don’t know anything about these things.

Anyone?

[phazed]

Or, use the smaller takeoff for the clutch servo (which is how it is piped up at the moment) and use a reservoir to enable a backup for more strokes.

?

[QBee]

phazed said:

Or, use the smaller takeoff for the clutch servo (which is how it is piped up at the moment) and use a reservoir to enable a backup for more strokes.

?

I bought a reservoir when I first had mine done, then never fitted it, as it was only for the start up scenario. If I can find it now you are welcome to it. I will go out to the man-cave when I have a break from tax returns.....

[Engineer1949]

peter as far as i am aware the electric volvo pumps use a pressure switch to switch on when required., may be the best solution as for the alternator needs to be the type with the pump on the back not like the newer ones with pump behind the pulley may well have to make alterations to the mount as the pump may come in contact with the rocker cover not 100% on any of it as havent really researched it yet, plus nicks is preserp so a bit different.


john

[phazed]

Thanks for that John.

I was having a read up last night and it seems people fit these reservoirs to cars that have highlift camshafts due to them producing less vacuum at low rpm.

I believe this is my problem so I think I will fit a reservoir.

Honestly, this modifying business is always the same. You improve something and then you have to modify something else to cope with it!

Now all I have to do is find someone who sells one of these reservoirs.

Any ideas or recommendations?

[phillpot]

phazed said:

Any ideas or recommendations?

This looks neat................. Vacuum reservoir ... But a strong plastic bottle would probably do,

Edited by phillpot on Monday 22 January 11:01

[QBee]

There are loads on Ebay at under £30 a pop. Just a case of seeing what would most likely fit in your available space.

Just put "vacuum reservoir" into the search bar.

I have unfortunately binned the one I bought a couple of years ago and never installed.

[Sardonicus]

Way too small for a servo vacuum res, those things are for small vacuum demands for actuators fitted to diesel TDI models for example using only 4/6m I.D vacuum line these are very popular on VAG stuff , but not man enough for a servo gulp however these are in fashion at the moment for stuff with a piss poor vacuum signal e.g big nasty cammed motors, or like John said diesel alternators with the vacuum pump attached to the rear, that style also need an oil pressure feed and return to the sump much like a Turbo I might add ...................................... ....

Edited by Sardonicus on Monday 22 January 11:52

[Steve_D]

If the pump is regarded as small then use it with a reservoir. Even a brake servo will give a couple of pumps straight after the engine has run so add in a reservoir should do the trick.

Steve

[SILICONEKID 357HP]

I'm looking in to this conversion ,I've heard 1.9 ratio from the MGB is to light and can make it difficult to find the biting point .

Anyone fitted a 1 6 ratio and if so which one was fitted .
Cheers .

[phazed]

I had this Daz on my Mcloed twin plate clutch which worked well.

Found out my super clutch was faulty and when replaced, the new one was as light as a standard clutch and can handle 800 bhp.

Only cost about £1K with all the trimmings.

[SILICONEKID 357HP]

So you are saying the conversion is not needed .
Is the new clutch fit and forget or like most mods it requires some matchi ng or somthing to make it fit .

[QBee]

SILICONEKID 357HP said:

So you are saying the conversion is not needed .
Is the new clutch fit and forget or like most mods it requires some matchi ng or somthing to make it fit .

Read his post again Daz. His replacement clutch is now as light as the standard one.
Your issue, like mine, is that they standard clutch is too heavy for your poor ailing body to cope in traffic. So you still need the servo. Peter might still have the bits he took off his car, if you are fancying doing the job yourself.

[phazed]

A bit of lateral thinking Daz.

My son fitted a new standard clutch obtained from powers to Alun’s car and it is as light as a feather!

[Classic Chim]

phazed said:

A bit of lateral thinking Daz.

My son fitted a new standard clutch obtained from powers to Alun’s car and it is as light as a feather!

‘‘Tis true”
BUT NOT A POWERS SUPPLIED CLUTCH
TVR PARTS SUPPLIED

My only concern would be if the clutch fingers are a bit weaker than say a Powers supplied pressure plate, it’s the only thing I can think of that has had such a positive effect on pedal pressure.
Now Peters son is a fine mechanic and lubed things up nicely around gear lever joints etc but the pressure is so light I do wonder if it would take serious abuse,,, saying that the Powers one I broke so,,,,,

In all fairness this is guessing and in-fact the clutch has grabbed fine when I have used my near 350ft of torque

It’s been great for sometime whilst it was being used daily.
Recently ran the car and the clutch is exactly the same. Really light and smooth action.

I sometimes get superstitious, I call it my gift from the Clutch lightening gods

Edited by Classic Chim on Thursday 10th October 10:26

Edited by Classic Chim on Thursday 10th October 10:32