Vacuum retard distributor

[xk.app.soc.]

Hello All.
I have a late series 2 E Type with a vacuum retard distributor, as I've removed all of the emissions, I've been advised to change the distributor to a vacuum advance distributor. I had a chat with Joe Curto in the US regarding this and he recommended I contact Rob Medynsky from British Vacuum Unit.
Rob said he could rebuild my distributor to an earlier series 1 41060 spec with vacuum advance and could machine the front carb for ported vacuum.
The alternative is to ditch the distributor and buy an earlier series 1 distributor.
My question is, can anyone recommend an engineering/specialist company that can machine the front carb for ported vacuum to save me the trouble of sending the carb and distributor for Rob to carry out this work in the US.

cheers Phil.

[Joes66]

Why not just fit an Pertronix distributer or a 123 distributer?
Then you get electronic ignition as well
Saves drilling and modifications and you can just keep the old one with the car if you ever sell it
Joe

[xk.app.soc.]

Thanks for your reply Joe. Does a Pertronix or 123 distributor not need a vacuum source

Cheers Phil

[mgcjag]

Hi Phil....you can get with or without vacume.....what carbs are you useing twin strombergs or tripple SU.....quite a lot of info on the US Jaglovers site on 123 etc as a replacement for the vac retard dizzy.....Steve

[johnetype]

There's a wide range of replacement distributors available but you do want one with vacuum advance or you could have your existing distributor rebuilt with the correct advance curve and vacuum advance added here in the UK.

Drilling the hole required in the front Stromberg for the ported vacuum is not difficult; any local competent machine shop could do it for you. I did it myself with the carb still on the car.

[xk.app.soc.]

Thanks for your reply Steve.


John......Any chance of a photo. Hole size, location ect.

Cheers Phil.

[johnetype]

My front Stromberg already had the threaded hole for the brass vacuum take off adaptor cast into it, it just wasn't drilled through to the inside. I fitted the brass adapter and also used it to centre the drill. I drilled a 2.5mm hole iirc. The aluminium carb body casting was very nice to drill and it was easy to dress the housing where the drill came out into the housing. I held the throttle fully open whilst drilling so the drill didn't mark the throttle butterfly.

[max-it-out]

Hi John , has the fitting been a success , ie. does the vac give the proper advance ? I drilled my Stromberg in a similar way , but when connected it doesn`t seem to have any effect .

[Drive35]

Looks like you've opened another can of worms, Phil!!!

Does drilling the top of the carb do the same job as the tube take off underneath the front carb, which mine already has and seems to be open? Assume I've got a 'vacuum retard' dizzy, like you, but as my car is auto, there's a slightly different part number quoted on jag-lovers, which might explain why yours was undrilled.

I also seem to have a spare take off at the back of the inlet manifold that is crudely plugged with a screw into a bit of tube? Where should that go otherwise? I've removed the vacuum pipes to the original air filter.
Cheers
Geoff

[johnetype]

No worms, it works exactly as it says on the tin..........

The drilled hole exits adjacent to the top of the throttle butterfly where it should be so that with the throttle fully closed the hole is shrouded to cut off connection to the main venturi but as soon as the throttle opens the hole and thus the pipe connected to it are subject to the same level of vacuum as in the inlet manifold.

It's identical to where Strombergs that come with a vacuum advance connection as supplied from the factory is so it has to work.

[vee12eman]

Hi Phil,

When I spoke to British Vacuum, here’s the answer regarding where to drill the ported manifold hole. Note I have a V12, so it could be different, but I doubt it. Several months later, I plucked up the courage and drilled it myself, using a Dremel type tool. My hole is a little larger than recommended, but the car is going very well now, having changed from retard to ported vacuum advance using the vacuum unit from British Vacuum.

Reply was as follows:

“I attached info of the TR6 Zenith carb ported vacuum. It’s the same for the Jaguar V12 Zenith carb.
The small port hole is .540 from the outer edge inside just past the disc on the air cleaner side.”

The reply also included a picture showing a drilled carb and stating the small hole diameter of 30 thou. Location is similar to photos earlier in this thread.

Hope that helps

Regards,

Simon.