E10 Specific Gravity

[john williams]

I have recently become aware of the smell of petrol in the garage where I keep my RL. There has always been a slight aroma, but recently it has become more noticable. Over the last week I have had the engine out to adjust clutch levers, and became aware of a constant slight leak from the reserve tap on the petrol tank. I have always made up my own "tap corks" from sadwiches of thin cork using a hollow punch, centre drilled in the lathe. I assumed that this method could not cope with the E10, so purchased the correct corks from Tony Betts. That cured the tap leaking. 
However, on getting the engine back in, I noticed a very slight drip of petrol from the 26va side draught I am using. My first thought was, add a fibre waher under the needle valve. It turns out, I have already done this,but had forgotten I had. I have since changed the needle valve and tried 5 different floats, but the leak from the carburettor persists.
I started thinking possibly, the Spefic Gravity of E10 petrol was lower than E5 and the old unleaded petrols, causing the float to sink slightly in the bowl. A quick "google" search on Petrol E10/5 Specific Gravitries, shows that E petrol have very slightly higher SG than unleaded!!! That report dated 2017.
So what to do next? I have thought of trying to solder a thin copper patch onto the top of the float, but I am not sure how much heat the float can take without distorting.
Any thoughts?

[Duncan Grimmond]

If you add wieght to the float will it not sink further and so exacerbate the problem? Or, am I upside down there? If the needle in the float is fixed rather than clipped and you want it to ride higher then a larger, more buoyant float is the only way.
I have adjusted the weight of brass floats in Amal pre-mono bloc carbs by using an electric soldering iron to sweat a little blob of solder to the float. Use an active flux like Baker's Fluid or Zinflo but be sure to wash it off well.
WARNING
*** Overheating it may cause the seam to split! ***

[circeonya@hotmail.com]

Not quite off topic I suppose. As 17 YO (now 83) I observed there was liquid in the Zenith float. I was advised to immerse the float in hot water and locate the leak by the bubbles. No bubbles. In hindsight it had probably been repaired and some liquid was left in it or maybe on purpose to lower the float level. But in my haste I decided to heat the float over the gas. That did not end well. I was wearing just a singlet and shorts at the time and the resulting explosion sprayed me with burning petrol which did not improve my singlet, for me i dived onto the lounge carpet to extinguish the singlet which luckily must have been pure cotton. Just a few blisters but it took me half and hour to find the now badly distorted float top. I was able to straighten it and resolder the float. Lesson learnt, after resoldering I tested it with hot water.

[john williams]

Thank you for your replies. Having failed to cure the fuel drip from the Zenith, I fitted an OM 1 inch SU that I have had on my shelf for nearly 40 years. 
Cured the fuel leak, and the improvement in performance is truely astounding. I had always thought the car ran so well with the Ruby carburettor, it wasn't worth changing. How wrong can you be.
John

[Chris KC]

No less a benefit John is an end to fiddling with jets at the roadside...

[Howard Wright]

Hi John

Well done…..You might even keep up with me on our next trip  .

Cheers

Howard

[phillips]

Hi all, we fitted a 1inch SU too our Ruby a number of years ago, what a difference, no more flat spots pulling better, all round good mod. S&P

[Terry McGrath]

Probably Sir Herbert would have fitted S.U. carbs to all his products if it had not been owned by his arch-rival Morris. Certainly I have always used SUs on all sevens I have owned (except the Type 65 which had its original 30VE1). Less hassle, more performance.

[john williams]

Barry,I have a nippy with it's 30VEI. With the improvement from the SU on my RL, I've toyed with the idea a Ruby manifold and an unused 1 1/8th SU I have. 
I now use the Nippy very infreqently, as Nora my wife has difficulty getting into the Nippy and feels very exposed when it. So I will probably leave it be.
John

[Harry Hales]

Hi John
Your problems art,n quite over yet as the float is affected by E10 Peter got me replacement floats  for my SU  from The SU carburetor company Tel 01722 412500 They might even have one suitable for our A7 carburetors Your lucky that you can now keep up with Howard's new super A7  You never know one day I will also be able to do the same.
Harry