Stromberg float and E5 petrol

[keith1948]

Just thought I would share my experience of a problem I have just discovered. This weekend on my 4A I replaced all fuel hoses with R9 ethanol compatible, changed the sender gauge float gasket for Viton, changed filler hose for compatible hose, changed O rings in Strombergs and installed 'stay up' floats. Looking at the original floats (over 30 years old) I noticed one had developed a 'blister' and there was a bit of corrosion just above the lower O ring on the lower jet assembly. In the last few years I have used E5 petrol. Not sure if these issues are ethanol related though. Probably worth using 'stay up' floats in carbs even with E5.

I also found that my sender gauge float is metal so not worried about that.

Keith

p.s. purists look away now but sender unit didn't want to come out so had to cut a semicircle out of the flange that the boot seal fits on to get the sender gauge out. It will be covered by the boot back panel so not visible. Alternative was to move the tank.

Edited April 16, 2022 by keith1948
typo

[Lebro]

I have been looking into fuel hose specs today, as I am going to replace all mine (TR3).  As far as I have been able to find out the "R" number dictates the maximum pressure the hoses can be used at (R6 max is 50 PSI, R9 is 150 ish)  The J30 refers to its ability to withstand ethanol etc.

So, for carburetter equiped cars J30 R6 is perfectly suitable.  I will actually be using a marine spec hose (cos I have some) J1527 + ISO 7840-A1 which is also rated at 50 PSI, & up to 15% ethanol.

Bob

[keith1948]

Hello Bob

Here is a link to fuel hose spec that I found. The main difference between R6 and the R9/14 is the permeability from the table in the link. R6 is 600 g/m2/day whereas R9/14 grades are 15 g/m2/day. R6 and R14 are both rated 50 psi whereas R9 is 100 psi. So for carbs R14 seems to be best bet whereas for fuel injection R9. Although R6 is ethanol ok, the higher permeability (in a boot area) might give rise to petrol smell.

I chose R9 because at the time I hadn't come across the R14. I would recommend stay up floats for either SU's or Strombergs (available from Burlen). I changed the O rings for Viton in my Strombergs and by noting how many turns the adjuster nuts took to be released I was able to keep the original mixture settings. As a matter of interest the small top O ring in the original was square cross section whereas the replacements are round cross section. I have a couple of other spare Strombergs where this O ring is round. I did a practice run on the spare. A couple or three years ago I got some Stromberg stay up floats from Joe Curto in New York. In the UK Burlen now stock them.

Keith

http://www.volksbolts.com/faq/fuelhose.htm

https://www.britishsuperior.com

http://burlen.co.uk/?___store=default

[Lebro]

Thanks for that. I think the marine spec hose J1527 + ISO 7840-A1 which I am going to use has a better resistance to fire than automotive hose. Which is why it has a thicker wall (16mm for a 6mm bore)

Bob

[stuart]

I would only use R14 spec now regardless of pressure applications.

Stuart.