mk1-forum.net

Are there any clever people who can convert 20 degree angles H4 float bowls to 30?
.. new they're £100 each!

I think there is no need for clever people - a simple float chamber adaptor from BURLEN shall do the trick.
http://sucarb.co.uk/float-chambers-spar ... ptors.html

I think those are for use with HS carbs only.

I did have the same question as the OP a few years back and some clever people did reply. I never got round to trying it myself and I can't find the thread now. ( not very clever).
As I recall it involved a bit of heat and judicious brute force. Making sure the forces are applied carefully so as not to distort/ break the casting.
There was also use of soap involved by one poster!

Mark F commented he had tried it but wasn't pleased with the result.

Alternatively several people have commented on here that you can run the 20° bowls with no problems.

I'm sure others will add to this.

'S'-type wrote: ↑Tue Oct 13, 2020 11:10 am I think those are for use with HS carbs only.

should have read the title more thouroughly

I tried on my set but they are too brittle and didn’t have much luck, ended up buying new one for the one side and a used Morris minor one for the other, I believe they work ok at 20 deg but didn’t try, unsure of which set you have but I had mga ones and changed choke levers as well. The linkage I modified

Although I have been away from the Metallurgy Dept for decades, I seem to think that if they are made from Mazac, their ductility will be zero. This means that they are brittle and will not deform even when heated. Mazac is a zinc based alloy and Zn has a hexagonal close packed crystal structure which makes it brittle. If they were aluminium it would be a different story. Al is face-centre cubic and deforms easily. (Too much info ?)
I would be impressed to see any Mazac ones that have been successfully altered to 30 deg.

I have had a few sets of early Alexander H4's that ALL had modified float bowls. This was common practice in the early days, before 30° bowls were widely available.

As has already been said it can be done quite easily, you just need to be careful with the temperature, but when they are done they do "look modified" it's not a flawless modification.

All round it is a MUCH better bet to just use 20° bowls and not worry. There are NO issues at all with using 20° bowls apart from the endless queue of smart alec's who won't be able to control their excitement at being able to tell you that you have the wrong float bowls on your carbs.

mk1 wrote: ↑Thu Oct 15, 2020 1:03 pm apart from the endless queue of smart alec's who won't be able to control their excitement at being able to tell you that you have the wrong float bowls on your carbs.

I don’t think I could live with that .. I may have to bite the bullet ..

I have done it by taking 5 degrees off both faces of the manifold, 5 off the head end, and, 5 off the carb end.......

You need to do something fiddly with the manifold mounting washers, but, not too difficult......

And, plug and re tap the mounting studs at 5 deg (to bring them back to 90)............Was about a days work puttering about......

There’s a Morris minor su on ebay with auc4815 bowl and a auc1019 choke lever for £39.95 or best offer, may be worth buying
Also another auc1019 choke lever for £10.