Posted By : John Davies,
20-Jun-2006, 08:06pm
John,
No argument with the above. Here's a pic of my old Vitesse that had HS6s on a 2500 manifold. Only one hole needed in the bonnet, for the
front carb dashpot, which I covered with a discreet, and IMHO rather dashing, little fairing beaten from a piece of scrap alloy.
I admire Van's mods, but if you are willing to have a hole in the bonnet, it's not necessary.
If you do follow his advice, remember that these HS6s are built to be at an angle. The float chamber is not vertical to the line of the
venturi, but correcting that would be an easier mod thna Van's. The float chamber is held to the body iof the carb by a single bolt, and
there is not fuel passage between the two. SU cunningly designed this carb to accomodate such canted applications. The body and float
chamber engage by flanges, that only allow them to be in one position. I expect that the body flanges are fixed and the floats would be
madefor each application. It would be easy to remove the gfloat flanges and position it at any angle, perhaps locking with an ST screw or
even Araldite.
Having said that, I never bothered to alter the angle of the manifold and the carbs ran fine with the float chambers off vertical.
John
Shiny new 1.75 HS6's
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Posted By : Van Hamlin,
21-Jun-2006, 00:20am
The carbs will work over a range of angles, on a Mini for example they are at 30 degrees to the horizontal, but the float chamber is
still upright. This is because there is a piece of metal called a "float chamber adaptor" between the carb and the float chamber which
has a slot in it so the float chamber only fits at one angle. If you take these off a Triumph, which has horizontal carbs, and swap
them over, left to right, you end up with the float chambers at an angle of 30 degrees to the carb - this is how they do it on a Mini -
it's the same bits just exchanged left/right.
If you fit this manifold to a Vitesse like John has, the carbs will be drawing air downwards slightly (6 degrees I think). If you fit
it like I have the carbs will be drawing air up. In both cases, the float chamber won't quite be vertical. When I did this mod I was
concerned that, if I fitted the float lids so the float pivoted on the high side of the lid, I would have more fuel in the float
chamber than intended. I'm not sure what problems this would cause if any and would rather fit float lids with the float pivoted on the
low side of the lid and have a slightly lower petrol level, knowing this would definitely be safe. I have a feeling this was just a
case of rotating and/or swapping over the lids.
Van
PS thanks for the compliment John!
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Posted By : John Donovan,
22-Jun-2006, 09:53am
Wow - fantastic, detailed info - I'm rather drawn to the dashing 'power bulge' in the bonnett but I will have to consult 'she'
.
Thanks Im now looking foward to having a play with these.
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Posted By : Tom
Longley, 22-Jun-2006, 01:36pm
Hi,
I fitted a pair of 175 SUs, using the inlet manifold from a 2500S, to my 2.5 litre Vitesse about 10 yeas ago.
I did some research at the time, and I recall that in the 2000/2500 "big" Triumphs, the engine is canted approximatley 6 or 7
degrees off the vertical. I did not have the manifold machined to compensate for this but I did fit the shorter dashpots, which
I think came from a TR7 (though I'm sure Dolomites had them too). At the fitting stage, carefull lowering of the bonnet
revealed that, although clearance was not excessive, no mods were required to the bonnet on my car.
I hope you have fun fitting these nice new bits!
Regards,
Tom
