The new OLD FTF gets a "Duesenberg DOHC 4-valve"

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Haynes makes a pretty good manual on SUs. Just don't admit to anybody that you bought one :LOL:
Now, if you could come up with a trio of Weber DCOEs....
 
THE FRENCHTOWN FLYER":11zym40d said:
Thanks for the info.

I measured my throttle bores and they are only 1.37. So yes, kinda small, but maybe good for cruising down the street in the 4th of July parade at 3 mph. A YF 1V has a 1.65 bore, but these SUs dont have a small venturi. I'm thinking they have about 40% bigger throttle area.

The SU carb line does have a few larger models in the same basic line. I gather the HS8 models which were used on some of the sixes in the Jaguar XK line between about 1971 and 1975 (or something like that) have a boire closer to 2". There were also the HS7 (about 1.87"), the HS6 (about 1.75), the HS5 (about 1,62") and so on, which were used on various other cars.

If you like the general look of the SU carbs, perhaps the HS8's or HS7's might be about right.
 
HS-8s are often (IMO) overpriced because they make people think of the E-Type. Plus there are some small variations of internals that are costly to bring up to speed if you start with a mismatched set. Not counselling against it, just flagging this point.

Even the HS-6s, which people initially think are "small", flow very well because venturi restiction is so much less than a standard downdraught carb. They're usually quite cheap, too!

RE: Webers - too common, too dear! Everyone overlooks Dell'Ortos, which frequently can do the same job and be purchased far cheaper...
 
Much as I hate to say anything good about the dreaded SU, if you can pick up a 3rd, the 1.5" ones should work nicely on a 300, There's going to be that problem of unbalanced intake pulses to deal with when you have 3 carbs but that's hardly insurmountable
 
Rumor has it that someone has offered him from two to four HS6s off of the early Zcars. :roll: They are the three screw round tops.
 
You mean a three bolt mounting flange, or the vacuum chamber is held on by three screws?

Last of the carbied Integras here, ran CD type carbs, and they not only complied with emissions, but went like stink. Trouble is, they don't look old-tech enough!
 
Many thanks to Stubby for giving me two nice HS6 SU carbs.

I built this intake last week for them. It usually takes me about two hundred hours to fabricate an intake manifold using hammerform dies. This time I decided to make it out of flat aluminum stock. It only took about 40 hours to get this far. I still have to make throttle linkage and an equilizer tube, plus polish it all up, but you get the general idea. Does it look old fashioned? I did zero calculations on it - just grabbed a pencil and sketched the runners kinda seat-of-the-pants like.

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THE FRENCHTOWN FLYER":3kse809w said:
Many thanks to Stubby for giving me two nice HS6 SU carbs.

I built this intake last week for them. It usually takes me about two hundred hours to fabricate an intake manifold using hammerform dies. This time I decided to make it out of flat aluminum stock. It only took about 40 hours to get this far. I still have to make throttle linkage and an equilizer tube, plus polish it all up, but you get the general idea. Does it look old fashioned? I did zero calculations on it - just grabbed a pencil and sketched the runners kinda seat-of-the-pants like.

Nice work.

:)

It looks pretty cool, should look somewhat "vintage" when it's all ground smooth and polished and such. The overall shape is pleasing to the eye, and they at least look like they'll flow pretty well. Not to worry, of course. Even if they're less than optimized I have a feeling that you'll still be making more than enough torque and horsepower to get that light vehicle moving in a sufficiently "brisk" manner for the car to provide some ripping good motoring fun.

:)

Assuming they're big enough to feed that critter I think you ought to be able to get them working just fine. I would imagine that the planned equalizer tube should do a lot to help them to get enough air into the cylinders if it's large enough to allow each of the cylinders to draw from both carbs.

I suppose you'll be needing to find some appropriate vintage looking air filters or air horns for those carbs, but I am sure there must be some out there in catalogs full of gizmos for the guys who mess around with vintage Jags and such.

I'm sitting here envisioning a throttle linkage with at least one bell crank that's drilled full of lightening holes. I'm also wondering if engine-turning some of the parts might not help with the illusion of if being something exotic. Then again that would be a heck of a lot of work, so ...

:)

Have you measured to see how close to the left hood side the overall assembly will be? It looks pretty darn wide, doesn't it?

One thing I do wonder about. For somebody not trying for a vintage look, would it be easier to build an intake like that using tubing and flanges and such? Sort of like a header, but with a plenum and carb flanges rather than a collector? Or does that approach just not work very well on the intake side?
 
addo":34zabz1w said:
What are the tag codes, or what're they off?
The carbs shown in the photos are HS3s that I had acquired earlier, along with the bolt up balance tube assembly. They were used for mock-up but it is now my intention to use the HS6s. Or try both sets at some point.

No tags on them but they came off an Austin Healy Sprite race motor that my friend has.

Stubby's carbs are Japanese copies from a 240 - 280Z.
 
I would imagine that the planned equalizer tube should do a lot to help them to get enough air into the cylinders if it's large enough to allow each of the cylinders to draw from both carbs.

The triangular pads just downstream of the carbs will be used to make a balance tube, about 3/4 x 1 inch in cross section.

I suppose you'll be needing to find some appropriate vintage looking air filters or air horns for those carbs...

I'll probably fab them from stainless tubing.


Have you measured to see how close to the left hood side the overall assembly will be? It looks pretty darn wide, doesn't it?

Good point. But when I remove the cast equalizer tube and make skinny isolater pads I'll trim off about 4 inches. I hope that will locate the air cleaner(s) just outside the hood lines.


One thing I do wonder about. For somebody not trying for a vintage look, would it be easier to build an intake like that using tubing and flanges and such? Sort of like a header, but with a plenum and carb flanges rather than a collector? Or does that approach just not work very well on the intake side?[/quote]

That would work too. The ports on this head are tall rectangles so they would have to transition from round into rectangles, so I took the easy way and just cut out flat patterns and filled in the sides.
 
i have a video dedicated to rebuilding/tweaking/tuning SU carbs Ill be glad to loan you.......ping me off line if interested....mutt
 
Geezer 300":3r5dzw0o said:
Looks great. Just curious why not more of a W pattern... carbs too far apart to do what you want?

The Sprite equalizer tube is where I started out - there is no other reason you couldn't space them farther apart.
 
Not to digress here, but where have you been Muki? The guys were asking about you. I said you were off ice bike racing until the sun came up in March or so.
 
This may be a dumb question, is the runner being so much longer for the 1 and 6 cyl and shorter for the 3 and 4 cyl's going tbe an issue? I always wondered why intakes aren't more like an equal leangth header. Thanks, Matt.
 
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