Triple SU Carbs and Intake

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I have received today the rebuilt carbs from Tom Bryant, who also set them up to open the throttles at the same time and rate of opening. I will leave them attached to the wooden spacer for now until I get the motor assembled. FWIW the 65 motor was bored 30 over, head cut 10 thou and block decked 90 thou and uses a 74 crank standard on both mains and rods

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I been dying to at least temporarily mounted the SUs to the manifold. I had provided the rebuilder - Tom Bryant - with center to center dimensions between the throttle opening. They came out to 7 inches between each opening which is what the carbs weee set as. They fit the manifold perfectly! Am now waiting on some air cleaners made for these carbs

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@65 Dartman, Nice set up for a /6 :thumbsup: I’ve worked with a few SU’s, I have info on calibrations for different engines and needle profile charts. Let me know if you need some info.
 
Thanks! What do you have for the Jag 3.8 series since they are similar in displacement to the slant 6
E
I sent these carbs to a noted SU gentleman who came highly recommended by slantsixdan. He went through them as well as synchronized them to open all at the same time
 
65 Dartman said:
Thanks! What do you have for the Jag 3.8 series since they are similar in displacement to the slant 6
E
I sent these carbs to a noted SU gentleman who came highly recommended by slantsixdan. He went through them as well as synchronized them to open all at the same time
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I’ll let you know, I’ll dig out the specs. Just bear in mind, a lot of the Jag’s were twin carb not triple. Also a lot were 2’’ SU’s not 1.75’’.
 
I do not. I gave intended usage including specs on the motor to the SU builder up in ME. I can check with him if needed
 
65 Dartman said:
Thanks! What do you have for the Jag 3.8 series since they are similar in displacement to the slant 6
E
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I checked the specs for Jag 3.8. It’s not really apples to apples with your setup. They’re twin 1.75’’ or triple 2’’. - HD6 & HD8.

There’s also two different jet sizes for the HIF6, 0.100’’ & 0.125’’. It’s important to know all this info before selecting a needle. Also, your carbs will have the spring loaded needles, the 3.8Jag’s have fixed needles (HD8 & 6) so I really need to know what you have first.

FWIW, the 3.8’s with triple carbs generally have the ‘UM’ needle (0.125’’ jet ) and twin carbs the ‘TM’ needle (0.100’’ jet).
 
Thanks on posting about the books. I shall ask my SU rebuilder about the jet and needle sizes
 
One important, fundamental thing not to forget with SU’s - 3psi fuel pressure maximum.
 
Don, looks good for sure.
On my Webers same fuel pressure concerns.
I ended up with a Holley Red Fuel Pump and their LOW pressure regulator.
I can send you the numbers if you want them.
You have to look for the LOW pressure regulator.
 
I had a set of matched genuine Italian Webers with the Aussie manifold and I bought a low pressure regulator. I believe I still have it so I’ll try to find it snd see what I have. I think I’d like to run a stock engine mounted fuel pump and the regulator OR a low pressure in-tank pump and the regulator
 
i run a standard slant 6 pump on my hemi 6 with my webers
messed about with a regulator granted it managed the pressure but it also reduced flow to the point where i ran low mid track.

disconnected it and have never looked back. you could run 2 gaskets if the pressure is too high

if you run an electric pump yes i'd think a regulator would be necessary.... as the pump takes no account of rpm



Dave
 
I dug out my regulator- it’s a Quick Fuel 30-804 QFT low pressure regulator adjustable from 1 to 4 PSI
 
A good setup on triples is to run a fuel rail / log. Make the rail a large size (1’’ or more). Inlet on the front, return line on the rear with an orifice to drop the pressure and return to the tank. Three tubes off the rail to supply the carbs.
 
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