Projects The Gin Runner 1926 T Gow

I had it running quite well using this carb and a 90º bend onto the updraft manifold, that wouldn't fit under the bonnet so this is variation 2

 

I had considered that, and it may happen yet

 

My attempt at an SU on my '28 Chevy, the manifold got ice cold, covered in condensation, but that velocity stack looked cool. It may have been due to the lack of an exhaust hot spot to warm it up, so I rigged up a warm air feed to it and it ran worse, gave up then.

 

I've tried a single 1 3/4 SU, and now duals of the same size on a slightly modified Model A with what I feel like is a little success. No icing, but I had to play around with the needle size a bit.

 

I was thinking coiling copper tubing around the intake if there is a icing of the intake issue and running coolant through the tubing. Hook one side to the water inlet and the other to the water outlet.

I'm hoping to not need a water pump, but if I do, the inlet of the copper tube can come off of that.

 

That's good to here (although my setup is 1 SU 1-3/4). But what you and @Blackbob have that @282doorUK and I don't have, is the exhaust manifold right next to the intake.

 

Ive got a '28 Chevy four to fit onto a T oil pan and trans in the pipeline, hoping to get it going with a pair of 1.25" SU's

 

Sorry, I missed that. Well, maybe my idea on heating the intake will work if they ice up.

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I know SU carbs have been used on British vehicles since just slightly after Noah landed the Ark, but (opinion) you are losing quite a bit of power compared to using an updraft Stromberg or Zenith.

Jon

 

You are probably right Jon, but I have a big box full of SU spares and no Strombergs or Zenith carbs or bits. Its a low budget farm yard/barn build

 

Interesting. Not that either of those carbs are withing my budget currently, but would you be able to elaborate on this? You can PM me if you wish to instead.

 

I almost agree Jon, I've had this adjustable main jet Zenith 267 on my stock '28 Chevy for a few yrs now and I really can't fault it.



Had to make adaptors but apart from that very easy to set up, and works very well with the stock vac tank and warm air tube from the exhaust.

But shipping, customs and other leeches mean they're very spendy by the time they land over here.

Worse still they just don't have the look I'm after on my pre war racer, everyone knows old racers have to have at least two carbs sticking out to suck in all the rocks, splinters and track debris, right?

 

I completely understand (and don't really care for) budgets. Dad always told me I had champagne taste and beer income!

Introducting the extra bend from carb to intake costs some power. By fabricating a completely new SIDEDRAFT intake manifold, you could recover some of the lost power. The updraft comment in my previous post is because the original intake was updraft, but the S.U. is sidedraft; gasoline molecules like straight lines, not corners.

Past that, if one looks at the design of the Stromberg and Zenith carbs (round venturi areas, with boosters) versus the variable area, more or less constant air velocity but no boosters of the S.U., the Stromberg and Zenith carbs just do a better job of mixing and atomizing fuel at all engine speeds.

Quote: "Worse still they just don't have the look I'm after on my pre war racer, everyone knows old racers have to have at least two carbs sticking out to suck in all the rocks, splinters and track debris, right?"

As to the multiples, agree completely! Just make sure the number of intake plenums (plenum style intake) are an even divisor of the number of cylinders. There are some good looking (opinion) brass sidedraft Stromberg and Zenith carburetors kicking around, but then we get back to that budget thingy.

Jon.

 

SU carbs can work very well once you learn how to tune them. Old6Rodder has two slant6 engines running three 1 3/4 inch SUs on each and they run great

 

I had the motor running significantly better than the stock T manifold and carb by using the same SU carb on a 90º adapter to the unmodified A manifold. This modification cuts the amount of bends the fuel has to go around drastically , will smooth the path and adds a bit of gravity so I'm hopeful it will be more efficient than what I have tried so far.

 

My single ran well on a modified stock manifold much like blackbob's in post 57. My duals are running on a homemade deal that shoots just about straight into the ports in the block. Just enough bend to get the float bowls perpendicular.


I'm still fiddling with the needles, trying to get it a little richer, but it runs well. Got that Jackleg dual header deal, old police head and a mild cam.

 

you gonna call it "GIN LIZZIE" ?

 

Do you know anything about these pistons? I have the same type raised crown piston in my B Sprint engine that once had a OHV Cragar head on it. They seem to be an effective way to fill the combustion chamber.
FWIW, years ago there was a guy that machined the bevel on 4" 366 Chev truck pistons to achieve the same pop-up.
Really like the gow build!

 

mr hotrod a, you should not use those old 2 piece valves ^^^, they are known to break the heads off. causes lots of problems then

 

They came already fitted to the motor, same as the set in my spare motor and i believe they are aftermarket alloy pistons available from Langs


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Its a pic of the valves I pulled out and replaced with one piece new ones


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Thanks, Blackbob.

 

I bought a 21TT chassis and some 27 panels from Neil Tuckett a long time ago. Nearly there now

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Looks great Blackjack, whats the motor?



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I got a bit more done on the model A manifold on friday. I used a 30mm starret hole cutter and roughed out the inlet stub through into the manifold, did a bit more grinding where the stub used to be and then used a 34mm cutter without the pilot drill to cut out a patch for the hole left in the underside of the manifold.. tbc


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347 Pontiac

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Another lunchtime T break.. i decided the cut tube “patch” wasnt going to be thick enough to fill the hole left by the old inlet stub position, so a rummage in the scrap found an old arbor press tool for cutting discs that was the right diameter.. a bit of grinding got the profile right for the inside of the manifold. I cut it slightly oversize and welded it in. Ive a bit of grinding to do on monday and maybe will finish it with some silver solder on the inside but it looks like i have a good seal

 

I reckon that's what John Gerber called a 'swirl dappled' finish, and it's looking period perfect..

 

Well now, I wonder what happened to this project. Some pretty cool ideas and interesting execution.