Chandler Groves Carb Logic?

[Fred A]

About a half century ago I ran these carbs in singles and doubles on my A but the supply chain for power valves has become more specific since then. To avoid incorrect enrichment we would ask for economizer valves for Ford 94, 92, or Zephyr and some forgotten others. The vacuum pulses were a problem for these V8 carbs on the models A/B. To tame these pulses with vacuum power valves which way should I nudge the choices. The recommendations for the V8 are pretty well known, but the bangers get far less attention. Any educated guesses for the Models A/B with mildish cam and 7:1 and straight through muffler? Trying to get a renewed sense of this kind of tuneing. Thanks: Fred A

[Walt Dupont--Me.]

This is just a guess but with your engine and a 94 carb, I'd start with 49 jets and 4.5 power valves. I have this setup on a Model A engine I just built this winter in a 30 stock roadster, engine bored .060, counter balanced crank, cam ground with a Esky 77B grind, down draft 94 carb, 37# flywheel drilled for a 9in. V8 clutch. The engine sounds and run great in the shop haven't gone for a ride yet. Walt

[ken ct]

Originally Posted by Walt Dupont--Me.

This is just a guess but with your engine and a 94 carb, I'd start with 49 jets and 4.5 power valves. I have this setup on a Model A engine I just built this winter in a 30 stock roadster, engine bored .060, counter balanced crank, cam ground with a Esky 77B grind, down draft 94 carb, 37# flywheel drilled for a 9in. V8 clutch. The engine sounds and run great in the shop haven't gone for a ride yet. Walt

Walt sounded like he wanted to run 2 of them. BTW 4.5 PV are no longer availible that need no modifications. I still have a few 3.5 ones and when these are gone thats it for supplying low # PV for multiple setups from me anyhow.. My supplyer cannot get them any more. sorry. ken ct.

[Fred A]

Use of the 94 on V8s has led me to prefer the 6.5 or even the 5.5 to tame some of the slobbering gas guzzling specimens 59A, but that possible pulse problem on the banger has made some rebuilders Ron Kelley say bad things about its use on a four. All I remember was that i was able to get better fuel economy after some attention than I got from the Stromberg without signs of lean mix at cruise speeds. I might slither over to the Model a forum but expect there may be more knowledge of these CG carbs over here. Thanks for the responses. Fred A

[Bruce Lancaster]

The lower numbers should reduce sensitivity to pulsing...might be intersting to tap in a vac gauge right below carb and see if you can find out the actual range of any pulsing. You would want to find a PV sensitive to less than the range of pulsing...

[Charlie ny]

Fred,
Holley vac operated PV's are still available at any speed shop. You
may have to special order the low numbers but that's usually a day or two wait.
The head on the Holley PV is a bit big and requires a slight clearance cut in the
bowl to eliminate interference. I use a .470 end mill to do this...no big deal.
I'm sure you are aware of the gasket situation under the PV.
Charlie ny

[Walt Dupont--Me.]

Originally Posted by Charlie ny

Fred,
Holley vac operated PV's are still available at any speed shop. You
may have to special order the low numbers but that's usually a day or two wait.
The head on the Holley PV is a bit big and requires a slight clearance cut in the
bowl to eliminate interference. I use a .470 end mill to do this...no big deal.
I'm sure you are aware of the gasket situation under the PV.
Charlie ny

Hey Charlie, I always thought the power valves were the same except for the bigger end and I have used the ones where I've inlarged that area with no problem, BUT, awhile ago I orderd 3 block off plugs for a race car engine with 3 carbs from a shop near me that builds alot of race engines, when I got them the threads were not long enough, even with a thin gasket, they would only catch about one thread in the carb. SO, this is a trick that I've used before and haven't had any trouble with yet. Instead of using block off plugs I used the spark valve, (I have alot of them left over from broken kits) thay stay closed all the time and the plunger has to push down to open and that's not going to happen in the float bowl. What do you think about that? Walt

[Charlie ny]

Walt,
I'm not sure about the use of spark valve plugs. I guess I'd be tempted to
place them in some corn gas for a while and see how they looked after a good soak.
I certainly agree with the Holley plugs being too short...additionally the 3/4 dia
gasket face is usually off square with the threads since this is not the face used to
seal in a modern Holley carb.
I'm building a multi carb setup now for a local customer...for the street...
I'll try those plugs on the end carbs. Thanks for the idea !
Charlie ny

[Walt Dupont--Me.]

Charlie, there should,nt be any gas on the diafram of the that spark valve as long and the valves stays closed. All there is is vacuum sucking down on that diafram whitch helps keep it closed, correct? Walt

[ken ct]

I would tend to agree with you great idea,i have a bunch of spare ones also,be good to put them to use.Great tip thanks.ken ct.