Holley 94 Rebuild - Secondary Carb

[1952henry]

I’m thinking that is a spark control valve, not a power valve.

[Ziggster]

Interesting. I’ve never seen one of those. It’s supposed to be a “plugged” PV.

[Mart]

Tried progressive duals years ago. Gave up and went with both together.

Mart.

[Ziggster]

Well, we’ll find out. I’ll do whatever works. Haha! Want though to try progressive first. Never did yet go back and check the intake, but pretty certain it’s the “open” type, otherwise this would be a none issue.

[Ziggster]

The tiny cutting disc worked. Finished it off with a tiny drum wheel. Have to leave no to do some errands.

[Mart]

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That's definitely not a power valve. It is used on later 8BA engines and is to do with vac signal for the advance mechanism. You don't need it on your carb.

[tubman]

Originally Posted by Mart

That's definitely not a power valve. It is used on later 8BA engines and is to do with vac signal for the advance mechanism. You don't need it on your carb.

Yep. Those are called "spark valves" and they come in just about all 94 rebuild kits these days even though they are not used on most of the earlier carbs. The result the prevailing "one size fits all" philosophy. I have a couple of actual 94 power valve plugs I got from Charlie Schwendler up at my shop. I can post a picture if you want to see what they look like.

Looks like you were working with the wrong "Charlie".

[petehoovie]

Originally Posted by Ziggster

The tiny cutting disc worked. Finished it off with a tiny drum wheel. Have to leave no to do some errands.

[Ziggster]

Originally Posted by tubman

Yep. Those are called "spark valves" and they come in just about all 94 rebuild kits these days even though they are not used on most of the earlier carbs. The result the prevailing "one size fits all" philosophy. I have a couple of actual 94 power valve plugs I got from Charlie Schwendler up at my shop. I can post a picture if you want to see what they look like.

Looks like you were working with the wrong "Charlie".

Sure. I would like to see what they should really look like. I got a few fuel fittings years back from Charlie in NY. Haven’t had issues with Charlie from
Vintage Speed until now. Will call him this week about some of these problems.

[Ziggster]

Installed the revised PV and now no issues with clearance/fitment, but that’s it for today. Will have to resume tomorrow for a bit.

[Ziggster]

Spent a bit of time doing some digging on the interweebs, and seems like that “plugged” power valve is indeed a spark arrestor which was never used on Holley 94s. Also found what is the proper power valve plug. Geeze! That looks like a proper plug. Damn!

[Mart]

I might be wrong on this but I think plugged power valves are more of a race application where the main jets are richer to compensate.
For street applications you can keep power valves in place.
I run twin 94s with stock jets and power valves as duals on a dual 8BA type manifold on a stockish 39 Merc motor. It runs great.
Each carb was ran as a single and checked to be running well before switching to the dual intake.

[Ziggster]

Thanks for the info Mart. Based on the little I know about you, I trust that you know what you are saying and doing. I know I’m going against the grain in terms of progressive linkage and a secondary carb with a plugged PV. I created this thread (not sure if I already posted the link previously) on the HAMB before I started all this, and yes, IIRC, most folks were of the opinion that progressive was not the way to go. However, I believe there were a couple of folks that went to progressive after not being able to get a dual carb setup to work properly with straight linkage.
There are so many factors involved with each engine, cam, intake, carb, carb tuning, timing, etc. I can see why there are some that had issues with straight linkage.
I’ll admit this is my first attempt at this, and I’ve only had my engine running for less than 20 mins after rebuilding it, so my actual experience level is zero. Haha!
That being said, the main reason for trying the progressive linkage is the design of my particular intake manifold. It’s rearward biased as the front carb is in the exact location as the stk Ford intake. This fact allows the stk generator to remain in the stk location. My pea brain figures that even with an Isky 1007B, and slightly higher compression than stk, a single Holley 94 is still more than sufficient in terms of required CFM. Therefore, having the engine run most of the time on the forward primary carb makes sense and will also aid in fuel economy (not really a concern though for me). Therefore, just having the secondary operate at times when the throttle is around 60% - 65% seems to make sense as it will be rearward biased in terms of fuel deliver. At least that’s what I’m thinking. I don’t really expect much in terms of any actual performance gains, but rather like most of us, it’s a vanity visual thing. lol!

https://www.jalopyjournal.com/forum/...tions.1343799/

[Ziggster]

Top body after sanding sealing surface with JB Weld.

[Ziggster]

The rebuild kit came with his “Rotoloc” disc float valve. Going to stick with the traditional for now. Even after taking the edge off of the four corner, the valve stillgets slightly stuck. I’m sure the fuel pressure will push it down, but I’ll take a little more off the edges. Then, I’ll set the float height, and button this thing up finally.

[Ziggster]

Back at it today. Yesterday was a write off. Made a template to adjust float height. Set it to 1-11/32”. Needle still sticks a bit, but it has nothing to do with the fit. I think it’s the black tip that sticks. Not sure what that material is. I’m guessing the fuel pressure will be enough to unseat it.

[Ziggster]

Polished the accelerator pump well surfaces with my Dremel wire wheel a bit. It just felt a little stiff. Added some 3 in 1 oil to the cup seal. Pic of the “return” spring. Seen some springs mounted to the plunger shaft.
Filled the bowl with some Varsol to check the fuel flow out of the squirters. Works great. Better than my first carb rebuild. Will double check the operation on that carb. Made a short vid, and will post to my YT channel later.

[Ziggster]

Went to install the top portion, and it wouldn’t seat. The tall cluster tower was interfering with it. Compared another top body, and the other one has a deeper recess to allow clearance for that tall cluster. So, re-installed the “original” style clusters. The other top sections were not yet painted, so didn’t want to deal with that.

[Ziggster]

Also went back and checked the float to make sure it was not leaking. Dunked it in some near boiling water, and saw no bubbles.
All sections assembled. I have qty 6 new Philster Head screws, but will use the original ones. Will clean them up and paint them later. Installed the throttle lever and link to accelerator pump. Noticed that the accelerator pump would not return to its “neutral” (all the way up) unless I “snapped” it. Removed the return siding under the plunger seal and stretched it a bit. That helped a little, but still would bind up and not “retract” all the way up. Determined that it was not an issue with the plunger/return spring but rather the the throttle linkage. Tried a new accelerator pump shaft link, and it made no difference. I think the throttle lever is rubbing a bit on the cast iron base. The throttle plate shaft surprisingly has some play end to end, but only when not in the closed position. I think an actual return spring might be required.

[Ziggster]

Made a plug for that vacuum port. I believe I did the same on the first carb (first pic). There was a bolt in my box of parts that was cut. A 1/8” NPT pipe plug kinda fits as well, but I doubt very much it’s a tapered thread.