8BA 94 carb

B

Boxhead

Senior Member
Hi All,

Was making the 1/4 line from the pump to the carb today and noted a small amount of dirt in the fuel inlet of the carb ( wasp rolled mud by the looks, my bad as I did not plug the inlet when I finished last week.

So I thought I better pull it apart and clean it out rather than just think I have gotten it all out. Glad I did as it is a mess inside not only at the inlet from the dirt but also some scale etc. Ironically it ran fine last time I started it.

So I have a kit and have disassembled and cleaning, I havnt done one of these cards previously and am wondering if there are any tips/tricks or things I should do while it's pulled down?

The kit has all the valves, gaskets etc, but are there jets etc that will work better for the 8ba than the ones in the kit? I will get the numbers off the ones in it tomorrow as I havnt taken the jets etc out as yet.

What are your suggestions?

Cheers


Corey




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Thanks guys,

I was looking at some videos but didn't see one by Charlie, i will go look again now. If i
Run into trouble i will touch base.

Thanks again

Corey

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Once apart, soak it in a covered container of acetone for 24 hrs or so. That, followed up with a liberal blasting of canned carb cleaner in all of the orifices.
 
Be sure to wear safety goggles to protect your eyes from the carb cleaner as it tends to instantly blow back when you squirt it into small orifices.
 
Thanks guys for the links, info, suggestions. I continued this afternoon to work on the 94 carb. Cleaning, inspecting etc and am now at the power valve. I read suggested posts etc and still have a couple of questions if you could help me out.

I have attached some photos, the valve on the left is the valve that was it the carb, the two on the left are what came in the kit and you will note they have a different head. What is the reasoning for this or are they used in different applications? I also note there is no step where it seats but just an internal radius so I assume this will seat correctly and seal.

Also attached a pic of the kit I am using, is it ok to just use the similar power valve to what came out if it? I think it had an 8 on it but would need to go and get a picture to confirm.

Any help appreciated


Cheers

Corey
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The one on the left of the two on the right (the middle one) is a "spark valve" that is used on later model Holley's. The 8Ba does not use a spark valve so it can be discarded (so someone is not tempted to use it as a power valve at some later time). The original has the mounting surface somewhat obscured by the gasket, but the replacement looks correct to me. As someone above said, testing the power valve for leakage before final assembly is a good idea.
 
x2 what Denny aka tubman says....I can suggest installing the jets ,power valve and front plugs
then fill the bowl 1/2 with gas and let it sit overnight and check for leaks. The new power valve should have 5.5 or 6.5 stamped on the brass nose.
Scroll back and check out an episode of Mart's Garage where Mart quite vividly shows
the steps required to machine the bottom of the bowl flat...to achieve zero vac leaks.
Charlie ny
cas5845@yahoo.com
 
Thankyou Guys appreciate the advice,

Makes more sense now, i will install and fill to check for leaks ( fingers crossed it is ok, if not i will look at the machining required).

I also tried the method of stocking it to your tongue for the old power valve, would hold at all. New one was fine.

Cheers

Corey

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Hi All,

Just another question, I have filled the reservoir with fuel to see if the power valve leaks.

When I fill the reservoir above the hole leading into the accelerator pump chamber I will have fuel leaking underneath the carb. When the fuel level drops to just at the bottom of the hole it stops ( hard to see exactly where it is coming from to be honest when I try and look).

Is this normal? Is it just its natural level? OR do I have an issue somewhere I need to look at.

No leaks coming from around power valve etc as yet ( will leave 24hrs as suggested).

I have attached a photo for reference

Any help appreciated.

Cheers

Corey
1b41a997370d72e8e5410cc0c5fb20b2.jpg


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Hi All,

So i left it the 24hrs and the fuel level went way down in the bowl, there was no puddle below the card on the sheet metal. There was only a slight residue.

Surely losing that much fuel it should of been wet underneath it, or maybe it evaporated off? I think i will give it another go and maybe screw the top on. I also did had a piece of ridgid plastic covering the bowl to limit evaporation ( although if was in the shed, overcast and also night time when i filled it)

Thinking if it is leaking out the only place is the power valve?

Any thoughts from the brains trust?

Cheers

Corey







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Covered or not big time evap takes place. Run your finger around the PV if no fuel
wetness you might be OK. When checking for leaks by filling the bowl stay below
the little bleed hole. GO FOR IT and keep us posted.
Charlie ny
 
Not had good luck with the power valves themselves.
Many won't hold vacuum, before they are even installed in
the 94. Cheap kit, not cheap kit..... doesn't seem to be the
determining factor.

Not on 94's but other carbs, same situation. Tested 2-3 PVs
from Walker while working on a 4100 the other day. Took that
many to get one that would actually hold a vacuum.
 
Thanks Guys,

I filled a couple of more times with cardboard underneath ust to see if it leaked, nothing on the cardboard and only a wisp of moisture around the powervalve, i will put back together and see how it goes. I did the stick to the tounge test for the powervalve and it seemed to hold ok, is there a better test to do?

Actually might try and either electroplate ot buy new linkages etc as mine look old, even after cleaning they flash rust quickly

Cheers

Corey
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