I will ask on the other forum too but all of you seem to have a lot of knowledge in general so here goes.

352 V/8-stock (66 Ford) stock FoMoco 2 barrel carb.

What size jets for 5000/6000 feet in elevation?

What size power valve?

What size accelerator pump ( so as not to pump to much or to little gas down inside)?

Have a friends truck with some running issues.

thanks.

 

If you don't get answers, I have a couple of those carbs I can look inside of, if that's any help.

 

Thank you, I will keep that in mind.

 

Sorry, too new......

 

I hoard all those manual choke 2100s I can get my hands on. The only 2 I presently have, I robbed all the choke parts for the .98s on my hotrod.

 

What you really want is the Shop manual, it will have that information listed in specifications. Maybe ND can look it up for you. You still want the manual.

But I bet you could start with size 50 jets or thereabouts for your altitude - keep in mind that today's gas is not what it was in 1965 and consequently the carburetor guys recommend jetting up a size or two from factory #s. You'll want to experiment but 50s should be OK to start with. The old timers would jet down until it started bucking or surging at steady hwy cruise, and then jet back up a number or two.

A 5.0 PV would be in the ballpark for that altitude. In those days Ford used colors to delineate power valves, not necessarily vacuum #s, i.e. yellow, purple, etc.

 

Thank you, I will tear into it and see what happens.

 

"A vacuum gauge is required to pick the proper power valve. Check the vacuum level at idle (warmed up and in gear if the vehicle is equipped with an automatic transmission) and at various *steady* cruise speeds. The power valve should be picked to open at 1 1/2" to 2" Hg below the minimum steady vacuum reading. For instance, if 11" Hg is the minimum observed, pick a #90 power valve (trips at 9.0" Hg). Don't use the generic un-numbered power valves that sometimes come with generic rebuild kits unless you test it first for the trip point."

http://members.tccoa.com/392bird/tuning.htm

Power valve or "economizer" is held closed by engine vacuum. So when you stomp on the accelerator, the engine vacuum temporarily goes away, and it opens to provide extra fuel. But remember what happens as we gain altitude - vacuum numbers decrease. So consequently the power valve must open at a lower value, or it will remain open. Flatlanders at high altitudes will have a steady stream of fuel exiting the tailpipe because of this, if they don't make prior adjustments to their carbs.

Keep in mind as you work through the tune, as far as the engine is concerned slightly rich is preferable. If you dial in everything to the gnat's *** for 12,000 feet and then drive down to 1,000 feet without rejetting you may grenade a piston or burn a valve.



Take the time to make sure the fuel level in the bowl is correct. Setting the float height may get it close or may not. Fuel level needs to be reasonably close to prevent starvation at cruise, or flooding. It also affects jetting somewhat. Great carburetors, about as close to fuel injection as it gets.

 

Just where would a person even find different power valves? The dual 2100s on my 260 really need some tuning but I never found this much information on power valves in all my searching. I would actually like to just try blocking them off.

 

Holley (and many others) sells them. From 2.5" Hg to 9.5" or maybe 10" Hg, I forget. Somewhere there is a chart that has the Ford color equivalents. Most folks will want something between 8" and 5" Hg. depending on engine and altitude.

For example, my 64 w/ 292 the specs in the manual goes from green PV (0-5k feet or 7.5"), yellow PV (or 6.5" 5-10k) and black PV (or 5.5" 10-15k feet.)

Using a vacuum gauge to discover cruising highway vacuum works good because it will mean a responsive engine when ya put yer foot on it. Jetting correctly, getting ignition timing and distributor curve right, etc means a V8 that almost gets good mileage, and will still smoke the tires and start right up, cold or hot.

I wouldn't block off a PV. With dual and multicarb setups, maybe all of them except one carb? I dunno. Drag racers block them off or install a dummy valve, but they don't care about mileage. Plus ya hafta jet up about 6 sizes from stock and it will run pig rich.

 

Thanks Tedster. I couldn't even find a definitive answer if the Holley pv would work. Both of my 2100s open at the same time. I have them sideways on a 302 efi intake.

 

Ok guys, here is what I think I have found.

Everything checks out with the new carburetor and related tune stuff however I have a vacuum leak that seems to be internal or related to the phenolic plate that sits between the manifold and the carburetor. I have had this problem once before with a similar plate on another ford engine. That plate had fissures and or cracks it it causing vacuum leaks. I replaced the plate and problems were solved.

In this case the leak is on the right or passengers side of the carb, drop in vacuum might be responsible for allowing the PCV valve to stay open causing the intake to pull more air from the crankcase instead of through that bank of the carburetor.

Here is my question. Where can I get a good aluminum or replacement plate like the one used on this engine (352 2 bb carb), that also has the port for the PCV valve? I am guessing that the old Bakolite is toast on the one on this engine and may also have hairline cracks or fissures in it.

 

Phenolic spacers for 2 bbl carbs are pretty tough to find for some reason. I've seen the aluminum type, with a large manifold vacuum port, for sale on eBay, as well as plain phenolic type with no vacuum ports. You'll need a part # to search the usual suspects elsewhere.

 

D4AZ-9A586-A (replaced C2AZ-9A586-B) .. 2100 series Auto-Lite/Motorcraft 2V Carburetor Kit (Motorcraft CT-499-D) / Available from Ford & auto parts stores