Model B carb

[Fastnaught]

Gentlemen,
Good evening. I'm new here so be gentle. I have just completed a Pietenpol aircraft with a model A engine. I need to up the HP. I'm going to change the head with more compression and the intake system. Anyone have model B carb for sale, or know where I can pick up two.
Thanks,
Jack

[Mike V. Florida]

Congratulations on you project. How far do you want to go with horsepower? The first place I will suggest is Bert's in Denver for the carbs. they sell a lot of original and rebuilt parts and while I don't know for sure, they may have what you need.

Since you are a member here now do a search on pietenpol and see all the threads we have on the subject.

[RandyinUtah]

I have to ask the question why a Model B carb. I have used both the A and B carb and found no advantage with the B carb over an properly restored Model A Zenith carb.

[Mike V. Florida]

Originally Posted by RandyinUtah

I have to ask the question why a Model B carb. I have used both the A and B carb and found no advantage with the B carb over an properly restored Model A Zenith carb.

He states that he is reworking the intake. If you just place a B carb on a stock intake, yes, you will see little to no difference but if you increase the interior diameter of the that stock intake you will see a difference.

the stock Model-A intake has a 1.00" rough cast intake. A Model-B intake has a 1.250" diameter.

Look here to see why there is better throttle response in a Model B carb.

http://www.fordgarage.com/pages/bpowertube.htm

[Bob Bidonde]

In an airplane, I would use a throttle body fuel injector instead of a carburetor because it should do well in an inverted flight condition.

[Terry, NJ]

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I was thinking the same thing as I read your post. Years ago, someone posted some pictures and description of how to bore out the A manifold to B spec and it was not difficult. I like to use a Bridgeport but it can be done on a fairly large drill press with a big angle plate. But you will need to have/make a locating plug to chuck up so you will get the drill correctly following the bore. Always remember! This is a thin wall casting and will crack fairly easily so take your time. When your done, polish it out with a flap wheel. This works well with a A carburetor too. HP Gain? about 2-3! A cheap and dirty way to gain a little ooomph and when you're dealing with only forty horses, ya need all ya can get.
The big problem with B carbs is finding them with the mounting ears intact. The ears/flanges break very easily and they are common. I have two that are broken and I brazed a 1/4" thick, threaded (5/16- 18) steel plate to the bottom of one and have yet to try it out.
Terry

Originally Posted by Mike V. Florida

He states that he is reworking the intake. If you just place a B carb on a stock intake, yes, you will see little to no difference but if you increase the interior diameter of the that stock intake you will see a difference.

the stock Model-A intake has a 1.00" rough cast intake. A Model-B intake has a 1.250" diameter.

Look here to see why there is better throttle response in a Model B carb.

http://www.fordgarage.com/pages/bpowertube.htm

[Rex_A_Lott]

Try this guy:
Ralph Roub
Ninety Six, SC
864 992 3230

I dont know him personally, but got his card at the swap meet in Fletcher, NC a year or two ago. At the time he had some B model carbs and he is not too far from you.
Good Luck!

[Benson]

Originally Posted by Fastnaught

Gentlemen,
Good evening. I'm new here so be gentle. I have just completed a Pietenpol aircraft with a model A engine. I need to up the HP. I'm going to change the head with more compression and the intake system. Anyone have model B carb for sale, or know where I can pick up two.
Thanks,
Jack

Jack,

Are you planning:

1. Gravity feed

2. Or a fuel pump with the Model B carb?

[40 Deluxe]

Originally Posted by Fastnaught

Gentlemen,
Good evening. I'm new here so be gentle. I have just completed a Pietenpol aircraft with a model A engine. I need to up the HP. I'm going to change the head with more compression and the intake system. Anyone have model B carb for sale, or know where I can pick up two.
Thanks,
Jack

How about using a "touring" cam? This should work especially well in an airplane application, since power at idle is unimportant. You want more at cruise and full power RPM, where these cams do their job.

[MrBruce]

Jack
I see your in the Carolina's. Give Carl Adams a call he is in Mooresville, NC and has a Pietenpol (the wings are done and the fuselage is done) he has a B motor ready but I don't think he will get any further because of health problems. He is real sharp on the engine side of it and can give you some valuable info. His phone is 704-785-6559

[Fastnaught]

Thanks all,
I've flown the airplane now for about 10 hours. The engine is a little underpowered. Thinking about a Lion head from SOSS and a Vertex intake with 2 model B carbs. The head alone boasts of 78 HP right out of the box. The intake is larger and will take the model B's. One advantage of the B is the hinge for the bowl is 90 degrees from the A. This make a difference in an airplane. Plus it breaths better. Still learning, any thoughts?

[Fastnaught]

Around 70 would just about right

[Fastnaught]

piete pols have the tank in the wing so it is gravity feed

[Terry, NJ]

I agree on all points! Especially the right angle of the float to the axis of the engine and the larger intake. I've been thinking about boring out this throat on a slight angle to increase the air volume going into the venturi. Then bore the the venturi slightly. Just some thoughts!
Btw what do you plan to do for carb heat?
Terry

Originally Posted by Fastnaught

Thanks all,
I've flown the airplane now for about 10 hours. The engine is a little underpowered. Thinking about a Lion head from SOSS and a Vertex intake with 2 model B carbs. The head alone boasts of 78 HP right out of the box. The intake is larger and will take the model B's. One advantage of the B is the hinge for the bowl is 90 degrees from the A. This make a difference in an airplane. Plus it breaths better. Still learning, any thoughts?