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Tri, Tri Again Part IIIPart III: Painting, parts selection, and reassembly of the Pontiac Tri-Power From the April, 2009 issue of High Performance Pontiac
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Jim Taylor is well on his way to completing the mechanical restoration of a correct 1965 Tri-Power unit. In Part I, he tore down and inspected the carbs and identified and cleaned the manifold. Part II covered throttle flange and airhorn issues, with in-depth repairs of the throttle shaft assembly and bowl cover. This installment at Phillipsburg, New Jersey-based Jim Taylor Engine Service will involve painting the individual carb components and choosing the correct gaskets needed for the job before starting the final assembly. After the 1965 manifold's mineral spirit bath in Part I, it was coated with one layer of Martin Senour's #7220 self etching primer. Once the primer was allowed to dry, Plasti-Kote's Pontiac Blue #208 went on as a top coat, and then the 5/16-in. studs were installed in preparation for the three 2-barrels. See the photos and captions for the rest of the details.  At this point, the center...  At this point, the center carb and one end unit have been painted and are ready for assembly. Taylor now concentrates on painting and assembling the other end unit. For the throttle flange, two cardboard discs prevent overspray on the throttle blades. The airhorn is prepped by running tape around the outside lip, then over the top. And for the carb body, Taylor uses a gasket with tape on it so paint isn't sprayed into the bowl area.  Jim coats the airhorn and...  Jim coats the airhorn and body with bronze-colored Eastwood Carb Renew. He likes to lightly coat the gasket area to make the new gasket stick better. For the base, Dupli-Color semi-gloss black paint is used. On the iridate for originality/paint for longevity issue, Jim had this to say: "Nothing replaces iridate, but that process will wear off eventually. If you decide to use paint, shoot a little clear after the color. This makes the carbs look like they were iridated. It won't fade away as quickly, and you can do your own touch-ups."  Here is a shot of the base-to-body...  Here is a shot of the base-to-body gaskets included in the '64-65 carb rebuild kit, Ames part No. N192. Several gaskets are included, but care must be taken to choose the correct one for your application and to avoid the troublesome vacuum leaks discussed in Part I  Taylor selects the first gasket,...  Taylor selects the first gasket, which has the correct air bleed, mounting, and main vacuum holes. As so, it won't cause vacuum leaks around the throttle bores.  He places the carburetor body...  He places the carburetor body upside down, sets the gasket down, and places the base on top of it. Original Phillips-head screws have good lock washers on them and are oiled prior to installation. "There is a future for this original stuff if you take care of it now," Jim explains.  From left to right, top to...  From left to right, top to bottom: venturi cluster, throttle pump assembly, throttle pump return spring, throttle pump check ball, pump discharge spring, ball, retainer, power valve, needle, seat, float, and hinge (float) pin. New pieces include the check balls, the throttle pump (with old spring), our float, needle and seat, the pump discharge spring and retainer, and the power valve. The venturi cluster and the float were thoroughly inspected and tested before they were reused.  A Trip's check balls are different...  A Trip's check balls are different sizes. The pump discharge ball is .188-in., and the throttle pump check ball is .155-in. Don't get these two mixed up during assembly, because ...  ... if you use the .188-inch...  ... if you use the .188-inch pump discharge ball in the throttle pump check ball location, the ball gets stuck down there. When the offending party tries to pry it out, he can't get a tool around the radius of the ball and it gets stuck tighter--even a magnet won't get it out. The good news? These carbs have very fine veins all through them, so if a ball gets stuck, the carb body's external access veins are your saving grace.  This is the lead plug that...  This is the lead plug that would have to come out to remove a stuck ball in the throttle pump check ball location. In this instance, Taylor would use a drill to remove it. Then air or a homemade tool could force out the ball.  Jim installs the pump discharge...  Jim installs the pump discharge spring, ball and retainer--the retainer "T" needs to fit...  ...flush into its detents,...  ...flush into its detents, or the venturi cluster will sit up off of its gasket.  Here are your four choices...  Here are your four choices for the venturi cluster gasket. They come in the same rebuild kit and will fit a lot of carbs, so it's up to you to choose the correct one.  At this point, you need to...  At this point, you need to get wet. Taylor installs a screen at the bottom of the float bowl to catch sediment, pours in a small amount of gasoline, and drops the throttle pump check ball in, followed by the throttle pump. Both check balls are in, so Taylor depresses the pump to make sure the check balls are doing their jobs. Fuel flows past the discharge check ball and through the vein that will connect to the venturi cluster.  Here is the correct venturi...  Here is the correct venturi cluster gasket in place on the carb body.  The venturi cluster is positioned...  The venturi cluster is positioned and tightened down. Both outside venturi cluster screws utilize a lock washer, but the center screw with the large head takes a fiber washer underneath it. If you don't use fiber, fuel will leak past the washer and you won't get the right amount of pressure out of the pump nozzles. Taylor greases an original GM fiber washer so it doesn't get torn up when it is tightened.  Once the venturi cluster is...  Once the venturi cluster is installed, Jim plunges the throttle pump to verify two strong streams from the venturi cluster veins.  The measurement of .825-inch...  The measurement of .825-inch that Jim is taking with a caliper is going to be relative to the desirable plunger position when the lid and linkage is installed.  Some people don't know that...  Some people don't know that these carbs have power valves. In this photo, Jim holds the power valve actuator, which is a simple vacuum over spring piston. When vacuum falls off (opeing the throttle), the spring on the actuator lowers to open the power valve. 63 jets are used in this small center carb application for a baseline. See the next issue where we'll complete carburetor assembly and our Tri-Power restoration.
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Jim Taylor Engine Service
120 S. 5th St.
Phillipsburg
NJ
08865
908-213-3456
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Tri, Tri Again
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