Holley Carb Restoration-Part 11-Throttle Body Assembly

[Gerard F.]

Well back on the job after a bunch of things around the house.

Per the last thread on this topic, we had bushed the primary throttle shaft and had test fit the shafts, made some adjustments. Decided to go with the teflon bearings for the secondary, as it fit so well with the teflon.

Next step was the touch up the base and top of the Throttle body with 220 grit wet-dry sandpaper on a glass plate:



Got to admit, it really didn't do to much but take any dirt and irregularities off the base plate.

Next was to set the throttles. No teflon on the bushed primary, curly teflon strips on the secondary.



Then it was time to install the throttle plates. Here's the set up:




I used nice slotted screws which I collected from older holley carbs and refinished each one. Didn't realize it but the older throttle plate screws have two H's stamped on the top, before they cut the screwdriver slot. Usually the slot is cut through one of the H's.

The instruction sheet is a 4 page Holley publication on the removal and replacement of throttle plates. You can find this pub at the following location:

http://www.holley.com/data/Products/Technical/199R9978.pdf

The pub recommends the use of Loctite 970 (green penetrating) threadlocker and duckbill vise grips to stake the screws. I used the green Permetex brand threadlocker and couldn't fin any duckbill vise grips anyplace.

Continued next post

[Gerard F.]

Re: Holley Carb Restoration-Part 11-Throttle Body Assembly

The pub in the last post has a procedure to install the plates and making sure that the shaft moves freely, and that there is an even gap between plates and the body when closed:



I used some refinished original plates (#109 and #118 or a 3810). If you use original plates make sure the edges are nice and clean and even. Last step before staking, is to look up the bottom into a light it insure there is an even gap arong the plates when closed.

Since I couldn't find a duck bill vise grip I used a needle nosed one with a washer to protect the head of the throttle plate screws:



The pub advises against using a centerpoint or flat chisel for staking for fear of bending the fragile shaft. The pub is right. I tried a center point chisel and backed it solidly with a cutoff broomstick. Had to start all over again in setting the throttle plates.

The needlenose vise grips really didn't do a bad job and was very easy:



Here's the finished throttle plates all in place and staked:



As usual, ran out of time at the pace I work. See you next time for carb assembly.

[Gene M.]

Re: Holley Carb Restoration-Part 11-Throttle Body Assembly

Jerry,
I might suggest to peen the thread end on the bottom to ever prevent the screws from backing out. I think that is why they are tight to remove upon disassembly. Holley may have done this originally. If you back up the head of the screw with a drift supported in a vice to peen bottom of thread it should prevent any shaft bending.

If memory serves correctly they are soft metal, maybe brass.

You do nice work, really like this series.

[Clem Z.]

Re: Holley Carb Restoration-Part 11-Throttle Body Assembly

i just use red lock tite even on race carbs and never had any come loose. if you want to stake them use a steel flat punch held tightly in a bench vise to back up the screw.

[Michael M.]

Re: Holley Carb Restoration-Part 11-Throttle Body Assembly

Great Article Gerald!