Is there a way to repair throttle shafts? Both the primary and secondary. After taking my base plate complete apart and inspecting the throttle shafts there is a significant amount of wear on the shafts where the come in contact with the base plate. The primary throttle shaft is my major concern because it is much less interchangable than the secondary shaft. The variations that are vehicle specific are related mostly to the attachment of the throttle cable and the cruise control stud and the brcket that is swedged to the end of the shaft. My base plate has already been the victim of a poor quality bushing job on both the primary and secondary shaft holes. Thoughts?
No problem at all to replace the primary shaft. Grind the staked area off the end, remove all the linkage, and put a new shaft in place of it. We MIG weld them in place, even though replacement shafts are threaded for a retaining screw.....Cliff
The secondary shafts require some clearance to work correctly. I do NOT recomend installing bushings for them, as they huge secondary throttle plates need to fully seat in the bores each time they close. Of course you can go out and buy a "stepped" drill bit, some 7/16" x 3/8" bushings, ream an off center hole in your housing, loctite in the loose bushings, and it will float around enough it will probably work flawlessly! Seriously, it's not uncommon at all to have to spend some time aligning and indexing the huge secondary throttle plates during baseplate rebuilding. Not at all uncommon either to find one or more of the shafts bent or twisted slightly. The goal is to have all the throttle plates fully seated when closed, and they should return to this position each time the throttle closes. ALWAYS tighten up the primary side first, or remove the link between two shafts, as for one reason or another the primary side may be held open slightly, and the plates will get installed off center. The Q-jet is extremely sensitive on the primary side, and the throttle plates must be in the same position side to side, or they will NOT work well when placed in service.......Cliff
Not sure. I bought all the remaining shafts some time ago from my supplier, and have sold out of them. They were really slow movers anyhow, and I have plenty of decent used ones, so never bothered to source out any more new ones to date.....Cliff
Many, if not all of the secondary throttle shafts were Teflon coated from the factory. They are olive drab green in color. Has anyone had the Teflon redone for a restoration of a Quadrajet? The guy that chromates my carb bodies says he knows of a place that would do it. It's a shop that builds Holleys for NASCAR. I don't know how critical the teflon is for consistent secondary throttle plate closing, but I'm sure Rochester engineering had the Teflon there for a reason.
The green teflon coating wears off over years of use. I much prefer to electroplate the secondary shafts. This protects them much better from rust and corrosion than the teflon coating that's going to wear off anyhow. Can't really comment on how well the teflon coating helps in actual use? Never had the first problem once with a plated secondary shaft provided they were not bent, twisted, and installed correctly.....Cliff
