MGD72Monte Posted July 1, 2011 Share Posted July 1, 2011 i bought the "how to rebuild and modify rochester quadrajet carbs" book by Ruggles. It should come in soon, I'll start by reading that. Yeah, good decision. Then you can truly say you fixed it! Quote Link to comment Share on other sites More sharing options...
Kevin Wiles Posted August 3, 2011 Author Share Posted August 3, 2011 the carb is rebuilt and is is purring smooth as silk now. rebuilt the carb with a custom kit from cliffs q-jet website. During the rebuild I did all the tricks like seating the check ball with a punch, (using an old check ball), enlarging some of the little holes in there, making the throttle blades open directly up to a perfect 90 degree angle, I also modded it where APT (adjustable part throttle, only on later model q-jets, not on our 70-72's) can be adjusted from the outside of the carb. I put brass bushings where the primary shaft goes. Gave it a good cleaning, even went as far as to remove the idle tubes. Polished the bores for the power piston and pump. After reading the book and studying web pages, and getting to know the carb, I oculd do another in much less time and now that I have some special tools, for much less money. (PS- I did not have to epoxy anything, as this carb is a later model and they had better ways of sealing the plugs) My other monte will need the epoxy. Anyway, success! It is running great! Quote Link to comment Share on other sites More sharing options...
Mo's70MCs Posted August 3, 2011 Share Posted August 3, 2011 great going.. & people like bashing Q-jets. When done right!, they're reliable as old Betsy. Quote Link to comment Share on other sites More sharing options...
wallaby Posted August 3, 2011 Share Posted August 3, 2011 Nice job Kevin. The Q-jet isn't that hard to rebuild. The extra steps you took are the time consuming part. Once you have one working right, it's hard to settle for less. Cliffs' book is great. Quote Link to comment Share on other sites More sharing options...
Andreas Posted August 3, 2011 Share Posted August 3, 2011 Quote Link to comment Share on other sites More sharing options...
stangeba Posted August 3, 2011 Share Posted August 3, 2011 Happy it's running well now. What did you find to be the root cause of the problem? I found the secondary opening spring tension adjustment important in removing a slight bog when I stepped on it. The secondary was opening to far too quickly I guess. The "rebuild" industry has done so many things wrong to so many rebuilt parts so many times, what you purchase may not be correct for your application. Bruce Quote Link to comment Share on other sites More sharing options...
rsorg Posted August 5, 2011 Share Posted August 5, 2011 hi, after having carb issues also,with my holley 780 spreadbore direct replacement , ,my mechanic used a small propane bottle ,and found out that the brass bushings in the throttle plates were worn out ,causing a vacuum leak, went back to a q-jet , also replaced the gasket with out the plastic spacers ,which prevented another vac leak, runs great now ,, Quote Link to comment Share on other sites More sharing options...
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