Addendum to Holley Seminar at Doug McClure's

Thanks again to Doug for the use of his shop on Sunday. As usual my drive home always brings to mind a few of the things I should have told them’s. Also thanks to those people who e-mailed me to say they felt ready to tackle their carburetor setup. It was nice to get a phone call from Doug to say he took the car for a drive and he noticed a big difference in the cars performance. One item that might be of help to people in understanding some of the carburetor settings when they look them up in the shop manual. The decimal settings e.g. .375 can be better understood if you are good with fractions by remembering 1/8 is .125 inches,1/4 is .250,3/8 is .375 and ½ is .500. As far as using drill bits and round metal stock for measuring, buy a cheap plastic vernier caliper C.T.C. or Princes Auto and the measurements will be close enough. I told a story about Quadrajet floats absorbing fuel and sinking in the bowl during operation and causing flooding problems. What I failed to mention was that the float weight can be measured with a tool (believe it or not) that I just happen to have but did not show you if you ever need one along with a tool used to measure float level on the Q-jet externally. A number of carburetor settings require three hands, what I use are some strong elastic bands especially the ones requiring the throttle to be in the wide open position. Please remember to remove the elastic before starting the engine, it has happened. By the way the large valve on the rear barrels of a Q-jet is not a choke valve but is an air valve for controlling the opening of the secondary throttle valves about 21/2 inches in diameter and is adjustable.

If you ever decide to check the float level on a Q-Jet (Quadrajet ) carburetor the float bowl gasket may be able to be saved if you are very careful or you may want to have the float bowl gasket handy in case!! There are at least a couple of carburetor rebuilders in the city where they will sell you the gasket, one is on Eugene street and the other one I know of is just off of the Queensway Ave. Just west of Kipling Avenue on the south side, for the specific address E-mail me. Removing the air horn assembly, float bowl cover is trickier than a Holley carburetor since there are metering rods etc. Possibly a topic for another tech. session. Well I think that’s it for now.

Haunted Holleys Shop Talk
Frank Knaggs

Recently I experienced a problem with my brand new Holley carburetor. I'm sure a number of NCRS members have had the same problem, in fact I know of friends who spoke of the same hard starting problem with the Holley carb. when the car had sat for a few days or more. Once the car is started the car starts and runs fine until the next time the cars sits a few days. Years ago a good friend and neighbour with a '66 coupe red on red 425hp car with the problem mentioned was so frustrated he contacted Holley personnel as well as various mechanics to alleviate the cause with no success. He ended up doing the last thing he wanted to do, replacing the carburetor. I can't even tell you if that corrected the problem because I moved away. In my case I had a 390hp engine with a 425hp Holley carb. which ended up having the same problem years later. After checking float levels,warped metering bodies,damaged gaskets, porous carb. parts I found leaking power valves and the problem was cured. I actually ended up rebuilding the cranking motor (GM's name) because of all the extra work the starter had to do during this problem.The other concern is all the fuel contaminating the engine oil. Back to the new carburetor story which I couldn't believe ended up having the same long cranking time problem. One day a fellow NCRS member called me from Carlisle to ask me if I would accept a brand new correct 390 hp carburetor for my 425hp. Hurry home I will be at the door waiting I told him and not long after I had a new carb. on my coupe. The last thing I expected was the Haunted Holley problem again. The only good news was I had lots of experience this time and I began the inspection. I checked for empty float bowls, and external problems, I did not want to start taking the carb apart. The float bowls were full to the proper levels and the oil was not showing signs of gas. Good news, so I headed for the choke operation. The one thing I had experience with was setting chokes up by the book and it worked ninety percent of the time. Even the dreaded variable venture Ford co-operated when the Motors manual was used. After checking the choke linkage I noticed the choke valve binding just before it fully closed. Gotcha! I called and ended up having to dismantle all the choke linkage in order to alleviate the binding valve. The automatic choke has a thermostatic coil which is used to close the choke fully and a vacuum break as it is called to pull the choke a preset amount e.g. 3-4mm to allow some air to enter during the cranking time. Eventually the vacuum break overcomes the choke coils force to fully open the choke valve. After dismantling all the choke linkage I found the vacuum break linkage the culprit. Next was the real test, let the car sit a number of days kick the gas pedal to the floor, crank the engine and VIOLÀ! she ran beautiful. I'm sure the cranking motor said thanks, I said thanks and wiped off the new carburetor.

I love those Holley carburetors.
Keep em' fueled and enjoy em'

Frank K.