I am having a problem with my car. At WOT it has what sounds and feels like a slight miss. Cap, rotor, wires and distributor replacement made no differance. If I run my stock 72 Qjet the problem is gone, but the car is slow. The problem carb is also a 72 Qjet with one size bigger jets. Rods are stamped CT. Used 1972 455 with mild cam. Any ideas? John
CT rods are kinda lean, with a power tip of .0774 Stock Stage1 carb used CV's with a power tip of .0527. Maybe you have a lean miss up top. What rods are in the carb that runs right? I would swap the secondary rods from one carb to the other, that's easy to do. Hope that helps.
Same rods in both carbs. Air valves open nicely when fully warmed up. Open to soon when cold. Big bog. Lock outs are missing, may swap bottoms after I get the bugs worked out. John
Yes John, Could be leaking throttle shaft. Spray some gumout around the shaft with the motor running.
Shafts were bushed when rebuilt. Located a set of DR rods. Any idea what size these are? I can't find a spec. Check these links. http://www.73-87.com/garage/damon.htm http://peterpam.customer.netspace.net.au/secd.htm John
Put the rods in and took it for a ride. Flutter MIGHT still be there. Took it to a spot in the orange groves and hammered it. BIGGEST burn out yet. All the way through second with the ass end trying its hardest to pass the front end. Took it out on the freeway and punched it at 60 MPH. Chirped the tires going back into third. While I was just cruising in the slow lane I saw an unmarked DPS car coming up behind me. As he was passing me in the fast lane some dummy came up between us. His wallet will be a little lighter. It is running very strong and I know the problem is 200% better, but I think it needs a little more. I think I'll try to find a different hanger, mine is a "N". I will keep you posted, thanks for the help. John :TU:
You definitely should try a "richer" hanger than the "N". Try at least a "K" or even a "G". These two are sold by Edelbrock and their part numbers are #1962 and #1961 respectively. While you are at it, get a set of CE rods (#1951). These rods are .041". This should get you very close on jetting in the secondary. What jets are you running in the primary? Don't worry about the bog when it is cold. I would leave the lock outs off. You shouldn't be driving your car that hard until it is warmed up anyway. Dean Oliver www.holsfan.com/deano
Forgive me if this input is stupid, but it happened to me. I had a malfunctioning Q jet choke pull off, so I disconnected it. It was warm and I didn't really need a choke, so I figured I'd just run it unhooked. Bad Move!!! I picked up a fluttering at WOT. My assessment is that the open, but unsecure, choke flap would try to suck closed under WOT. Anyway, the new pull off fixed this. So do you have a good pull off? Is it disconnected for any reason? And am I an Idiot????uzzled:
HAD THAT PROBLEM BEFORE, i tore it down and soaked it overnight in carb cleaner then it ran fine. if the rebuild is not to old and you are careful you can use the same gaskets.
The Carb only has about 100 miles on the rebuild, all in the last month. First pull-off was dead, but the car had the most power with it. Swaped the good one from the slow carb and it only slowed it down. I think I will swap a G hanger on it and take it to the track and see what happens. It's on my 71 Skylark convertible, so 14.0 is max with out a roll bar. I might be dreaming, but the 455 feels 2 seconds better than my 16.2 second 350. The 350 had no fine tuning done and single exhaust. If you can find last months Hot Rod there is a fast Buick in it. Read what the owner says about the pull offs. John
John, Sounds like the rods have it, but there's one other thing to check...I had this happen on a 71 Q-jet. The "miss" didn't go away... it was constant under full acceleration and was AFTER the secondaries were open. There are a pair of feed tubes to the secondary wells that love to come loose during a rebuild. They're just a friction fit (and a very poor one) that usually lets one ot both of the tubes fall into the secondary wells. If changing the rods doesn't seem to have much effect then you can be fairly certain this is the problem... the rods arent doing much because fuel isn't reaching the ports. You'll have to pull the top off at that point and check the float level, feed tubes, and jets. Hope that helps!
Well I got some time to work on this thing. Pulled the carb apart and started checking things out. One of the small tubes under the top is plugged solid. 49b rods with what looks like 74 jets. May have to rob a tube out of the other carb and see what happens. What do you think of the 49b/74 combo? Mild cam and 2.5 exhaust. John
I have .76 jets with 46B rods, and BG secondary rods in my John Osborne 72 Q-jet. Thats with the KB118 mild cam and headers. 74/49 sounds kinda lean to me. Stock 72 Stage1 carb is 75/45
I took my other carb apart to get a tube. Found 44 rods and an "I" hanger. I am now running 74 jets with 44 rods and an "I" hanger with DR rods. Plus I got rid of the plugged tube. I think this will be it. I will have to wait until tomorrow to give it a spin. John
Well, no more flutter. Tube fixed that, I think. Thanks to Leviathan. Seems to have slowed again. I think the car likes the 49 rods better. Guess I'll be swaping them back in. Three more weeks until I run it. John
