My 318 w/850 Thermoquad never idles well in gear, and stumbles off the line
No offence taken, I do not have much carburetor experience or I wouldn't have needed to have written this post now would I have? ;)
The 850 is a vacuum secondary carburetor and very rarely (if ever) dips in to the secondary sides. The secondaries only open if you leave the gear selector in 1 or 2 and hold WOT intentionally well in to higher RPM's. You can hear the gushing whoosh of the secondaries opening, so them giving the engine too much isn't really too much of a concern. The carburetor is never really allowing the 850cfm to be taken ;) However! when you do hold the throttle open and allow the secondaries to come on line it handles it well and does not bog down or do anything odd. It gains speed, and you can feel the power come on.
I have seen other people run the 800/850 TQ's on their 273 or 318, as well as some low power 360's. To say the Thermoquad is too big for a 318 seems a little ignorant to me no? They came on some 318's and I have seen them used on super sixes even! lolol. *do not take my light heartedness as disrespect* I chose the 850 because it was what was available to me at the time, and this car was not running anywhere near right with its stock 2bbl and ELB/ESA system. This system has gotten the car back on the road, so far it is a win-win.
My TQ is a 1975 400 federal application, 9046S is the build number or what have you.
I am unaware if my ignition system is functioning properly, it is entirely new last year (time of 4v upgrade) with less than 5k kms on it all. (plugs, wires, cap, rotor, coil, wiring, spark box, distributor and carb rebuild). Now that you mention it, and I had a friend ride with me tonight, we may be thinking it is an ignition miss at idle.. it goes away once the RPM is brought up at all though, which is a weird one to diagnose. He thinks it is ignition related because of how quick the miss is, 1 cylinder ever so often seems to miss.. and then maybe it will be 3 cylinders in a row where it really brings the idle down. I am at a loss on how to test that one exactly.
He suggested to get it to do the stumbling, and then get the timing light on every plug wire to see if and what cylinder is misfiring.
This engine, one day, will have some aluminum heads, a superb cam and some headers added to its repertoire of awesome LOL.
No offence taken, I do not have much carburetor experience or I wouldn't have needed to have written this post now would I have? ;)
The 850 is a vacuum secondary carburetor and very rarely (if ever) dips in to the secondary sides. The secondaries only open if you leave the gear selector in 1 or 2 and hold WOT intentionally well in to higher RPM's. You can hear the gushing whoosh of the secondaries opening, so them giving the engine too much isn't really too much of a concern. The carburetor is never really allowing the 850cfm to be taken ;) However! when you do hold the throttle open and allow the secondaries to come on line it handles it well and does not bog down or do anything odd. It gains speed, and you can feel the power come on.
I have seen other people run the 800/850 TQ's on their 273 or 318, as well as some low power 360's. To say the Thermoquad is too big for a 318 seems a little ignorant to me no? They came on some 318's and I have seen them used on super sixes even! lolol. *do not take my light heartedness as disrespect* I chose the 850 because it was what was available to me at the time, and this car was not running anywhere near right with its stock 2bbl and ELB/ESA system. This system has gotten the car back on the road, so far it is a win-win.
My TQ is a 1975 400 federal application, 9046S is the build number or what have you.
I am unaware if my ignition system is functioning properly, it is entirely new last year (time of 4v upgrade) with less than 5k kms on it all. (plugs, wires, cap, rotor, coil, wiring, spark box, distributor and carb rebuild). Now that you mention it, and I had a friend ride with me tonight, we may be thinking it is an ignition miss at idle.. it goes away once the RPM is brought up at all though, which is a weird one to diagnose. He thinks it is ignition related because of how quick the miss is, 1 cylinder ever so often seems to miss.. and then maybe it will be 3 cylinders in a row where it really brings the idle down. I am at a loss on how to test that one exactly.
He suggested to get it to do the stumbling, and then get the timing light on every plug wire to see if and what cylinder is misfiring.
This engine, one day, will have some aluminum heads, a superb cam and some headers added to its repertoire of awesome LOL.
