ozconv
Well-known member
I finally started my new engine to break in the cam. Break in went fine but afterwards when I tried to adjust carb idle, it will not run well under about 1500 rpm. Engine specs are as follows:
-200 six, essentially stock short block rebuild but with ARP fasteners, 0 decked, double roller timing set, and H264/274 cam with 112 lobe center, advanced 4 degrees.
-Rebuilt OZ-250 head and intake, ported with 1.8" back-cut intake valves and 1.5" exhaust valves, 3 angle valve job, 302 valve springs.
-1.6:1 Adjustable roller tip rockers.
-Classic Inlines header (rest of exhaust not yet installed).
-Post 68 Pre DS1 dizzy with mechanical and vacuum advance (currently un-hooked and plugged), Pertronix Igniter II, Flame Thrower II coil, Pertronix Wires with 0.040" plug gap.
-Rebuilt 1.02 245cfm Autolite 2100 with manual choke, 48F jets.
-0.048" compressed head gasket with 6.5CC stock dished pistons for CR of approximately 9.4:1.
I decreased the idle to 1200 rpm and with the engine running rough, set the base timing to 12 degrees BTDC. Vacuum is also about the best at this setting but is between 16 and 17 with a shaky needle unless rpm is increased. Lifters were adjusted following procedure on this forum. Idle mixture screws will not completely stall engine when turned all the way in (one at a time). Once they are about 1 turn out, they seem to have no effect at all.
I do not believe it is a vacuum leak since the idle increased and smoothed out when I created one by disconnecting a hose to attach the vacuum gage. I believe the engine is running way rich from the following observations:
-Exhaust smell and effect on eyes.
-After turning the engine off and then when trying to restart, I get a white cloud coming out of the carb.
-I removed the top of the carb and float is not full of gas-logged and is about 3/8-1/2" below gasket line.
I suspect that the float is either set too high or that the power valve is bad.
Does this sound likely to anyone else??
-200 six, essentially stock short block rebuild but with ARP fasteners, 0 decked, double roller timing set, and H264/274 cam with 112 lobe center, advanced 4 degrees.
-Rebuilt OZ-250 head and intake, ported with 1.8" back-cut intake valves and 1.5" exhaust valves, 3 angle valve job, 302 valve springs.
-1.6:1 Adjustable roller tip rockers.
-Classic Inlines header (rest of exhaust not yet installed).
-Post 68 Pre DS1 dizzy with mechanical and vacuum advance (currently un-hooked and plugged), Pertronix Igniter II, Flame Thrower II coil, Pertronix Wires with 0.040" plug gap.
-Rebuilt 1.02 245cfm Autolite 2100 with manual choke, 48F jets.
-0.048" compressed head gasket with 6.5CC stock dished pistons for CR of approximately 9.4:1.
I decreased the idle to 1200 rpm and with the engine running rough, set the base timing to 12 degrees BTDC. Vacuum is also about the best at this setting but is between 16 and 17 with a shaky needle unless rpm is increased. Lifters were adjusted following procedure on this forum. Idle mixture screws will not completely stall engine when turned all the way in (one at a time). Once they are about 1 turn out, they seem to have no effect at all.
I do not believe it is a vacuum leak since the idle increased and smoothed out when I created one by disconnecting a hose to attach the vacuum gage. I believe the engine is running way rich from the following observations:
-Exhaust smell and effect on eyes.
-After turning the engine off and then when trying to restart, I get a white cloud coming out of the carb.
-I removed the top of the carb and float is not full of gas-logged and is about 3/8-1/2" below gasket line.
I suspect that the float is either set too high or that the power valve is bad.
Does this sound likely to anyone else??