Car seems to bottom out or bog down at about 4200 rpm, Suggestions for finding problem and getting to run better.
jim larson said
Apr 27, 2013
As most of you may know this is on my 66, with a 396, aftermarket cam (told it is equivalent to crane 10309 which is suppose to be close to crane 284 H12), original heads, stock valves, original stock holley intake, stock holley carb, with original distributor and points ignition.
Second time I have had the car out this year. It seems to run fine from idle to about 4200 rpm and kind of want to stall there; but will go higher.
Wonder the order of events to take to get it to rum better up to 5000 rpm. First I will burn out all the old gas, then what would you suggest.
Advance is set @ 16 degrees.
Thinking plugs, check timing advance maybe reduce it a little, check points, check dwell, maybe replace points, maybe rotor. Could the carb be an issue? Thanks.
Tim H said
Apr 28, 2013
Fuel filter, bowl adjustment, fuel line colapsing, too small of fuel line, mesh bag in the sending unit plugged, no ventalation into the gas tank, or the fuel pump would probably be where I would start. Do the easy simple stuff first alot of times that is what it is.
jim larson said
Apr 28, 2013
Thanks for the advise. I also was considering a fuel issue. I have a filter in the back installed in the rubber hose from the fuel tank to the hard line that feeds the fuel pump. There is also a fuel filter in the inlet of the Holley Carb. Fuel line is the original size 3/8" line, in fact it is the original line. Fuel line from fuel pump to carb is also a hard line. The rubber hose of the fuel line are only about 2 yrs old. Original vent for the fuel tank, its easy to check , it just attaches with a rubber hose to the fuel tank. Gas tank used a non-vented cap. I don't want to have to pull the sending unit to see if mesh bag is plugged or colapsing. I will have to check the fuel level in the bowls.
I was talking to a guy tonight and he mentioned that I should consider the condensor and the points. They are about 5-7 yrs old.
dashboard said
Apr 28, 2013
Jim, is this a new performance problem just now manifesting itself after bring your car out of storage or did you have the same issue last year?
Vacuum or mechanical secondary’s on the carb? If vacuum are you sure the secondary’s are opening?
Tim H said
Apr 28, 2013
you can always back blow the fuel line to clear the bag some.
jim larson said
Apr 28, 2013
Tim H wrote:
you can always back blow the fuel line to clear the bag some.
do you mean to just take the hose off at the rear of the tank and blow some air in there? How much air pressure? Probably should replace the fuel filter that I stuck in the line back there a few years ago?
jim larson said
Apr 28, 2013
dashboard wrote:
Jim, is this a new performance problem just now manifesting itself after bring your car out of storage or did you have the same issue last year?
Vacuum or mechanical secondary’s on the carb? If vacuum are you sure the secondary’s are opening?
New problem after being stored for the winter. I will have to check on the secondary's
As most of you may know this is on my 66, with a 396, aftermarket cam (told it is equivalent to crane 10309 which is suppose to be close to crane 284 H12), original heads, stock valves, original stock holley intake, stock holley carb, with original distributor and points ignition.
Second time I have had the car out this year. It seems to run fine from idle to about 4200 rpm and kind of want to stall there; but will go higher.
Wonder the order of events to take to get it to rum better up to 5000 rpm. First I will burn out all the old gas, then what would you suggest.
Advance is set @ 16 degrees.
Thinking plugs, check timing advance maybe reduce it a little, check points, check dwell, maybe replace points, maybe rotor. Could the carb be an issue? Thanks.
Thanks for the advise. I also was considering a fuel issue. I have a filter in the back installed in the rubber hose from the fuel tank to the hard line that feeds the fuel pump. There is also a fuel filter in the inlet of the Holley Carb. Fuel line is the original size 3/8" line, in fact it is the original line. Fuel line from fuel pump to carb is also a hard line. The rubber hose of the fuel line are only about 2 yrs old. Original vent for the fuel tank, its easy to check , it just attaches with a rubber hose to the fuel tank. Gas tank used a non-vented cap. I don't want to have to pull the sending unit to see if mesh bag is plugged or colapsing. I will have to check the fuel level in the bowls.
I was talking to a guy tonight and he mentioned that I should consider the condensor and the points. They are about 5-7 yrs old.
Vacuum or mechanical secondary’s on the carb? If vacuum are you sure the secondary’s are opening?
do you mean to just take the hose off at the rear of the tank and blow some air in there? How much air pressure? Probably should replace the fuel filter that I stuck in the line back there a few years ago?
New problem after being stored for the winter. I will have to check on the secondary's