1966Coronet440
New Member
Hi All-
I have a bit of an issue with my 66 Coronet 440. For some background, she has a 318, and about 10 years ago the motor was rebuilt. During the rebuild the cam was replaced with a Crane purple, a new intake edelbrock manifold and Holley 650cfm carb installed. About 500 miles after the build she sat in my garage for about 7 years, only being started every so often.
I've brought her back into regular service, but have run into some tuning issues. The first is that the pcv valve was connected to the air filter housing by the rebuilder. This resulted in vapor escaping form the oil rebreather cap to a point where it smells up the cab a bit. Discussing with my mechanic he suggested I connect the pcv valve (checked and seemed to be ok) to the vacuum port on the rear of the carb. Doing so completely removes the vapor issue, but makes her run pretty poorly initially from cold. When cold she really wants to stall despite the high idle kicking in as it should. Basically, when the accelerator is depressed past, say, 10%, she bogs down and wants to stall. Backing her out of my somewhat steep driveway is a real trick involving juicing the accelerator and letting off and repeating. If she does stall its after a pop from the motor. Once REALLY warm (say 30 minutes in) she gets a bit better, but there remains a notable bog on hitting the gas. The way around this, if this makes sense- is to let off, sort of flick the accelerator and then apply more, sort of skipping the bog (similar to the driveway trick).
Here's where it gets a bit odd- as a test I reconnected the pcv valve to the air filter housing today and voila- markedly better performance after being started- MUCH less bog and generally running fairly well, save for the vapor coming out of the oil breather cap. After getting fully warm though (say 20 minutes) the bog comes back as bad, if not worse than when it's flipped around the other way.
I know she sat for a long time, and the fuel could've gummed up in the carb (added a chevron fuel system cleaner last fillup)- but could that really explain all/any of this? I feel like I'm getting closer to an answer, and leaning towards it being a air/fuel mixture issue, but wanted to see what the wizened wizards of b-bodies thought!
I really appreciate any input.
I have a bit of an issue with my 66 Coronet 440. For some background, she has a 318, and about 10 years ago the motor was rebuilt. During the rebuild the cam was replaced with a Crane purple, a new intake edelbrock manifold and Holley 650cfm carb installed. About 500 miles after the build she sat in my garage for about 7 years, only being started every so often.
I've brought her back into regular service, but have run into some tuning issues. The first is that the pcv valve was connected to the air filter housing by the rebuilder. This resulted in vapor escaping form the oil rebreather cap to a point where it smells up the cab a bit. Discussing with my mechanic he suggested I connect the pcv valve (checked and seemed to be ok) to the vacuum port on the rear of the carb. Doing so completely removes the vapor issue, but makes her run pretty poorly initially from cold. When cold she really wants to stall despite the high idle kicking in as it should. Basically, when the accelerator is depressed past, say, 10%, she bogs down and wants to stall. Backing her out of my somewhat steep driveway is a real trick involving juicing the accelerator and letting off and repeating. If she does stall its after a pop from the motor. Once REALLY warm (say 30 minutes in) she gets a bit better, but there remains a notable bog on hitting the gas. The way around this, if this makes sense- is to let off, sort of flick the accelerator and then apply more, sort of skipping the bog (similar to the driveway trick).
Here's where it gets a bit odd- as a test I reconnected the pcv valve to the air filter housing today and voila- markedly better performance after being started- MUCH less bog and generally running fairly well, save for the vapor coming out of the oil breather cap. After getting fully warm though (say 20 minutes) the bog comes back as bad, if not worse than when it's flipped around the other way.
I know she sat for a long time, and the fuel could've gummed up in the carb (added a chevron fuel system cleaner last fillup)- but could that really explain all/any of this? I feel like I'm getting closer to an answer, and leaning towards it being a air/fuel mixture issue, but wanted to see what the wizened wizards of b-bodies thought!
I really appreciate any input.
