Check your PCV valve

[nickstewartroc]

Just as a tip that has taken me 5 years and all of $2 to learn...

If you have problems with your carb such as not wanting to idle correctly, a stumble, etc. Try a new PCV Valve. I bought my 67' 5 years ago, and ever since I bought it, I've had problems with idle and stumble. I never suspected the PCV until lately. I had tried various carbs, and even when I converted to a 2bbl still had similar problems. I had it hooked up to the spacer properly when it was a 1bbl, but with the 2bbl I hooked it into the manifold vacuum port as they should be similar, however when I would, it would idle like crap, stumble and fall over itself. I thought on the current 2bbl that I have, the one port coming off the top of it would work and had it hooked up there with no stumble or idle problems. I never really put any thought into it, or even as to why the breather would would have some blow-by coming out when you would blip the throttle. However, I was doing research into breathers and discovered I had hooked up the PCV correctly before when it would stumble, and incorrectly now, in fact I had it backwards! The port I used on the carb pushed air out, not suck it in. I decided to go buy a new PCV and hook it up, and would you imagine that, no idle problems, no stumble, just a sweet sweet running engine!

So basically, if you are having problems with what you think is the carb, spend a couple dollars and get a new PCV!

 

[xctasy]

Well done, and if your engine is no longer stock, make sure it is the right type.


Mustang Geezer and others with the early advent of large carb Holley carbs on direct mount and 2V iron headed Smalll sixes found a large array of replacements which were in some way modified from the stock types, some worked only with the baffled rocker cover used in 1978 on Fords, some didn't. There are different restrictions. Straight replacment is a first step.


Its possible that if you use an unbaffled PCV valve, with a flow rate too big, or if its too close to the fantail spray of oil from the valve gear, you can end up with a very bad idle and a backwash of oil whihc may fool you into thinking your car is running pig rich. Especially so if you are running a Holley Weber 52xx/62xx/65xx , 32/36 or 38 Weber carb or a Carter AFB based Edlebrock 4-bbl carb designed to take the PCV line to the carb itself.