Engine: 1954 Ford Wagon 239 - changed all parts to fit in my 55 F250 Crank case vent blocked off and placed a pcv valve in intake with a correct valley pan. Carb/intake: Holley original with 1955 F250 239 intake Truck and engine ran for 35 miles without any problems. But now, this heat problem and some small oil leaks. Pcv valve tested before placed in and valve is from a 1964 Ford F100. Any ideas what is going on? Thanks for any info. Chris
That is the heat riser to the intake, basically it is a crossover from the echaust ports. Wanna keep it pristine? Block the heat risers, it won't say exactly pristine but win't idscolror as far up the intake. It is not a sign of a problem if that is what you are asking.
Difference in pressure in the exhaust causing high flow under the manifold. Restrict or block the exhaust crossover.
Crankcase vent blocked and PCV installed where it won't vent crankcase pressure is what's likely causing your oil leaks. Heat riser causing the scorched paint on the intake.
Shrek, When I have an engine with a rod draft tube I usually stick the PCV valve in the hole that the road draft tube left when removed. You will need to make sure that you n have breathers on the engine normally they are stuck in the rocker cover but sometimes they can be stuck on the oil pan above the oil lever. If the only breather you have is your oil fill tube more ofter then not you are only venting your lifter valley and not your crank case.
I guess I need to make a hole in the old crank case vent (blocked off now), place the pcv valve inline and run the hose to the valley pan or ???
No, that won't vent anything as you'd be tying it right back to the crankcase. The PCV needs to be placed where it will vent the crankcase.....valve cover, old vent tube, oil pan or even the valley cover. The hose will then need to run to a vacuum port....like the one on the manifold where you currently have the PCV valve. Where do you currently have the hose hooked up?
The factory valley cover had oil fill at one end with a breather cap and the PCV hose went to the back where the old road tube was.
For many years, Ford simply either vented internal pressure of the engine right back to the air cleaner. They used an oil filler cap in some instances, and ran a rubber tube to the side or the underneath of the air cleaner base. Look at a 428 Cobra Jet engine on the web, if it has the air cleaner on it, you will see exactly what I mean. For a pcv, ford went from a valve cover port, usually on the passenger side valve cover to the intake, some plugged into a spacer plate under the carb. Hope this helps?
That was called the Closed system, any excess pressure vented to the air cleaner instead of the Atmosphere. Normal ventilation air was drawn from the AC housing to the crankcase out the PCV hose or grommet to the valve to the intake. Under heavy load with no vacuum it would backflow and vent pressure into the AC housing where it would be pulled into the carburetor and burned. Here are some pics of the Y-Block PCV Valley Cover.
There a class one and class two PCV systems. The early or class one used a valve and a vent usally the oil cap. worked well at an idle or high vacuum times not at wide open throttle. Type two vented the system to the air cleaner using the air flow into the carb to pull on the crankcase vapors at wide open throttle.
Great info and pics! I went with a 3/8" hose from the valley pan to a 1/2" hose to the pcv valve into the intake manifold. But, how was the set up back then because I placed on an earlier type Y block valley pan.
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