I have a few questions about doing this, and thought i'd make a separate thread for the topic. So, i'm planning on building a 283 or 327 with the old script valve covers. I haven't bought the block yet but i'm trying to plan out my build. I'm going for a single carb setup and a vented oil filler neck. My question is about where the pcv valve needs to go and where do i need to run a line from. Should i put the valve right on the end of the road draft tube, and then run a line into the back of the carb? or do i run it from the intake instead? Also, does it need a baffle both ways? or just if i run it into the intake? Bear with me this is my first engine build so i'm learning as i go. Thanks in advance for the help.
You can get a fitting that bolts to the rear of the block where the road draft tube goes, then use a length of hose between there and the carb base to install a PCV valve into. It's how the factory did it beginning in about 62, until about 67. Be sure to get the valley cannister to separate the fumes from the oil. Start with a complete donor engine, and the parts should be there. The individual parts are getting hard to find, and can be expensive. The oil fill tube access only works if it has a closed cap, and a vent elsewhere on the engine (valve cover through air cleaner).I am Butch/56sedandelivery.
alright, so then if i do the road draft to pcv tube, then i need a non vented oil filler? my valve covers are closed and i'm not going to drill breather holes in them.
Here, this kit will do the job for you. https://www.danchuk.com/ItemForm.aspx?Item=13282 Remove the road draft tube and replace it with the grommet in the kit, the elbow in the grommet, the hose from the elbow to the pcv valve, to the fitting placed in the base of the carb or in the manifold. You will want to use a vented oil filler cap. The vented cap allows air into the crankcase, the pcv ventilates the crankcase to the intake. Air goes in, air goes out, and everything is happy.
alright, so what i need to do is use the vented oil cap, and then run the tube from the road draft hole to the intake or carb. do i still need a baffle? I was going to just buy the parts separate instead of a kit. Thanks for the replies guys
The baffle is located under the intake manifold, it should already be installed in an engine with a road draft tube.
I just picked up a complete, stock 66-67 283 with all the plumbing on it. Be happy to snap some picks it that would help you out.
Thank you for the pic. Helps me out. i was thinking the baffle would have to be external but this makes it easier on me, being my first build. yeah that would be awesome! thank you!
The 67 327 Impala engine in my old van had the external fitting at the rear of the block with PCV fitting and hose going to manifold from memory. Fairly simple
I did pretty much what is pictured above with odds and ends to fab my own baffle. Then I found a grommet that fit the hole to the rear that was plugged on my motor and a PCV. Just had to run a hose from the PCV to the port on the rear of my center carb, works great.
so i've been doing some thinking and i'm going to a few junkyards in the coming weeks to hopefully find my block. although i'm not real fond of the idea, i may end up with a 350 just because for my first engine build i don't want to end up messing up a 283 or 327. if i get a 350, since it has no road draft tube, how would i use my valve covers or will a chevy 350 not work with closed valve covers?
If you go with a 350, you could drill and tap a hole in the intake that accesses the lifter valley. Then run your hose to the carb base and use the vented oil fill cap and closed valve covers.
I fear to ask this but what is the Danchuck setup? (I'm guessing it bears resemblance to the Henway setup)
You could and it MIGHT work, but the preferred method would be to have the air flow travel from opposite ends of the engine block. Expensive. I used a freeze plug with a hole drilled in it to accommodate the proper grommet for a PCV valve. Then used some 3/8's steel tube and two short pieces of rubber hose for connecting the ends to the carb and PCV.
Ok, my cheapest, easiest option is to get an older intake with an oil fill tube, and drill a hole through the intake where it would go all the way through to the lifters and then plumb a line from that to the base of my carb. Alright, as long as it's doable i'll hopefully find a decent engine. for a 283 or 327 i want to look in pre 1969 trucks right? i know where there are a few 60s chevy trucks in yards around here maybe one has the mill i'm looking for. and for a 350 i think it's pre 1990 that's good right? i'm not sure what changes were made in 1990 but i've been told that pre 1990 350 chevy's are the best for an old style setup.
Well, the pcv is meant to provide positive ventilation for the crank case. It does that by pulling a vacuum to draw the g***es in the crank case into the intake manifold. Because it's pulling a vacuum, there also needs to be an inlet. Thats why there is a breather on the oil fill tube. Air goes in the breather and goes out via the pcv. When manifold pressure drops and the pcv closes, like when you got your foot into the throttle, the breather then provides a way for excess pressure to be ventilated out of the block and prevent blown seals/gaskets. If all you have is a pcv in the oil fill tube, then where is the inlet? And where does the excess pressure go when vacuum drops? And if you put a breather on the oil fill tube, then all the pcv is doing is pulling air in via the breather, it's not ventilating the block.
Sure, you can do that, but all that does is allow excess pressure in the crank case to escape, which is good, but it's not ventilating g***es and condensation. Not good for oil life. You should probably have an aggressive oil change schedule to prevent deterioration of the oil and severe deposit formation and/or sludge. 4x a year at least.
Lol i wish i could find those around here. I'd be taking home a lot more than the engine [emoji6] What'cha got in there, kid?
Which setup would you recommend? You seem to be pretty knowledgeable on the topic so i thought i'd ask what you would do. What'cha got in there, kid?
I've got some old Cal Custom valve covers that have an access for pcv valve, I didn't have to drill them. The draft tube hole is blocked off. I have a breather in the oil fill tube and one on the opposite valve cover, though I'm thinking of going to a closed system, where the pcv is plumbed to the base of the carb and the opposite valve cover is plumbed to the air cleaner. This provides full ventilation at all times, as well as filtered air going into the engine. For you, I think either putting the pcv in place of the old draft tube, or drilling the intake to reach the lifter valley and installing a pcv there with a breather on the oil fill tube is the best best. That will provide good ventilation while maintaining the originality of the valve covers.
Danchuck is a company that deals mostly 55-57 Chevy parts. A very reputable company whose products work
The best option is an early block which was designed for a draft tube/rear vent. If you can't find that, then a 1985 or earlier 350. Starting in 86 or 87 the 350's have center bolt valve covers.
Here's a couple of threads that covered some of this: http://www.jalopyjournal.com/forum/threads/small-block-chevy-venting-question.112441/. http://www.jalopyjournal.com/forum/threads/pcv-valve-for-road-draft-tube-block-sbc.151629/ I have a '58 283 that I am thinking of doing the PCV off the original draft tube connection so I will be pulling air out thru that while it comes in thru the filler tube up front as I plan on using vintage Corvette valve covers. I have also seen where the PCV and breather were put on the inside rear part of the valve covers as to keep it more "hidden". It was a greenish '37 Ford in TRJ. Very trick install and did the job and you didn't have the big breather caps on top of the valve covers.
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