The Stovebolt Site Forums The Shop Area Engine Shop adding PCV to 350/283 intake conversion 57 3100 V8

I have a 57 3100 V8 with a later date V8 in it from 1970 a 350. I put the old style valve covers on and old intake maniform. Runs fine, but blew the front rubber intake valley gasket out from between the block and intake in front by the water pump.
Must be a lot of pressure.

I had a PCV added at the time before it blew out. It was drawing air from under the intake manifold in the valley area. It was sucking from a small hole in a bolt that holds the Coil bracket on. This is apparently too small a hole or it got clogged.
This bolt used to be a front stud that held the carburator in place. *** What is that special Stud with a hole through it for? optional Manifold vacuum? *** It use to vent into the intake runner area.
Also under the manifold there is a pan cover below the carberator area on the underside of the intake. *** What is the purpose?


But anyways I get some oil spatter on firewall from fumes coming out of the breather. Yup it is suppose to go in but it is coming out, blow-by as I said it needs a better PCV system. So I need a better solution. A bigger hole. So I need to try to drill a hole in an original cast Iron intake. *** Is that possible? *** Will it weaken or crack the cast iron?

I would like to find a good flat spot to drill into that goes through to the valley area and then add a home-made baffel of some sort to help reduce oil pick-up.

I have seen others do this like here: 1965 Corvette PCV

But his is for a 4 barrel and aluminum intake and no coil in the way. Althought he shows a picture of a traditional solution up top in his post. But searching around I can find no documentation of such a solution.
I looked on H.A.M.B. and lots are talked about but not a lot of detailed pictures.

I think he used a 9/16 drill bit and a 3/8 18 NPT Tap and screwed in a 3/8 fitting to a 5/8 hose connection.

I would like to try this with my original cast Iron intake if that is possible. *** Can you drill and tap cast Iron? ***

Here is my setup: My manifold setup and posible PCV tap locations
Also I have looked at my 2nd spare intake and tried to figure out a likely place to drill the hole.
There are a few things to navigate around. I would like to have it as far to the rear as possible to allow as much "cross through" venting as possible between the breather in the oil fill and this tap into the intake/valley area.
Things to watch out for are the coil and coil brackets, distributor clearance, intake port runners clearance and not drilling into them etc.

There are some flat round tab areas torward the rear that look ideal but the one on the drivers side labled 1 seems to not enter the valley but into a port that appears clean on my extra manifold.
The mate to that on the passenger side labled 2 seems to have some exhaust or oil build up on it. But I think these do not access the valley area but some port in the heads?
*** What are those ports? *** I know the 8 main ones are fuel. Then it looks like two center ones are maybe exhaust/heat riser type (but most gaskets have these blocked off?) *** What are those two ceneter ones for?***
The front two ports are for water and go to the thermostat and heater hose.

*** But what are the rear most two for and where do they go? ***
I was wondering as if they actually vent to under the valve cover that might be a possible place to tap from to help ventilate.

Also if you look at My manifold setup and posible PCV tap locations The area labled #2 goes to a place that is next to the tin cover under the carb.
*** What is the purpose of that cover?*** Is it to help heat the carb or something? or just to keep oil spray out of there from some reason? On some old manifolds that area is caked with crap under between the cove and the manifold.

But #2 looks like a possible pick area that I could use for the PCV tap. But it is not too far from the breather so it is less than ideal. I perfer a place further to the rear. But it would be easy to baffle this area as it is already partially covered by that tin plate.. *** What is that for?*** What is this flat spot normally used for? ***

I do not have the normal Road Draft Tube area in the block/bellhousing area as this is a 350 and they did not have them. So that does not appear to be an option for me.
Bummer as that would have been too easy!

The best place may be the areas I labled as #6 or #5 but the intake runner is very high there and may make it hard to clear if I used a 90% elbow.


So what do you guys think my best bet would be on the location to drill?

And what are some of the answers to my questions marked with *** ?


Thanks!

I have been searching the posts on stovebolt and found another post that I posted on in response to the Original Poster. It has some ideas older post But does not go into the location of the place to put a hole into the intake manifold. Which is my current question. Where and how to drill it?

Hy svwilbur, lots of questions, if you will use the original oil fill tube in the front of your manifold shown in your picture [without the fill tube] you could buy a cap for it with a hose connection in it, you could hook your pcv system up to that. No need to reinvent the wheel and start drilling holes in your manifold. Incidentally of course cast iron can be drilled and tapped. The tin cover is there because exhaust gas is circulated under the carburetor, without the cover, oil would burn to the area and cause quite a carbon buildup in very short order, hope that helps.

3B,

"if you will use the original oil fill tube in the front of your manifold shown in your picture [without the fill tube] you could buy a cap for it with a hose connection in it, you could hook your pcv system up to that."

I thought about that, well having a oil fill tube with a PCV tap off of it with a closed cap on top but if I did that there would be no clean air getting into the block. I think that is needed.

Ones I see that had that setup had the fill tube hose running to the air cleaner to get clean air and still had a separate PCV hose going from the carb to the road tube.

"None of the above". Don't drill any holes in the intake manifold. Just cut a hole about 1" in diameter in the back of one of the valve covers and put in a rubber grommet that the PCV valve will slip into snugly. Make a sheet metal baffle to fit inside the valve cover to prevent oil splash from getting pulled in by the vacuum. Some PCV's have a 90 degree elbow built on that will help with firewall clearance. Run a 3/8" diameter vacuum line to the port in front of the distributor. If necessary, drill and tap the vacuum port in the manifold to 3/8" pipe, and install a tee with reducers down to 1/4" NPT on both sides. Run the power brake hose to one side and the PCV hose to the other. Use a vented oil filler cap to get air into the crankcase.
Jerry

Hotrod Lincoln,

no power brakes here and no need for other vacuum other than to suck in PCV fumes.

But you say "Run a 3/8" diameter vacuum line to the port in front of the distributor" - what port is that? You mean the back of the carburator as that is the only vacuum port I have if you looked at the pictures. It is the tap off the back of the carb. Or are you saying that other flat spot between the carb and distributer?

Well you say "If necessary, drill and tap the vacuum port in the manifold to 3/8" pipe, and install a tee with reducers down to 1/4" NPT on both sides. Run the power brake hose to one side and the PCV hose to the other."

So now you want me to drill the manifold in the rear upper runner? And you are cutting the vaccum down to 1/4 inch? I am not sure that is enough for PCV? Also if you do not use the vacuum tap on the back of the carb then you are using the vacuum in the general intake plenum/runners specifically only connecting to cylinders #3 and #8 (the rear High Runner). That would lean out those two cylinders and also send all the crap from the PCV only to those cylinders. I think that is really just for Vacumm and not for hooking a PCV to. Vacuum is one thing, a constant contaminated infow of air is another and would cut down on your vacuum if you needed it for something. I converted my vacuum wipers to electric so I do not have any vaccuum needs now.


Am I missing something with the vaccuum port on the intake runner? In general that sounds bad to use for a PCV vacuum.

I could use the port on the back of the carb as I have been as that just leans everything out and you adjust the carb for that.

I was trying not to cut into the CHEVROLET Scripted valve covers but I could if that is better as a PCV source. I guess the original 350 had the Breather on drivers valve cover and the PCV on the other Passenger cover. So it kind of vented across the block front corner to the opposite back corner.

The old 283 in 57-58 vented front intake valley area to rear valley area to road tube. Which I was trying to do by drilling a hole torwards the rear of the intake.

Your way would go from the breather in the oil fill in the intake valley to the passenger rear end of the valve cover. That may be good for the passenger side for ventilating but may not do anything for helping to clear the drivers side valve cover.

I guess I could run two lines one off each valve cover rear. But then there may also be clearance issues as the spark plug wires are suppose to pass thru that area when i put the original style plug wire retainters on it.


I need to figure out the best approach to this PCV valve arrangement that will work and look OK and not cause more issues.

This is one that looks kind of what you were talking about. comming off the back of the valve cover but with a tube to a hose (to the PCV I guess): 283 Valve Covers on a 350 Engine with that one he says: "The smog hose routes behind the distributor (hiding the smog valve at the rear of the manifold) and comes up on the driver's side, attaching to the rear of the carb via a fitted hard line."

It is also posted here with pictures inline : 283 valve covers on a 350 complete

But I do not think that would work with the stock 283 tin script covers as they ramp in on the ends more. There would be no room for the baffle he made for his more virticle covers.


Here is someone elses solution, like what I am thinking of doing but it did not work for him. But it looks like his baffle under the intake manifold was too small and had too big an opening for oil to get into possibly. He ended up putting the tap off the valve cover with a baffle in it instead. Vintage intake and valve cover install

just answering some of my own questions.

The tin cover under the intake manifold under the carb area is said to be an oil splash shield "The factory shield is used to keep your oil from frying on the bottom of the intake where the exhaust crossover goes through." So I guess that makes sense. That would assumme the crossover is still in effect. I see that some gaskets have that center port blocked OFF with a metal plate so maybe that tin cover is not always needed now? I guess it depends on the setup, the block, heads and intake in use and all.

Another possible solution?

gromit that incased the bottom of the pcv valve and had a slit cut across the bottom

Moroso 68772 - Moroso PCV Grommets with Integral Baffles

Maybe cutting a hole in the side of the valve cover and using one of those would work if I could find a good spot for it that was flat and cleared the lifters and all inside. But thes old covers have groves in the two places that I would want to do that so that would not work in the side by may work if done way low at the end by the firewall. It is flat but slanted some but may clear the lifters. Maybe not that seems pretty long.

Does anyone else have an opinion as to whether it is better to drill a hole into a valve cover or into the intake manifold to the valley to get a source for the PCV valve?

I am considering either the place in front of the distributor to drill and tap a 3/8 NPT hole and add a baffle undernieth or possibly drilling a hole in the rear or back side end of the scripted tin valve covers and welding a tap maybe a fuel line or something onto it with a small baffle welded inside.

Which would suck less oil?

Which would be safer?

Which would be less prone to break or cause an issue?

Well no suggestions?

I am thinking that I will try the drill and dap of the intake manifold infront of the distributor and try to tap in there to pull the blowby and fumes from and send to the PCV and into the base of the carb.

I will try to rig a baffle and screw it to the little V area in that area with some sheet metal and red loctight on the taped threads.

If that ends up sucking too much oil then I can plug this and try getting it off the valve cover some how.

I will try to do something like this PCV retrofit but to my cast iron manifold.

I tried using a large port behind the carb on my Edelbrock Performer intake to provide vacuum to my pass side rear located pcv valve. Hookup was a no-brainer until I started noting that my air/fuel mixture gauge was indicating VERY lean. Back cylinders weren't getting the same amount of fuel as the fronts and there was a noticeable increase in temperature in the #7 and #8 cylinders.

Switching the pvc pickup to the front designated pvc vacuum port of the Edelbrock carb solved the lean air/fuel issue. The small port on your intake isn't going to support a fully functional PCV setup. I think in your case I'd use a 1" riser block under the 2 bbl, tapped for a hose barb. That way you aren't causing an imbalance between the cylinders. Add the PCV to the pass side valve cover with a grommet and you'll be in business.

BTW.....capping off barbed vacuum ports with rubber caps WILL come back to bite you if you don't monitor their condition. Think I have picks of the PCV setup in my webshots "Hot Rod" album.

Dave

Yes that was a concern of mine if I used the vacuum tap on those rear risers, leaning out those back cylinders, on mine they apper to be cylinders 5 and 8 as that riser feed 5 and 8.

But I was always going to use the spot on the carb for the vaccuum side of it.

My issue was were to draw the blowby from. I would like to tap into the spot in front of the distributor not in a riser but into the valley area but several people say it is too much oil mist in there and you will burn oil up too fast. Other say putting a baffle of some sort in there will correct that.

I was just trying to not have to cut into my valve covers which are the old tin scripted type.

I may still try the putting a tap in front of the distributer and try to baffle it. If that fails to work I will have to go the way of a baffle and tap into the valve covers some how.

Seems easier to drill a hole in the valve cover, you know it works, the factory did it that way! As HotRodLincoln mentionned, drill at the back end of the valve cover, so it is somewhat hidden and does not fully "ruin" (esthetically) your valve cover.
Then, still to keep it simple and the way the factory did it because it works, take the vapours to the air cleaner, "before" the air filter.
It works, it is simple and pretty discreet.

Well I decided to try the "drill a hole in a valve cover" approach.
I was going to put it on the passenger side and before I drilled the hole I checked to see if the fitting I was using cleared.
Lo and behold the firewall is really close and it did not look like it would clear!

I checked the driver side cover for clearance and it had more room so I drilled the driver side rear of the cover. I used a brass plumbing fixture and used some threaded rods to screw into it that are for lamps as I wanted non-pipe threads in order to use a nut on it on both sides of the cover with some loctite and RTV.

I also made a baffle out of sheet metal and folded it to fit the small amount of space at the end of the valve cover. There is less than you would think as the metal valve covers slope on the ends. But I have clearance.

I drilled and threaded the valve cover and threaded the fitting into the cover and into the baffle and then tightened the thin nuts down with loctite and then closed the baffle at the bottom. There is plenty of air flow and hopefully will also keep much of the oil out as most of the open area is at the bottom.

I took some pictures and will post a link in a while. I am hoping this works better than my old method. There should be lots of flow as long as there is vacuum as the hole seems large enough. And everything seems pretty secure.

Time will tell.

Here is a link to the pictures on how I made a baffle and added the fitting for the PCV Hose. Adding PCV tap and baffle to stock valve covers