283 PCV Script Valve Covers

[threeonthetree]

Just finished dropping in a low mile 1966 283 .060 over has about 2,000 miles on it.
I am running a stock intake with a 600 cfm Edelbrock 1406. Intake has the oil fill tube and I have a vented cap on it. Running script valve covers with no pcv provisions.

Having an issue with the pcv. What I’ve done is ran an elbow off the hole in the back of the bock behind the dizzy. I am running vacuum hose to a pcv threaded into my carb spacer. With a vented oil tube cap.

Basically this set up

https://m.ebay.com/itm/1967-Camaro-L...kAAOSwnTdZ5470



The problem I’m having is I just got it on the road and it seems to be building up crankcase pressure. For one when I get on it I got a big smoke cloud behind the truck. It also shot the filler cap out of the fill tube lucky for me when I got home it was still sitting on the intake and I didn’t lose it. Also seems to be blowing oil out the gaskets because I have some sort of leak now there was a small spot on the floor after it sat.


But idk why this pressure is building. Seems my set up should work any ideas?


Should I ditch this set up and run conventional vavle cover set up. Or anything I can check any ideas ?

[special-K]

Is the cap on the fill tube vented?

[notsolo]

PCV mod in search field, there used to be a couple threads that modified the back of the older valve covers....http://67-72chevytrucks.com/vboard/s...=556602&page=8

[Rich69shortfleet]

Well, a couple of things. Did you install the baffle in the lifter valley that is supposed to connect to the hole at the back of the block? If not, you are probably just sucking up a ton of oil, thus the cloud behind you.

The other thing is, that hole at the back of the block is really intended as an air INLET. It would be better to route your air inlet and outlet in the opposite direction than what you have now.

[100%Chevy]

Is the new pcv in backwards?
It only allows flow one way.
Mike.

[Grumpy old man]

Without seeing a picture of the engine what your describing is crankcase BLOW BY , If your pcv system is intact and working you may need to try a catch can to relive the problem , being a 283 bored .060 over there are a number of things that could produce your problem , ring gaps aligned ,worn out ,etc,etc Now you know why it was pulled back out with 2,000 miles on the fresh rebuild .

[CaptRMW]

Originally Posted by Grumpy old man

Without seeing a picture of the engine what your describing is crankcase BLOW BY , If your pcv system is intact and working you may need to try a catch can to relive the problem , being a 283 bored .060 over there are a number of things that could produce your problem , ring gaps aligned ,worn out ,etc,etc Now you know why it was pulled back out with 2,000 miles on the fresh rebuild .

Grumpy is right on as usual. Excess ring gap is my guess and blow by with the accompanying crankcase pressure is the end result. This is why you see racing engines with a breather everywhere there is a spot big enough to put a breather. Your PCV system will likely not ever be a successful remedy for the problem.

[threeonthetree]

Originally Posted by CaptRMW

Grumpy is right on as usual. Excess ring gap is my guess and blow by with the accompanying crankcase pressure is the end result. This is why you see racing engines with a breather everywhere there is a spot big enough to put a breather. Your PCV system will likely not ever be a successful remedy for the problem.

I don’t think it’s blow by in the engine I think it’s blowing oil out the gaskets because of crank case pressure.

Originally Posted by 100%Chevy

Is the new pcv in backwards?
It only allows flow one way.
Mike.

I don’t believe so it is a threaded type, how can I test this tho.

Originally Posted by Rich69shortfleet

Well, a couple of things. Did you install the baffle in the lifter valley that is supposed to connect to the hole at the back of the block? If not, you are probably just sucking up a ton of oil, thus the cloud behind you.

The other thing is, that hole at the back of the block is really intended as an air INLET. It would be better to route your air inlet and outlet in the opposite direction than what you have now.

I believe the baffle is there cause. I pulled the hose coming from the vent and it is dry.

So run the pcv on the filler and air inlet on the rear of the block?

Originally Posted by special-K

Is the cap on the fill tube vented?

Yes I made sure to get a vented cap

Originally Posted by Grumpy old man

Without seeing a picture of the engine what your describing is crankcase BLOW BY , If your pcv system is intact and working you may need to try a catch can to relive the problem , being a 283 bored .060 over there are a number of things that could produce your problem , ring gaps aligned ,worn out ,etc,etc Now you know why it was pulled back out with 2,000 miles on the fresh rebuild .

I was under it today and the smoke I’m seeing only happened one time and it looks like it was just oil on the headers. But I still don’t understand why the filler cap is getting blown out.




I will try and get some pics today of what my set up is.

[threeonthetree]

Originally Posted by notsolo

PCV mod in search field, there used to be a couple threads that modified the back of the older valve covers....http://67-72chevytrucks.com/vboard/s...=556602&page=8

That mod looks nice I may try a different set of valve covers and if that solves it I will do this mod!

[geezer#99]

Your 283 should already have the baffle in the intake. They can get clogged up though with sludge. If it’s plugged up your pcv won’t work and the pressure blows the cap off or blows out a seal/gasket. Back of the intake gasket leaking will put oil on the headers.
Pull the pcv hose off and blow some compressed air into it and you should hear air coming out the tube at your breather.

[tjc]

Maybe you could try running hose from pcv to an air filter/ breather and not carb base

[Grumpy old man]

Read up on blow by ,

https://www.youtube.com/watch?v=Wadmzv1Vs0Q

[threeonthetree]

Originally Posted by Grumpy old man

Read up on blow by ,

https://www.youtube.com/watch?v=Wadmzv1Vs0Q

I will read up on it but I don’t think his was my issue.

Originally Posted by geezer#99

Your 283 should already have the baffle in the intake. They can get clogged up though with sludge. If it’s plugged up your pcv won’t work and the pressure blows the cap off or blows out a seal/gasket. Back of the intake gasket leaking will put oil on the headers.
Pull the pcv hose off and blow some compressed air into it and you should hear air coming out the tube at your breather.

Okay I tried this and I have good air flow from the vent to the filler cap. But this also figured out my issue for me! I will post some photos of what is going on.

Originally Posted by tjc

Maybe you could try running hose from pcv to an air filter/ breather and not carb base

I think I’m the photos you’ll see why my carb base was not working.

[threeonthetree]

Couldn’t get the photos work anyway I had that spacer on there and didn’t realize that tapped hole was blind. I’m gonna drill it out tonight any work tonight deep enough that it penitrates.

[geezer#99]

It’s always something strange! LOL!
You should just pull the plug out of the back of the carb and screw your pcv in there.

[threeonthetree]

Originally Posted by geezer#99

It’s always something strange! LOL!
You should just pull the plug out of the back of the carb and screw your pcv in there.

I was thinking about doing that Edelbrock doesn’t recommend it though that’s why I was using the spacer plate