Gooner

Hey guys,

New to the Olds 455 as I just bought a 1971 Cutlass for the wife last summer. I am having oil spraying out of what appears (hard to tell when driving) the oil fill tube and working its way up the oil pressure sender.

I have a PCV valve in the passenger valve cover going to the carb base, and a breather on the drivers side to atmosphere. At idle and driving at lower RPM is seems okay. Once on the highway it begins to have the problem.

My GUESS... is the PCV valve isn't working at highway RPMs and there isn't enough ventilation. Your more expert opinions are more than welcome.

Thanks!

oldcutlass

Sounds like you have blow by. Make sure the PCV is serviceable and hooked to manifold vacuum. You might change the breather on the other side so that it connects to the air breather to give some extra assistance.

Gooner

Could you clarify a bit more for me on the second part. Right now, in the drivers side, I have a PCV valve that is hogged out (empty of guts) with a tube venting to atmosphere (backyard style baby!). The PCV on the passenger cover is connected to the large vacuum port on the front/bottom of the Edelbrock 750. Seems to be working okay.

Would switching sides make any difference?

oldcutlass

Take the vent tube and fabricate one for the air cleaner if there is none existing, connect the tube to the air cleaner with a piece of rubber hose. It will give a little more positive vacuum at higher rpms and relieve some of the pressure building in the engine. Make sure the oil fill tube cap is secure.

Blow by is caused by combustion gases passing through worn rings into the crankcase.

Gooner

Thanks for the tip. There are two circular sections at the air cleaner base that look like they can be "popped" out for a tube. I will do that and run the tube into the air cleaner.

Can't afford to yank the motor and rebuild anytime soon... so getting that oil to stay in the motor and not ON it is priority number one.

Gooner

However, as I understand it, fresh air needs to be pulled IN to the motor from somewhere. So where, with the setup we were discussing, would I draw that air in from?

oldcutlass

Hopefully down the oil filler neck.

Gooner

HA! Let's hope so. But... if the oil filler tube cap is sealed... how is air getting in there?

oldcutlass

If oil is coming out air will go in.

Gooner

I hear ya. But, I had a vented oil filler cap on it when this happened and have no put back the stock cap that should seal. Do you think this alone might fix the issue. Allowing the PCV to do it's job better?

Also, when running the tube into the air cleaner base... does it need to be sealed or can it just run in there? It is an aftermarket open element housing.

Thanks again for the repeated help, it is really appreciated!

oldcutlass

I had this same problem on my 67 330. I also ran an open element air cleaner and installed the extra fitting that came with it (similar to picture below). Here's what I did. The fitting to the air cleaner was sealed.

Gooner

Okay... I will purchase a grommet to run the tube into. Running it through a catch can first so I shouldn't need a filter INSIDE the housing should I?

Octania

Right now, in the drivers side, I have a PCV valve that is hogged out (empty of guts) with a tube venting to atmosphere (backyard style baby!).
================
Pardon me while I bust yer ***** a bit here.
What, pray tell, would possess you to think that destroying a carefully engineered and calibrated ventilation valve would provide better results? What you have there now is basically a large uncontrolled vacuum leak. But that's neither here nor there with respect to your oil expulsion at elevated speeds and loads.


The PCV on the passenger cover is connected to the large vacuum port on the front/bottom of the Edelbrock 750. Seems to be working okay.
===============
Ah. Terminology fail. I suspect you have the carb vacuum [correctly] connected to the "pcv valve"[ with its guts intact], and your other rocker cover bears a hollowed out "breather" or "filter" as used by the factory. Still no need to remove its filter, but at least that is not as bad as removing the guts of the "pcv valve" as you stated. What you are doing there is drawing dirty filthy unfiltered air into the engine. Not better. THIS is a filter or "breather" commonly used on the Olds V8 after 1968:

http://www.ebay.com/itm/USED-1966-84...af4269&vxp=mtr



Would switching sides make any difference?
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I can't imagine that having any effect one way or the other.


I had a vented oil filler cap on it when this happened and have not put back the stock cap that should seal. Do you think this alone might fix the issue. Allowing the PCV to do it's job better?
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Back to second-guessing the engineered system there. Chances are, you will be hard pressed to IMPROVE on the factory PCV system, though you can CHANGE it all you like of course. May I suggest you read thru the factory service manual explanation of the PCV system and how it works? It's only about 2 pages. CSM free at wildaboutcars.com. Use the proper factory sealed oil fill cap.



Also, when running the tube into the air cleaner base... does it need to be sealed or can it just run in there? It is an aftermarket open element housing.
==============
That seal is not crucial. That part of the system is designed to
1) provide air to the crankcase filter under high manifold vacuum conditions, and
2) direct excess [blowby] gasses to the air intake to be burned in the engine, during conditions of low manifold vacuum = high loads/ speeds.

Remember that different is not the same as better and unless you understand the systems and how the components work, you are unlikely to _improve_ things with various random changes. Trust the factory engineers.

Gooner

THANK YOU! This is by far the most helpful car forum I have been a part of.

I am trying to undo the hack workmanship (term used loosely) of the previous owner. How I have it as of this minute thanks to some advise from all of you:

1) Passenger side PCV (working PCV) connected to carb vacuum port at bottom center of front of carb.
2) Driver side EMPTY PCV (just the shell so it fits the grommet hole) with hose to catch can inlet.
3) Hose from catch can outlet into air cleaner base of open air filter element. The drill bit I used to open the hole in the base was the same size as the tubing, so it fits in there nice and snug. The tube ends inside the filter assembly just inside the filter itself.
4) Original oil cap replaced in fill tube with new rubber washer that seems to seal well... without the washer it was a bit loose.

Does this seem correct? Should this alleviate the oil spray of doom!?

Thanks again guys!

oldcutlass

Don't know till you try it...like I said it worked for me.

Gooner

well... still leaking. Oil definitely working it's way up the sender, so replacing that with a new one and putting pipe tape on it.

Still coming out of the fill tube as best I can tell... hard to pinpoint. Grrrrrrr...

oldcutlass

The sender just might be loose unless its coming out the center. Its pipe thread, use some thread sealer instead of tape. Did you put the stock cap back on the oil fill tube?

bccan

Is it possible the little oil baffle/shield @ base of fill tube is missing? If you are unfamiliar with it, it is a shiny, flat 1 1/2" square that keeps oil flung off timing chain from climbing up the tube. It slides into reliefs cut in the timing case of the block & is installed w/ timing cover off.

It is visible in copper's timing mark alignment thread, upper passenger side corner.

https://classicoldsmobile.com/forums...-question.html

Check baffle (pull tube & look), leakage @ sender and get PCV config straightened out & hopefully things improve. Check seal @ front lower edge of intake manifold as well.

jag1886

My GUESS... is the PCV valve isn't working at highway RPMs and there isn't enough ventilation. Your more expert opinions are more than welcome.
My GUESS is you have an engine with a LOT of crankcase pressure from rings starting to leak past.
You can vent all that stuff back the air cleaner but then you are going to have a nasty air filter every few thousand miles.

Gooner

Oh I am not GUESSING you are right... I am sure of it. I clearly have a lot of crank case pressure. I am not pulling the motor for a rebuild any time soon... this is the wife's car and she wants to DRIVE it this summer. Maybe in the winter when it is stored I can pull it and do a rebuild if funds allow. So in the mean time I need to get the oil blow by out of the engine compartment.

I will pull the fill tube and check. Is there a trick to getting the fill tube off?

I let it idle a while, and then revved it to about 3k for a few minutes. About one minute or so in I saw a spray from the oil fill tube and another out of the dipstick. That one smoked a lot as it hit the headers. This is with the working PCV valve and the tube from the drivers valve cover to the catch can and back to the air cleaner. I don't care about a dirty air filter... I care about burning oil and smoke.

Thanks again for all of your help!

Fun71

If that's the case, installing a PCV valve in each valve cover might help. Going back to the vented oil fill cap may be necessary with 2 PCV valves.

Gooner

What vacuum port would the second PCV go to? I am willing to try any combination in the hopes that I will find the magic one for my motor.

tru-blue 442

About the best you could do for this
is put a T in for both, feeding into the carb base.
Also be aware the port is going to clog after a while too.
You might also try a thicker oil.
What blend are you running now?

Gooner

I will give that a try.

My first attempt tomorrow will be to run the tube from the catch can outlet to the carb base where the PCV is currently plumbed. That should be maximum vaccum since it is a straight shot from the valve cover to the catch can, where the gunk will sit, and then back to the carb. Then I am going to run a straight tube from the other valve cover to the air cleaner like stock. Then I will pray.

tru-blue 442

Always a good thing. Good luck with it.

oldcutlass

You don't want to use a catch can if it leaks vacuum. You need as much vacuum to the pcv/s that you can get to relieve the pressure.

Texas69

I had a similar issue, with oil pushing out of the oil dipstick and seemingly every other oriface due to blow by on a tired engine. I replaced the 5-30w oil with 10-40 high mileage vehicle oil, replaced the oil laden breather in the valve cover and replaced the PVC. I have to change out the breather periodically because it gunks up with oil. However, this set up stopped the excessive oil leaks ( which conveniently dropped right on the header and created a protective smoke screen behind me) and was a lot cheaper than the rebuild that I really need, but cannot afford at the moment.

Gooner

Might just try the same thing. Going to experiment with a few different solutions recommended here today, and see what works. I see myself getting very familiar with the PCV section at Advance Auto.