y-block blow by..
 

hi guys! I need your thoughts? I have a 272 (1956).
that I rebuilt less than a year ago. I'm running "trips".
the problem I'm having is, I'm getting a lot of blow by
from the oil filler tube! I know the engine is mechanically
healthy, as I rebuilt it. I have a pcv installed in the top
of the block. (not the valley pan). the road draft tube
has been eliminated.(blocked off). I understand, the
oil filler tube also acts as a fresh air intake. but, something
I'm not doing right, because there is too much blow by
thru the filler tube, thus fumes are getting into car..
I know all you guys are extremely sharp! so, I'm sure
someone has a fix.
thanks!!

Re: y-block blow by..
 

Can you show a photo of the PCV SYSTEM install?

If she is pumping fumes out of the filler cap, it is either non-functional and/or has extreme blow-by.

Re: y-block blow by..
 

Sorry guys, having a difficult time uploading
A picture...

Re: y-block blow by..
 

Keep trying. If you need help, yell.

Re: y-block blow by..
 

The pcv valve is next to distributer.

Re: y-block blow by..
 

Has the engine been having this issue ever since you installed the PCV system, or did it start later on it's own ? Even after a fresh rebuild things can happen to cause more blow by.


Sal

Re: y-block blow by..
 

I can't tell where your hose is connecting to in the block from that picture. What you should be trying to do is to ventilate the crankshaft.
Best way is to have openings at opposite ends of each other in relation to crankshaft. The original ideas of having the oil filler cap with an integral filter and ventilation tube/screen cannister in the lower block is good and the other being at the back of valley pan instead of the tube is okay also.

Re: y-block blow by..
 

Sorry guys, couldn't get a better picture .as
I stated previously. The pcv valve is tapped
Into the block. It's vacuum is supplied from the
Port between ctr. And front carb. I'm wondering
If I should put the road draft tube back on it?
Such as Dave said about having ventilation
At opposite ends. Does anyone have a good
Canister and tube?

Re: y-block blow by..
 

Do you mean the PCV install is as shown below?

Re: y-block blow by..
 

Yes kultulz. That's exactly what I have! I'm thinking the engine is not breathing properly so it's just blowing it back out of the oil filler tube?

Re: y-block blow by..
 

You do not have an effective system. The valve has no baffling and will ingest spray/vapors making the system ineffective.

Re: y-block blow by..
 

I had a PCV valve in the valley pan without sufficient baffling. It pick up a lot of oil, which on my set up mainly ended up in # 7&8 cylinders. But that was into the rear carb fitting on a 4 barrel. A stuck PCV valve will also produce your symptoms, to the point of blowing out a valve cover gasket in extreme cases. (Ask how I know, and the mess of oil on the exhaust is almost as bad as the heart attack when all the smoke shows up).

What engine was that PCV designed for? Did it mount vertically in the OEM application?

How much oil is the engine using, and how many miles since the rebuild?

Re: y-block blow by..
 

I believe the pcv valve was supposed to be
For a y block application.the engine doesn't
Use oil. There's probably a couple thousand
Miles on Rebuild.

Re: y-block blow by..
 

Let me be more concise, the setup @ the carb is fine. It is the actual valve setup that is ineffective.

Re: y-block blow by..
 

So, what needs to be done to
Fix this problem?

Re: y-block blow by..
 

what kind of rings did you use.i had trouble with a set of moly rings.the first time i saw a pcv in that spot i wondered.the dist, spinning in the cam gear is going to throw a lot of oil around.most of the top end oil is running down there.

Re: y-block blow by..
 

Exactly! Good point ...

Re: y-block blow by..
 

Thanks for hanging with me guys!
This is an issue that needs to be resolved,
I can't breathe those toxic fumes... Can't
remember what type of rings are used?
Pcv valve#255.

Re: y-block blow by..
 

Read this thread - https://www.fordbarn.com/forum/showt...19#post1821719

Don't worry yourself as it can be solved. BTW- Where did you get the info to set up the valve location?

Re: y-block blow by..
 

I acquired the motor that way...

Re: y-block blow by..
 

You read the URL I showed describing the OEM SYSTEM?

Because of your intake type (plenum hanging over valley cover). there will have to be a few modifications. I am sure that what the original owner attempted.

Re: y-block blow by..
 

Yes sir I did! Very good info..

Re: y-block blow by..
 

What do you guys think about adding the road
Draft tube, I have it blocked off..

Re: y-block blow by..
 

That would be a step backward! Those road draft tubes only worked at highway speeds, and not too effectively then. Around town. speeds were too slow to generate any draft at the road tube. One reason why so many Y-blocks sludged up and starved the rocker arms.
Try this: With the engine idling, lay a piece of cellophane over the fill tube. There should be enough vacuum build up after a few seconds to pull the cellophane into the tube. If not, check the PCV valve for proper flow. Some valves threaded into the carb/intake, so the flow was from the barbed (or hose) end into the intake. Other similar looking PCV valves threaded into the block/valve cover so the flow was from the threaded end, out through the hose and on to the intake. The internal check valve will block flow if the PCV valve is backwards.
You could make/adapt an oil fill cap with a hose running to the air cleaner to reburn the blowby, like OEM PCV systems do.

Re: y-block blow by..
 

the fumes shouldnt be that bad.what do you have for tail pipes.your not getting exhaust fumes by chance

Re: y-block blow by..
 

Simply put a VACUUM/FUEL PRESSURE gauge on the dipstick tube. That will tell you if there is a partial vacuum or a pressurized crankcase.

A PCV Valve is not a precise piece. The OEM was calibrated for a specific engine(s) and was calibrated to work with several. The fuel/IGN curves were modified to work with whatever valve. As the engine wore/lack of maintenance, the system failed. Modify manifold vacuum with a cam or never adjust the valves and it will throw off the OEM System. That and the early designs were not that concise.

There are also not as many valve applications as there once was. Many have been deleted and/or replaced (the one fits all and CHI-COM).

Re: y-block blow by..
 

In addition to or in lieu (Fr.) of the PCV?

Re: y-block blow by..
 

Read This - http://mewagner.com/?p=444

Re: y-block blow by..
 

As usual guys, great answers! I think we're slowly making progress? I was leaning toward the road draft but thanks I'm not going to do that now. I tried the cellophane trek put it over the oil filler tube, it did not get sucked down in! What I did find was the breather cap was filled with oil! As far as the toxic fumes, it's just the blow by coming out of the engine. I have dual exhaust with the tail pipes coming out the back and I'm positive there is no leaks. So it's all getting down to I don't think my PCV valve is working properly? If it was when the engine was running it should have sucked that piece of cellophane down in the filler tube. But it didn't.so my question now is I have vacuum going to the PCV valve why is it not working?

Re: y-block blow by..
 

Re: y-block blow by..
 

Bad sign. Now there are two styles of caps, one is OPEN, its having a filter element in it and CLOSED, the cap drawing fresh air through the air cleaner. What style do you have?

I hate to be disrespectful, but that PCV install is gnarly ... :eek:

Is the car a daily driver?

Re: y-block blow by..
 

No disrespect at all! You are absolutely right it is gnarly and it needs to be remade! Yes I drive it daily when it's
Not too cold. No heater! Lol! the cap is a repo of an oem
It has a logo on it stating front. It has a foam filter in it.
there are no air cleaners on this car so there's no hose to run it back to.

Re: y-block blow by..
 

Why not hook up a hand-held vacuum pump (like the ones used for bleeding brakes) to the hose that is hooked to the carb port? Unhook the hose there and use the vacuum pump to suck air through as a simple test to make sure the PCV valve is oriented in the correct direction to flow air from the crankcase to the carb port.

If you have a set up like Kultulz showed in his post as a suggestion, I do not think that the threaded boss (I think originally meant for carburetor/accelerator bellcrank assemblies) goes through to the crankcase on every single block cast from the factory. As I recall, I have seen blocks that contained holes that that did not go completely through. You may just want to double check that the hole goes completely through in that location.

Re: y-block blow by..
 

Thanks for joining the conversation hot rod Reverand.
I'm sure between everyone I'll come up with a solution.

Re: y-block blow by..
 

To add to this, some years back (late '80's-earluy '90's) some vehicles (I think Ford Ranger was one) specified that the PCV valve be changed to a different part# after break-in. That's how specific the calibration was.

Re: y-block blow by..
 

It might be worthwhile to copy most '70's or so Ford systems: That is, fresh air into the engine through one valve cover, then fumes out the other valve cover through the PCV valve into the intake manifold (the system on your car will leave stagnant fumes/condensation under your valve covers, allowing for possible sludge and rust). Do those nice valve covers have pads to drill holes to add rubber grommets for the PCV valve and fresh air inlet? Or hide them on the back sides? If you do this, you will need to block the oil fill tube with a solid cap so no air flows through. Also, OEM PCV hoses were larger than on your car for better flow.

Re: y-block blow by..
 

I also have that same repro oil filler cap they sell for the '50's Y-blocks with the foam filter inside. I did NOT like that foam filter. When it came time to clean it, I submerged the whole cap in a coffee can full of gasoline. After a day or so, the gas melted the foam filter enough that I could pull it out thru the middle underneath.
Then I took a bat of household fiberglass insulation and cut enough off of it to stuff it down inside that cap. It turned out to be a pretty good filter.
The gas also dissolved the black paint, but no big deal, I just repainted it with some cheap Rust-O-Leum black paint, and voila, like new again. Still using that cap.

Re: y-block blow by..
 

This is a little off the subject, but why are we seeing Connecticut and Pennsylvania residents now converting their Y-blocks to PCV ??? Are the northeastern States laws now demanding emission controls like calif ?

Re: y-block blow by..
 

Disconnect pcv and run engine and see if is puffing smome. If it is not you have poor pcv vaccum or crank case ventilation. If is puffing smoke a broke ring , not seated ring or intake gasket not seated properly sucking oil from under the intake.

Re: y-block blow by..
 

Converting your engine to a good PCV system from a road draft tube is one of the best things you can do for it! Positive Crankcase Ventilation removes corrosive combustion blowby gases that would otherwise condense and form acid and sludge. No matter how good the rings are, every engine has some combustion gases getting past the rings. With a road draft tube, these gases went into the atmosphere to add to the smog problem or condensed into the oil. Sucking this stuff out of the crankcase and "recycling" it back through the intake was a major reduction in smog. It was about the first step in pollution control, and works wonders in keeping older engines clean. So it's a win-win!