What a mess! - PCV or no PCV ?!?

[85lebaront2]

I think I have found the culprit. I don’t think these rubber gaskets are a good fit for the older trucks. Not sure why, it was a suggestion from the Facebook groups. Anyway, I happen to have a new cork gasket so I will try that.

This also explains why the oil was leaking from the back.

Gee, what did I say, been there, done that an my bosses 1987 F150, only it was all the way on the back end. The 240/300 valve cover gaskets are a pain due to the length of the engine. I used to hake good luck with Fel-Pro cork/rubber combination gaskets.

[Gary Lewis]

I think I have found the culprit. I don’t think these rubber gaskets are a good fit for the older trucks. Not sure why, it was a suggestion from the Facebook groups. Anyway, I happen to have a new cork gasket so I will try that.

This also explains why the oil was leaking from the back.

Whatever gasket you use, don’t coat it in RTV and then torque it down. Wet RTV is an excellent lubricant and the gasket will ooze out from under the cover. So if you use RTV let it set up overnight before torquing it down.

But Jim’s suggestion of gluing a cork gasket to the cover works well. It’ll even hold the cork/rubber gaskets.

[tanman]

This has peaked my interest. I’m 100% certain the oil mess was due to the valve cover gasket not sealing. I’ve added a cork gasket and will test drive tomorrow.

But, so comments have me reading to understand the purpose of the PCV valve.

There are several purposes that originated as pollution control. The benefit is to prevent unburned fuel from condensing and causing oil to sludge and prolong engine life.

When I purchased this kit from Clifford Performance , Larry explicitly stated that a PCV valve should NOT be used and that I should use push in breathers.

So, when at idle the new cork gasket appears to be working as expected. But there is not excessive blow by at idle. It’s at operating speeds where there is blow by.

The PCV valve vents gasses at higher rpm back to the intake. I have two breathers installed. Do I really need to hook up a PCV valve?

 

[ArdWrknTrk]

This has peaked my interest. I’m 100% certain the oil mess was due to the valve cover gasket not sealing. I’ve added a cork gasket and will test drive tomorrow.

But, so comments have me reading to understand the purpose of the PCV valve.

There are several purposes that originated as pollution control. The benefit is to prevent unburned fuel from condensing and causing oil to sludge and prolong engine life.

When I purchased this kit from Clifford Performance , Larry explicitly stated that a PCV valve should NOT be used and that I should use push in breathers.

So, when at idle the new cork gasket appears to be working as expected. But there is not excessive blow by at idle. It’s at operating speeds where there is blow by.

The PCV valve vents gasses at higher rpm back to the intake. I have two breathers installed. Do I really need to hook up a PCV valve?

While a PCV does eliminate the oil mist blown into the atmosphere that 1950's cars deposited all over the roads one of the primary advantages is extracting condensation and water vapor that etches and corrodes engine internals.

While mandates for low sulphur fuels and oils have helped tremendously in keeping that moisture from turning to acid in your engine, cars today are expected to run a lot farther than the 50-60,000 miles you could get out of one back then too.

[tanman]

While a PCV does eliminate the oil mist blown into the atmosphere that 1950's cars deposited all over the roads one of the primary advantages is extracting condensation and water vapor that etches and corrodes engine internals.

While mandates for low sulphur fuels and oils have helped tremendously in keeping that moisture from turning to acid in your engine, cars today are expected to run a lot farther than the 50-60,000 miles you could get out of one back then too.

Does the vacuum line connected to the PCV valve “open” the valve?

I’m imagining my truck at high speed. Lots of fuel and air are being drawn into the engine. The vacuum line connected to the PCV draws the valve open and pulls air through the valve cover.

Or, does the higher pressure inside the engine open the PCV valve sending the gasses through the vacuum line back to the intake system.

Does the vacuum line trigger the PCV or is it the plumbing for the nasty gases to escape?

[ArdWrknTrk]

Does the vacuum line connected to the PCV valve “open” the valve?

I’m imagining my truck at high speed. Lots of fuel and air are being drawn into the engine. The vacuum line connected to the PCV draws the valve open and pulls air through the valve cover.

Or, does the higher pressure inside the engine open the PCV valve sending the gasses through the vacuum line back to the intake system.

Does the vacuum line trigger the PCV or is it the plumbing for the nasty gases to escape?

The PCV is just a simple check valve.

It is meant to draw filtered air from the vent into the engine and evacuate moisture and oil mist.

Really, it is drawing more air through what is essentially a controlled vacuum leak at idle than at wide open throttle because at idle (throttle closed) manifold vacuum is much higher.

If the vacuum line were simply dumped under the truck like an old road draft tube it would relieve some of the blow by but would really need a check valve at the inlet vent to keep flow going in one direction.

It's both...

[ratdude747]

The PCV is just a simple check valve.

It is meant to draw filtered air from the vent into the engine and evacuate moisture and oil mist.

Really, it is drawing more air through what is essentially a controlled vacuum leak at idle than at wide open throttle because at idle (throttle closed) manifold vacuum is much higher.

If the vacuum line were simply dumped under the truck like an old road draft tube it would relieve some of the blow by but would really need a check valve at the inlet vent to keep flow going in one direction.

It's both...

Easiest way to look for blowby is to remove the oil cap with the motor running and see if oil mist gets puffed out. In my case, since I still had the stock PCV system with hose between the oil cap and air cleaner, the literally smoking gun was an air filter soaked in oil and with the hose disconnected it puffing clouds of oil mist. Ended up being that every cylinder other then #4 had a snapped upper compression ring and a scarred up cylinder (had to rebuild the engine, and the block bored 0.030" oversize). As for why that happened, it's hard to say but a PO running it with the ECU disabled and the iginition timing extremely advanced (and yours truely re-enabling the ECU without checking such an overadvanced base timing) probably pinged it to death.

[Perkinator]

When I got my truck it was leaking so bad from the valve cover every time you filled the Tank with gas you had to add a quart. I pulled the valve covers straighted the lip with 2 hammers. I used FEL-PRO VS 13264 T Valve Cover Gasket Set. From Amazon they advertise that they are made to seal uneven surfaces. Still leaked but cut it down by 90% still leaked on the back the passenger side so I ordered some valve cover clamps and now hasn’t leaked since. Don’t know if this will help but helped me and was a simple fix. Also my pcv valve was backwards plugged into driver side with passenger side having the breather so I put it back the way I’m pretty sure it came stock with pcv on passenger side. Not sure if it had any effect but with all that fixed the leak.