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

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tanman

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

This post was updated on .

Maiden voyage after installing all my new parts and oil was literally pouring down the back of the engine from the valve cover. I used the expensive $30 gasket. Torqued to 7 ft-lb, I verified all the holes were nice and flush when I painted the valve cover… I’m at a loss, I can see the oil just puddle around the cover.

Pulling my hair out …

86 F150 4.9 Automatic

85lebaront2

Re: What a mess!

Administrator

Could the gasket have gotten folded?

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

ArdWrknTrk

Re: What a mess!

Administrator

In reply to this post by tanman

Is the PCV functioning properly?
Do you have excessive blow by?
Is the valve cover flange distorted around the bolts from previous over tightening?

There should be a constant slight negative pressure in the block and valve cover.
If not, then many (if not all ) seals and gaskets are going to leak.

I use a super soft silicone valve cover gasket from Original Gasket Company in Tennessee.
If I had cork or rubber gaskets and stamped valve covers I would glue them to the tin.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

tanman

Re: What a mess!

There is no pcv valve. I put two breather caps on.

The valve cover is not bent.

I will have to google “ excessive blow by”

86 F150 4.9 Automatic

ArdWrknTrk

Re: What a mess!

Administrator

I think you've already found the problem..

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

85lebaront2

Re: What a mess!

Administrator

Sounds like you need a can of compression. Had a friend's Corvair years ago, had a plume coming out of the breather tube, put my thumb on it and the dipstick lifted up and oil started coming out.

Worst I ever saw was a Mercedes-Benz 220D that one of the salesmen had the lube rack boy help him plug the inside the valve cover oil separator tube. The gasket on these engines is a U shaped cross section that the cast aluminum valve cover goes into. The pressure built up so high it actually bowed the valve cover and blew the gasket off on the manifold (straight) side, 7 of the 9 quarts of nice black Diesel lube oil went everywhere, including out onto the fenders and windshield.

Bill AKA "LOBO" Profile

tanman

Re: What a mess!

Wouldn’t the breather caps actually prevent the pressure from building up? Wouldn’t I just have low power. I’m gonna swap the cork gasket for the rubber one and see if that does the trick.

86 F150 4.9 Automatic

ArdWrknTrk

Re: What a mess!

Administrator

There's a reason it's called a positive crankcase ventilation system....

Even if you had an incredibly tiny leakdown, like 4-5%, you're still going to see pressure building up.
Things like front and rear main seals are designed to work with negative crankcase pressure.

But if I were in your shoes I would definitely do a leakdown with the pistons at various points in the bore.
(This requires the crankshaft to be locked in place)
If you decide to investigate blow by you will understand how this testing is accomplished.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

tanman

Re: What a mess!

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.

86 F150 4.9 Automatic

ArdWrknTrk

Re: What a mess!

Administrator

If you've going to try making a cork gasket seal I'm going to suggest (again) firmly gluing it to the tin cover with gasket shellac, like old school Indian Head before assembling.

I usually leave a thin film of grease on the head itself so I can get the cover off without a chisel.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

85lebaront2

Re: What a mess!

Administrator

In reply to this post by tanman

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.

Bill AKA "LOBO" Profile

Gary Lewis

Re: What a mess!

Administrator

In reply to this post by tanman

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.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

tanman

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

In reply to this post by 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?

86 F150 4.9 Automatic

ArdWrknTrk

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

Administrator

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.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

tanman

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

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?

86 F150 4.9 Automatic

ArdWrknTrk

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

Administrator

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...

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ratdude747

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

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.

1984 F150: 300 L6, AOD, RWD. EEC IV / TFI, Feedback Carter YFA Carb. Stock everything but radio (for now).

Perkinator

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

In reply to this post by tanman

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.

“Lexi” 1986 f150 xlt lariat, 351 winsor,
Short bed 4x4.

2006 f150 fx4, 5.4 triton super cab short bed 4x4