Oil consumption and PCV valve

[Scufty]

ok guys ..need some input ...rebuilt the motor during the last summer ....427
1.
Checked the rings and honed and replaced.
Lemans rods ...great shape all good
went to new mild cam and solid lifters
Had heads checked and Valve Guides were good
New Teflon Valve seals ...all good

heres the deal ...seemed to gothrough alot of oil..thought maybe it was just the rings seating and that it would go away eventually

When I rebuilt the engine I did notice quite alot of oil on the back of the valves ...both exhaust and intake...thought that was a little odd since the guides and seals were good.

anyway just took motor back apart for clean up deatiling and paint. Noticed again that there was alot of build up on the back of the valves. Maybe 400 miles on rebulid. Didnt quite understand this again.

Now ....I kinda overlooked the PCV valve ..never touched it ..not sure how long its been on the car. Looked at the valve covers and they dont have any baffles.(not good) alluminum 427 valve covers. see gallery if you like. Now could I be pulling enough oil into the engine through the PCV valve to cause me to burn blue and also go through oil consumption?
Thoughts
Thanks guys

[olddog]

My opinion yes. However oil would burn in the cylinders, and therefore should not be on the exhaust valves. Also I would think oil coming in through the intake would not tend to pool on the intake valves, as it would be coming in at high velocity mixed with the fuel. I would suspect oil pooled on the vavles is leaking down the stems.

Just an opinion from a non-expert.

[Rick Parker]

Absolutely. Do a test. Temporarily eliminate the PCV valve and drive the car and monitor oil consumption. If it drops, the valve or lack of baffle is at fault. Be sure you have a PCV valve intended for an FE they are internally weighted differently and open or close at different manifold vacuum levels which is controlled by the cam timing.

[Scufty]

VERY ineresting...gotta love overlooking the simple things. I just really cant see it being the valve guides or seals ..Brand new

Anyone else? the more opinions the better

[HSSS427]

Leaking intake gasket - sucking oil into the intake runners from the valley. Been there, done that!
Thanks!
Scott

[Scufty]

sure wish I could figure out if it was my intake gasket. guess I will put her back together and do a leak down test.

[HSSS427]

Leak down test won't show it as the leak is upstream of the valves. It tends to leak right along the lower edge of the intake gasket. I actually had a gouge in my intake along one of the edges that was agravating the situation. In addition, when running, you've got a vacum inside the intake runner that also "sucks" oil through any gap. Haven't figured out any way to test for this and just tried to be liberal with gasket sealer - particularly along the bottom edge of each of the intake openings in the head. Cornering hard also can aggravate it when you get oil sloshing up to one side. You might try to see if you're getting smoke upon hard cornering.

Oh, and the other issue - this might now be the issue! Mysteries of the 427 are never ending sometimes

[mr0077]

If the PCV hose is dry the problem is not the PCV valve. I had the same problem, turned out to be the intake gaskets...bottom side wasn't sealing, causing oil to get sucked out of the lifter valley into the intake ports. If this is the problem, when you pull the intake you'll see dry intake runners in the manifold but oily intake ports in the heads (exhaust ports dry, or at least not oily), indicating the point of entry into the intake system.

[Scufty]

I think when I put it back together I will take a hard look at the intake...No real science to all this ...drivin me nuts
Thanks guys

[SuperHart]

Most likely the PCV valve is your culprit. Remember, at idle, the PCV valve is sucking with the same suction as exists in your intake manifold, maybe 14-18 in/Hg. That is definitely enough to suck oil out of the valve train. The PCV valve MUST be shielded from the oil via a baffle. A baffle is an easy thing to make out of thin sheet aluminum. You can secure it underside the valve cover via the PCV grommet as long as it is constructed properly. Here is a simple diagram that you may find useful. I made baffles for my valve covers and they have performed flawlessly for two years now. The diagram calls for a 1 1/4" hole but you should measure your PCV valve grommet to determine the proper size. Drill the hole before bending the sluminum sheet to size. As you can see, the baffle should allow oil to drip off the edge towards the exhaust side of the cylinder head.

[Mike Bartlett]

I have my motor torn down right now. I also noticed quite a bit of oil on the back of both intake and exhaust valves. I was burning a ton of oil, 1-qt per ~200 miles. I do not run a PCV valve but I do have a tall solid breather on both valve covers as well as the intake. I am assuming my rings are bad hence all the oil burning. My heads were rebuilt, valves, guides, etc about 2800 miles ago so I don't think they were the culprit. My assumption is with the amount of oil blowing past the rings and with the large cam overlap, 254/266 @ .050", the oil was getting to the top side of the valves? Seem plausible? When I pulled my intake the gasket seemed ok?


Mike

[vettestr]

Mike,
Oil on the intake valves is coming from the guides. The Ex. valves can be coated from guides also or from a combo of guides and rings. Look at top of your pistons to see if they are clean just around the outer diameter and crusty on the more center of piston top. A clear ring around piston diameter shows washing past the rings.

[Barry_R]

Very good chance it was seals/guides. The teflon/white plastic style seals are not very good - very unforgiving of any guide looseness or surface issues on the stem. You can get viton style seals that fit in the same spot and are far better on a driver.

I spend an inordinate amount of time on intake fitting - they are very prone to leakage as already mentioned. I install gaskets on the heads, and then use the distributor as a plug in locator. I square the vertical "china wall" spacing front and back. Then I stab a feeler guage at the upper and lower corners of each end of the manifold/gasket interface. Its not at all unusual to fit a .015 or more guage at one spot and have a snug fit at the other. I make notes on the intake with a Sharpie, and then mill it to get things square. I install with a very thin skin of silicone everywhere and a thick bead front and back. The silicone seals things up and also gives you a visible indication that contact has been established - you get a very tiny "squeeze out bead" if done right.

Note: avoid Ultra Black silicone like the plague. It will never harden - even after 24 hours and a dyno run. I pulled an engine down for a water leak and that stuff was still wet! First and last time I ever used it... gray/silver looks nice and works well....

[Rick Parker]

I recall a picture that was posted here depicting how to pressurize the intake to check for leaks. It had the carb removed with a plate bolted down on the intake manifold in place of the carb. Attached to the plate was some sort of air hose connection. I believe the idea was to back off all the rocker arms to effectively close all valves and then lightly pressurize the manifold and check for leakage.

[Mike Bartlett]

Barry,

I assume you do not use the cork gaskets at each end, front/back, of the intake? Also, when checking with the feeler gauge do you check between the intake gasket and manifold or I-gasket and head or both? I assume you do this front and back but also around the top of each head where it meets the intake?

Sounds like you are thorough about this and since I have not installed my brand new Edelbrock heads and intake I want to be sure and do it right.

Thanks.....

Mike

[Scufty]

Well I must say that I appreciate all the comments ...it could certainly be 1 or all of which you all talked about ..I hope to get all the things mentioned sorted out ...I will be painting the block today and starting the assembly ..I will keep youall posted and shoot up some pics of the progress I hope ...thanks again for all the help ..keep it coming
Cheers

[SuperHart]

Hey, guys, regarding the comment that Barry_R made about UltraBlack Silicone, I'd like to hear more comments. Personally, I use UltraBlack all the time because it has the best oil and fuel resistance of all the silicone sealers other than aviation grade. I have never had a problem with UltraBlack not setting up. True, it may take somewhat longer to cure up but it has always worked well for me and it is the sealer I recommend for use with my valve cover adapter kits.

If there is something about this product I am missing, please let me know. Scufty, have you made your baffles yet?

[Scufty]

Hey Heart ..No the baffles are not made yet but willbe before the motor runs again ..I got a product from my race shop called "the right stuff" made by Permatex? I think?
He says its the best form a Gasket stuff PERIOD? Never used it ...anyone?

[Rick Parker]

"The Right Stuff" IS the best out there. Once you use it you will realize why.

[Ron61]

I agree with Rick. I have used both the Ultra Black and had good results with it and the Right Stuff. I think the Right Stuff is better. But that is just my opinion as both worked well for me.

Ron