oily crud on intake valves

[Grumpy]

I'm swapping out intakes and noticed an oily buildup on the intake valves that I could see (all with the same amount). The engine has about 5000 miles on the complete rebuild including head work and new seals.

When I got the car, it had one pcv valve connected to the carb on the passenger valve cover plus with a round mr gasket filter vent on the other. I (thinking it was a good idea) moved the pcv valve to the driver valve cover (and to the carb), then added a hose from the bottom of the air cleaner to an inlet on the passenger valve cover. Was this a good idea? Is it sending too much crankcase oily air into the carb?
Ron

If the valve springs are to be removed with the heads still on the car,
the last thing you want is too remove a valve spring and have the valve to drop into the cylinder,
if you use air the crank tends to want to spin the crank to BDC, youll want to verify TDC ,
and make sure the flywheels temporarily prevented from turning from that the TDC position,
Ive used both methods both work,you can put 6 ft of rope in the cylinder while its in BDC then turn it to TDC, Ive used both with zero issues,
If you use the compressor youll want to keep it at 120 psi and constantly feeding pressurized air to keep the valves held in place,
and theres a small chance the compressor pushes enough moisture to allow water to accumulate in the cylinders,
so be sure you spin the engine with the starter with the spark plugs removed several times before you re-install plugs.
if you use the rope, theres a very low chance that the rope will tangle and form a knot that makes removal difficult,
in either case be sure the pistons locked at tdc,
before removing the valve springs, on each cylinder.
https://youtu.be/OsGqmOQus6Y
no! you need to do a leak down test, and other testing to determine the oil source getting into the intake runners and ports,when you see that much oil residue on an engines intake valves in under 20K miles on a newly rebuilt engine, its a great indication your valve seals are either defective or improperly installed,or the wrong valve seals for that application, or have been damaged by the retainer hitting the seals due to insufficient clearance, and probably your valve guides are worn, OR YOUR INTAKE MANIFOLD GASKETS, leak ALLOWING OIL TO BE SUCKED FROM THE LIFTER GALLERY
IF your RINGS were worn or never seated to the bore walls ,the LEAK DOWN TEST SHOULD EASILY SHOW THAT, but it sure looks like a valve guide or seal issue!
light surface ,oily deposits in the intake runners ,are fairly normal due to reversion during the over lap cam timing

http://garage.grumpysperformance.co...w-cam-now-engines-burning-a-bit-of-oil.14569/

almost any cam will cause intake manifold reversion or pulsed low speed air flow in the engines intake runners , this often results in the PCV valve rapidly oscillating in response to the changes in air vacuum/pressure

but that picture shows HEAVIER oil use than reversion alone would allow in that mileage
one old time test you should do, is the following procedure

(1) get a buddy in a second car to follow your car and ideally video tape what he sees to show it to you

(2)put the car in first gear on a section of road that you can safely play with the car on without causing issues with other cars

(3) briskly accelerate (but not had enough to spin the tires) through two gears up to about 40 mph, then with it still in gear, pull your foot off the gas and let the engine slow the car.

(4)exhaust smoke during brisk acceleration is probably rings and blow-bye due to high cylinder pressure
exhaust smoke on DE-acceleration while the engines slowing the car, is due to high engine vacuum, and is more than likely defective valve guides or valve seals


http://garage.grumpysperformance.co...-vortec-heads-and-other-heads.401/#post-10405
http://garage.grumpysperformance.com/index.php?threads/removing-valve-seals.4283/#post-11290

http://garage.grumpysperformance.co...-to-be-a-forgotten-art-form.11838/#post-56133

http://www.cylinderheadsupply.com/valve-guide-tools-guide-top-cutters.html

http://garage.grumpysperformance.com/index.php?threads/leak-down-test.332/#post-14272

http://garage.grumpysperformance.com/index.php?threads/oil-on-plugs.11044/#post-49058

 

[Grumpy]

Tech Tip - 2002

What Causes Intake Reversion? Once and for all, let us have the TRUTH!

With the proliferation of the Motorsports Industry over the years, many new faces have come on the scene. In the cam grinding business today, there are many younger, less experienced companies struggling for recognition of their talents and a few have turned to postulating new theories in order to attract attention. However, they are I believe unfortunately, too often guilty of shooting from the hip.

Two in particular are responsible for perpetuating the "myth" that an earlier opening of the intake valve (even by a mere 2 or 3 degrees) causes the phenomenon known as "reversion". Nothing could be further from the truth! This misconception not only defies common sense, it also establishes a false premise from which other, incorrect conclusions can be drawn. Simply put, those who focus on overlap are on the wrong end of the cam-timing diagram!

Reversion, carburetor/Injector "stand-off" or the general effect of the backing up of the intake Fuel/Air charge normally associated with longer duration high-performance camshafts is actually caused by a Later Intake Closing! How do we know this to be true? The answer lies in the basic principles of physics. For as with geometry and trigonometry, these sacred truths do not change simply because someone chooses to ignore them in an attempt to garner a reputation.

Specifically, when the intake valve opens some 40 or more degrees before T.D.C. at the end of the exhaust stroke, very little (virtually no) exhaust gases remain in the cylinder. The piston is in the vicinity of T.D.C. (only .425" down the hole @40o BTDC - on a typical 350" Chevy with 5.700" rods) and no appreciable threat is posed to the forthcoming intake charge. The "False Reversion Hypothesis" taken to an extreme would lead one to the equally false conclusion that any overlapping of the intake and exhaust valves is totally undesirable. Automotive engineers of the late 1800's and early 1900's used to think this way. They were deathly afraid of overlap, so much so they actually employed "Negative" overlap (minus 5 or 10 degrees) to be absolutely sure none would occur. What was the result? These engines were severely "throttled back" or limited to low speeds and mediocre output. [ Reference: Iskenderian's Tech Article "Cam Degreeing is Simple"] But, more progressive engineers of the early 1920's who performed "brazen experiments" with longer duration cams proved these overlap fears to be only so much "stuff and nonsense", as both power, rpm and performance were actually improved. These engineers demonstrated that overlap did not cause engines to quiver, backfire or lock-up on the spot! Although, the ignorance displayed by their predecessors is easily explained by their lack of experience, (internal combustion engine design being in it's infancy) it was none the less the result of an incorrect hypothesis.

Should you need further persuasion that reversion is not caused by earlier intake opening and the resulting extension of valve overlap, consider this: What happens when you advance any camshaft? The intake as well as the exhaust valves open earlier. Does this advancing of the cam cause more reversion? Of course not. Throttle response and torque are enhanced. Yet, if these theories were correct wouldn't the engine run more poorly, especially at lower RPM? The answer is obviously yes, and because so, these theories are invalid. A brief look at what's happening on the other end of the valve-timing diagram will tell you why.

For when a camshaft is advanced, not only do both valves open earlier but they of course also close earlier - and here in lies the key to reducing Intake Reversion. Close your intake valves earlier and any tendency for the occurrence of Reversion or the backing up of the intake charge as the piston rises on the compression stroke will be reduced. It's not complex, nor is it a mystery. And the circumstances surrounding it's occurrence have not changed. In fact any experienced mechanic could tell you as much, for, as Ed's good friend the legendary Smokey Yunick might say, "Only country smarts are required to solve the problem."