Working on a 440/512, Stage 5 iron heads, 284 purple shaft hyd. cam, Holley 850, Indy intake, MSD ignition w/o vacuum advance (18 + 18 degrees all in by 2500 rpm), Champion J12's. Don't know comp ratio but said to be 10:1.

Engine had a oil consumption problem so the old teflon valve seals that appaired to be the issue was changed to Viton seals. Ran through a couple of tanks of gas without any change in oil level. Then pulled the old 160F thermostat and put in a new 180F as the 160 had been messed with by drilling 5 holes almost 1/4 big in it. Apprently to increase flow and/or keep the temps down.

After that the car was run three times with a total about 50 miles, Outside temps in the 80's, and we experienced run-on a couple of times when stopping the engine. It now pings under load around 3k (let off imidently) and the oil level was down 1/4 on the dip stick.

Pulled the plugs and five were quite black and had oil in the threads, one were black and dry and number 5 and 8 were light grey and dry. Wonder why two plugs are light grey.

Noticed the idle oil pressure creeped down to 15 psi when hot. 10/40 dino. Was a little higher with the drilled 160F stat. Gets back to 55psi when reved a little.

Wonder what is going on here!? So many things changed when changing the thermostat: Run-on, detonation and oil consumption. Is it just running too hot making the oil too thin and heating the combustion chambers to the point where it pings and runs on? No temp gauge on the car but it doesn't overheat. Thermal fan clutch, 7 blade fan, alu radiator with shroud.
Sure could put back the 160 stat and see what happens but would like to shine a light on things as it should run fine with a 180 stat.

Sounds like several things are going on: Run-on likely to be butterflies opened too much. Oil consumption likely to be ring seal or wall scoring. 2 grey plugs may be the 2 sealed cylinders, depends on how you're reading them, what the color is down in the porcelain. Oil has very low octane. Not much info to go on, but I'd suggest a compression check, check the total timing, see what jets are in the carb, post some spark plug pics.

if the guides were reduced in height for the Teflon seals and then you replaced them with umbrellas that could be a problem. I don't like to see the top of the guides exposed with umbrellas and short guide bosses will do that. also could be the intake manifold sucking oil. 10:1 compression, probably non-quench, by itself is an issue. a lot of stuff could be going on but oil with 10:1 non-quench won't be happy with pump gas.

get some cranking psi numbers.
also, isn't a J12 champion a really hot plug?
might look into that.

should be real easy to build compression with a 512 so I would be looking to what the cranking psi #'s are.

The J12 plugs might bee too hot for this combo. I sealed thw intake with double paper gaskets when the valve seals were changes. Port matches thw intake, valley pan and gaskets to the hesds and then there was not much ledt of the gasket and valley pan. Might have oil getting through there. Checking that first. Valve seals are positive seals - Viton. Absolutely no oil consumption the firs couple of tanks. Then 1/4 down on thw stick in a fes miles. Can it just be an internal oil leak causing detonation?

I went through some detonation and run-on problems several years back. I posted here and at a few other forums looking for help. I did get some good advice, Some said I should S L O W down the rate of ignition advance. I also read about using colder spark plugs. I had the recommended RC12YC plugs and switched to RC9YCs. That stopped my run-on.
I heard from several people that detonation can leave evidence of damage to the tops of the pistons, marks that were supposed to look like someone used an ice pick. I pulled the heads in my car and the pistons all looked fine. I put in thicker head gaskets to lower my compression and I've been fine since.

Thanks Frankenduster! I'll try colder plugs. But I have to find out what causes the oily plugs first. I have slowed the advance down by about 500 rpm after last test. Will see how it responds.

j12y is not a hot plug. that heat range shouldn't be an issue. oil in the chambers is a killer.

Update: Pulled pcv hose: Has fresh oil in it. Pulled pcv valve: Rattles but is wide open. One can suck or blow all one can through it without feeling any restrictions - also when tilted to the position it sits in when mounted. Then give it a little "bump" and it restricts but will open fully when sucktion is introdused and stay open.

Pulled carb from the dual plan intake to see small puddles of fresh oil in the grooves at the bottom of the plenum - most in the lower half.

Intake is shaped so that the runners for cylinder 5 and 8 are higher than the other two pointing to the back. These were the ones that had the dry, light gray plugs. The two high runners pointing forward goes to the two plugs who was black but dry (only some oil in the threads). All 4 low runners leads to the oily plugs.

Conclution is that the pcv got stuck wide open letting oil get sucked into the engine and oiling the plugs with the lowest runners. This caused the oil consumption.
Open pcv caused a lean condition wich leads to more heat and causes detonation and run-on.
Oil introdused to the combustion may have contributed to the detonation problem.
The two light gray plugs are the only two that - because of the position of the intake runners- did not get oil fouled and can be "read". Those two show the lean condition.

Agree? Please feel free to comment!

I have a couple of "known to be good" pcv vales so next is to put one in, reassemble the rest and give it a try.

The PCV is always wide open if there is any vacuum in the engine. The most vacuum is at idle. You will feel no restriction in it because as soon as vacuum is applied through suction, it opens. Some people refer to the PCV system as a "Controlled vacuum leak". If you say it rattles but the valve never fully closes, that is a different matter.
Oil in the chambers does contribute to detonation though.
I don't recall seeing any compression test results. Through all of the things that I tried, lowering compression made the immediate difference. I had cylinder #s as high as 195.at one point, A guy at FABO suggested a Lunati cam with some rowdy specs...I installed it and oddly, the numbers went UP on average 3 PSI per hole. The switch to .075 thick head gaskets dropped the CR about 7/8 of a point and the car didn't knock anymore. The cranking PSI went to 170.
Plenty of people suggested to tear down the engine and install dished pistons set to a zero deck. In truth, that is a better way to go but I was too bull headed to do it. Looking at it now, am probably leaving power "on the table" with the way the engine is currently. If I get a sudden spark of motivation, I may back pedal and rebuild the engine the "right" way.
Back on topic: You could plug the PCV inlet and stuff a breather in the valve cover and drive around to see if it makes a difference.

As easy as it is to pull a BB intake - no coolant in them, either - I'd want to look at the intake/head/bathtub sealing. Some guys get away without paper gaskets, but I prefer thin ones glued to each side of the bathtub, and have never had a problem there as a result.

If the intake gaskets are leaking this will also cause oily intake.....

make sure there's a baffle in the valve cover under the pcv valve.

Well, pcv definetly hangs open. Needs to be hit or shaked to respond but will stay open at next try. Like having a broken spring. Not anything like the others I have.
Oil in the pcv hose and intake plenum don't come from a leaking intake gasket. The two readable plugs shows a lean condition and are serving the upper rear runners where there is no oil.
Valve cover has a baffle under pcv port. I can' tell how good it performs, but I know for sure the car just ran through two tanks of gas without any oil consumption.
Testing a new valve before pulling intake or doing any pressure tests.

It sounds like you're on the right track.

Contrary to what some think, the PCV valve flows very little at high vacuum and flow increases as the load increases and vacuum decreases.

From Wikipedia: The PCV valve is a variable orifice that controls the flow of crankcase fumes, admixed with fresh air admitted to the crankcase by the breather, into the intake tract. With no manifold vacuum, a restrictor—generally a cone or ball—is held by a light spring in a position exposing the full size of the valve's orifice to the intake manifold. With the engine running, the restrictor is drawn towards the orifice by manifold vacuum, restricting the opening proportionate to the level of engine vacuum vs. spring tension. At idle, manifold vacuum is high, but a large amount of extra air would amount to a vacuum leak, causing the engine to run too lean and/or too fast. So at high manifold vacuum, the PCV valve allows only a low flow rate. This is in accordance with the low volume of crankcase fumes generated at low engine speeds. At higher engine speeds, with less manifold vacuum, the PCV valve permits a greater flow rate to keep up with the greater volume of crankcase fumes; because of the higher engine speed, a greater amount of "extra" air via the PCV system can be tolerated without upsetting the engine's running. At full throttle, very little manifold vacuum is present, so there is little flow through the PCV valve. However, this is the condition under which the maximum volume of crankcase gas is present. Most of it escapes under its own pressure via the crankcase breather, flowing into the engine's intake tract via the air cleaner.

It's similar to the vacuum secondaries on a Holley 4160.

R.

Hope so, Dogdays
Your text says the pcv valv should only flow a small amount at high vacuumn, wich I agree to. The suspected valve is literally a huge piece of piping when it hangs up.

I've installed a clear canister in the line between PCV valvecover and intake to try and seperate the oil from the ventilated air.
On my previous (318) engine, the canister filled up with white sludge in a matter of a 2-3 weeks, during colder weather.
Now the current 360's leaks much less oil

The canister is the one from a mighty-vac brakebleed unit. 'Mighty' handy for this purpose as well.
I modified it with a rubber 'downtube' on the incoming charge that reaches all the way to the bottom to prevent any oilspatter still making it up into the intake.

You could always put a fuel filter inline between the pcv and intake and see if it makes a difference.I do like your poor mans catch can though.

On your deal with iron heads and 10.0 to 1 + compression ratio the pinging can cause the rings to stick in the ring lands which can lead to oil consumption What altitude(in feet please) do you drive your car at?
I would do a compression and or leak down test to see if all the cylinders test the same, oil on the plugs is a way to start pinging also
I like my plugs to be dry and white to barely light brown To hot of the heat range on the plugs will make them look grey
On your motor with iron heads try using some RJ10YC or colder, Autolite 3922 or 3921
Please let us know your results