Looking for some Help...SBC Oil fouling plug

[steve cowan]

I changed oil after the first hour of running.

I’ve put a few tanks of gas through it since then. I’ve been keeping a close eye on the dipstick and to be honest I haven’t seen much change if any???

You probably won't see a oil consumption issue at those miles.the tune up is key,if you are washing cylinder walls from to much fuel you will kill the rings/ bore and nothing will fix it.
On a new engine your spark plugs should look pretty new all the time,I think most people run there street engines way to rich .

[Horder]

Waited for a week for the borescope to show up. Definitely the intake gasket is low on the drivers side. The printoseal is showing on the top of the port. Is it possible this caused it to pinch lower on the top and Im not getting any squeeze on the bottom of the port?

Top of the port is on the right in the pic

[Horder]

Here is a picture of #1 cylinder that is oil fouling

[Tom68]

Here is a picture of #1 cylinder that is oil fouling

Appears to have a lot of scratches up and down the bore, hopefully just the bore cam magnifying minor marks.

[Horder]

This camera is helpful, just maybe not for me as I am not exactly sure whats right and wrong. Definetly thenintake gasket isnt good and should be redone. But, as well, I got a shot of the #1 with the intake valve opening. It would appear that the edges are oil soaked???

[Horder]

A little more diagnosis. Appears to be coming from up top

[dannobee]

Obviously start with the intake. Pull it off and look for oil residue in the head port and dry on the intake runner.

Did you look at any other intake runners? And are the valve stems dry inside the ports?

[Horder]

I saw no evidence of oil in any runners. I have some new seals. I will change them and reseal the rocker studs and re-evaluate. Ill report back. Thanks for the help. Appreciate it

[swampbuggy]

I will add a possibility to the list. 50 years back when i had my first Hot Rod in high school a 1966 Chevelle SS 396 4 speed Muncie here is what happened. When we purchased the car we quickly learned that one cylinder was oil fouling the plug. After pulling that piston out it first appeared that nothing was wrong, but my next door neighbor an excellent engine mechanic looked the ring package over focusing on the oil ring assembly (3) pieces the expander and 2 scrapers. He said here is your problem....the expander is overlapped 1 section, fixed that, end of problem . I sincerely hope this is not the case with your oily cylinder. Mark H.

[Horder]

Thanks for the info. Yes, have put some thought into a ring issue and… it may very well be.

Ill do the easy stuff first I suppose. Seals and stud reseal. If it still fouls plugs Ill do the intake. If it still fouls plugs Ill yank it all out this fall.

[Tom68]

I saw no evidence of oil in any runners. I have some new seals. I will change them and reseal the rocker studs and re-evaluate. Ill report back. Thanks for the help. Appreciate it

Dry port oily valve, most likely guide/seal to stem issue, pay to check there's no problem with the guide install in the head.

[stealth]

Not sure if you tried this, but disconnect the PCV valve and block off the hose so it doesn't have any vacuum leak. Add vent to the hole in valve cover.

I've had lots of trouble with these pulling oil into the engine.

Try it... see if the plug stays clean..

[Horder]

Thanks for those replies

The PCV is mounted in the oil fill tube. Vacuum pulls on it via a hose connected to manifold vacuum. The hose seems dry so I think I'm ok there.

[Horder]

Havent had a lot of time for the car.

Some video with the borescope made me feel that the rocker studs were leaking. I pulled them and for sure oil was getting past them. I meticulously cleaned, degreased and sealed with Loctite 592

I took it for a good ride with old plugs as there was some oil in the manifold. I then installed new plugs. Took it out for a good ride. Pulled plugs. #1 seems better. But some other plugs show signs of oil. I pulled the carb and there is oil in the intake again. I checked the PCV hose and its dry. Its not being pulled into the carb base from the PCV.

How far can oil leaking from valve seals or rocker studs migrate up the intake? What about rings?

Or would that be more indicative of a cracked intake? Seems to be in both plenums? The divider does have a recess at the carb base so plenums are somewhat joined

[Tom68]

Havent had a lot of time for the car.

Some video with the borescope made me feel that the rocker studs were leaking. I pulled them and for sure oil was getting past them. I meticulously cleaned, degreased and sealed with Loctite 592

I took it for a good ride with old plugs as there was some oil in the manifold. I then installed new plugs. Took it out for a good ride. Pulled plugs. #1 seems better. But some other plugs show signs of oil. I pulled the carb and there is oil in the intake again. I checked the PCV hose and its dry. Its not being pulled into the carb base from the PCV.

How far can oil leaking from valve seals or rocker studs migrate up the intake? What about rings?

Or would that be more indicative of a cracked intake? Seems to be in both plenums? The divider does have a recess at the carb base so plenums are somewhat joined

You resealed the rocker studs and didn't bother checking valve stem seals ?