360 LA getting oil in #3 cylinder.

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tinman2

tinman2

Too Broke for Missiles, Switching to Guns
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My brother in law recently bought this 74 Duster 360 auto from my neighbor who only had it 3 or 4 months. Now I am hoping I didn't lead him to make a huge mistake.
It has plenty of vibration that seems to come and go at different speeds or throttle pressure. Pretty new plugs #1, 4, 3, 6, 7 are black soot covered. Plugs #8 and 5 are light beige. Plug #3 is black crusty. There is some oil smoke coming out driver's side exhaust. Trying to figure out where oil could be coming from. I turned the engine over 2 or 3 rounds trying to see if all the rockers were moving but I did not measure movement. Bought an inspection camera today to look in the cylinders. And #3 cylinder has at least ⅜ inch of oil on top of a clean aluminum piston. I don't think that was left in there after driving it. All other piston tops are sooty black. Does LA 360 oil rockers through passages in block and head? If so, could oil be leaking into cylinder at head gasket from me turning engine over by hand?

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Look for an unbaffled PCV, a leaking intake gasket. Also post the pictures of the plugs if you don’t mind. I forgot, get a good look at the valve seals.
 
Autolite 65 just like looking from front of engine.

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Dammit, that's enough oil to hydrolock. My guess is a bad valve guide. If one is that bad, they are all probably worn.
 
Rat Bastid said:
Look for an unbaffled PCV, a leaking intake gasket. Also post the pictures of the plugs if you don’t mind. I forgot, get a good look at the valve seals.
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I can see that valve seals are present but can't tell condition.
If the engine was running, would it leave that much oil in the cylinder at shut down? I turned it over by hand 2 or 3 rounds with valve covers off.
 
tinman2 said:
I can see that valve seals are present but can't tell condition.
If the engine was running, would it leave that much oil in the cylinder at shut down? I turned it over by hand 2 or 3 rounds with valve covers off.
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No, it's probably dribbling in from a valve guide.
 
RustyRatRod said:
No, it's probably dribbling in from a valve guide.
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That seems like a lot though.
Am I right or wrong about oil to rockers through block and head through head gasket? I thought I read that somewhere.
Didn't Magnums switch to oiling through pushrods?
 
tinman2 said:
That seems like a lot though.
Am I right or wrong about oil to rockers through block and head through head gasket? I thought I read that somewhere.
Didn't Magnums switch to oiling through pushrods?
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I've never seen that passage leak into a cylinder. Ever. First time for everything I guess. That rabbit hole wouldn't even be on my radar. At least not without checking everything else first. Besides, if that's what it is, head's gotta come off anyway, right?
 
RustyRatRod said:
I've never seen that passage leak into a cylinder. Ever. First time for everything I guess. That rabbit hole wouldn't even be on my radar. At least not without checking everything else first. Besides, if that's what it is, head's gotta come off anyway, right?
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Yes. That's what I'm afraid off. If it's a possibility. This car has AC. I hate to mess with all that. Even just to pull the intake.
 
Thanks to all. I'll tinker with it more tomorrow.
 
Yeah, that's pretty wet. What kinda valve covers are on it?
 
Also, that ball in the valve doesn't even look like it's seated good at all. Plus, it's a total POS PCV valve. You need one with a metal body at least.
 
Personally, I'd start by pulling a valve cover and then roll the motor over by hand. Make sure all the valves open in the proper sequence.
I've seen engines lose an intake rocker or lose an intake lobe and oil gets sucked up past the rings.
It's a longshot, but you'd also get a chance to see inside the engine and valve covers for oddities.
The only time I've seen that much oil in an engine was when my sister put 12qts in her Nissan pulsar, capacity was 3.5...
It was blowing oil out the breather into the air cleaner..
Can you post a picture of under the hood? Show where things are routed and connected? Might not be a bad idea to check the oil level, or even drain and refill.
 
Danged if I wouldn't try a better PCV valve first.
 
I did turned the crank about 2 or 3 rounds by the crank bolt looking to see if any rockers got a loose spot but I wasn't thinking about it correctly. That was before I took the carb off.

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Don't really know anything about inside of engine. I did run my new inspection camera down the #3 intake port and I could see intake gasket and/or face of head port sticking out slightly on 3 sides of the intake port so there is another issue. I'm guessing no on head porting. And I'm learning a lot about racing type parts on a street engine. It has an Edelbrock RPM/Airgap intake and a Holley 4779 750cfm mechanical secondary, double pumper. Also an MSD billet mechanical advance distributor. When I took the carb off, gas was standing in the ribs in the intake floor. So cold intake and big lopey cam creating less vacuum maybe not keeping gas vaporized. ???
 
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Do a compression test. Cylinder 3 plug is black and crusty. Smoke out driver's side. Burning oil. Cyl 3 piston clean with oil on it. Broken compression rings.
 
Yes. That's coming up. I bought a compression tester when I got my new inspection camera. I'm moving kinda slow on all this. I wasn't expecting to get so involved as to have to disassemble the engine.
 
tinman2 said:
Don't really know anything about inside of engine. I did run my new inspection camera down the #3 intake port and I could see intake gasket and/or face of head port sticking out slightly on 3 sides of the intake port so there is another issue. I'm guessing no on head porting. And I'm learning a lot about racing type parts on a street engine. It has an Edelbrock RPM/Airgap intake and a Holley 4779 750cfm mechanical secondary, double pumper. Also an MSD billet mechanical advance distributor. When I took the carb off, gas was standing in the ribs in the intake floor. So cold intake and big lopey cam creating less vacuum maybe not keeping gas vaporized. ???
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Fuel atomization and vaporization is a big problem with todays fuel (blended for EFI) and cold air intakes.

I won’t do a cold air intake without a quality annular boosters any more.

As a general rule, that series of carbs were “universal” which means they universally fit nothing.

The idle circuit is so rich it’s crazy. Like most everything else they need T slot restricters.

They need some work but if you tune them they work well.
 
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