Driver 318 cam/valve issues?

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Traxfish

Traxfish

Convertible Cruiser
Joined
Jan 11, 2018
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Location
St. Louis, Missouri
I'm in the process of giving my barracuda a valve job, removing the heads and cleaning everything. I verified it has a sticking valve with a piece of paper getting sucked to the exhaust test. The engine was ran with a badly rusted gas tank and red particulate for a while which I blame for bad carbon buildup. It had strong vacuum, if not a steady vacuum, so I didn't suspect other issues. It ran pretty strong except for a seemingly random misfire at low rpms and a lot of water and soot in the exhaust, with some oil burning especially when cold, and gas mileage much lower than expected (~13). The entire fuel system up to the manifold has been replaced under my care.
Engine idling:

Would you suspect other issues?
Soot is probably carbon buildup in the valvetrain but could the water be another issue?

Once I got the manifold off, I looked at the cam and the wear patterns concern me. Some of the lobes are worn across the top. How normal is this? I have not yet looked at the lifters.

PoXXwHWPRCLChYRu8

If the cam and lifters need replaced, what is the OEM lift/duration? This car is a driver/cruiser and I like the low end torque. It shouldn't see high RPMs often.

I have several books including the Plymouth service manual but not the experience of building and tuning one myself. Trying to get the latter.

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Yep, best to just load those photos directly to the site.
 
Traxfish said:
I'm in the process of giving my barracuda a valve job, removing the heads and cleaning everything. I verified it has a sticking valve with a piece of paper getting sucked to the exhaust test. The engine was ran with a badly rusted gas tank and red particulate for a while which I blame for bad carbon buildup. It had strong vacuum, if not a steady vacuum, so I didn't suspect other issues. It ran pretty strong except for a seemingly random misfire at low rpms and a lot of water and soot in the exhaust, with some oil burning especially when cold, and gas mileage much lower than expected (~13). The entire fuel system up to the manifold has been replaced under my care.
Engine idling:

Would you suspect other issues?
Soot is probably carbon buildup in the valvetrain but could the water be another issue?

Once I got the manifold off, I looked at the cam and the wear patterns concern me. Some of the lobes are worn across the top. How normal is this? I have not yet looked at the lifters.

PoXXwHWPRCLChYRu8

If the cam and lifters need replaced, what is the OEM lift/duration? This car is a driver/cruiser and I like the low end torque. It shouldn't see high RPMs often.

I have several books including the Plymouth service manual but not the experience of building and tuning one myself. Trying to get the latter.

View attachment 1715748618

View attachment 1715748619

View attachment 1715748620

View attachment 1715748621
Click to expand...

Looks like normal cam wear to me.
 
AJ/FormS said:
I want a cam like that!, lol


If that is an original hi-compression 318, those certainly are torquey.
Click to expand...
As far as I am aware, it's OEM, which means 9.2:1, 230 hp and 340 lbs ft at a low 2400 rpm. Great numbers for a driver. I figure it puts about the same power to the wheels as my 2012 focus daily driver (~160 hp) but more than double the torque, which caught me off guard when I got over confident in the rain lol.
 
Looks great for a used cam, nothing wrong at all. Look how clean it is inside, very nice.
 
The problem with a fresh valve job on a tired motor is the increased cylinder pressure on the cylinder/rings is going to make wear and blowby worse. I had a buddy that did a valve job on his z28 and it doubled oil consumption to
A quart every 400 miles.
Is a basic rebuild something you’re willing to do. I would guess that you could do it for about $1200 barring expensive machine work !
 
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Your video to me almost sounds like the timing is pretty far advanced and its dropping cylinders.
 
Brooks James said:
The problem with a fresh valve job on a tired motor is the increased cylinder pressure on the cylinder/rings is going to make wear and blowby worse. I had a buddy that did a valve job on his z28 and it doubled oil consumption to
A quart every 400 miles.
Is a basic rebuild something you’re willing to do. I would guess that you could do it for about $1200 barring expensive machine work !
Click to expand...
I've considered that a rebuild is in order. I was hoping to get this done myself, but I would definitely need help with a rebuild. I'm kind of stuck right now as the exhaust manifold bolts to the y pipe are badly corroded and I'm having a lot of difficulty turning them by my self. I really should replace the whole exhaust system as well.
 
You didn't say if you did compression test or any other/further diagnosis. Simply switch 2 plug wires to make it run poorly and suck a piece of paper up the tail pipe is a shady mechanics trick. Let us know if you actually find a sticking valve.
 
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