1969 340 is down

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Bennoel 10

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Long story short I acquired a 69 340 swinger that has a rebuilt engine. Everything was fine until I hear a noise similar to a flywheel/ring gear hitting the inspection cover. Noise lasted about 5 seconds give or take. After the initial noise stopped I realized lost of power. My destination was 3/4 mile away so I proceeded. After removing the spark plugs and doing a compression test one cylinder was zero, #3 I believe (second from the front, pass side). Removed the value covers and low and behold the rockers appear to be out of place. (See pictures). Anyway I'm pulling the engine and going from there. Just wondering what the membership has to advise. Thanks in advance.

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Seen that once before and it was the cam thrust plate came loose and the cam walked forward. The noise you heard could have been the Distributor drive gear or the fuel pump eccentric.
 
Bennoel 10 said:
After removing the spark plugs and doing a compression test one cylinder was zero, #3 I believe (second from the front, pass side). Removed the value covers and low and behold the rockers appear to be out of place. (See pictures). Anyway I'm pulling the engine and going from there. Just wondering what the membership has to advise. Thanks in advance.
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The odd numbers are on the driver's side, so if it's on the passenger side the second hole is #4.
 
Uncle Bob said:
The odd numbers are on the driver's side, so if it's on the passenger side the second hole is #4.
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Yes that's what I thought odd numbers left or driver's side, even numbers right or pass side just couldn't remember as I've got other things I'm thinking about.
Thanks though
 
If the valves are closed it's hard to see how the rockers/pushrods could leave one hole with zero compression. The random rockers might just be a sign of other things put together wrong.

Can you describe what you saw in that hole with the bore scope?
 
Hopefully tomorrow I'll be able to report. Pretty much ready to pull now. Got to go attend to some family obligations at the moment but tomorrow is a new day.
Thanks again
 
A lot of Mopar people i have spoken to also don't know that on the factory stamped rockers, the pushrod bowl is off center and they need to be matched up but it's one the first things i noticed when I cracked open my 440.
 
Uncle Bob said:
If the valves are closed it's hard to see how the rockers/pushrods could leave one hole with zero compression. The random rockers might just be a sign of other things put together wrong.

Can you describe what you saw in that hole with the bore scope?
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Yes I agree. Kinda lost confidence when I see the rockers mismatched. #3 cylinder intake valve doesn't move at all hence zero compression. Can't spin the pushrod and I believe it's stuck down for what ever reason and the piston hit the valve until it broke (noise stopped) . Gonna remove engine and take a better look.
Thanks again for all the input.
 
Vamisk said:
A lot of Mopar people i have spoken to also don't know that on the factory stamped rockers, the pushrod bowl is off center and they need to be matched up but it's one the first things i noticed when I cracked open my 440.
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I will definitely look into that. Thanks
 
Sorry to hear. The things I have found...........I'd rather do the engine and bodywork myself. Hopefully not too much damage.
 
As viewed from your first picture: There are 2 different stamped rocker arms, a left and a right. They should an L or an R stamped on them. For EACH cylinder, L is on the left and R is on the right. They are not related to intake/exhaust valves.

The notches on the rocker arm shafts are on the left sides of the heads pointed downward [toward the cam]. The rocker arm shaft washers are correctly placed.

The scraping of the pushrod on the cylinder head is a giant clue. I would pull the heads and check things before I pulled the motor.
 
Are those big block rockers on a smallblock. I thought small block rockers the cups were all centered. I could be wrong.
 
Just a quick update....engine is out and I intend to put a spare 1969 340 engine in for now. When time allows I will definitely get into the hurt engine as it is numbers matching. Problem was I purchased the car with the understanding that it was rebuilt engine and it went like a scalled ape. Didn't abuse it but used it. Then all of a sudden a noise and loss of power. And this is what I found so far. My quick fix is replace with spare engine and enjoy the summer.
Thanks to all and I will update as I go.
 
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