New, bad engine noise. Shake...rod?

[rjscott]

Engine had a shake. Replaced plugs and wires. Same shake. Had to drive. Drove about 80 miles on highway. Then this. Pullled over immmeduately. Had it towed home. Noise a bit louder than in video. Best guess?

 

Thanks in adavnce

IMG_1826.MOV

[ray_]

What's the history?

 

Try and isolate with a stethoscope (or screwdriver).

 

Pull each plug wire individually and see if the sound/running changes. Have a look under the valve cover too. 

 

I'd look at the pulleys and also maybe pull the flywheel inspection plate and listen.

[percy]

37 minutes ago, rjscott said:

Engine had a shake. Replaced plugs and wires. Same shake. Had to drive. Drove about 80 miles on highway. Then this.

 

 

Looks and sounds like a typical 4-cylinder engine misfire.  Replacing plugs and wires might be a good thing . . . if you could confirm that any one of them was defective.  In addition to Ray's advice about isolating the noise (and probably detecting a misfiring or non-firing cylinder), it might be helpful to examine each spark plug.  One would likely be different from the others.  Although it is presumed that the gaps are carefully checked, it is possible to mistakenly take (new or old) plug gaps for granted.

 

Your problem could be related to a defective or poorly gapped spark plug or defective or crossed high tension lead/s.  This also includes a possible problem with the distributor cap or distributor rotor.  If one or more of your valves is poorly adjusted, permitting a valve to remain open or closed, this could also lead to one or more misfiring cylinders.

 

You have not provided any engine history or condition information.  If, for example, combustion chambers were heavily laden with deposits, deposits could dislodge and interfere with a spark plug's ability to fire.  This situation was more prevalent when fuel contained tetraethyl or similar additives.   Plug replacement or cleaning ordinarily resolves this type of problem.  However, even though you changed plugs, it it not impossible for this situation to recur.  (Not suggesting this is your problem, but without any evidence of condition and maintenance, it is a consideration.

[rjscott]

20 minutes ago, ray_ said:

What's the history?

 

Try and isolate with a stethoscope (or screwdriver).

 

Pull each plug wire individually and see if the sound/running changes. Have a look under the valve cover too. 

 

I'd look at the pulleys and also maybe pull the flywheel inspection plate and listen.

Thanks Ray. Ive had it fifteen years. No engine trouble. I store it most of year, drive it about two months out of year. Cared for. Start it and short drives regularly. Milage unknown, but no smoke. Previous owner took very good care. Head is shaved a bit. oil leak recently. I changed valve cover gasket to start. Still slow leak. As far as I got.  Engine shake started two weeks ago. Thought mis-fire. Gave New wires and plugs. Same shake. This as of yesterday...A couple months ago my mechanic said 2nd valve needed a job. But he didn't think urgent. 

[rjscott]

8 minutes ago, percy said:

 

 

Looks and sounds like a typical 4-cylinder engine misfire.  Replacing plugs and wires might be a good thing . . . if you could confirm that any one of them was defective.  In addition to Ray's advice about isolating the noise (and probably detecting a misfiring or non-firing cylinder), it might be helpful to examine each spark plug.  One would likely be different from the others.  Although it is presumed that the gaps are carefully checked, it is possible to mistakenly take (new or old) plug gaps for granted.

 

Your problem could be related to a defective or poorly gapped spark plug or defective or crossed high tension lead/s.  This also includes a possible problem with the distributor cap or distributor rotor.  If one or more of your valves is poorly adjusted, permitting a valve to remain open or closed, this could also lead to one or more misfiring cylinders.

 

You have not provided any engine history or condition information.  If, for example, combustion chambers were heavily laden with deposits, deposits could dislodge and interfere with a spark plug's ability to fire.  This situation was more prevalent when fuel contained tetraethyl or similar additives.   Plug replacement or cleaning ordinarily resolves this type of problem.  However, even though you changed plugs, it it not impossible for this situation to recur.  (Not suggesting this is your problem, but without any evidence of condition and maintenance, it is a consideration.

Thanks Percy. The engine knocking is quite loud, don't know if video captures it well enough. It sounds like metal is loose in there. A consistent tapping. (I confess though it hadn't had a full tune in along time. Same distributer w/ Pertronix, etc.).

[Preyupy]

When was the last time you adjusted the valve lash? It sounds like they are all very loose and you might have a single broken rocker, this should be easy to spot just by taking the valve cover off. if you don't see anything obvious do a compression test and that could help you narrow it down to a single cylinder. 

[percy]

4 hours ago, rjscott said:

The engine knocking is quite loud, don't know if video captures it well enough. It sounds like metal is loose in there. A consistent tapping. (I confess though it hadn't had a full tune in along time. Same distributer w/ Pertronix, etc.).

 

Still looks like a dead cylinder to my long distance eyes.  Per other suggestions, I think it would be a good idea to isolate the misfiring/dead cylinder, by pulling individual leads.  The one that makes no change in engine operation is the likely culprit.  If you can localize the problem to one cylinder, test for compression, spark and fuel.  Could you have two high tension leads crossed?  It doesn't happen often, but it happens.

 

That "knock" as you describe it, could be an exhaust leak or even a problem with one or two valves that are not fully closing or failing to open.  This can be due to poor adjustment or even worn components, e.g., a worn cam lobe.  Stripped spark plug threads can lead to cylinder misfiring and a noise, not unlike yours.  Sadly, it does not get better and a loose spark plug can eventually become detached "blow" from the head.

 

Not to belabor the point but one dead or misfiring cylinder out of four is not easy to ignore, both due to shaking and noise.  One misfiring cylinder out of eight is not so much of a big deal.

[Mike Self]

When I pulled my '69 out of its winter hibernation in April, it started right up--but only ran above idle on three cylinders, although it ran just fine the last time I drove it (November).  Turned out to be a bad spark plug, although it didn't look any different from the other three, and only had 3-4k miles on it.  A new plug solved the problem and it's running fine now.  Not the first time I've had a plug go bad well before its time.  

 

mike

[oldguy]

Yeah I'd go with a dead cylinder but I'd be more incline to think the adjuster came loose on the exhaust rocker.  Sounds like it's poping back through the intake.  Doesn't sound like rod knock or piston slap if that makes you feel better.  I'm going to guess #3 if we're playing for the trifecta.

[JerryC]

Check the crankshaft drive pulley bolt. I had one loosen up once that made a funny, sort of intermittent knock sound like that. It could ruin your crankshaft key slot, so don't let it go if that's it.

 

Edit: I found mine by grabbing the fan and turning it. The crank pulley moved back and forth with a clunk.

Edited June 19, 2017 by JerryC

['76mintgrün'02]

loose spark plug(s)?

 

interesting that the steady beat of the 'knock' speeds up at the end of the video...

[rjscott]

Diagnosis made. #4 rocker arm broken. Intake side. Piece was lying in the head. Does not seem to have bounced around. (I had pulled off the road as soon as the noise started). Still, not good news.  

 

I read up on the topic here on the forum. Seems basically a full head job is in order?

 

Any thoughts on that?...also what might cause this?

 

(Thanks to everyone prior.) 

[Preyupy]

Actually that is Cylinder #2 exhaust rocker arm.  Cause is cheap aftermarket rocker arms, week valve springs and about 6500 rpm.  Valve float will kill rocker arms.  Yes you need to remove the head and do a full rebuild.  Look at the cam closely as well as the rocker shafts.  Buy good rocker arms and new valve springs. 

[rjscott]

Correct and corrected. Thank you Preyupy

[arminyack]

wow...who knew a broken rocker sounds like MOAR COWBELL!!