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Discussion Starter #1
on my 69 cougar with 351 w, i have a ticking noise coming from first cylinder on pass side. When i pull the spark plug wire off while it is running the noise stops. Does this mean the lifeters are bad? any help and recomendations would be great just got the car and i dont know too much about these cars and what they can do

thanks
dave
 

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just out of curiosity, is the spark plug in there tight enough?? my car would tick like mad for a while and i thought it was an exhaust leak. turns out i forgot to tighten a spark plug. i tightened it and the noise stopped and i was running on all 8 cylinders again LOL Duh me.
 

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Be a little more specfic

Dave, a little more back ground is needed to answer these types of questions. How many miles on the engine? Is it all stock valve train? mm
 

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Discussion Starter #4
the engine has 95,000 on the clock and it seems to be stock except for intake manifold. I will prob in the next week or two just pull the intake off and check out the lifters but i am curious what else it could be. The higher the revs the louder the noise gets.
 

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The ticking that stops when you unplu the spark plug should have kept going if it was the lifters. My thought would be that you have the spark arcing on the outside of the plug wire somewhere down the line. If it is dark enough when you are under the hood sometimes you can even see this happen. I have experienced arc from the wire to the exhaust manifold. Just a little movement of the wire or covering it with an insulator of some sort might help.
--MG
 

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Discussion Starter #6
definalty not arching because i pulled them off with my bare hands and i got no shock. it is more like a knocking noise i would guess and it gets louder with revs.
thanks
dave
 

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Well with 95k on it I would venture a guess that you probably have a a worn rocker and rocker ball. When these non adjustable parts start to wear you lose the preload on the lifter and you get the noise you describe. Without being able to check it myself this is a common problem for these that would be worth checking.:wave: mm
 

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Discussion Starter #8
how would i check that, i am a boat technician so i have some sort of exp with motors.
also do u have an aol screenname.
later dave
 

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If it was something mechanical, it should still be there without the ignition. A lot of times, an exhaust leak can make a very metallic sound. An exhaust leak would go away without the ignition, since the pressure going through the exhaust port would be far less. Sometimes, you can feel the air pulsing out of the leak area---don't get burnt.
 

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I'm sorry, I read the post again and realized what you said about the noise going away with the plug wire off. A worn rocker would still make noise.

Aod, explain please how there would be less exhaust pressure with the plug wire off. I don't understand that. :confused: mm
 

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The difference between idling dynamic compression and lighting off the air/fuel mix?
Well, with the cylinder firing, the expansiveness of lighting off the fuel mix will make a lot-lot more volume and pressure burst out that exhaust port at very high speed when the exhaust valve opens--making the "tic" sound through an exhaust leak.
Now with the plug wire disconnected, you are only going to mechanicly pump through what you took in--and nothing more. At idle with a closed or only partially open throttle, the intake charge is very small making dynamic compression really low--resulting in an exhaust pressure not much more then atmostphereic--if even. Also, the air/unburnt fuel will only pass through the port as fast as the piston pushes it. Much less and slower in comparison to if the cylinder was firing, causing the exhaust leak sound to greatly --if not completely decrease to where it won't be heard beside a running engine.
 

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I agree, except I don't.
Your quote "Also, the air/unburnt fuel will only pass through the port as fast as the piston pushes it. Much less and slower in comparison to if the cylinder was firing, causing the exhaust leak sound to greatly --if not completely decrease to where it won't be heard beside a running engine."

If the engine is idleing and you pull a single plug wire the piston on that one cyl, it is not going to change speed by itself,(there all connected to the same crankshaft!!) thereby changing hardly nothing. Therefore the exhaust leak would hardly change. I'm not saying your wrong in therory, just it wouldnt be relavent in the real world under idle conditions. Right? mm
 

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I have to agree with Mark on this one, the amount of pressure will increase dramatically when you have the "explosion" in the combustion chamber. Don't rule out a rod bearing either, I've seen them knock and quiet down when the plug wire was rmoved due to less stress in the cylinder. First thing I would do is pull the valve cover and inspect the valvetrain for looseness. It could be that the rocker arm nut just backed out if the self locking power is wore out for some reason. If nothing loose is found I would make some cardboard oil deflectors and start it up and observe. Here's a trick, take a piece of hose about three feet long and hold it to your ear while searching for the source of the tick with the other end.
Good Luck
John

Forget all that, drop in a big block!!!!
 

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Discussion Starter #14
ok, i need to change the dio, when the plug wire is pulled of it still knocks, gets louder with the revs. I had the valve cover off all the rockers seem to be moving the same height ( old owner told me different, he saod that they were not moving as high.) any sugestions what to do? ( owner also told me that it pops at high speeds over 60 mph and if you add marvel oil and it stops its a lifter) well i did that and it knocks but dosen't pop over 60. so any sugestions would help.
thanks
dave
 

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Don't rev it too hard. Sounds like a rod bearing ready to go.
With no explosion with the plug wire pulled, it could make it almost impossible to hear.
 

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Sounds like a rod bearing or wrist pin knock to me.
How's the oil pressure? Steady, or does it drop a lot at idle?
Is it a single sharp knock or a dull "double knock"?
Try the old broomstick or long screwdriver as a stethiscope trick - that may help you hear it more clearly and also give you a better idea of where it is coming from.
I would put my money on it being a wrist pin. Whatever it is - don't rev it too much! :)
 

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Discussion Starter #17 (Edited)
how should i dio this situation. It is a sharp single knock and increases loudness with rpm. any help appreciated.

what do i need to do to drop the pan.

thanks
dave
 

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The way it sounds, at a minimum, you need the cylinder heads rebuilt. You may have fatigued valve springs causing the popping at higher rpms. An oblonged valve guide could make a knocking noise--and contribute to the pop with the valve not seating staight to make a complete seal.

MM---I had meant the pressure of the escaping gas---yes the piston will still be at the same speed. After combustion takes place, the "exhaust" air mass is multiplied from what was taken in as "air-fuel". That is the difference I had meant in "with or without the ignition".

Without the ignition and combustion there would be no multiplication of the gasses. At idle, the piston would actually be pushing out less air mass then the cylinder's static (measured)volume---because at idle, the dynamic compression is low, due to the reduced intake charge mass from the restriction of the closed throttle blades--- which in turn develops a vacuum. Wide open throttle is different---you'd be pumping closer to 100% of the cylinder's static volume.


I hope this explanation isn't worse to understand,
 

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Discussion Starter #19
i pulled the valve cover off and took a hose to listen for the area for the knocking sound, well it is coming from the foward cylinder on pass side, i placed the end og the hose on the rocker arms and it is loud at the second valve. So my question is is it the valve making the noise or the lifter or somthin else. It kinda looks like the pushrod isn't going its full travel but i could just be imagining that. Anyway any help appreciated.
thanks
dave
 

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AOD, Yeah I think I get your drift. I really don't like to think that hard unless I really have to!!! mm
 
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