I have a 302 that is making a consistent ticking noise that increases in repetition as the rpms increase. I initially thought it was a bad lifter, but after further inspection all the lifters appear in good condition. It is firing on all cylinders, so that also rules out a misfire. When I start the engine the sound almost seems like a hissing sound. The only other thing I can think of would be an exhaust leak, but all the exhaust components appear fine. Does anyone have any ideas as to what the problem may be?
Thanks,
-Brian
Location: In the Shenandoah Valley of Virginia....
Posts: 2,918
Worst case maybe---broken piston skirt.
__________________ My '70 Pro-Street. Mildly built 302, Mallory 6AL ignition, Hurst w/4-speed, 74 Maverick rear w/3.40 gears. Tied frame with 6 point cage. Trunk mounted battery, Dynamax Exhaust. Building a 351W 40 over now...
I checked the plugs and they're all tight, how would I know if the fuel pump is the issue? Would I remove it then crank it over by hand to see if the sound went away? I sure hope it isn't a piston skirt...
Location: In the Shenandoah Valley of Virginia....
Posts: 2,918
Remove the pump and see how much slap/freeplay so to speak you have in the pump arm up and down.. Since the pumps off you could just turn it over to see if you still hear any noise. Might just be a noise you will hear only with it running though. May just be the pumps wore out also.
Loose spark plug can also do this. Also, if it's noisiest on the driver's side, front, a fuel pump can make this noise.
I've actually had both of these occur over the years. Use a wooden broom stick cut off, or other piece of wood and use it as a stethoscope. Put it right on they fuel pump and listen. The ticking should be loudest there.
I actually replaced a lifter thinking it would solve my problem, turned out to be simply the worn out spring in the fuel pump.
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Have someone grab a rag and plug the end of the exhaust pipe(s) to see if it changes the noise. If so, you've got an exhaust leak at the manifold, either between it and the head or between the manifold and the head pipe.
On small aircraft engines, I have a small exhaust leak sound like everything from a tappet to a serious rod knock. More concerning at 9,000 feet. Just a thought.
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Thats exactly what I was thinking. That or a loose crank bering.. really hope its just an exhaust leak or something easy but I'd get that checked out before whatever it is potentially causes something to fail. If its in the exhaust start your search at the headers and work down. My friend had his header crack right off the engine but it was wrapped which caused the broken half to vibrate against the engine as it ran sounding like a rod knock. His was broken right in half which is why it was so loud but maybe yours has cracked and is still mostly attached causing a ticking sound? Let us know what you find out
-Dylan
Last edited by Dylans '66; 01-16-2013 at 11:46 PM.
I took the plugs out one by one and cranked the engine over by hand with the other hand blocking the hole on each removed spark plug with no success in the noise going away, so that rules out the spark plugs, how can I check to see if it's a broken piston skirt?
Location: In the Shenandoah Valley of Virginia....
Posts: 2,918
One way to maybe check for a broken piston skirt is try this. If you have loud exhaust or a leaking exhaust gasket, etc. you probably won't be able to do this because you have to be able to hear wants going on inside the motor good---but with it running pull one wire at a time and listen carefully to the motor. If you have a broken piston skirt it will sometimes get quieter when you pull off the wire to that cylinder because there's no combustion/downforce etc. going on. Also might want to put on a rubber glove so you don't get the ---- knocked out of you.
__________________ My '70 Pro-Street. Mildly built 302, Mallory 6AL ignition, Hurst w/4-speed, 74 Maverick rear w/3.40 gears. Tied frame with 6 point cage. Trunk mounted battery, Dynamax Exhaust. Building a 351W 40 over now...
I did a leakdown test on #3 cylinder today and it's holding zero pressure
When you did the leakdown test did you pay attention to where the air was escaping? Air coming out the carb or exhaust would indicate a problem with a valve sealing. Air coming our the oil filler cap would indicate a problem with cylinder sealing (rings or severe cylinder wall damage) or piston (hole or crack).
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Engine ticking noise
My '70 Pro-Street. Mildly built 302, Mallory 6AL ignition, Hurst w/4-speed, 74 Maverick rear w/3.40 gears. Tied frame with 6 point cage. Trunk mounted battery, Dynamax Exhaust. Building a 351W 40 over now...
