New Ticking Sound

[FiatRunner]

Hello all,

My '74 Spider started making a ticking noise a couple days ago, and it's got me concerned.

It sounds like noise from the valves or lifters, as it sounds very similar to a friend's Miata that used to have lifter tick issues, but that doesn't make sense. The engine has 28k miles overall and the top end has 10k. I just changed the oil, and the engine makes very good oil pressure.

It is a sharp ticking sound, but it doesn't happen all the time. It varies with engine rpm, and seems to go away once revved up a bit, but there is a chance that I just couldn't hear it due to the exhaust noise. It isn't a loose exhaust, as my old truck has an exhaust leak and I know what it sounds like. It seems to happen mostly at idle, but it'll go away, and then come back.

What do you think it could be? A cracked/loose cam gear? I'd be surprised if the lifters are far enough out of spec.

I'll see if I can get a youtube video posted to accurately show the sound.

[TX82FIAT]

From your description it could be just about anything. Engine noises travel and echo. I've fond a harbor freight metal rod stethoscope for about $3 very useful to isolate noises from the engine. The louder the noise in the stethoscope the closer you are to the origin of the event creating the noise.

[18Fiatsandcounting]

Did the ticking sound appear right after you changed the oil? What kind of oil are you using? Viscosity?

-Bryan

[FiatRunner]

Here’s a link to my youtube video showcasing the sound:https://youtube.com/shorts/K8TvHVECM8A?feature=share

You can hear it start to tick at the 13 or 14 second mark, it ticks for a few seconds, then stops for a few seconds. It starts ticking again, hopefully it is noticeable on camera. Twice more it ticks for a moment or two and then stops. Hopefully you can also see/hear how inconsistent it is.

I changed the oil about a week ago, and I used 4 and 1/4ish quarts of 15w-40. I’ve driven it more then 60 miles since then, and it hasn’t had any issue. The engine still runs great, fires right up.

[Nut124]

A valve train tick does not come and go. These are solid lifters, not hydraulic so should not be affected by oil pressure.

I was going to say exhaust gasket leak but you had eliminated that.

From what I heard in the video, spark is what comes to mind, ignition arching. Just the sound of it.

[FiatRunner]

I'll keep an eye out for an arcing electrical connection. The noise is definitely coming from the top of the engine, but if a spark plug wire was arcing, wouldn't that make the engine misfire? I had an old outboard boat motor with a misfiring problem, and it was because the old plug wires were arcing to the block.

It still feels/sounds like a mechanical noise to me, but I agree with you in that valve noise doesn't just start and stop. I wonder if there is something rattling that could be making the noise.

[Nut124]

I'll keep an eye out for an arcing electrical connection. The noise is definitely coming from the top of the engine, but if a spark plug wire was arcing, wouldn't that make the engine misfire? I had an old outboard boat motor with a misfiring problem, and it was because the old plug wires were arcing to the block.

It still feels/sounds like a mechanical noise to me, but I agree with you in that valve noise doesn't just start and stop. I wonder if there is something rattling that could be making the noise.

Yes, if arcing, one would expect misfire. However, at idle, that is not always obvious. Are you running stock ignition? Some electronic ignitions use higher voltage and provide multiple sparks.

[FiatRunner]

Yes, if arcing, one would expect misfire. However, at idle, that is not always obvious. Are you running stock ignition? Some electronic ignitions use higher voltage and provide multiple sparks.

Unless the seller was incorrect, it's got a completely stock distributor. I've had the car for only about 3 weeks, so there are many things (including the distributor) that I haven't fully dug into. It sure looks stock.

[18Fiatsandcounting]

After "hearing" the video, I agree it doesn't sound like valvetrain noise or an exhaust leak. The "frequency" of the clicking sounds too fast to be arcing on a single plug wire at idle, although it could be more than one wire that's arcing. Or the central lead to the coil. So, I'm leaning towards a mechanical rattling sound like a piece of loose piece of metal that is vibrating at certain engine speeds.

One trick to rule out some possibilities is to warm the engine up until you get the ticking sound, turn it off, temporarily loosen the fan belt so the water pump and alternator don't spin, and then restart the car. Don't run it more than a few seconds like this or it will overheat. If the ticking noise is still there, then you've eliminated the alternator bearings and water pump as the issue.

-Bryan

[FiatRunner]

If the ticking noise is still there, then you've eliminated the alternator bearings and water pump as the issue

I’ll see if I can try this out. I should be able to, but it’s getting colder every day. I’ll also make sure to check the pulleys to make sure they run true and smooth.

[kilrwail]

Open the distributor and examine the four posts that the rotor passes by. It sounds as though there might be the slightest of contact between the rotor and those posts, judging by the speed of the ticking. Might be time to replace the rotor and cap, just to be on the safe side, since you haven't serviced it yet.

[PaulC]

Definitely check the dizzy. I got a replacement cap and rotor from Rock Auto with the cap poorly molded. The result was the rotor hitting the terminals .

[TX82FIAT]

if you put a $5 mechanics stethoscope on the Distributor you will know immediately if that is where the noise is coming from.

[FiatRunner]

I'll make sure to buy a stethoscope and report my findings.

In the meantime, do you think I can still drive it? It runs great, and doesn't misfire at all. I was driving the car every day, but I've driven my old truck the past few days because it's been too cold. It's going to warm up over the weekend, and I'd like to be able to use it.

[FiatRunner]

Well, I ended up driving the Spider today.

My faithful Toyota Tundra left me stranded for the first time ever, in 292k miles. One of the idler pulleys for the serpentine belt decided to seize, ripping the belt and rendering the truck useless, as all of the accessories now didn’t function.

However, the much older, Italian sports car runs great. The ticking sound is nerve-wracking but everything functioned exactly how it should’ve.

The stethoscope will arrive soon.