Help With Source Of Ticking Noise

[Vince C.]

Hello Fellow Members!

I have a mysterious and very prominent ticking noise noticeable from inside my '69 390HP Coupe (almost non-detectable from outside the car). It seems the sound is most prevalent from just behind the passenger seat. The sound increases or decreases with engine RPM and is only present while the engine is running (the sound can't be duplicated while coasting with the engine off). It also seems to subside once the car reaches full operating temperature. My best guess is I may have an exhaust leak where the pipes join at the front exhaust hanger. The pipe joints are compressed by a single clamp that acts as a hanger as well. Since this clamp loops over the hanger, could this be creating a poor seal that would produce a very noticeable ticking audible from inside the vehicle but virtually undetectable from outside the car? Is this something that could be addressed without pulling the pipes apart?

Could the noise be something other than an exhaust leak? Am I chasing my tail here?

Thanks in advance for your comments / suggestions!

Regards,
Vince

[Edward J.]

Re: Help With Source Of Ticking Noise

Victor, Exhaust Manifold Leaks Are More Common To Tick, Than A Pipe Or Gasket. Check For Signs Of Loose Exhaust Manifold Bolts ,or If You Have Gaskets That Bolt To Manifolds Check To See If Theres Any Signs Of Black Carbon Around The Area Of Each Port On The Manifolds.

One Other Thing That Comes To Mind, Is The Flywheel Shield, Sometimes They Hit The Flywheel, Which As The Engine Warms Up Can Move Away And The Noise Disappears.

[Vince C.]

Re: Help With Source Of Ticking Noise

Hi Ed!

Thanks! Noted. Will check.

However, if a manifold leak is the culprit, could the sound travel through the exhaust system where the noise exits from under the passenger compartment? I can hear almost no trace of the sound from the motor compartment or lying on the ground. It is most noticeable from inside the car. You would swear its coming from the passenger seat! At first I thought it was the driveshaft striking the tunnel insulation but I ruled that out. Bizarre!!

Regards,
Vince

[Edward J.]

Re: Help With Source Of Ticking Noise

Vince, noise would not travel through exhaust like that. but a noisey exhaust manifold does get quiet when heat gets to after a few minutes, generally no more than that though, a look will tell spend a few minutes inspecting the areas around the manifolds for signs of black carbon that would should up.

Is your 69 a side pipe car? auto or 4 spd?

[Vince C.]

Re: Help With Source Of Ticking Noise

[Joseph K.]

Re: Help With Source Of Ticking Noise

Just a remote thought.... the grounding strap is located under the seat and is conected to the pipe. Could it be loose or off and touching the body. When the engine is cold the rough idle could be making it sound that way??

[Vince C.]

Re: Help With Source Of Ticking Noise

Joseph, great suggestion! Never thought of that. I'll check that grounding strap as well!! Keep those suggestions coming!

Thanks,
Vince

[Edward J.]

Re: Help With Source Of Ticking Noise

Vince, when starting a cold engine you should hear a tick in the engine compartment if theres a leak.

What was apart in the car that you removed the front pipes?

[Vince C.]

Re: Help With Source Of Ticking Noise

Good Morning Ed,

The rear exhaust pipes were disassembled from the front pipes to replace the mufflers and then reassambled. All the correct parts were used upon reinstallation. You really don't notice any ticking when the car is started cold. The sound is not evident until fast idle is kicked down and especially when driving. I did find a loose ground strap. Once the weather clears tomorrow, I plan to look at this further, take the car for a drive and report back...

Thanks for your suggestions! Very helpful.

Best Regards,
Vince

[Edward J.]

Re: Help With Source Of Ticking Noise

Vince, was the noise there before the the exhaust was dropped?

[Vince C.]

Re: Help With Source Of Ticking Noise

Ed,

It did but not to this extent. I feel it's either an exhaust leak at the pipe junction or due to the loose ground strap. Again, you would swear the noise was directly below or behind the passenger seat...

[Jim M.]

Re: Help With Source Of Ticking Noise

Vince, I have had the same ticking noise on my 69 too and to date haven't figured out what may be causing it. It comes and goes but usually when when I'm just getting going and the engine is cold. I thought it was something rubbing on the drive shaft or a short shaft, but can't find anything that would be hitting those two items.

[Edward J.]

Re: Help With Source Of Ticking Noise

Vince, if theres a leak around the joint where the front pipe meets the inter. pipe try puting you hand close to the joint and see if you can feel some exhaust coming from that joint. being extra careful the pipe will fry a egg when hot.One other way is to take a coupe of towels and stuff the end of the pipe with car idling this will show any leaks in the exhaust. it may take a extra hand to hold the towels in the pipes.

The other thing I questioned the manifold bolts take a 9/16 wrench and check to see if there tight. if its a a/c car that will be a tough thing to do,but check the ones you can.

[Vince C.]

Re: Help With Source Of Ticking Noise

Jim,

I'll let you know what I find (if I'm successful in identifying and resolving the issue). Perhaps this may also assist you in your quest. Or perhaps we are both destined to drive possessed cars...

Best Regards,

Vince

[Kenneth T.]

Re: Help With Source Of Ticking Noise

Heat Riser flapping???????

Ken