Is this sound normal?

[adam.stevenson]

Hi there all,

I’ve slowly been getting things improved on the Mach 1. It has 351c 4 V. I recently had brand new custom headers and exhaust installed, new push rods and gauge plates. It has a solid cam and solid lifters and my mechanic assures me he has the lash set correctly and that this “sewing machine “ sound is normal. He’s a bit deaf though. What do you think? Is the tapping sound normal? Thanks. Adam




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[JohnnyJ]

Hi there all,

I’ve slowly been getting things improved on the Mach 1. It has 351c 4 V.  I recently had brand new custom headers and exhaust installed, new push rods and gauge plates. It has a solid cam and solid lifters and my mechanic assures me he has the lash set correctly and that this “sewing machine “ sound is normal. He’s a bit deaf though.  What do you think? Is the tapping sound normal?  Thanks. Adam

I'd wait for the experts to reply, but it sounds like a header gasket leak from here

 

[Stanglover]

I am NO expert by a long shot, but to me I think I'd agree with JohnnyJ, massive exhaust leak.

If not that, then perhaps your mechanic dropped a bucket of bolts inside! I can't imagine the valves been set that far off to rattle like that, but anything is possible.

I used to own a 72 Q code, but the block was Boss 351 ( I didn't find that little nugget until many years after I sold the car) but I did know it had solid lifters and that was about all I knew at the time, 1980.

What I'm getting at is it never sounded like that, not even cold. Something is wrong for sure. Was the motor broken in properly with a very good break-in oil? It might have wiped the cam out already if not. I would run it any more until you know what the heck is going on.

Geoff.

 

[tony-muscle]

It sounds like a lawn mower. Could be the lash but there are others here with more experience.

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[Fabrice]

Hard to say on this recording,

Based on sound, I would tend to think its a leaky exhaust gasket above an head gasket first.

Not saying for sure it's not, but the engine turns too nicely for a blown head gasket.

Also when they blow on Cleveland's, you often have coolant leaks when that happens.

Check fluids level to be sure. Also you could lift a valve cover..

 

[digadam]

Ok thanks everyone. I’ll take it to another mechanic. I only just (last week) had an entirely new custom made set of headers put on so I assumed it wouldn’t be an exhaust leak. The last set of headers definitely leaked. Should I take it back to the exhaust shop? My assumption is they would have hooked the new headers all up correctly and eliminated any exhaust leak - especially with the price I paid.

 

[Carolina_Mountain_Mustangs]

When the engine is right there should be no sound the is not is harmonics. I sounds like something it off.

 

[Don C]

Solid lifters will definitely make some noise, a light clatter. Most video cameras, and all cell phones, have compression/amplification (compander) circuitry in the microphones, which amplifies sounds to a level that can be heard during playback, so it's hard to tell just how loud it is.

However, I believe we're hearing both valve noise and an exhaust leak, or one really loud valve on the driver side.

Take a short section of copper or steel tubing with a piece of rubber hose connected to it (a homemade mechanics stethoscope), hold the rubber hose to your ear and run the metal tube along the header connections and you'll be able to hear where the exhaust leak is.

 

[Hemikiller]

I'm going to agree with the guys above, something isn't right and it's hard to tell with a cell phone audio. I can easily tell the difference between an exhaust leak and valvetrain noise in person.

If it's a header collector to h-pipe gasket leak, the noise will be under the car. A header to head gasket leak will usually make a "popping" noise and get much louder if you rev the engine, or put it under load. If the volume of the noise doesn't increase, it's probably valvetrain.

At that point, I'd pull the valve covers and check the rockers for one adjusted out of spec.

 

[digadam]

Hi everyone. Thanks so far. A quick update. Went back to the exhaust shop. Definitely not leak. So I dropped into an old school mechanic around the corner and he will look at it properly in a couple of weeks as he is too busy this week but he thinks it’s rear passenger side lifter or rocker. Will let you know in a couple of weeks. I’m not much of a mechanic and never lifted valve covers myself so probably should just the experts to do it.

 

[c9zx]

Good decision. Let us know how it works out. Chuck

 

[waterlife]

Hi there all,

I’ve slowly been getting things improved on the Mach 1. It has 351c 4 V.  I recently had brand new custom headers and exhaust installed, new push rods and gauge plates. It has a solid cam and solid lifters and my mechanic assures me he has the lash set correctly and that this “sewing machine “ sound is normal. He’s a bit deaf though.  What do you think? Is the tapping sound normal?  Thanks. Adam

 

[digadam]

Well folks.  Thank you all for your advice.  Turns out it wasn't the headers leaking.  Turns out it was.....just about everything in the top of the motor.  Valves were stuffed (several of them) and leaking and not closing off and damaged.  Roller rockers were stuffed - several of them (from bashing aroundwith the valves).  Push rods were worn.  Lifters were worn.

So a few $ later.  Actually a lot of $ later and its running like a charm.  Guess i'll tackle the bottom end another day    I'll post up the new sound soon.

 

[c9zx]

I'm glad you got it fixed and sorry to hear it was a costly fix. Were the valves sticking in the guides? Insufficient lash? Chuck

 

[digadam]

I'm glad you got it fixed and sorry to hear it was a costly fix. Were the valves sticking in the guides? Insufficient lash? Chuck

Yes Chuck that wa one thing and there was no spring pressure and valves all burnt out and not sitting and damaged on ends.