Lots of Engine Drone

[AnahRabekka1501]

Its not exhaust, I’ve done my own exhaust work.

I have a 4 banger, it needs to be rebuilt, but thats it.

I don't think the truck has any insulation, so is all the engine drone just from lack of insulation? It is constant and LOUD. Coming directly from the engine bay. The drone is so loud, I cannot talk on the phone or listen to the radio at a reasonable volume. I’ve tried searching google, but god forgive me for typing “drone” into google.

Please help save my poor ear drums.
~Anah

 

[Curious Hound]

Insulation can help a lot. Padding under your flooring (whether carpet or vinyl) helps. There are self adhesiv e pad materials you can install. The headliner helps.

But proper exhaust system design has a lot to do with it. Make sure the exhaust turns out the side or exits straight out the back can help. Installing a resonator helps because that cancels out certain frequencies of noise. Proper muffler makes a difference.

Sent from my SM-G960U using Tapatalk

 

[AnahRabekka1501]

I built my own exhaust system from 2 inch piping. It's straight-piped, welded up, in a stack behind the passenger side. The drone is definitely coming from the engime bay. So i know i can put insulation above/below, but my comcern is between me and the engine bay, like, under the dash. How would you see about putting insulation back there? Taking out the dash, im assuming.

 

[alwaysFlOoReD]

Lets make sure it is the engine.
1] Does the drone happen while parked?
2] Does the drone change in pitch, or get loader as the rpms change?
3] Or does happen while driving?
4] If while driving does it change sound with engine rpm or with speed?

I ask because there could be other sources, such as a bearing.

 

[AnahRabekka1501]

24/7, increasing with RPM, including dry-revving. A bearing wouldnt be loud enough to drown the thoughts out of my head.

 

[Curious Hound]

I built my own exhaust system from 2 inch piping. It's straight-piped, welded up, in a stack behind the passenger side.

you mean no muffler? no resonator? etc. Just straight pipe to the stack?

 

[AnahRabekka1501]

The exhaust was rusting out starting at the intermediate exhaust pipe. I replaced it, then put a line of piping including what autozone calls “resonator” which is essentially a pipe with two “female ends”. After the extended cab, i used a 90° angle pipe, followed it with more piping, a 2-2 1/2 inch adapter, and one thick 2 1/2 pipe. It looks good, sounds good, and since I’ve had many exhaust issues with the original setup, I know it isn’t that.

 

[tomw]

Do you have an A.I.R. pump on your engine? It was called a 'smog pump' back when, was belt driven in most cases(electric in some nowadays), and just pumped air that was sent to the exhaust manifold or to the catalytic converter. If they have a bad 'diverter' valve they can make a good racket.
You might try the old length-of-tubing-stuffed into an ear and the other end waved around underhood to localize the sound source.
The engine itself can drone if the crankcase is open to the air. The pistons go up the pistons go down and they cause a LOT of air movement. I can attest to the noise from experience with an old Pontiac 4. I'd check that your PCV system is intact, and also check that the oil separator on the side of the block under the intake manifold is jammed into the hole in the block. If that was loose, or punctured/rusted, it could allow for a lot of noise.
tom

Added: you can add insulation to reduce noise under your carpet or floormat rather than removing the dash. I have seen that reflective, rubbery, sticky pad stuff also adhered to the outside of the firewall. I would not go to insulation until I was sure the drone was not caused by something gone bad.