SixCylinderMike
New member
Hi guys,
So I recently added AC to my 64 1/2 Mustang, and in doing so had to cut away some of the insulation on the firewall in order to fit the evaporator. After I got the car running, I noticed a big increase in noise when the engine was under load -- specifically a rattling or knocking sound at the same frequency as the engine RPM. Initially I put this down to the reduced acoustic insulation, but I am wondering whether I might actually have a problem with detonation.
Given how pathetic the engine performance is, it's really not hard to put it under enough load to make this noise and I want to make sure I'm not causing any damage. This is happening regardless of whether the AC is running.
Here's a recording. I'm cruising at 50 on a slight uphill, and I put my foot down between 5-10 seconds and 13-18 seconds which causes the noise.
[soundcloud]https://soundcloud.com/cliponmike/knocking-under-load[/soundcloud]
Is this just exhaust noise? Or something I should investigate? The car is due for a change of plugs / cap & rotor, so I also bought a timing light and thought I'd check that. Haven't done that before, and I haven't had to investigate this sort of problem so I'm not really sure where to start. Since it's consistent and happening at the same rate as the RPMs I figured it might be a problem with just one cylinder. Is there something I should be looking for when I change the plugs?
Thanks for your help!
So I recently added AC to my 64 1/2 Mustang, and in doing so had to cut away some of the insulation on the firewall in order to fit the evaporator. After I got the car running, I noticed a big increase in noise when the engine was under load -- specifically a rattling or knocking sound at the same frequency as the engine RPM. Initially I put this down to the reduced acoustic insulation, but I am wondering whether I might actually have a problem with detonation.
Given how pathetic the engine performance is, it's really not hard to put it under enough load to make this noise and I want to make sure I'm not causing any damage. This is happening regardless of whether the AC is running.
Here's a recording. I'm cruising at 50 on a slight uphill, and I put my foot down between 5-10 seconds and 13-18 seconds which causes the noise.
[soundcloud]https://soundcloud.com/cliponmike/knocking-under-load[/soundcloud]
Is this just exhaust noise? Or something I should investigate? The car is due for a change of plugs / cap & rotor, so I also bought a timing light and thought I'd check that. Haven't done that before, and I haven't had to investigate this sort of problem so I'm not really sure where to start. Since it's consistent and happening at the same rate as the RPMs I figured it might be a problem with just one cylinder. Is there something I should be looking for when I change the plugs?
Thanks for your help!