Three-nuts
Well-Known Member
[ame="http://www.youtube.com/watch?v=7zz_3h4quNI&feature=youtu.be"]74 Dart 225 Motor noise - YouTube[/ame]
Bought the car two weeks ago. Has approx 160K on it.
When I run it on the highway, it makes a jackhammering sound from under the hood. The knock stays for a couple of minutes after a highway run, then fades away. As you can see from the video, it's a pretty hard knock on acceleration/sustained high RPM.
Compression is even & good, all plugs are the right brown color. Oil is clean. It does have blowback (some oil in the air cleaner housing).
I have a shake at idle in D (or any gear). Hard shudder through the column & front end on take off, lessens quite a bit in higher gears, not noticeable at all at highway speeds. Trans shifts fine, the flex plate is fine and all bolts are tight. Driveshaft & U-joints are likewise tight. Left mount & trans mount replaced, neither were particularly bad. Valves were adjusted (painted the valve cover then).
I can't tell whether this is a rod knock or some kind of valve train issue. It's loudest at the #6 exhaust manifold neck, but it's really hard to localize (using a mech stethescope). Last (& only) rod knock I had, it did it all the time & never went away.
Thanks for reading & input.
(edit) VV did pull the belts off. The alternator bearings are starting to grate, but it ain't it. It is not being driven, this was a short test hop. My son was driving it to work (about 3.5 miles each way, never exceeds 40MPH) but he's using another car now. VV
Bought the car two weeks ago. Has approx 160K on it.
When I run it on the highway, it makes a jackhammering sound from under the hood. The knock stays for a couple of minutes after a highway run, then fades away. As you can see from the video, it's a pretty hard knock on acceleration/sustained high RPM.
Compression is even & good, all plugs are the right brown color. Oil is clean. It does have blowback (some oil in the air cleaner housing).
I have a shake at idle in D (or any gear). Hard shudder through the column & front end on take off, lessens quite a bit in higher gears, not noticeable at all at highway speeds. Trans shifts fine, the flex plate is fine and all bolts are tight. Driveshaft & U-joints are likewise tight. Left mount & trans mount replaced, neither were particularly bad. Valves were adjusted (painted the valve cover then).
I can't tell whether this is a rod knock or some kind of valve train issue. It's loudest at the #6 exhaust manifold neck, but it's really hard to localize (using a mech stethescope). Last (& only) rod knock I had, it did it all the time & never went away.
Thanks for reading & input.
(edit) VV did pull the belts off. The alternator bearings are starting to grate, but it ain't it. It is not being driven, this was a short test hop. My son was driving it to work (about 3.5 miles each way, never exceeds 40MPH) but he's using another car now. VV