Distributor vibration/humming

[kylep123]

Hey guys,

My 1994 Mazda B3000 3.0 V6 2wd just started making a whining/humming noise from the back of the engine. I popped the hood and tried to figure out where it was coming from and it sounded like the distributor area. I touched it and felt a vibration with a frequency which matched the humming sound emitted. What does this mean? i recently replaced my head gaskets and replaced the heads with rebuilt ones. So the whole top end was taken apart about a month ago, the distributor was removed, but I had no problems initially after reinstallation. Also the sound seems to start after the engine warms up slightly and seems quieter as RPMs increase (could just be engine noise masking the sound).

Thanks!
Kyle

 

[RonD]

I use a broom handle as a stethoscope, without the broom part attached
See if you can confirm the source.

If it is the distributor I would put the crank at TDC, so distributor is at #1 on the rotor/cap.
Pull out the distributor and check the rotor shaft for wobble, see if you feel any slack in the shaft.
There are bushings that can wear out.

Also there is usually a mounting gasket between distributor and block/intake, did this fall off the distributor when engine was reassembled, if so the distributor could be sitting slightly low and may be rubbing, causing a vibration.

 

[kylep123]

I will look into that asap and get back to you, thanks! I cant remember there being a seal, so it is likely that I may have missed it.

 

[PlumCrazy]

Sounds like the drive gear on the dizzy is on its way out.

-PlumCrazy

 

[kylep123]

Sorry, final exams are approaching and I'm studying my tail off! I will probably work on it over break in a couple weeks. I don't drive it too much... The noise has been intermittent though-although mostly making the sound, at times it can completely go quiet for an extended period of time.

 

[PlumCrazy]

If it goes out the oil pump stops and yoir bearings are toasted

Sent from my DROID RAZR using Tapatalk 2

 

[kylep123]

Haha Thanks! I will ride my bike for the rest of the week!

 

[kylep123]

Thanks! I fixed it!

I went to the junk yard and pulled about 10 distributors in order to find the best one, when I went to remove the distributor from my truck I could not turn it or remove it. After tapping it with a wrench it jarred loose and came right out. I threw the other one in and had no binding, also I have no whining. Im thinking that the original must have been binding between the distributor housing and the heads and was tightened down to cause it to be misaligned and squeal? Noting the original position of the distributor, as I installed the new one it would not drop due to this interference, soooo maybe nothing was wrong in the first place other than my poor mechanic skills...

Thanks for all the help!
Kyle