MSD DISTRIBUTOR buzzing

[madmaxx]

Anyone experience the Distributor buzzing? I know the msd 6al ignition box buzzes like a bumble bee, but I get noise from the distributor. Called useless "techs" at msd and they said bearing. Funny if I remove the distributor and turn on the key on and work the rotor back and forth I get a noise. I am sure it is between the mag pickup and spoked wheel. Anyone experience this, car runs perfect. Is this a sign of the mag pickup going bad?


Thanks for any help

[Rick Parker]

Is everything tight in the distributor? See if the field coil (blue) wiggles on the magnetic core, or perhaps the epoxy or potting material that secures it to the distributor body has fractured and is now loose.
With the distributor in hand does it vibrate and make the noise only when being rotated while energized, or does it do it also doii it when the key is off? Look for something that is loose.

[madmaxx]

Thanks for the suggetions,

everything appears tight. pickup is rusted. I can make the dist generate a popping noise with the key on, dist cap off and rocking the dist rotor back and forth. The rotor only moves back and forth about 1/8? inch or the backlash in the gears. I'll check some more.

[madmaxx]

Update,

I went out in the garage, pitch black and what I am seeing is the coil arcing from the pos and neg terminal to the lead when I rock the dist rotor back and forth, key on dist cap off. Anybody have any idea what the heck is going on??

[patrickt]

Originally Posted by madmaxx

Update,

I went out in the garage, pitch black and what I am seeing is the coil arcing from the pos and neg terminal to the lead when I rock the dist rotor back and forth, key on dist cap off. Anybody have any idea what the heck is going on??

It's arcing from the lead over to the pos and neg terminals. The voltage has to jump somewhere, and with the distributor cap off there is no "normal" path to the plug, so it takes the best short cut it can find. It's a red herring.

EDIT -- This would be easily confirmed by watching your engine, while running, in the dark. Hopefully, you would see no arcing.

[madmaxx]

Patrickt THANKYOU!!!!!!!!!

I just went out there put it back together and no spark across coil!!!! Rock on, you were right.

On a side note I checked my ground, and I am sure it is no surprise but nobody buffed the paint off the frame tab. I buffed the paint off the frame tab and to be a smartassss i even put some dielectric grease. i doubt this was the problem but I know it has a good ground now.

Cant work on it anymore tonight, she will leave me if I go to bed smelling like gasoline from the exhaust and that would cost way way way way way to much, LOL!!. I'll get back it on tomorrow. Thanks again!

[zrayr]

Originally Posted by madmaxx

"................ I buffed the paint off the frame tab and to be a smartassss i even put some dielectric grease. i doubt this was the problem but I know it has a good ground now.............."

alway keep the dielectric grease off the metal contacts as it IMPEDES, not promotes, the transmission of electricity. It should only be used on the rubber boots.

I lost my lights one night on a dark twisty 2 lane road after putting it on the blade terminals of the headlight switch. After that terrifying experience I learned where NOT to put the grease..

http://www.wisegeek.com/what-is-dielectric-grease.htm

http://continuouswave.com/ubb/Forum6/HTML/001202.html


Z.

[madmaxx]

One step forward two steps backwards, you are right, I will clean off the dielectric grease.

[Z-linkCobra]

What kind of coil are your running? You have a MSD6al....pull the limit chip out of the MSD box if you have one in there(dont ever do that while its running...hurts like hell...lol). I have had chips fail and cause some really weird problems that you wouldnt think were even related.

On a side note when you pull a rev limit chip out while its running it throws a really pretty arc from the chip to the box. Problem is that arc jumps right up to your thumb and finger...again hurts like hell....lol.

[madmaxx]

I pulled the distributor and the bearing appears perfect, gear wear perfect (if there was any) spins freely, end play within range, magnetic pickup perfect resistance. Yet when installed and running it will hum like a bumble bee and is sporadic, sometimes it does sometimes it doesn't. My only guess is the arc between the rotor and cap. It appears the spark transfer from rotor to cap lugs is at the very bottom.

Who knows

[patrickt]

If you tap the side of the distributor with the back of a screw driver whle the engine is running does it change the sound of the buzz? That would indicate something vibrating that is making the noise, like maybe something harmlessly loose inside the magnetic pickup. Probably, I would just ignore it. If it's anything serious, it will get worse and then you can just replace it. It's not like it's going to seize your engine or anything.

[madmaxx]

Thanks,

I tapped around quite a bit everything seamed tight. I just swiped the $700 ultrasonic listening tool from work, this should help pinpoint the noise when I get home.

[patrickt]

Originally Posted by madmaxx

I just swiped the $700 ultrasonic listening tool from work, this should help pinpoint the noise when I get home.

Yeah, I got one of those...

[madmaxx]

problem with yours as with mine is there is to much peripheral noise with the side pipes the coolant fans etc. I also have a leak around my window in my lexus I need to find. I will put the tone generator inside the car and listen around the window until i find it

[Z-linkCobra]

Is this a problem that just started? A weak coil, old plug wires etc. can cause problems like what your having.

Again, check your rev limiter chip if you have one installed.

[madmaxx]

Yea the noise just started, only has about 1500 miles on it, car runs flawlesss, I was punching at 55 mph on saturday and breaking the rear tires loose. Run it up to 6K rpm rev limiter kicks in. Just a noise. Now MSD tech says it is the spark between rotor and cap and nothing to worry about, probably right, but since I am bored I will hunt it down.

On a side note I looked at the cam with a mirror through the distributor hole. I was blown away it looks like it just came out of the box, zero wear whatsoever. That was cool.

[madmaxx]

I surfured the MSD forums and found that the rotor tip is oriented at the bottom of the cap lugs. Theory is it is more efficient for the spark to jump across sharp corners than large flat areas. My cap lugs have the edges worn away at the bottom. I guess it is possible that the spark enegy is greater now that the sharp edges are worn creating the noise. So in theory as the cap wears it should continue to make the noise until it is constant or I could just get another cap, but what fun is that. I also have a hard time beleiving I am the only one the hears the noise, LOL!!!

[Bobcat]

Hey Madmaxx .... do you also hear voices ??? Just kidding ! Do you have a spare cap ? That way you could tell real quick if the lugs are causing the noise . Is your cap drilled for ventilation to let the ozone out ?
Things like that can drive you crazy .

Bob

[patrickt]

Originally Posted by Bobcat

Things like that can drive you crazy .

Yep, had a Pontiac a few years ago with a dashboard squeak on the highway. Drove me nuts. I removed the entire dashboard and drove it around and it still squeaked. Turned out it was the sun visor....

[madmaxx]

No spare cap except the one with the center button burned out. Need to buy a new one, a cap should not wear out in 1500 miles.

My 22 year old boat with points and condensor starts and fires every season,no issues, marine enviroment. Maybe I should switch ignition systems.