Engine vib

[Anonymous]

Just found your site. Got a long standing prob. on my 200 looks like some of you guys / gals might have an idea about.

My engine was rebuilt about a year ago, however this issue predates the rebuild. However, during the rebuild I was able to isolate the prob. to the engine.

I have a regularly intermittnet "vibration" - kind of a whaaa whaaa whaaa sound. If idleing in park (c4) the rate is about at 'one thousand one - one thousand two - one thousand three etc. How's that for a description?

Anyway, wrap your minds around this one and give me your thoughts.

Glad to have found the site.

Randy

 

[Anonymous]

What kind of effect do you get when adjusting the timing?

 

[weeds]

Stump not only Glenn, but most of us too.

The sound that you are describing can be one of a hundred thousand things. If you go back to high school physics, the number of 'beats' is the difference in frequency of two vibrations. For example. If you set a vibration up at 350 hertz and add another vibration ot 351 hertz, you will get exactly what you are describing. One 'beat' every second.

So, back to the original question. What is causing it? Could be the length of the fan belt, the diameter of the pulleys, the number of blades on the fan, and the list goes on.

Or it could have nothing to do with the harmonics of the thing and it could be something mechanical. Since I have never had this problem, I ain't got a clue. Sorry.

Have fun. Let me add a couple more for you.

 

[xctasy]

Welcome dude!

The car, is it an early four bearing 65 or 66 200, or is it something later? The crank isn't fully balanced, and isn't always peachy smooth, but its lots better than a four or odd-fire V6.

The fan on early cars is an issue, sometimes the factory C4 flex plate can be out of balance, or the heat from the exhast manifold can cause heat related dieseling or the distributor advance can cause roughness, or several other things like the sump acting like a giant tunning fork on the early vehicles when under load.

I've noticed rough idle is a hard one to fix, but its a light vehicle, with lots of steel gussets hanging in the engine bay.

More details on what year, trans and body your engine is in. And if the starter motor is above the level of the sump in your ride.