Vibrations, not the Beach Boys kind...

[myk]

Hello gents.

The car has a bit of a shake that consistently occurs every 2 seconds while in idle and park.  As the car gets into gear and starts to move out, the vibrations come sooner and a little harder.

So, I checked the motor mounts, they look good to me.  I just had the transmission mount replaced with a polyurethane one, the torque converter and flywheel were changed last year, but the vibration was there even before those changes; it's just getting worse now.  All of my plugs and wires are good and I'm sure the motor is firing propery.

So I was thinking the harmonic balancer is the problem?  How can i determine if it's the balancer?  Only problem is I dont know which one to buy.  This isn't the original motor to the car and I have no idea if the crank I have now is internally balanced or not; I do not know about any of the internals in this block.   So assuming the balancer is the problem how do I pick one?  Do I get one of those balancers that have a detachable weight for either internally or externally balanced  engines and just try it out?  I just don't know which way to go on this.  Any advice and information is appreciated,  thanks in advance...

[69wannabe]

Do this before you go to do a balancer swap, take the fan and alternator belts off the front of the engine and start the engine up with the crank pulley/balancer only spinning and see if your vibration is still there or if it goes away. I have seen a bad cooling fan cause vibrations and even a bad alternator bearing cause a vibration. Try to eliminate the simple things first. Do you know what model your engine is? If it is internally balanced it will have a thin balancer on it and if it is externally balanced it will have a thick balancer on it. You can google the thin and thick balancers to see the difference. Also pull a few spark plugs just to see if they may be close to being fouled. Vibrations can be a aggravating and sometimes hard to pin point. Hope some of this may help.

[myk]

Thanks for the reply!  The balancer on it now is the thin one, but I can't even be sure if this is the proper balancer for the car because the engine has been rebuilt twice and I have no idea what type of crank I have.

Next chance I get I'll take the belts off and run the motor and see what happens...

[c00nhunterjoe]

Best thing to do is drop the pan and look at the crank

[myk]

.........oh wow, i hadn't even thought of that.  Then I can use that diagram of the differences between cranks!

Now, just in case I determine that the damper is bad, what do you guys think about this one from 440source?

http://store.440source.com/Internal-_-External-Balance-Black-Damper/productinfo/200-1128/

[HeavyFuel]

Did the vibration start after your accident?

[BSB67]

The car has a bit of a shake that consistently occurs every 2 seconds while in idle and park.  As the car gets into gear and starts to move out, the vibrations come sooner and a little harder.

I don't know what your vibration source is, but it's not the balancer.

[myk]

Did the vibration start after your accident?

No.  The vibration was always there, it's just getting worse.   Before the accident I figured the vibrations were just life with a big block and a cam.  Now I can feel that it just isn't right.  The vibrations became more prominent after the torque converter, flex plate and poly-trans mount install last year...

[John_Kunkel]

This isn't the original motor to the car and I have no idea if the crank I have now is internally balanced or not; I do not know about any of the internals in this block. 

I think you'll find this is the basis of your vibration, engine assembled without balancing. As previously discussed, some of the aftermarket pistons/rods are way different in weight than the originals.

[c00nhunterjoe]

The poly mount is probably amplifying the vibrations so while you feel it more, it may not necessarily be getting worse. Drop the pan and make sure you have the correct balancer and converter for your crank, but from there it is probably the lack of balancing of the rotating assembly during overhaul.

[myk]

Ok.  But then do you guys think a new fancy  balancer could help?  If anything do you think the balancer that I've had on there for Lord knows how long needs to be replaced anyway?

[BSB67]

Is your damper for an internally or externally balanced motor?

1) An imbalance will not come and go every couple of seconds
2) Usually imbalance is not detectable or very slight at idle, and will get progressively worse with rpm
3) It will not get worse overtime particular if it is a neutral balanced damper.


Do you have a video, or is it something you can only feel?

[myk]

The damper on there now is the thin style, so I'm thinking it's the damper for internally balanced engines.  That damper has stayed with the car over the last 24 years even though the engine has been rebuilt twice and with a new crank on the 2nd rebuild.

It's not so bad that you could see it on video, it's rather something I can feel.  I just don't want this thing grenading on me lol.  I guess that rebuild I've always wanted to do should happen sooner than later.

[cdr]

Make sure ALL the bell housing bolts are tight. & thank you for the email, it is always good to hear from you.

[myk]

Make sure ALL the bell housing bolts are tight. & thank you for the email, it is always good to hear from you.

Good point.  I'll check that out. 

As for the email, quite the ordeal, huh.  My Charger and I never get any respect...

[John_Kunkel]

Drop the pan and make sure you have the correct balancer and converter for your crank

Dropping the pan and inspecting the crank will tell nothing, some forged cranks need external balance and an internal balanced forged crank with heavier than stock/rods will shake.

[c00nhunterjoe]

Drop the pan and make sure you have the correct balancer and converter for your crank

Dropping the pan and inspecting the crank will tell nothing, some forged cranks need external balance and an internal balanced forged crank with heavier than stock/rods will shake.

If he has an internal balanced forged crank yet weights bolted to his converter..... but yes, it will not solve ALL of his problems without a teardown and proper machine job.

[69wannabe]

Kind of a rule of thumb, always have rotating assembly balanced when building an engine. The 440's are something that really needs to be balanced since there were internal and external balanced engines and there was the 440 +6 that had a steel crank but was externally balanced. May even be a bad engine motor mount, alot of different things can cause a vibration.

[c00nhunterjoe]

All engines that are rebuilt should be balanced. There are many factors during a rebuild that change the balance, and the factory jobs across the board are not exact either. Its just one more part of a rebuild that can define a good machine shop from a not so good machine shop.

[myk]

Yeah I know.  But this engine was rebuilt 22 years ago when I didn't know anything about cars, engines or anything like that, and my mom had some random shop rebuild it.  Christ, i didnt even have the internet back then to get information from you good people.  Believe you me; when the rebuild for this block comes in the near future, I will be informed and know EVERYTHING about the build. 

Meanwhile I'll try running it without the alternator and fan belts attached, just to see what happens.   I'll also switch back to a rubber trans mount to lessen the felt vibrations.  Thanks again everyone...

[c00nhunterjoe]

 

[flyinlow]

X2 on what 69 wannabe said.

I looked for a vibration ,started down the drive train path.... then a buddy suggested , did you try running it without the fan belts?   Bad alternator, out of balance. 

[don duick]

I had a vibration that was caused by a broken transmission mount.