Need some guidance tracking down a vibration

[zimmstoy]

Hey everyone been trying to track down a vibration on my 440/727 setup and would like some of your advice on next steps. I initially noticed the vibration on a test drive around the block and it starts and stops between 1500-2200 ish rpm. It was initially fairly violent where it shook the column, dash and console. I started by taking out the driveshaft and getting it balanced. The result there was good. The shop said the shaft was out of balance and now its corrected. I then got on the forums and moved up to the transmission mount which was broken as well so I went ahead and replaced that. However I still have some vibration.

Had a friend by the house tonight and noticed that we are able to get the vibration to happen sitting in the driveway in park. Not sure what to make of it. The exhaust work under the car can be better than it is, it has stock manifolds going out to an H pipe and then mufflers and turndown tips - could it be related to that?

Again - I am at a loss - any guidance would be greatly appreciated.

 

[RustyRatRod]

The 440 is balanced two ways. Externally (cast crank) and internally (steel crank). They must each have their specific balancers and flexplates or converters to match the specific engine. An externally balanced engine requires a weighted balancer and converter. Which type crank do you have? Cast or forged? If it's forged, you should have a neutral balanced balancer with no type notch cut out of it or offset weight on it. Also the converter should not have any weights welded on it.

If the crank is cast, the balancer should have a notch cut out, or an offset weight on it, along with weights on the converter. Just somethings to look for.

 

[zimmstoy]

Thanks Rusty. I will check that out in the morning.

 

[Supershafts]

Yep your issue is all at the motor exactly like RRR said , driveline doesn't happen every time you see a specific rpm in all gears

 

[zimmstoy]

So I got out there this morning to poke around. All the paperwork I have says that this is a Forged Steel OEM Crank. Now here is something interesting. When looking at the balancer I noticed a bolt was missing from the pulley that mounts to it. Not just missing but even if I had it you wouldn't be able to get a bolt through the hole to thread because it doesn't line up. I went through the entire pattern and no matter what position it is in, it looks like there is always a hole that can't be bolted in.

My guy tells me that if that pulley is not fully mounted it could be causing some of this problem. So my question is - do I have the wrong pulley on there and if it is the wrong one how do I go about getting the right one?

 

[67 coronet]

factory balancers have offset holes so you can only align the pulley one way.most aftermarkets have uniform holes and need a pulley to match.you just need to figure out which one you want to change.pulley or the balancer.take a close look at the rubber on the balancer to make sure it is not cracking and alowing for that vibration.

 

[WP29440SE]

So I got out there this morning to poke around. All the paperwork I have says that this is a Forged Steel OEM Crank. Now here is something interesting. When looking at the balancer I noticed a bolt was missing from the pulley that mounts to it. Not just missing but even if I had it you wouldn't be able to get a bolt through the hole to thread because it doesn't line up. I went through the entire pattern and no matter what position it is in, it looks like there is always a hole that can't be bolted in.

My guy tells me that if that pulley is not fully mounted it could be causing some of this problem. So my question is - do I have the wrong pulley on there and if it is the wrong one how do I go about getting the right one?

one missing bolt is not going to cause a vibration. with five bolts in, mark which side of the 6th hole needs to line up, take the pulley off and oblong the bolt hole so the bolt will fit. i have done this more times than i can count . if the pulley is on with five bolts and fully seated, there is no way it will wobble, unless its been smashed with a hammer or something. if you have that serious of a vibration , as stated above, you have a converter/balancer issue.

 

[zimmstoy]

So if the balancer looks fine (which it does) and the converter doesn't have any weights on it (which it doesn't) what would the next course of action be to troubleshoot this? Should I throw a new balancer at it and see what it does or is there a way to test without throwing parts at it?

 

[WP29440SE]

So if the balancer looks fine (which it does) and the converter doesn't have any weights on it (which it doesn't) what would the next course of action be to troubleshoot this? Should I throw a new balancer at it and see what it does or is there a way to test without throwing parts at it?

do you have a pic of the balancer you are using? are you positive there are not any weights welded on the converter by the drain plug?

 

[zimmstoy]

I can snap a pic of it and double check the converter. I'll be back out there in about an hour or so.

 

[WP29440SE]

one more question, when the vibration starts , is the engine visibly shaking?

 

[zimmstoy]

it doesn't appear to be, but I will double check that once I get the pulley back on and reassembled. what does it mean if it is shaking hard in that range?

 

[Photon440]

factory balancers have offset holes so you can only align the pulley one way.most aftermarkets have uniform holes and need a pulley to match.you just need to figure out which one you want to change.pulley or the balancer.take a close look at the rubber on the balancer to make sure it is not cracking and alowing for that vibration.

Something I hadn't known before, but comes from 440 Source.com:

One important note is that starting in 1972, the bolt pattern on the front of the damper was changed to be exactly symmetrical. (Damper 1858382 is the only exception to this rule) Before this (71 and earlier) there is one bolt that is offset slightly, forcing the pulley to be installed only one way. (In case you are curious, the bolt is the second hole away from the woodruff key in the counterclockwise direction - it should be right in line with the timing mark.) So, because of this any pre 72 pulleys/dampers are not interchangeable with post 72 models.

 

[zimmstoy]

here are the pictures of the balancer. I know they aren't the best, but best I can do with the angle.

 

[RustyRatRod]

Have you busted it off without the pulley on to see if it still vibrates? If it does, then my guess is you have all that neutral balance stuff bolted onto a cast crank. No way to tell then but drop the oil pan.

 

[zimmstoy]

I haven't. I will try that again in the morning. I drove it again today after elongating the pulley hole and its still kinda there.

What I did notice is my rpm range (stated earleir) may be off slightly. I can say its most noticable right above idle, so if I lightly apply fuel it starts to vibrate - same thing when I slow down when it hits that range.

 

[RustyRatRod]

That's classic engine vibration. That's usually when it's most noticable, right off idle.

 

[zimmstoy]

Is it safe to assume the balancer on there is correct for a neutral balancer?

 

[Jeremiah]

If you had a bad drive line vibration I would make sure all of the bellhousing, etc. bolts are tight. I (foolishly) drove around with a s-shaped drive shaft on my Valiant for a few weeks and the bellhousing bolts became so loose it actually cracked the bell when I grabbed third one day (185 miles from home). I would be looks very closely at the flex plate and torque converter.

 

[RustyRatRod]

Is it safe to assume the balancer on there is correct for a neutral balancer?

Yes, it sure looks like one.