Vibration and Balancer/Flywheel question

[covert]

Hi guys,

I have another problem with my recent 440 swap.  (I'm beginning to wonder why I ever went down this path...    )

When I finished the swap of my 400 with the new 440, the new engine created a really strong vibration.  I attributed it to 1) my drive shaft needing to be balanced and 2) new really hard engine mounts.  I used the some of the new poly mounts that are now out.

Well, the guys as the mopar shop where my car has been getting the new rearend bolted together say that the vibration is still really bad, even after getting the drive shaft balanced and installed.

They believe that the motor / trans were put together with the wrong type of balancing.  They believe that when the transmission was put on the engine, that a non-externally balanced flywheel was used, when they should have used an externally balanced one should have been.

They also said something about the harmonic balancer on the front.  I'm probably not restating what they said exactly right, because I was seeing red when they were telling me this (mostly because I was getting frustrated with them and these problems in general by this time)

The engine is a 1973 440 block.  I've been trying to research here on the forums, and this is what I think I know so far (please correct me if wrong!) -- OK, so the 1973 should have a cast crank, and cast cranks are externally balanced.  So the front harmonic balancer should be for an "externally balanced cast crank" and the flywheel should be for an "externally balanced cast crank"

Is there anyway for me to check that all of these are correct or not correct?  How do I make sure I have a cast crank, the right front balancer, and the right flywheel?  Can I check the flywheel without dropping the transmission, like by removing the inspection plate?

Its hard for me to believe that the engine / trans have been put together wrong all this time.  The car it came from was a daily driver for the guy I bought it from -- but I can't say for sure that the it didn't have the same problem in the other car because we didn't drive it enough before pulling the engine.

Also, could this all just be a red herring, and the vibration is just caused by the stiffer engine mounts?

Thanks guys -- This forum has been a huge help.  (BTW, as I was talking to the shop guy, the only thoughts going through my head was that I had to come back and ask here before I did anything)

[hemiken]

What is your gearbox.............Auto or manual.

[Moparal]

If it's an engine vib, it will vibrate without the driveshaft even turning.  You never know what a person has done to internals after a rebuild, but if it was stock, the balancer should say 440 cast crank  right on it. The flywheel would be different for balancing too. If it's a 4 spd you may have a problem inside of it causeing the problem like a bad roller bearing or pilot bushing /bearing gone south.

[moparman11]

check to see what kind of flex plate you have, my 440 had a 360 flex plate, causing vibration.

[hemiken]

Hey, don't forget that if it is an Auto it may have a balanced converter in place of a no balanced converter or vice versa. 

[covert]

Its a 747 automatic.

Maybe they did say "converter" instead of "flywheel"  -- That I had a non-balanced converter where I should have a balanced one.  Is the converter / flywheel / ring gear is all one unit in a Mopar? 

(I know some of the theory and names of stuff between the engine and the trans -- but have no experience there at all.  never separated the two nor have looked between when I was doing the swap.  So I'm probably just completely talking nonsense)

I guess the flex plate is in there too, between the motor and the converter? 

Any easy way to tell if I have the right / wrong flex plate and converter?  Just drop the trans and look?  How do I identify them when I do?

Thanks guys,
Covert

[hemiken]

  That is one of those Boeing ones.

[hemiken]

The flex plate is shaped sort of like a cross.  And yes the ring gear is part of the converter and if it needs to be a balanced converter it will need two weights fitted in the correct position. 

[covert]

   Opps -- yeah, 727.  I wonder what kind of freudian slip that's considered to be...

[Chryco Psycho]

the only way to know for sure if the crank is steel or cast is to pull the oil pan & look , either balancer can be fitted to the crank & swapped with the wrong one , a steel crank will have a wide parting line & the metal will have a stretched look to it & rounded counter weights,  the cast has a narrow parting line , often has #s cat into it & has square counter weights
 removing the inspection plate from the tranny will allow you to see the converter & the weights to ba;ance the crank if they are there

[covert]

So I went down to the shop today, and pulled the trans inspection cover.  There was no weights on the converter.  The balancer on the front is an externally balanced one. 

All signs point to the shop guys being right, the vibration is from not having the right converter.

Now I'm looking online for a new converter.  I could use a stock one, but, if its going to be apart anyway, I might as well go with something better right?  I was looking at the TCI Saturday Night Special (cause my engine is pretty close to stock). 

The problem I have now, there are 3 different types of externally weighted converters:
http://www.tciauto.com/Products/AMC/#balance_weight

Which one would I need for a 73 cast crank 440?

[Chryco Psycho]

the info on their site is to Vague to determine which you will need , you can also weld weights onto the converter you have if that is easier & you like the converter in there now

[hemiken]

  If you can borrow another converter, even a 360 converter to see where the weights belong and you can get some wieghts, your welder should be able to perform such a task even while the converter is still in the gearbox, in the car if money for labour is costing too much, rather than pulling the gearbox out.  I do not recomend this action unless the person performing the task is absolutely capable and trust worthy as a welder and mindful of what he does.   

[covert]

You know, its funny -- If you want to order one of their converters with the weights already on it, they have that obtuse table to look at, that doesn't mention anything about engine sizes, years, etc.  So its almost impossible to figure out what you need.

But, if you look at their flexplates, and you want to move the weights from the converter to the flexplate and use a neutral converter, they are very specific -- "71 & up, 383-440, external balanced, dual bolt circle, 5/16" bolt, 6 hole cast crank"   That fits me to a T, so I'm going to get a flexplate instead of a converter, then use the no-weight converter.

Welding the weights on seems like real act of faith -- I can only imagine what happens if the welds break at 4000 RPM. 

Out of curiosity, how do you know where to put the weights?  You know, I was thinking about what these weights are supposed to compensate for (which I hadn't really thought of before) -- Do they need to line up opposite of something else in the engine, or is it just necessary that they be somewhere (anywhere) on outside rotational surface? 

Anyway, those are just curiosity questions -- I'll let you guys know how it goes back together when I get the externally balanced flexplate and the neutral converter.

Thanks for all of the help
Covert

[rottenfish]

Your best bet is to get the balanced flex plate, and keep your neutral converter. I believe that the Mopar Chassis manual has all the specs on where to add weights for TC balancing (I know the flywheel drilling info is in there, but there is a *much* easier way), and at one time MP sold a weight kit with a template.

Speaking of curious... the 400 you had, was it running the same neutral balanced converter with no trouble? If so, do you know the origin of the engine? If the 400 was running in balance with a neutral balanced TC, it would imply that the 400 had a forged crank. I have entered into many a debate over whether or not 400's ever had forged cranks, so I would be curious to know more about your old setup.