*"Tis the last rose of summer"* The Sept. 2012 Banger Meet

OK--Here is a question for you experienced gear heads.

All seem to agree that adding a SBC harmonic dampener to the front of a banger Ford crank is very beneficial. Agreed.

But I gotta think that a dampener, designed for an 8 cylinder, relatively short stiff cast iron crank is the optimum dampening for a 4 cylinder steel much more limber one. Works, yes-undeniably - but optimum?

So-- does anyone know, or even better, have experience "tuning" a damper?
Some day I hopefully will get back to work on a 224 Chevy 4--an engine with a steel crank, even worse looking in torsion that the Ford. I envision making a dampener like the early Rolls Royce used which was a free disk, captured between to other plates keyed to the crankshaft, sprung together with friction material between them and the free-to-spin disk. This could be "tuned" by playing with the spring pressure.

Any automotive engineering books that I have looked the subject up in describe different types--but that's as far as they go. I'm sure that there is some SAE paper done on the subject--but even if there is, I know that it would be full of algebraic equations, and not much help to dumb ole me.

Anyone able to help--or to add info??

Herb

 

Sac Vintage Ford lists a Winfield CRANK PULLEY/VIBRATION NEUTRALIZER 1928-34

The part # is 01535 and it's not cheap. Might save you a lot of time though.

 

Rob--I know about that one, but thanks for posting it anyway

I want to MAKE one.--I have a complete machine shop, and I intend to make mine so that the amount of mass, and the amount of restriction to it's movement can be changed.

My question--perhaps better stated--is how does one know when the optimum has been achieved?

I am hoping that someone in the HAMB family has payed around with this, and can tell us what and why they did. It would be great to hear from--

DaddyO
J P Bill
Rich
Jimmy B
George Miller
Norm
8 Ball
AND OTHERS

I have discussed this with Bluto

As a related aside--Clayton--do you use one on your T?

Herb

 

There has been discussion on another forum relating to this.
Here is an article which might help you understand the dynamics.

http://www.bhjdynamics.com/downloads/pdf/tech/BHJDynamics_Damper_Info.pdf

Remember that an in-line 4 motor has mechanical issues that compound the harmonic issues. Reducing the weight of the pistons makes the biggest impact on this issue.

John

 

I haven't played with dampers, but I have a friend that is working with a company that is doing work with racing teams and aerospace companies to develop a balancing system that used mercury filled tubes.

Basically the mercury is allowed to find the spot or spots that need weight. They have had success eliminating vibration in things like jet rotors to motor cycle road race wheels.

He has offered to set up my flywheel. I might do it on this engine build.

I have had conversations with people that are on both sides of this issue.

The people that argue against dampers say that adapting a balancer from another engine may do more harm then good.

Their thoughts stem from the facts that the damper is a last ditch effort to balance the engine externally after everything has been tried to balance the spinning mass inside. So adapting a damper from a V-8 will have a different weight effect then one for a V-6 or I 4

Nobody I have talked too have empirical data to support their theory.

My $ 0.02

.

.

 

I have feedback from a couple people that this damper does not hold up on high performance engines. Something about it coming apart at speed.

 

Thanks John and Craze

John--I will certainly take a look at that link

Craze--I heard the same thing about the Winfield clone dampers.
Also, the last part of your post is exactly why I'm interested in this.
The mercury thing is VERY interesting. Same principle as the glass beads inside tires, I guess. If an annular groove, with some restrictions at regularly spaced intervals was partially filled with Hg, it would be exactly the effect that I think is needed--plus the effect of the amount of Hg would be easy to change. I would say--"great, but where the f##k am I going to get Hg" Lucky me, I have somewhere between 6-8 lbs of it squirreled away.

Now all I have to do is finish making parts and assembling the '07 Stanley engine that's in the shop, and getting as much done on the installing of a 5 cyl Deutz diesel in a '61 Willys wagon, before the weather gets too cold--outside job.

If any of you other guys have something to add, please do. All comments are helpful!!

Herb

 

Herb,

I know it's OT, but would you mind sharing a pic or two of the Stanley engine ?

 

John- That's an excellent article!

I have it bookmarked.

Herb

 

Bill-

I have a lot of pix of various engines, but they are all details of parts, or mods.
I looked, and I don't have a overall shot. The present engine is all apart, so I guess that I won't be able to fill your request, until I get it back together.

Herb

 

Ok Herb, you started the discussion on dampers. Here's a dum question. Why do some engine need them or benefit from adding them and others don't need them at all? I'm thinking horizontal opposed, like Corvairs, Porsches and VW's. Very few VW's have them, some big inch drag cars do. I understand old bangers not haveing them they only spin 2 or 3 thousand revolutions. But what about the others?

 

From @ 1965 on Corvairs had dampers.


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Doug-

Take a look at the excellent link that John Neilson posted.

It answered a lot of questions that I had.


Herb

 

I have also tested this damper on a flat head performance engine and it started to rattle apart after 5 dyno pulls.

 

Wow, wish I was smart enough to absorb all that. It did answer some questions.

 

From what I have learned about engine design, the in-line 4 motor has the worst harmonics because of the 2up/2 down timing. Basically, the pistons accelerate at different speeds between tdc and bdc. This is lessened by reducing the amount of weight of the pistons and somewhat the little ends of the rods. The boxer motor design with opposed cylinders canels somewhat and a V configuration motor typically have more slugs to stagger the timing and smooth out the effects. From experience with other I4 motors, just turning up the rev limiter from 7k to 8.5k has drastic effects, especially if the pistons have not been visited Jenny Craig. Strange things like shaking the throttle shaft to breaking and breaking oil pump annular gears on the crank. I'll post more when I get the tank running, it has no flywheel and no balancer but the crank itself is massive.

John

 

Fair enough Herb,

I can relate to that. As to adapting I'd think one of the fluid damper range would work best. I'm not sure what fluid they use but suspect Mercury as stated elsewhere here.

Thanks too for those with feedback on the one I posted a link too. They can't be very well made if they're falling apart at the relatively low operating rpm of an A/B/C engine.

Cheers,
Rob

 

Herb,

Once constructed, how would you know if you had enough dampening?

Would it be a "seat of your pants" test, or do you have a test stand that has some sensors that would give you feed back?.


.

 

Very interesting how would a balancer work if it was built into a redesigned flywheel? We all know that the stock flywheel although well designed for the stock understressed 1920s/30s motors is no good for a performance motor may be it is time for a radical new design?

 

IMHO, the balancer is needed on the opposite end of the crank from the flywheel.
The flywheel acts like a balancer on the rear.

 

That is ONE thing I understood from the article. John, thanks for the link.

 

And here is what 5 hours of welding shop time will do for a Morton & Brett head. Not leaking now. Hope it stays that way.

 

Rich, my understanding is you have to pre heat and post heat. Why didn't they burn off your yellow paint?

 

The pre and post heat is apparently the old way. This guy has welded iron for me before and it seems to work fine. Hope it still does.

 

Crazy wrote

"Herb,

Once constructed, how would you know if you had enough dampening?

Would it be a "seat of your pants" test, or do you have a test stand that has some sensors that would give you feed back?."

Well that was sort of why I started this thread--see the first few posts --but then John's link made it obvious that to truly test one required a lot of stuff that I don't have, can't afford, and wouldn't know how to use if it fell from the sky and hit me on the head. So I dunno. The only thing that I can think of is that I have a Vibro-Tach, a device made by (or more likely for) GE. How it works, is that it has a thin vibrating element that can be varied in length to "tune" it. When the element vibrates at its maximum, the frequency can be read off on a scale. So PERHAPS if a baseline measurement is taken with no dampener, the frequency could be adjusted (with the dampener) to a range above the intended operating range of the engine. PERHAPS!

Then again, by the time that I get around to doing all this, I might decide that it is too much of a craps shot to be worth trying. (perhaps)

Herb

 

Sorry guys I was meaning new flywheel designed in conguction with dampener( oposite ends of the crank) I think the two can be made to interact better

 

hi guys, just wanted to let you all know that there is a show coming up in New Jersey called The Race of Gentlemen. It is being held in Oct 20 this year. The big news with this show is that the cars will be racing on the beach!! It has an early cut off for the cars racing on the beach. It's post war and pre war style ONLY and some of the guy are starting a cash prize for the fastest 4 banger!!! So here is a Real chance to uses your Iron!

 

Herb,

the most obvious answer to the question of "is it working" is when parts stop breaking!!

John

 

John,

Unfortunately, you are 100% correct. I guess it all depends on whether you run out of cranks, or years first.

Me--it'll be years.

Herb

 

Herb,

that is probably true, but, what I was referring to are the breakage in auxillery parts.
For instance, one particular motor design was prone to breaking throttle shafts when the balancers were bad. I would keep an eye on the distributor and carb(s) as they are at the most distance from the crank and have the least support.

John