Signs a crank pulley or harmonic damper is malfunctioning

It's hard to know what the problem is when your engine begins vibrating at odd speeds, or your passengers start being ill, or the windows wind themselves down.
These are all symptoms of the damper being out of whack.

Rubber weakens with age and also deteriorates due to excessive heat, oil exposure, solvent exposure, and contraction. So what happens when a harmonic damper is malfunctioning? What are the symptoms?
Here's a handy list for you to check out.

1.  Deterioration of the rubber between the hub and the outer ring. Shown as cracking, bulging or shrinking instead of forming a smooth layer level with the metal components. This will be likely in any crank pulley over 10 years old because of the natural deterioration of the rubber. So old OEM dampers may well not last well or perform their duty even if they have only sat on the shelf for the past 10+ years.

Don't forget rubber is a natural product that simply deteriorates over time.

2.  Any wobble of the balancer or wobble in the drive pulley.

3.  Excessive engine vibration.

4.  Crankshaft cracking or failure.

5.  Squeaking that does not stop when all other possible sources have been eliminated.

6. Excessive bearing wear.

7.  Excessive gearbox wear or failure.

8.  Failure of other rotating or reciprocating engine elements.

9.  Loose flywheel or pulley bolts.

10.  Slipping, slapping or noisy drive belts. Having to change belts frequently.

11.  Loss of horsepower and lessened fuel efficiency.

12.  Highly polished asymmetrical spons in the pulley grooves, means a warped inertia ring.

13.  Elongation of the balancer key-way or wear on the balancer hub or crankshaft.

14.  Failure in the alternator, power steering pump, A/C or water pump.

15.  Engines that don't run properly when adjusting the timing.

16.  Irregular idle.

When a damper wears, what happens, at a minimum, is that the outer ring will move so the timing mark will be in the wrong position. Or, at worse, the ring comes completely off while you're driving and becomes the worlds heaviest "Frisbee" under your hood. Your radiator is one of the favorite items your newly found toy likes to go through.

Causes of damper failure:- age, cracked hub keyways, incorrect damper for the engine or crankshaft, damage from improper mounting or removal. Bent or out of balance drive shafts, buckled or out of balance driving wheels, excessive heat and age.

If you have a high performance engine without fitting a correctly calculated high performance damper, a standard damper could completely self-destruct sending high speed shrapnel throughout the engine bay with destructive consequences that are not hard to imagine.

It is important to understand that while an engine from any manufacturer is designed by a team of qualified engineers, after market dampers are often designed by people who do not understand the very important principles of physics that are used to design harmonic dampers. Great care should be taken in the selection of any damper to be used as replacement for a stock or for use in high performance engines.

If a cast iron damper is replaced with a steel damper care should be taken that the mass of the steel damper is equal to the mass of the damper being replaced. Because steel is much lighter than cast iron this means the damper will be somewhat larger than the one being replaced.

I have seen after market-dampers that have failed in spectacular fashion after brief use and have customers who are returning to a stock damper due to unsatisfactory results with after-market replacements. As in any field of after market componentry there is a small sector that know what they are doing and a wide range of pirate imitators.

John Mallett

Vibration in my 38 Packard straight 8 - the fix

ENGINE HARMONY
What's the most misunderstood and ignored engine part under the hood of your of your machine?  The harmonic damper or balancer.
I suspected that the harmonic damper could be the cause of an annoying harshness that was part noise and part vibration and which seemed to be in everything from the ash tray to the tyres in my 38 Packard straight 8.
Problem is you can't call a part defective when you have no idea how it works or what it does.  I served my mechanic apprenticeship some years ago at South Auckland Motors (Ford) where this engine part was never mentioned on the floor or in any training material - if it's not giving a problem you don't get told about it.
Having had no luck in trying to find the information I needed within the trade, I then Googled it on the internet and hey presto.  If you are looking for something you never expect to find it on your own door step but the solution was!

Harmonic Damper Rebuilds Ltd 07 863 3350 (John Mallett the Damperdude) is in Waihi and he overhauls and services harmonic dampers.  After talking to John about my 38 Packard straight 8 damper – all my questions were answered.
John explained the damper's job as follows:

'All objects have a natural frequency that they resonate or vibrate at when struck. An everyday example of this is a tuning fork. The sound that a particular fork makes is directly related to the frequency that it is vibrating at.
Crankshafts twist back and forth a small amount every time a cylinder has a power stroke. This motion is complicated because the amplitude of the vibration varies along the shaft. Eg. the combustion process bending the con rod is one of the complications. The crankshaft will experience torsional vibrations of the greatest amplitude at the point furthest from the flywheel or load.'

These forces are absorbed and neutralized by the damper.
If the damper is seized as it was on my Packard 8 not only was driving it a little unpleasant but I was risking bearing and/or crankshaft failure.

Consider these points:
1) The more con rods an engine has, the more capacity the damper needs to have.
2) If a manual trans is replaced with an auto trans the damper spec could well be different.
3) The length and number of main bearings a crankshaft has determines the dampers capacity.
4) Horizontally opposed 4 cylinder engines although small rely on dampers due to con rod layout and distance between main bearings.

‘By the way the Packard delivered the bride very smoothly!’
Cheers Nigel

Limited Warranty TAC up to 5 yrs

Yes we do warranty our work repairing harmonic dampers.
The basics are :- 12 months unlimited kms warranty, return to our base.
Racing, drags, rallying, boy-racing, and other non-standard driving of the engine are expressly excluded.
For those dampers we make supercharger fittings for, or which are expressly for high performance we will cover on a case by case basis if there is defective workmanship and/or materials for our work.
If you only drive your vehicle occasionally we are happy to extend the warranty to 5 years.
If you are re-selling/passing on our work to another person/company we regret that we cannot extend our warranty to cover third parties (or more) without our express permission.
We particularly exclude original equipment manufacture (OEM) faults and materials from this warranty - since the remanufacture of the pulley relies upon re-use and repair of OEM parts.
Damage to the damper before it reaches our workshop is also expressly excluded from this warranty and repair of bent or broken parts will cost extra.
If the fault is not found to be our workmanship after we have repaired it at your request an additional full hourly charge for all time and materials will be made.

Customer Responsibilities are to:-

1. Remove the damper from the engine in an appropriate manner which does not damage it. 
2. Provide accurate timing marks - email photographs of the timing cover or mark TDC on the damper before sending it to us.
3. Providing your full contact details and honest details of the use for the damper eg boating, car, racing.
4. Handling and transporting the damper safely to us.
5. Re-fitting of the damper upon return in a way which does not damage it.

If you don't know how to do these things please ask us. damperdude (at) gmail.com or call 0064  7  863&3143

In all cases New Zealand consumer law and New Zealand laws apply to all transactions.

Oil Seals

There are a number of types of stainless steel oil seal sleeve available to quickly stem oil seal leaks once your damper spigot becomes grooved and worn from an old oil seal running on it for too many miles.
The oil seal surface is grooved on a balancer or harmonic damper most mechanics will apply a cheap stainless steel sleeve and send your damper away with an oversize spigot too large for the oil seal. The stainless steel of the ss sleeve has no lubrication and this causes heat build up and thereby ruins your new oil seal. This is why many engines leak shortly after a stainless sleeve is fitted.
If the keyway is cracked the stainless sleeve will not help hold the cast iron damper together.
The solution? I hand-make 1040 mild steel sleeves for all the balancers I repair.
Your seal surface will be restored to mint condition with a heat-shrunk or press-fitted steel sleeve.
Cracks will not crack further or move as the whole spigot is held firmly intact by the steel sleeve. I make the sleeve surface the correct size to fit your oil seal.

Oil seal surface on the spigot worn and grooved

A custom made steel sleeved spigot ready to fit on the engine.

Contact us damperdude -at- gmail dot com for more information.
Thanks for reading our blog post - is there more you want to know? Leave a query in the comments.

How YOU can help US

So your pulley, balancer or damper needs repair or modification; a new rubber; needs the timing realigning; must be modified so you can put that awesome supercharger on your engine for terrific performance.
To help us get the remanufacturing work done faster and your damper back to you in a brand new state, there's a few things you can do before you send it.

• Clean it - in the wash tank or sand blaster.
• Take photographs of the front, back and edge and email them to us.
• Wrap it up well and put it in a box to send it to us. Label it as 'Fragile' - cast iron can break like a tea cup if dropped.
• Include the position of the timing mark by marking the hub or sending a photo or diagram.
• Do include your name, address, contact phone no and the year, make, model and capacity of the engine the damper belongs to.
• Email us to let us know the parcel is on it's way.

We will call or email you to let you know it has arrived safely.

We have an eftpos machine and can process your credit or debit card once the damper is repaired to our satisfaction.

Perished rubber on a harmonic damper

Harmonic Damper History - Who invented crank pulley balancers and why?

The inventor of the harmonic damper was Dr Frank Lanchester. He and two of his eight brothers started the Lanchester Engine Company in 1900. They had high standards for their engines and Dr Lanchester would tinker with each motor that went out the door to make it more perfect than the last one. He invented the Torsional Crankshaft Damper [harmonic damper] and the harmonic balancer to cut vibrations in the Lanchester 38 hp six which was introduced in 1907. In 1910 he invented the single and double counter-rotating balance shafts. The patents for which were purchased in the 1970s and used by Mitsubishi and licensed to other manufacturers to the present day. He also invented the steering wheel, amongst many other things.

Luke Brennan has corrected our account with more recent information: You may wish to refer to him as Frederick W. Lanchester. Fred, not his brothers Frank or George.

His damper patent was 12th September 1910. He licenced this to Daimler shortly thereafter. Not Frank – Fred.

Also you may also wish to read the superb “Royce and the Vibration Damper” by Tom C. Clarke, which casts strong doubt on the primacy (though not the brilliance) of Lanchester.

It would now appear that Henry Royce had developed a friction-based harmonic damper for his 30HP engines in 1906 but had failed to patent it.

Royce then developed an extremely effective spring-drive/viscous damper that was used on all RR vehicles until the 1950’s. 

Thanks Luke, as you can see, the inventors of things can be mis-reported or debated, they are long dead so who knows who really did what and when?

Harmonic dampers are called by a wide range of varied names. In truth they are all torsional vibration dampers. Terms like crank pulleys, balancers, power pulley etc are to varying degrees erroneous. The term harmonic balancer comes from some manufacturers using the hub as a convenient location for external mass balance weights. The reason for this is that it made fine tuning of engine vibration simply done by adding or removing weight from the mass balance.
Though it is common belief that large steel parts such as crankshafts are rigid and inflexible this is not true, when a force acts on a crankshaft it bends, flexes and twists just as a rubber band would. While this elastic deformation is often very small it can have a significant impact on how an engine functions.
All objects have a natural frequency that they resonate or vibrate at when struck. An everyday example of this is a tuning fork. The sound that a particular fork makes is directly related to the frequency that it is vibrating at. This is it's natural frequency which is dictated by the size, shape and material of the fork. A crankshaft is a series of tuning forks in a line, it has a natural frequency that it vibrates at. When an object like a crankshaft is exposed to a heavily amplified order of it's own natural frequency it will begin to resonate with increasing vigor until it vibrates itself to pieces. This is called fatigue failure.
Crankshafts twist back and forth a small amount every time a cylinder has a power stroke. This motion is complicated because the amplitude of the vibration varies along the shaft. The crankshaft will experience torsional vibrations of the greatest amplitude at the point furtherest from the flywheel or load.
Engines have major and minor critical rpms and are different due to the fact that some harmonics assist one another producing large vibrations whereas other harmonics cancel each other out. Major critical rpms have harmonics that build on one another to amplify the torsional motion of the crankshaft. Conversely, minor criticals are at rpm that tend to cancel and damp the oscillations of the crankshaft. If the rpm remains at one of the Major criticals for any length of time fatigue failure of the crankshaft will result. These major critical rpms are dangerous and must be avoided or properly damped.
The oscillation of an undamped crankshaft at a major critical speed will commonly shear the front crank pulley and/or the flywheel from the crankshaft. I have seen hub keys sheared, flywheels loose, and pressure plates coming apart. These failures have often required crankshaft and or gearbox replacement and in extreme cases the diff.
Technically, 'the primary purpose of a harmonic damper is to cancel out third harmonic distortion by using intermodulation between the second harmonic and the fundamental in the space charge regions of the triodes.'
Put simply the harmonic damper works by relaying resonance and torsion energy out of the crankshaft and dissipating it as heat by flexing a heavy metal inertia ring which is mounted on a vulcanized rubber cushion. Essentially the damper is a simple spring of rubber plus a vibration and heat absorbing mass - the hub and inertia ring.
Harmonic dampers are made of cast iron for the primary reason that cast iron has the ability to absorb and dissipate large amounts of energy because of it's high specific gravity. The damper on each engine is designed for the specific range of vibrations that a particular engine produces. Keeping the damper cool is also of primary importance.
The key weakness of the harmonic damper is the rubber. Next blog we will cover signs your harmonic damper or crank balancer is dying or dead - it's serious engine damage ahead if you keep driving it vibrating like that folks.

Ford Thunderbird repaired ready for painting.

Porsche 944 damper alteration to run a supercharger.

The Job:- to drive the supercharger faster. To provide more boost pressure to the engine requires a larger diameter pulley than the standard Porsche 944 3 litre four cylinder engine damper.

The solution John found: He machined a new steel belt drive pulley ring for the supercharger which runs over the existing damper on the same belt drive line as the original but on a larger diameter belt drive line.
The damper itself was bonded, re-rubbered and strengthened with a custom made hub turned up from a special grade of  aircraft aluminium which was positioned in the centre of the damper hub to provide additional support to the hub because the original is only a thin steel pressing.
As the original inertia ring could not be altered because of its design the new pulley was attached to the hub of the damper via the new aluminium hub. The whole was bolted together, balanced and polished
Today Graeme, the owner of the Porsche 944 called to say that the modification is successful and that he has raced his machine successfully in two races.

This modification is not cheap but it is an effective solution for a racing car with limited space for modifications. If you seek an innovative solution to a supercharger issue like this give Damperdude a call or drop us an email damperdude . at . gmail. com.