Harmonic Balancer

[Alpine Addict]

Is there an issue with these from Rootes Spares?

 

[puff4]

Not that I know of. What have you heard?

Having said that, I bought mine here:

https://harmonicdampers.com/index.php?main_page=index&cPath=75_25&zenid=okilovacvptvr7drms99lje8m7​

Admittedly, it’s awfully expensive, but they do produce a top quality product.

 

[Tim R]

Why not fit the solid aluminium one as used on the later 1725 engines? There is no noticeable difference when driving the car and at least you know that it won't split in two and wreck the radiator, timing chest etc.

Tim R

 

[mxp01]

I was told once that they are called "harmonic dampers" because they counter vibrations from the crankshaft. Having a solid pully would not do this and would possibly cause damage or shorten the life of the crank.

I'm saying this because I had the solid pully on at one point and was told to take it off for that very reason. Its been awhile but I'm pretty sure I bought my current pully from the link Kevin posted. I paid $250 for that pully back then, they have gone up a bit I see.

 

[jumpinjan]

The pulley is used to control down "torsional vibrations" inside the crankshaft. Torsional "twisting" of the crankshaft due to the power impulses.
So I never understand why it's okay to use a solid pulley and ignore the problem.
Jan

 

[jumpinjan]

Have you noticed a crank pulley that doesn't need a puller to remove it...and noticed that the key way is cracked? Most all of these crank pulleys are a press fit, so they can grab the crank. I have seen some modern engines that have no key way, but the pulley is tighten with a 6 foot long wrench to over 200 lb-ft torque.
Jan

 

[RootesRooter]

The pulley is used to control down "torsional vibrations" inside the crankshaft. Torsional "twisting" of the crankshaft due to the power impulses.
So I never understand why it's okay to use a solid pulley and ignore the problem.
Jan

It might be that those "power impulses" are a lot more powerful and potentially destructive on the aluminum head, twin carb Alpines vs the rest of the Rootes fleet. What pulley did the Rapiers run?

 

[Filister]

My 1959 Rapier, twin carb, iron head, has a solid crank pulley.

 

[husky drvr]

It might be that those "power impulses" are a lot more powerful and potentially destructive on the aluminum head, twin carb Alpines vs the rest of the Rootes fleet. What pulley did the Rapiers run?

The iron headed 1725 in the '69 Arrow that passed through my hands, did not have a dampener pulley, just a solid, plain one.

I'm thinking Bill's coupe with its iron head engine also has just a plain pulley.

 

[Tim R]

We have had solid pulleys on two of our Alpines for many years. We cover serious mileage in our cars. One won the UK Owners club award for doing the most miles in a year and the other is driven by me almost every day. If a solid pulley was going to cause a problem to the engine we would have had it by now.
I suspect that Rootes fitted the harmonic balancer because they were always going the extra mile to raise quality and make their cars as good as possible. In my opinion it is one of those things that may be nice but is not strictly necessary. As a number of UK owners have suffered from modern versions of the harmonic balancer breaking up and wrecking the engine I feel a lot safer with the solid one.
Tim R

 

[alpine_64]

I had a solid pulley on my 3 mian alpine motor when i got it, i ran it like that for 12 years then swicthed to a harmoic one.. It did seem a little smoother as it got higher in the revs than before... But maybe that's a mental perception

 

[alpine_64]

I should note that checking the keyway for cracking is vital for the pulleys solid ir Not.

 

[Alpine Addict]

I have on my shelf a harmonic balancer from Rootes Spares and one from BHJ Dynamics. Is one better than the other?

 

[puff4]

... As a number of UK owners have suffered from modern versions of the harmonic balancer breaking up and wrecking the engine I feel a lot safer with the solid one.
Tim R

Tim, do you know which new ones are failing? I know the old ones have DEFINITELY been failing - they're all reaching the age where the rubber is shot - but I wasn't aware that the new ones are failing.

I have on my shelf a harmonic balancer from Rootes Spares and one from BHJ Dynamics. Is one better than the other?

Given that BHJ *only* makes dampers, I'd say they're the one to beat. They've been in business for decades doing this, and they have a good reputation.

 

[pruyter]

The one from Rootes Spares in The Netherlands are the ones that are failing! When I found out I returned the one I bought from Rootes Spares and ordered a solid one from them.

Regards,

Peter

 

[Tim R]

As Peter says there have been reports of pulleys from Rootes Spares failing but the one that failed on our 1592 came from another UK supplier. Where they got it from I do not know. It was fitted brand new following a complete engine rebuild. It failed within a fairly short space of time and when it did so it split where the two parts are joined with a rubber between them. It wrecked the radiator, timing chest fan, belt etc. The company were good and replaced all of the damaged parts but after that experience I have no intention to fit the balancer type of pulley again. There is no need as the solid one works perfectly well.

Tim R

 

[puff4]

I’m sorry to hear about the Rootes Spares pulleys, but the BHJ one in my car is doing great. But then BHJ has been making them for high-performance & race cars for decades, so they’ve got a reputation to protect.

I do think there’s value in a harmonic balancer, but of course opinions differ. Basically, a harmonic balancer really only does its job at high RPMs where the harmonics can become stress-inducing and potentially cause crank fractures. I tend to wind my engine out pretty good when driving, so I see the benefits. If you drive sedately then any old pulley will do.

For the technically inclined, here’s a paper on the engineering behind harmonic balancers:

http://harmonicdampers.com/index.php?main_page=page&id=4&chapter=0