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Harmonic damper and thin belt conversion kit


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I have decided to fit a thin belt conversion kit, with harmonic balancer, to my '59 3A and have been pricing them up. I live in New Zealand which makes this kind of purchase rather more expensive and risky than if I lived in the UK. I wonder if any one has any experience of the kit sold by Rimmers. From what I can tell from the Internet it looks exactly the same as the one sold by Moss, but is £100 ish cheaper. I have never had reason to complain about anything I have bought from Rimmers before, or Moss for that matter, but I wonder if the price difference is reflected in the quality. I'd gladly pay the extra if it was worth it, but £100, or around $nz200 would be a valuable saving which could be directed elsewhere in the car. I hope such questions don't contravene any policies, but any advice or experience would be much appreciated.

Thanks, Tony

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Hi Tony,

it doesn't contravene any rules - ask away.

 

I have a query. People go on about harmonic dampers.

1 - what does it damp?

2 - Is the damper designed for that engine.?

3 - why haven't the car withput dampers fallen apart after many thousands of miles.?

 

Roger

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Roger

 

Early crankshafts snapping comes to mind. Also of course the other choice of a Kenlowe suction fan which means the removal of the original one. and the damper in it´s place.

 

Dave

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Hello Roger

 

As I understand it, although crankshafts are as rigid as their designers can make them within their budget allowance, there is still a certain amount of twist put in to a crank with every power stroke, more so on a power stroke in cylinder number one, less on number four, with the former being further from the flywheel than the later. As the flywheel catches up so to speak, the twist in the shaft unwinds and to some extent puts a twist, or torsional force, in the other direction. Apparently this constant winding and unwinding can result in vibrations in some engines at certain rev ranges particular to that engine. This can result in broken crankshafts, for which TR four cylinder engines are not unknown. That's how I understand it anyway.

 

The damper is designed for this engine in as much as it has to fit the crankshaft and work with the timing cover seal. I believe people have adapted dampers from MGBs (considered by some to be the most boring sports car ever made, I refuse to comment). My series one land rovers have harmonic dampers fitted to the crankshaft nose and I have considered trying to use a spare one I have, but would still need to buy/make the other pulleys for the 3/8 belt.

 

MyTR3 has a harmonic balancer built into the fan and extension I believe and so I wish to continue to have one fitted. I wouldn't probably have bothered consider replacing the tractor belt with a thin one if I wasn't having problems adjusting my generator because of it fowling an extractor manifold I have fitted, but there seems to be a few benefits associated with going down the thin belt route. I would rather have a harmonic balancer fitted than have a broken crankshaft without one and wonder what if.....

Having said that it might still break, as did the crankshaft on my poor old TR4......just after I sold it. As you say, many engines do many miles with out one, but new cranks are rather heavy to post to NZ.

 

Cheers, Tony

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Tony,

 

I fitted the Moss version and i don't know if they have made any modifications but i had to spend a lot of time to get all the pulleys to line up .

The other thing is i don't know why they have the sleeve that needs to be pressed into the crankshaft pulley unless they use the same pulley for a different engine?

 

If you do go ahead and fit the kit you will need to make a TDC mark on the crank pulley which i think is directly opposite the keyway , you will find it very useful at some time in the future.

 

Graham

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I bought my narrow belt with damper kit from the TRSHop and when I asked some technical questions they referred me to their supplier - Moss!

I wonder if there maybe only one source for the uk retailers.

Crankshaft still in one piece.

Regards

Rog

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Hi Tony,

 

Fitted one as part of a complete cooling system upgrade. I believe some of them are modified MGB ones. All my upgrade parts came from TR Enterprises and fitted fine. The difference in smoothness throughout the Rev range was very noticeable. Almost feels like a modern engine.

 

Regards, Pete

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Whilst changing pulleys and belt, it's worth thinking about changing to negative earth and fitting an alternator.

So much more convenient, and it's not difficult - see Section J4 of the Technicalities CD (or TR Action 118, which is on the TR Action CDs), and TR Action 248.

Ian Cornish

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Hi Tony,

I believe there are no dedicated harmonic dampers for the TR - 4 pot engines. If it is not tuned for the correct resonance band it will do nothing.

I would put money on there being any cranks broken due to harmonic processes.

I would put money on there being any cranks failing due to torsional failure.

Every failure I have seen has been on the #4 big end journal and it has been a simple tensile failure due to stiffness imparted by the flywheel.

There have been a few other areas - #2 has had a couple; yet is in a lightly loaded area.

 

Dump the damper, fit the thin belt and be happy.

 

Roger

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Hello everyone, thank you for all the input.

 

Mike, you are an absolute Saint, and I am an idiot. Yes the prices are very similar. I was comparing Rimmers prices with moss USA. So the moss price was in $. My brain read the $ sign as a £ sign and I feel such a wally. Thank you so much for going to the trouble of posting those links.

 

Graham. Yes, I did read the instructions on the web page and know about the timing mark. I wondered why the sleeve wasn't already pressed in as did you.

 

Pete. Interesting to know you found a noticeable increase in smoothness. Moss sell a dampener for the MGA and MGB, made in Australia interestingly enough. It is considerably more expensive than the kit for the TR, but looks vastly superior, it's held together cap screws, always a good sign. Seriously.

I shall look at TR enterprises offering.

 

Ian, I am already negative earth, I thought about an alternator upgrade, they are shorter I believe and so possibly wouldn't foul my extractor manifold. However, I believe they are also more sensitive to heat and there's not much room for a heat shied to protect it from the manifold. I shall refer to the relevant register magazine.

 

Rog, thanks for the info.

 

RogerH your views are appreciated. I understand where you are coming from concerning tuning for the correct reasonance band. Perhaps an argument for a lightened flywheel? Oh no! More necessary expense and time off the road! You obviously know far more than you let on in your first post which doesn't surprise me as I have known of you for a long time from Traction. I recognise your stylish headwear. A man endowed with such sartorial elegance is a man to be taken seriously indeed. Unless I have cocked up the prices again, the undamped kit is slightly dearer than the damped one so I shall go for the damped one. It seemed to work for Pete.

 

Sincere apologies if I've missed someone. I shall update you on what I do cos I'm sure you will all be waiting to know with baited breath.

 

Thanks, Tony

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Hello Tony,

I am in Aus and have a balance pulley from a Holden red motor. (20 years service so far)

These should be available in NZ?

You will need to get a spacer made up and go to your local Auto Electrician to get a narrow pulley for your generator.

This method will save you a packet of foreign exchange and be of better quality, going on the quality of parts supplied by one of the compaines mentioned.

Cheers,

B

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Tony - a heat shield is a must if an alternator is fitted, but you need little space to accommodate a thin sheet of metal.

I have an old-fashioned, quite large (but modest output - 34 amps) alternator as was fitted to the TR7, and a 4-branch tubular exhaust, but I managed to re-mount the heat shield which the Works fitted in 1962 to protect the dynamo.

Even at 900 rpm, an alternator is capable of generating many amps, which means there's scarcely ever any drain on the battery once the engine has been started.

Ian Cornish

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Ian

 

Why do you say a heat shield is a MUST for the alternator. I must admit though my s/s exhaust manifold is highly lagged with the materials from Moss and painted over. I say highly lagged as the spiral wraps are about three thicknesses over the whole thing down as far as just past the starter motor, it took at least two rolls of that lagging. I know that helps the hot gasses to flow faster and out through the tail pipe as my one over-rider turns straw coloured on short hops and a light blue if I give it welly for a long run.

Our daytime temps. are far higher than yours and I do not have such a shield. I do have the ali ducting in front of the rad and surely that should make it hotter in that area due to no air flowing over it from the intake.

I had my flywheel lightened and the whole engine balanced together including the clutch components, also have the engine rear oil seal fitted (Landy I believe). So it made sense to go for the narrow belt conversion and alternator, and glad too I am having just seen the prices for the kit.

 

Dave

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Hi Dave,

most people do not go overboard with the lagging or even none at all. This is OK with a dynamo as it is all mechanical.

 

However all the electronics are stuffed in the back of an alternator. These are very heat sensitive devices and will cook.

Even the skimpy plastic cover will melt.

 

The tubular manifold makes things worse.

 

A simple heatshield will save a lot of grief.

 

Roger

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Hello all

 

B (trolleybus) did your Holden pulley fit straight on without any modification? (Apart from the spacer) What did you do about your water pump pulley?

Would you recommend a second hand crank pulley - I guess that is all that would be available. What exactly is a Holden red motor? I read somewhere that the rubber perishes and the pulleys delaminate when they get beyond a certain age. What do you think?

 

Ian, is a simple sheet of steel sufficient as a heat shield for an alternator? I envisaged having to use a composite material, say an asbestosy type of stuff sandwiched between two sheets of steel, because I thought steel sheet on its own would radiate enough heat to cook the elactronics. Did you use the stock TR7 pulley?

 

My tubular manifold is mild steel. I bought it at a register auction ran by the southern group when Ian Evans was group leader in the late seventies. I have the name of the chap that made it in my notes somewhere, I shall look it up. His manifolds were very highly thought of I remember. I had a coating applied by HPC coatings in Auckland which is supposed to help prevent heat loss, radiation, whatever. The manifolds look fantastic, a bit of rust pitting shows but that can't be helped. They fit the cylinder heat absolutely perfectly, no bashing or bending needed with them at all. Unfortunately my rebuilt starter motor packed up a couple of months ago, which is where this whole saga began. To get it off the car I had to remove the entire exhaust system to get the tubular manifold off so the starter could come out. Inlet manifolds, carbs off too of course, and cooling system drained. Reason for the stater failure? The chap who did the rebuild didn't do up the screws that held the new field coils in and they were rubbing on the armature. The commutator needed skimming too cause he hadn't done that either.

 

http://www.hpcoatings.co.nz/

 

I'm off to bed now

 

Cheers, Tony

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Tony

As I said earlier in the thread I fitted a damped pulley thin belt kit.

I had this kit for sometime before I fitted it. When I got round to fitting the pulley I was surprised to find that the spigot of the damper, the bit that goes into the oil seal, was a thin walled annulus made even thinner by the the tapered lead in to help entry through the seal.

This meant that the "nose" of the pulley is nearly a knife edge and in my view would not be able to transmit any vibrational torque into the pulley from the crankshaft. My question to Moss was why make it like that rather than flat nosed and solid. Then I was informed that it was modified from another existing design. MGB?

Any way I wanted some thing to drive the water pump and alternator so after machining the alternator pulley face to get everything in line I tightened everything up and it has been running fine for some three years.

IMHO There are two hopes of this design providing significant torsional vibration damping in the TR application - no hope and Bob Hope.

Regards

Rog

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Hi Tony,

a simple bent sheet of mild steel or Ali will do fine.

 

Roger

Thanks Roger

 

Rog - what you say is interesting because tr enterprises clearly state on their web page crank damper, "manufacturer, TR enterprises"

A bit of a porky if they then refer you to Moss as their supplier. The way I see it is that the spacer, sleeve, whatever you want to call it is simply something to fill up the empty space, if you will, for the oil seal to run on. It slips over the damper boss, not inside it. Therefore the bore of the damper is still in direct contact with, and hopefully a good fit on, the crankshaft nose. The damper is still driven by a, hopefully, good fitting key and key way. Vibration should still, therefore, be passed directly to the damper. I can't see how the sleeve for the oil seal interferes with this. Perhaps I am missing something.

 

I can't see how one can prove definitively whether the damper works or not. Pete T noticed a significant improvement in smoothness and reduction of vibration. To me this provides solid evidence pointing towards the device working. If that is the only parameter he changed (apart from a water pump pulley and alternator, which no one has ever said to affect engine vibration) then the improvements have to be due to the damper. Everything else seems to be opinion, well informed or not.

 

The "simple tensile failures" to which Roger H refers may or may not be simple IMHO. I'm not sure what constitutes a simple tensile failure. Is a metallurgist able to tell from the grain structure in the fracture whether the break was caused by simple stress fatigue, or by a harmonic vibrational or torsionally induced stress? I don't know, perhaps Roger H does. If you can elaborate on it Roger I for one would be very interested to here more about it.

 

The fact of the situation is that all this dithering about is keeping my car of the road for which I am getting a tiny bit of grief from the wife. I need to make a decision based upon the evidence in front of me. Pete T has supplied one good piece of evidence for. No one has suggested it might do any harm. The prices of the damped and undamped kits are so similar as to not come into the equation (assuming I've not cocked up the prices again). The natural conclusion must therefore be to go with the damped kit. Life is too short for me now to want to fluff around trying to adapt other parts, I do enough of that on my land rovers. I want to drive my Triumph. At the moment it's just one vehicle too many in bits. Having said all that other people's experience and advice is still more than welcome.

 

I am enjoying this discussion with you all. Thanks, Tony

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Tony

I purchased mine from the TR Shop London who referred me to Moss, not from TR Enterprises, whose kit may well be different.

Whilst I fitted mine a good few years ago and time dims he memory I had the view at the time that the design was compromised even when compared with original. If I remember correctly the original ST pulley "nose" has an outside diameter that fits the seal and and an inside diameter that is a clearance on the bolts thread. My thinking was when the bolt is tightened the end face is compressed onto the crankshaft nose and it is this face to face joint which largely drives the pulley rather than the key, whose primary function is to time the TDC mark on the pulley to the crankshaft, rather than transmitting significant torque. My thinking may have been flawed but I bolted everything up and thought along the lines of what harm can it do, life's too short, let's stop dithering and it's been fine, probably no better than an undamped pulley but no worse either.

Hope the job goes well

Rog

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Tony

 

perhaps save your self some money and earache, the verdict is still out. I know of one very reputable Retorer/engine builder who does not use them. His opinion is much as Rogers.

 

Iain

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Sorry Rog, I got confused with Pete T who got his parts from TR enterprises, and he noticed the improvement. The picture on their web page looks like the item is the same as moss's, but that doesn't mean that they don't make it themselves, I'd be surprised though.

I see what you mean but personally I am still of the opinion that the key takes the thrust. If it does not then why put a key and key way in the water pump and many other belt driven devices for that matter that don't need timing. Even taper shafts have keys, and a taper is a good way of locking a shaft and pulley together, much better than a parallel shaft.

You are right though Rog, life's too short, it can't hurt and you need something to run a thin belt on so why not this.

 

Iain, if I'm going to run a thin belt it looks like I've got to spend something! But yes, all forums have one thing in common, you ask a question and end up more confused than before, ear ache, brain ache, but it doesn't stop us asking does it! Nice apple green(?) TR by the way.

 

Cheers everyone, Tony

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B (trolleybus) did your Holden pulley fit straight on without any modification? (Apart from the spacer)

Yes

What did you do about your water pump pulley?

Oops forgot about the water pump. I found a pressed metal one form a Mazda, then had the old channel turned off the body of the old pulley and fitted the new bit with screws. I seem to remember that this is all in the Australian TR Register's 'Technical Tips Books' and they recommend using the pulley from a Triumph 2000/2500.

Would you recommend a second hand crank pulley - I guess that is all that would be available. What exactly is a Holden red motor?

Holdens came out in the 50s with a grey motor some time later they changed to a red motor early seventies(?)

I would get an old Holden one and have it rebuilt.

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