alloy pulleys

Who do I see about becoming a trader ?

 

 

Cheers

Mawby

id be interested if these are any good.

how much lighter would the whole pully set be?

It's not just a case of inserting a rubber ring between the hub and outer ring. This rubber has to be of the correct specification, including hardness, in order to acheive the correct frequency. If the damper does not act correctly, then the (undamped) torsional vibration within the crank system can break the crank (or camsahft).

Note the word "can", not "will":)

I Have pm'd Mawby so I better not say anymore incase I get told off..

cheers

So this would be an exact replica of the stock crank pully but made with alloy? I might be interested, but I think you should PM Mawby to get traders/hobbyist licence thing, or he might tell you off

 

What are other peoples thought on these if they're made with rubber inbetween like the stock one? Mr Wilson?

Flukey, it can't be an exact replica.

It's reduced weight dictates that. The mass of the damper, as part of the system, factors into the correct hardness of the rubber used.

If you change the mass, you change the system and therefore should revisit the frequency.

This takes testing, usually of a variety of different hardness rubbers (keeping the hub and ring constant) to acheive an acceptable level of damping.

I have spoke to Mawby ,

I will become a trader but have to wait three months so I can get known by everyone before I start which is fair enough, Like I said to him I understand they would only like hign standard of traders on here ...

Also does give me plenty of time to get some performance pulleys in and see how they are made...

If anyone would like to ask me any engineering questions please feel free ,

Look forward to getting to know everyone and start a good relationship here .. as I have on scoobynet

Cheers chris

hi chris i have dropped you a PM

didnt get your pm .. I had a full inbox

cheers

sent it again thanks.

mat

Chris, looking at cdfracing.co.uk you are selling the full Supra set for £300, but they are stated as being underdrive i.e. smaller, and needing a new belt; as opposed to the above where you state that a full set is £180 and is stock size. I'm confused!

I've also been doing a spot of reading up recently regarding 6-cylinder engines - the rubber dampener on the stock crank pulley is not to cancel out vibrations, but dampen the torsional movement. Due to the length of the crankshaft in the inline 2JZ engines, and the firing sequence, the shaft suffers a kind of 'coiled spring' effect after each stroke. It is this that is dampened out with the stock pulley, and that which may cause crank failure in an undampened situation.

Apparently, the crank in an average i4 engine isn't really long enough to cause worry in this department (though I have read of oil pump failure on the gen7, atributed to additional vibration caused by 'underdrive' pulleys).

All my current (limited) grasp of the crank tech stuff gleaned from books and this site atm, but I'm getting there bit by bit

 

The reason the harmonic balancr is in the stock pulley is because it is bloody heavy and yes if it didn't have it inside it would vibrate like mad - I personaly think it isn't required in the ally pulleys,

 

But for piece of mind we can insert a rubber / plastic part to do the same job or even make the pulley out of two parts!

I'm afraid I'm taking the word of a powertrain engineer and his vast knowledge in designing these things for real (see FAQ entry) over the glib assurances of someone who knocks them up and sells them. I find your comment "But for piece of mind we can insert a rubber / plastic part to do the same job" rather naive and somewhat laughable.

Also, I've deleted your advert. Please speak to a supermod if you wish to apply for trader status or to provide a one-off group buy. Blatant adverts are not allowed in technical anyway, and pricing/supplier quotes are only allowed if specifically asked for by the thread starter.

-Ian

from what i understand the damping part of the damper is between the hub and the outer drive ring for the accessories,

Nope, it's for crank nodding.

See the crank pulley damper FAQ I linked to above.

the more i look into it, the less i find about actual evidence, of ``what the need`` is for the damped pulley.

Hopefully the FAQ entry will provide you with the evidence you need

Also I reiterate again the noticeable difference in the car is zero when a light fixed mass alloy underdrive pulley is fitted. So why chance the accelerated wear and possible crank fracture for precisely no gain?

-Ian

See the crank pulley damper FAQ I linked to above.

Ooh, I missed that one somehow Makes good reading

I'm afraid I'm taking the word of a powertrain engineer and his vast knowledge in designing these things for real (see FAQ entry) over the glib assurances of someone who knocks them up and sells them. I find your comment "But for piece of mind we can insert a rubber / plastic part to do the same job" rather naive and somewhat laughable.

 

Also, I've deleted your advert. Please speak to a supermod if you wish to apply for trader status or to provide a one-off group buy. Blatant adverts are not allowed in technical anyway, and pricing/supplier quotes are only allowed if specifically asked for by the thread starter.

 

-Ian

Hi,

I am very sorry by the words I choose .. It's not quite as simply as the way I put it . The rubber part pressed onto the pulley then ground .001" limit.

Yes thanks for deleting my post ... very kind of you after I said I wouldn't trade on here for three months after applying to be a trader ...

We are actually the biggest pulley and gear manufacture in the U.k , and if you think we are not good enough then that's fair enough .... Im sure you will look into my quote of being the biggest U.k manufacture and I look forward to your reply...

Chris

ok, so i understand the reasoning behind the addition of the damped pulley, but from the Questions ive put to my friend at TTE in germany who incidently is an engine /powertrain engineer for Toyota Motorsport, he has told me a few nuggets of infomation that need to be considered.

the damper pulley is designed to only work at low rpm of the crankshaft when the rotational mass doesnt automatically balance the crank, as the speed of the crank increases its mass will cancel out the vibrations, also, the damper will only be effective on a std engine, i.e no change in the designed mass of any of the componenets in the Engine or power train.

so if like me you have a lightweight flywheel, HKS multi plate clutch, different rods and pistons, then the damper is in effect, doing nothing, as the engine vibrations are now outside of the design parameters of the crank damper.

even a simple aftermarket clutch has enough difference to cancel out the crank damper

Hi,

 

I am very sorry by the words I choose .. It's not quite as simply as the way I put it . The rubber part pressed onto the pulley then ground .001" limit.

 

Yes thanks for deleting my post ... very kind of you after I said I wouldn't trade on here for three months after applying to be a trader ...

 

We are actually the biggest pulley and gear manufacture in the U.k , and if you think we are not good enough then that's fair enough .... Im sure you will look into my quote of being the biggest U.k manufacture and I look forward to your reply...

 

 

Chris

I'm sure you are. However your post was pulled for the reasons Ian stated. Advertsing in Tech on this forum is a big no no, albeit mistakenly I'm sure. Don't get me wrong, we welcome your technical input, it's always good to have a diverse base of knowledge and understanding. But it can be easily misconstrued when your first post on the forum is referring to your company and its' products. You have the option to edit your post if you so wish.