E-Bay crank pulley

[DodgyRog]

Is this a stupid idea:blink:

 

It would be a short term fix until the summer at the latest, just to give me a bit of time to save up a bit more cash, instead of loading the credit card.

 

http://cgi.ebay.co.uk/Toyota-Supra-Lexus-CS-GS300-RX300-Engine-Crank-Pulley_W0QQitemZ350121813937QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item350121813937&_trksid=p3286.c0.m14&_trkparms=72%3A1301%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

[AlanM]

I wouldn't, damping is there for a reason

[DodgyRog]

I wouldn't, damping is there for a reason

 

 

I was just hoping really:innocent:

[DodgyRog]

I guess that answer my own question........

 

Cranktrain vibration comes in more than one flavour. First of all consider the crankshaft as a watch spring, oscillating back and forth (but generally turning in one direction). This is torsional vibration. Secondly, consider the crank as the ruler from earlier on. Except this time instead of a single desk edge as a support we have a series of supports in the form of the main crank bearings. Also, instead of a single energy input we have all four strokes of the four stroke cycle all acting at different places along the crank in different degrees at different times. These forces can cause the crank to bend along its length. This makes for a very complex system (both in torsion and bending) but it will still exhibit resonances in both.

 

However, resonance can work for us, and this finally brings us to the purpose of the crank damper.

 

The torsional vibration damper (TVD) consists of a mass of a known intertia which is attached to the crankshaft via a piece of rubber of a known stiffness. The mass can spring torsionally around the crank centreline. The inertia of the mass and the stiffness of the rubber are precisely tuned so as to go into resonance in an equal and opposite manner to that of the cranktrain. Therefore they cancel each other out.

 

A bending damper has a mass which is added to the end of the crankshaft via another piece of rubber. This type of damper nods up and down and cancels out bending vibrations along the crankshaft.

 

These masses, for convenience, are usually added to the front crank pulley.

 

Pros:

The most common reason to remove the damper is to reduce weight to lighten the car, or to reduce inertia to make the engine rev more freely (inertia by definition resists changes in rotational speed). However to do this you have to sacrifice the damping actions of the stock pulley. You cannot retain the same damping effects and reduce the mass at the same time. This is akin to having your wheels balanced using stick on balance masses, and then binning them and replacing them with lighter masses. The wheel will obviously go out of balance again. Likewise if you remove the damping pulley, the crankshaft will go into resonance.

 

In short – it revs up a bit quicker and the engine has marginally less rotating mass to move.

 

Cons:

As mentioned above it can be as little as noise and vibration or as severe as total crankshaft failure through fatigue. Fatigue is the failure of a part through repeated application of loads which are far smaller than those which would cause failure in a single application. These are most severe when the loads are reversing or alternating (like bending a paperclip back and forth). This sits nicely with the kind of vibration seen in undamped cranktrain systems.

 

In short – your crankshaft could eventually break.

 

 

Note to self do proper search before posting

[Chris Wilson]

Overload the card, better and potentially a lot cheaper than overloading the crank. Removing inertia does NOT give more BHP, the advertiser's obviously clueless or a charlatan.

[DodgyRog]

Overload the card, better and potentially a lot cheaper than overloading the crank. Removing inertia does NOT give more BHP, the advertiser's obviously clueless or a charlatan.

 

Thanks Chris, to be honest the supposed HP gain was of no interest, just trying to save the pennies, but obviously a false economy as usual:rolleyes:

[matt k]

Thanks Chris, to be honest the supposed HP gain was of no interest, just trying to save the pennies, but obviously a false economy as usual:rolleyes:

 

I got a stock one from Paul Whiffin..much cheaper than main dealer prices as well.

[DodgyRog]

I got a stock one from Paul Whiffin..much cheaper than main dealer prices as well.

 

Thanks for that Matt

 

£161 inc vat:D

 

http://garagewhifbitz.co.uk/index.php?option=com_virtuemart&page=shop.product_details&flypage=flypage.tpl&category_id=2335&product_id=8238&Itemid=53&vmcchk=1&Itemid=53

[SupraDave99]

WOOHOO!!

 

Thankyou guys so much! I have been searching for this part all weekend.

I created a thread.. Crankshaft Pulley... Any Ideas?

This will explain the problem i have had.

Anyway, I am doing the work myself and I had a real nightmare getting the old one off but now i know how Its not so bad. Prompted a cam belt change too which was good.

Now all i need is a radiator cooling fan which the crankshaft pulley destroyed and im rocking and rolling!

 

Thanks again!

 

1993 Silver N/a JZA-80 70k

[gsportcars]

Older 2jz engines do not have the crank dampners. I don't see the immediate need but I do realise the difference in having it in place.

Higher RPM's obviously require the dampner to be safe but at a factory or near factory state of tune I could not see any problems occuring on a temporary basis.

My opinion....