Machined Crank Pulleys with 36-1 pattern (MegaJolt etc)
Turbo Mini Forums

These pulleys are now available.




They allow you to use a crank sensor with your standard crank pulley, for ignition injection etc. The missing notch is machined at true TDC on the pulley. The sensor can then conveniently be positioned at 90degrees BTDC, this works out well on our A series engines. If you require the notch in a different place this can be done.

In addition, the pulleys can either be supplied machined with notches and balance details supplied, or machined with notches and returned to standard spec balance for you. This is at no extra cost.

The cost for this is £35 incl return postage. This is the price to machine a pulley that you supply.

Any genuine enquiries please use the PM system so as to not clutter this thread up if possible.

Anyone who has had one of these machined via myself please feel free to make any comments or suggestions for possible improvements......

Edited by Tom Fenton on 25th Aug, 2007.

I can vouch for the quality of the machining. That's my pulley on top!

Well done Tom.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

ok, i'm ready to be shot down in flames, but when i enquired with Avonbar about machining the pulley, i was told it wasnt a good idea as the pulley is rubber damped and thus would cause slight variations in timing, that have any validity?

Yes it does but nothing to worry about. +/- 2 degrees at most i'd say.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

is there a chance that it would slip permanently or does it always 'bounce back'?

Its rubber... it bounces back.

If it didnt the pulley would fall apart.

Remember the only time the rubber will twist is on acceleration and deceleration, so most of the time it will be fine.

Alex

AlexF

k, might got one, will see how this MED wheel performs like first.

The pulley damps out torsional vibrations. That is minute changes is speed through a single revolution.

I doubt if the position of the missing tooth varies more than 0.5 degree at the point that it is timing the ignition.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

On the STD Damper 1 degree is equal to a nats ass over 1mm so it would have to move this much to change by a degree in either direction.

Std Damper = 380mm / 360 degrees = 1.05mm per degree.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

The rubber is about 4mm thick and 'kin stiff.

It is very unlikley to move any more than 0.5mm, if that.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I also suspect it's 0.5 degrees max in either direction - but that is 1 degree overall.

To be honest, if you're running so close to the edge that this could make a difference, then you're a fool anyway. A dizzy has a lot more scatter.
I've never seen one of these 'fluid dampers' I hear about in the V8 world (Doody - any pointers?) but it'd probably be a bad idea machining it into them...

Not 100% sure how they work but from what i gather it an oil based fluid with a floating ring sealed into the damper.

The NON fluid ones I've used and rebuilt have an inner and outer ring separated by large rubber o'rings. Very similar to the A-Series but fully serviceable.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

The machining on my pulley is to a very high standard and a quick turn around to! thanks Tom

PS. Cant wait for the sensor bracket now!

Cheers guys. I'll keep you updated.....

received mine today, wahoo. it looks very good.

thanks tom and his mate

no longer a series, but still 1.3 turbo.

I know a few of you are very keen to hear of any progress on the sensor brackets I keep threatening to make to accompany these pulleys.

So here are some prototype pictures. There are a few mods to be made to this bracket before it is ready for production but I thought this might whet some appetites..........

Good work, Tom.

Having made my own a couple of weeks ago, I suggest that you check that the fan belt does not foul it like mine did!

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Looks great Tom, def put me down for one when they are in production.

Cool Tom, nice looking bracket!

Please put me down for one.

Mk 2 of the crank sensor bracket-





Now has mount to secure sensor, altered strut locations for better clearance, and cranked baseplate to fit timing cover better.

are these for sale yet tom if not when will they be ready for sale,

cheers
carl

no longer a series, but still 1.3 turbo.

Hoping they will be ready for general sale in the next 2 or 3 weeks. Need to get the parts together (such as longer bolts, etc) to go with them.

very neat job tom!

Team www.sheepspeed.com Racing

I can't take much of the credit really, these have been made by the Spannerbitch-Racing stig, my tame fabricator/machinist mate, never to be seen without a welding mask or a pint of cutting oil......


The same guy who machines the pulleys.

Put my name down for the trigger wheel and sensor mount

I donated, but somehow didn't get the label! :(