Pulley fitment..suggestions please?
Turbo Mini Forums

The problem ive got is that the crank has a dia of 25.4mm and the bore of the pulley is 28mm, leaving a small gap. have you got any suggestions of how I could get one to fit the other?

Ive thought about making a sleeve, then cutting a key that fits into the crank through the adaptor/sleeve then into the pulley, but not sure how strong this would be as the key would would fairly 'tall' (best way I can think of describing it!) , any ideas?

Here's a pic.



Its the last damn pulley I need to fit and i just cant think of a good reliable way of fitting it?

Any suggestions guys?

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1/4mile in 13.2sec @ 111 terminal on 15psi

How much would it cost to get one machined up that does fit?

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Not sure....its not a standard pitch for the profile so many companies have said they won't do it!!

Ive spent £40 on this one, so hoping to get it to fit. I was hoping that when I ordered it it would have a smaller bore size than the crank so I could just bore it out and put a keyway in it....I should of know it wasn't gonna be that easy...Lol

It can be done, as TurboHarry has done it, just can't get in touch to find out how?

Edited by matty on 10th Aug, 2007.

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1/4mile in 13.2sec @ 111 terminal on 15psi

I would take the std crank pulley (chain one , machine it to make a good press fit into your crank pulley, (even if need to bore it a little more (belt pulley), then point weld it (to avoid overheating)

Friday afternoon comment - Chemical metal?

Being serious where did you get the pulleys from?

Good luck
M

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1/4mile in 13.2sec @ 111 terminal on 15psi

Build up th crank dia with insulating tape

Paul

I seriously doubt it!

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1/4mile in 13.2sec @ 111 terminal on 15psi

the welds will be a pain to turn ,cannot you make a V on both side and carrefuly weld inside, if it does protude it will be easier to turn, you don't need to make full weld, just 6 points , this is why you need a good pressfit

Trouble with a high press-fit is that these are likely Powder-metal parts - and the more you machine out the bore, the reduced section remaining of the low-strength material.
A high press fit will add significant hoop stresses into the remaining material - which could promote failure.

Not saying it will - but it's of concern to me.

Just to add another dimension to this(quite literally) 12mm of the pulley is going to have a 40mm bore!!

Edited by matty on 10th Aug, 2007.

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1/4mile in 13.2sec @ 111 terminal on 15psi

cant you just bush it, weld the bush in place and then machine the key way? seems quite simple.

I was thinking of something like this, but not sure on how strong it would be as the key would be holding three parts together?

Edited by matty on 10th Aug, 2007.

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1/4mile in 13.2sec @ 111 terminal on 15psi

i cant see that being a problem or have the bush even bigger. there may be some load on the pulley that concerns people but it drives a rubber belt, how much stress can the belt take compared to a metal pulley?

how about using bearing fit glue stuff and drilling and taping down at the sleeve to pully joint and fitting a (or more) coutersunk screw.

I think I know what you mean. So the screw is half and half in the pulley and sleeve?

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1/4mile in 13.2sec @ 111 terminal on 15psi

i'm not going to comment much as i have'nt the technical knowledge but is'nt the standard crank damper pulley with rubber in a,

crank, sleeve, key & pulley setup, i'm 99.5% mine is a machined sleeve in the middle!!!!! so no differance to your diagram/idea above matty, OE quality is'nt the worst to copy in what ya doing!

thats my 1/2 pennys worth :)

Edited by clubminiflip on 10th Aug, 2007.

SKYLINES ARE LIKE CLITS, EVERY FLANGE SEEMS TO HAVE ONE: see this sticker on my silvia

the Search-section on this forum is blummin superb & simple to use, unlike some other forums, without the search-section & the help of this bunch of chaps on here i'll never be able to !!!Start the day with a 998cc turbo!!! :) i'm getting closer though!

Tom Fenton says: I have it all, make me an offer

MM, this was one reason I chose the Fiesta 1.25 pullies.

The fiesta pullies are 36 and 18 toth respectively, Rather than the Honda pullies 34 and 17. The crank pulley has a diameter of 25mm only needing a flash off the center bore and keyway machining, also has a belt guide spot welded to it on one side.

Bummer was trying to find ally vernier pullies in 38 tooth in the same profile, I eventualy found some in the US, funily enough off a Honda.

Incidently the Honda and Fiesta pulies use the same HTDA 9.525 belt profile.

I think Jimster uses the Honda pullies, but i think he went about the crank and jackshaft pullies the easy way, the puff

Personaly, i would sleave the pulley, use bearing fit to retain it. Looking at it the Crank damper would still clamp the pulley so you are only really ensuring that the pulley is running true on the crank.

Sprox - are the fiesta (cam) pulleys larger than the Honda ones then?

yep thats what i mean, kinda like a key. I think oodles of bearing fit is a good idea though!

Dave, i just read what i typed earlier and realised what i said wrong, sorry my mistake. The center bore of the crank pulley is only about 25mm, the tail of the crank is 1" so, the bore of the pulley only needs machining out a midges dick and a keyway to locate it.

By nature of there being an extra tooth on the fiesta pulley over the honda pulley, yes the diameter is larger, but not by much, obviously the cam pulley has an extra teeth.

Working back, the belt profile is 9.525 pitch so 34 x 9.525 = 323.85mm circumferance, thats 103.084mm diameter. 36 x 9.525 = 342.9mm circumferance, and 109.148mm diameter, a difference of just over 6mm diameter.

The crank pulley is half that so 3mm difference in dimeter, not much in it and more belt in contact where its needed