Crank grinding
Turbo Mini Forums

A daft crank grinding question. If the crank is ground 20 thou undersize is that 20 thou off each face or 10 thou off either side. I don't have anything to hand to measure.

I have been waiting six weeks for a crank Grind and now the bloke seems to think he can't do it. Hopefully taking it somewhere else tonight.

Cheers Ron

It's the diameter that counts, not the radius.

it makes the diameter 20 thou smaller
not sure i understand the 10 thou each side/ you mean like 10 thou all the way around
imagine the dotted line is the original and the solid line the 20 thou undersized

Yes i moved to the darkside

Instagram @jdm_brett

Definately take it somewhere that knows what they are doing with it Ron.

If something is worth doing, it's worth doing half of.

Sorry I was supposed to say on the thrust faces.

You are going to struggle to get oversize thrust bearings to suit.

They only come in +3 thou and +30 thou.

Niether on which will suit a 10thou or 20thou regrind, oh and the +30 thou are like rocking horse shit.

Edited by 01smartc on 14th Apr, 2010.

you will need t get 30 thou bearings and surface grind them to the correct thickness

Team Racing

Do you have to take material off both surfaces Jim? I would imagine that the bearing material is only so thick?

If something is worth doing, it's worth doing half of.

No they dont

Moss do +0.005"

You can mix and match the over size thrusts, as one side is only half of the stated total oversive. For example, a +0.003" thrust set will give +0.015" if you use one side along with STD thrusts on the other side.

So using a combination of all the available thrusts you should have a selection available similar to the below

0.0015
0.0025
0.003
0.004
0.005
0.015
0.0165
0.0175
0.030

Edited by Sprocket on 14th Apr, 2010.

I assume you can also achieve 0.0025" by using half of a +0.05" set?

Yep, true :)

Ron, is rthew crank hardened, if not ive simply turned a new face on nice and steady, if hardened i can use ceramic inserts to do that too,


carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Edited by Sprocket on 7th Oct, 2010.

ah ,i tought it was a typo ,thanks colin.

Edited by robert on 14th Apr, 2010.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I thought I had it right in my head and the chap that was doing it was wrong in what he was trying to say!

Carl I have found somewhere local that should be able to sort it for me, but if they can't I will let you know!

Cheers Ron

Edited by mowog on 15th Apr, 2010.

We've had the same problem recently.

Carl has machined the thrust face for us. It took 0.005" to get it clean again.

And the point of my post...

Moss had std and +0.005" thrust but they where expensive.

Minits had std, +0.003", +0.005 and +0.030 and where much more reasonably priced. I rang up at 12.00 on a Saturday and sorted it. Rang back at 12.30 to add to the order, but it was already on it's way to the post office

On 14th Apr, 2010 Vegard said:

On 14th Apr, 2010 John said:
Do you have to take material off both surfaces Jim? I would imagine that the bearing material is only so thick?

The bearing material is very thin. Ask me how I know

If you know someone with a surface grider with a magnetic table, grinding these down are a piece of cake.

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

CLOWN!!.lol

On 7th Oct, 2010 Sprocket said:

On 14th Apr, 2010 Sprocket said:

On 14th Apr, 2010 robert said:

On 14th Apr, 2010 Sprocket said:
No they dont

Moss do +0.005"

You can mix and match the over size thrusts, as one side is only half of the stated total oversive. For example, a +0.003" thrust set will give +0.015" if you use one side along with STD thrusts on the other side.

So using a combination of all the available thrusts you should have a selection available similar to the below

0.0015
0.0025
0.003
0.004
0.005
0.015
0.0165
0.0175
0.030

For example, a +0.003" thrust set will give +0.015" if you use one side along with STD thrusts on the other side.


im probably being really thick but ...do you mean +0.0015 here colin ?


and how do you get all those other options from a choice of 3,5,and 30 thou over ?

Yes Robert that is a typo.

You can achive all those sizes by mixing the different sizes per side. Going back to my original example (without the obvious mistake) standard thrusts on one side and '+0.003" on the other side is an increase of only 0.0015", it is half of the +0.003" set as you only get +0.003" with the complete set of +0.003" thrusts.

I thought this was common knowledge?

This is all bollox, and totally wrong!!

Sorry chaps

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

What can I say

well, I will say this. If you buy a set of +0.010 main bearings, its +0.010 on the full set. If you buy +0.030 thrusts, its +0.060" on the full set!! WTF is that all about. It says +0.030" on the packet, you get four thrusts, two bottom two top, but its +0.060" and not +0.030". So if you only wanted +0.030", you need to buy a standard set AND the +0.030" and use half of each set!

I rest my case