Crank end float
Turbo Mini Forums

got 0.010 mm
Book says between 0.005 ish and 0.0075ish
Thrusts are used standard ones so guess no bedding in to go.
Life expectancy of engine probably about 5000 miles, would you use these or just buy new and get to within the book tollerance?
Money not a problem it just doesn't feel like a massive ammount of play! Not sure im happy going tighter with an engine thats gonna be ragged from day 1!
On a grey plate btw.
Cheers

Ok you have a couple of options,

first off have you knocked back the letter stamping on the rear of the thrusts? if not give the backs a go on a bit of wet&dry just a couple of mins each to lose any high spots from the stamping.

Also I always mic them up and pair the closest ones,

for road builds I aim for 2 thou, for somthing thats going to get reved a lot personally i'd say 3-4 thou,

You could get a set of +3 thrusts and just use half of them which should take it from 4 thou to 2.5 thou,

I think i'd go with you have TBH

Oh and sorry I', working in thou, heres the equivlents

0.1 =4 thou
.075 = 3 thou
.05 =2 thou

edited to be right!

Edited by Joe C on 10th Dec, 2009.

0.01mm is 0.4 thou isn't it?

Thats what I thought.

I think there are one too many 0's in mini13's post

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

hmm...

i used an online calculator.... and it lied!

i thought it looked wrong...

Edited by Joe C on 10th Dec, 2009.

0.10mm is on the high side. I would not use this, especially with a hard clutch spring.

Never thought of mixing pairs to make it right!!!! Or thinning them down!!!
Got some fairly thick ones kicking about i think, by the end of the eve i will have a perfect 2.5 thou.
Cheers chaps.

1mm equals 0.03937"
therefore one tenth of 1mm equals 0,003937or 3.9 thou.

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maybe not, they take ages to thin down!

i'd say the most you can take of the back is about 2 thou before your hand falls off. it'd be a bastard keeping them a uniform thickness too.

I have mine done in a surface grinder. The only way do do it right.

Well got it to 0.08mm using what i have and think im gonna go with it for now.
Think i'll get some oversize for the future though.

The search function threw up this thread so rather than start a new one....
I've started building the engine for the MM. Got the bits back from the machine shop, put the crank in, fitted new thrust washers and I've got no end float what-so-ever.
I've run the backs over the wet and dry (as mentioned above) and while they now fit in easier, still no end float.
Is it just a case of keep on going with the wetndry? Can you buy thinner thrust washers?
Foolishly I got rid of the old ones when I had a clear out

Measure them and tell us how thick they are just in case you've got some oversize or just badly made ones.

Did the machine shop do anything to the mains - check there are no burs or dings from mishandling that are stopping the thrusts from sitting flat.

Check the cap is on the right way (Sorry if that sounds obvious).

If it all checks out ok, IMO it's possible to thin the thrusts down as long as you have a micrometer and take lots of measurements, good technique and shit loads of patience. I'd look at other options first, especially if you've not done anything similar before.

does it spin without the thrusts in... ie its not the mains nipping up so the crank wont move to give end float?

Phil, I have two sets. One measured 2.4mm, the other a little bit less.
After cleaning up the slightly thinner one it measures just over 2.3mm.
I also ran a carborundum stick over the machined surfaces that hold the thrusts to make sure there wasn't any burrs. (Idid clean everything up after).
I phoned Green & White up (who I get most of my bits from) and they said they'd come across this before. Seems the new thrusts can vary in thickness a bit. They sent me a single set that had been thinned down by 2 thou on the rear face..
Putting these in tonight with the 'best' pair that I'd cleaned up I get 0.035mm (not quite 1.5 thou according to Google).
So is this enough, or should I keep going with my cleaned up set until I get to a couple of thou or so?
Joe - should've added, yes spins freely enough with no thrusts in.
Cheers,

Edited by Cooper1999 on 1st Oct, 2015.

1.5 thou is too tight in my opinion. I always aim for 3 thou. With a too tighter clearance you could run the risk of oil starvation on the thrust faces.

i always start off by pairing the thrusts up so they are matched pairs, stone off the stamping, and make sure the backs are completely flat, and mic them up in 3 places to make sure they are uniform thickness. Then fit one half on each side and check endfloat, then put the second half in and check again. Any difference in endfloat you know the crank is thrusting biased to one half.

I would always make sure both halves of the thrusts are working together to spread the loading equally over the largest area possible.

When I fitted my crank, the endfloat was about 8thou so I ended up buying two sets and surface ground the oversized set down the give the correct end-float.

If you don't have acces to a surface grinder, and you only need to take a thou or so off then, use some Emory stuck down to something flat and rub it down on that.

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

5 thou achieved - is that now too much?
To be honest I didn't think I'd taken that much off (by that I mean I've still got some skin left on my fingers)!

id guess that nearly dubble what matty trys for might be a bit lose

when i asked the shop what to set mine at i was told 1.5 times the mains 1.5-2 mains 2.25-3 thrust was told loose was better in case the crank gets the twisties going from a missed gear shit it might not grab a bearing

take it for what you want i dont build engines for a job the other guys are a better choice for solid info