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Thrust washers
https://ausmini.com/forums/viewtopic.php?f=2&t=95083		 Page 1 of 2
Author:  carter [ Wed Mar 22, 2017 2:54 pm ]
Post subject:  Thrust washers
G'day guys and girls! I am currently in the process of rebuilding a 1275. The thing is I am putting a Cooper s crank in an 1100 s block I read somewhere, which I now cannot find, that 15 thou needed to be taken off standard thrust washers for it to work. So I have just picked up my thrust washers from the mechanic and he took 7.5 thou off each which would equal 15 thou. I have just started assembly and there is no end float at all...... was he suppose to take 15 of each washer which would equal 30 all up? This is what I am thinking which means I need to take them back to the mechanics.... which is in a different town :s
Author:  justfanginaround [ Wed Mar 22, 2017 4:24 pm ]
Post subject:  Re: Thrust washers
I thought it was +30's when using 1100's in cooper s block so I assume it would be the opposite going the other way
Author:  drmini in aust [ Wed Mar 22, 2017 5:30 pm ]
Post subject:  Re: Thrust washers
I run an S crank in an 1100S block, standard washers need approximately .015" taken off each washer.
Centre main web on an S block is 1/32" narrower than all other 1275 blocks.
Why??? No idea, except this makes the S crank webs 1/64" thicker, so it's stronger.
Author:  GR [ Thu Mar 23, 2017 6:47 am ]
Post subject:  Re: Thrust washers
Hi Kev
Other way round 1100S have thicker webs.
Graham Russell
Author:  drmini in aust [ Thu Mar 23, 2017 7:00 am ]
Post subject:  Re: Thrust washers
GR wrote:
Hi Kev
Other way round 1100S have thicker webs.
Graham Russell


Big journal 1100S crank webs yeah I agree, because their conrods are narrower width.
Not so with small journal 1100S cranks which use S rods..
Author:  carter [ Thu Mar 23, 2017 4:39 pm ]
Post subject:  Re: Thrust washers
Well I took them to a mechanic to have ground down.i said I wanted 15thou off so he rang me back and said was that total so 7.5 thou off each to which he had done. I tested this and could only just get the 2 bottom washers in not the top and sliced my thumb open in the process. So I rang him and told him it was 15thou off each not 7.5. Just tried fitting them and I have 45 thou end float according to my dial indicator! So something's gone wrong.....really hoping to hurry up and get this built but things aren't looking good :(
Author:  Phil 850 [ Thu Mar 23, 2017 8:20 pm ]
Post subject:  Re: Thrust washers
So if he already took 7.5 thou of and you told him you wanted 15 thou of, not 7.5.
I suspect he did what you said and took 15 thou off. Unfortunately they already had 7.5 thou off.
So the original 15 thou plus another 15 thou off each = 45 thou.

Looks like a simple communication error to me !
Author:  i got a mini [ Thu Mar 23, 2017 8:36 pm ]
Post subject:  Re: Thrust washers
yep will need some more thrust washers and start again sadly
Author:  carter [ Fri Mar 24, 2017 3:06 pm ]
Post subject:  Re: Thrust washers
Well I was just on the phone to the mechanic and guess what the problem is I have a dial indicator that's measures in mm not inches! So I have double checked and I have 0.4 which equals nearly 16 thou...... so I need new ones and not as much taken off so instead of 15thou taken off I need 8 thou taken off each washer....... correct?
Author:  drmini in aust [ Fri Mar 24, 2017 6:00 pm ]
Post subject:  Re: Thrust washers
Make sure it has at least .005" end float. The .003" in the books is NOT enough if you are going to rev past 6000.
I found this out the hard way. Oil pressure went South after 3 laps at Wakefield Park running .003". I now use .007".

Edit-
the crank webs flex and tear the bronze off the washers if too tight.
Author:  carter [ Fri Mar 24, 2017 6:06 pm ]
Post subject:  Re: Thrust washers
What happenes if youa have too much end float?
Author:  drmini in aust [ Fri Mar 24, 2017 8:10 pm ]
Post subject:  Re: Thrust washers
Way too much, and they fall out.
I'd replace them once you get to .015", but that's nowhere near what's needed to drop one. Measure the step in the thrust face on cap or block. Get to that and they're gone.
Author:  carter [ Fri Mar 24, 2017 9:24 pm ]
Post subject:  Re: Thrust washers
No worries thanks doc for your input once again. I will get my bro to pick me up a new set at mini King tomorrow and get them ground with less taken off this time. So instead of 15 I'll get 7 or 8 thou off each. Cheers
Author:  carter [ Thu Mar 30, 2017 5:06 pm ]
Post subject:  Re: Thrust washers
So went to build my motor and I didn't realise I need s rods as well because I have changed the crank. I already have my new pistons pushed onto 1100s rods....
Author:  Morbo28 [ Thu Mar 30, 2017 8:02 pm ]
Post subject:  Re: Thrust washers
Ergh. God that sucks. Ah well, live and learn, keep on going and chalk it up to experience :)
(Yeah I didn't expect that to make you feel better, but in 3 months time it'll just be another war story about rebuilding the engine :) )

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