crank problem ?
Turbo Mini Forums

ok i am ready for a red face of embarassment here. I have put me pistons in the block and have put the crank on, I have not even torqued it down fully yet, and i cant get the crank to turn, iam using +10 shells it is as if they 8nt right, but they are the ones supplied by the folk that pollished the crank, i did notice that the thrusts were pretty tight, anyone any ideas ? i have plenty of lube on em. only thing i havnt done is take center strap off and turn it around, but this should not make a diff should it ?

______________________________________________________
TRADER HALL OF FAME
BENROSS...MINIMARK..WOLFIE (comic genius).....CARL....MARTPAUL.......AXEL
______________________________________________________
TRADERS OF SHAME
1 user....pm me 4 details

LEGENDS
MikeRace, Mini13

have you mixed the order or the bearing caps up or anything i did this and it made a difference.

have you heard of plastiguage? its like plastercine you put under the bearing cap and tighten it up.then you remove it and see how much it squishes.by the width of the squish of the plastercine you can compare this to a little chart you get with it and see if the clearence is right.

if you think its the thrusts leave them out and try it.

Edited by Carl on 30th Dec, 2006.

no longer a series, but still 1.3 turbo.

the mains are all matched i sent the center one away to get machined so i could put the strap mod on. and i stamped all my rods and endcaps prior to removal. Will pop out the thrusts, just wanted to ask before i pulled it to bits as all, if it turns out to be the thrusts i am at a loss of how i will sort it, i thought the thrusts were all one size.

Edited by Richie on 30th Dec, 2006.

______________________________________________________
TRADER HALL OF FAME
BENROSS...MINIMARK..WOLFIE (comic genius).....CARL....MARTPAUL.......AXEL
______________________________________________________
TRADERS OF SHAME
1 user....pm me 4 details

LEGENDS
MikeRace, Mini13

I'm sure someone else posted a similar question a while back (I'll have a search and see what I can come up with) but have you tried assembling the rotating assembly without the piston rings? I'm wandering if it could be an issue with the ring gap.

Found the thread I was thinking of:

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=11210

Hopefully it'll be of some help to you.

the compression ring / top ring have 13 thou clearence, i have tried taking the rods off the crank and pushing them up the bores, then trying the crank again, but there is no change

______________________________________________________
TRADER HALL OF FAME
BENROSS...MINIMARK..WOLFIE (comic genius).....CARL....MARTPAUL.......AXEL
______________________________________________________
TRADERS OF SHAME
1 user....pm me 4 details

LEGENDS
MikeRace, Mini13

have you had the crank ground to .010. or is it at standard.??

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

Sounds like you need to take a step back and think about it logicaly.

First check the bearings are the correct size for the crank
If they are ok then check that they are seated correctly into the caps/block, and that the caps are on in the right place/way round etc.!
Put it together without thrusts and check (or check the end float!)
If it dosent turn without thrusts take one cap off at a time and check if it frees it up.

Generally if you do that kind of thing you will narrow down the problem!

the crank was ground +10 and the shells were provided by the engineering firm to match the crank, i have already tried taking the thrusts out and still no difference, all shells seated correctly, and all caps etc are correct way and are the ones for the block so to be fair slater i have tried to narrow it down, hence why iam now scratching my head asking the lads if they can think of anything else.

______________________________________________________
TRADER HALL OF FAME
BENROSS...MINIMARK..WOLFIE (comic genius).....CARL....MARTPAUL.......AXEL
______________________________________________________
TRADERS OF SHAME
1 user....pm me 4 details

LEGENDS
MikeRace, Mini13

Hi,
Just because the shells were provided by the engineering co doesn't mean they're right. I twice had cranks ground and once they supplied the wrong thrusts the other time they ground the crank to some bizzare size that meant I had to use 1/2 a set of oversize thrusts to get it right. They also did Mini race engines, go figure....
Cheers,
Gavin :)

VEMs Authorised Installer / Re-seller. K head kits now available!

WB/EGT gauges. Click here for customers write-up

Visit www.doyouneedabrain.co.uk

My Mini build diary

I can only think off two possible options;

1) One or more of the caps is/are from a different engine.

Could the main caps have been mixed up with another set at any point? The guy who machined your centre strap could have sent you someone else's by mistake. Have you tried taking the centre cap off completely so the crank is only held in by the end caps? If it rotates freely with just the end caps it would suggest that they chap who machined you centre cap sent you the wrong one by mistake.

2) Either the shells are not +10 thou or the crank has not been ground +10 thou, normally a polish would only remove a few thou.

Have you got a mic? if so it might be worth measuring the journals to see if they are actually 10 thou under size. Also I think if should say +10 thou on the back on the journals (can someone confirm this)

I think Slater is right here, there is a bit more of an investigation needed.

When I build an engine I always do the following with the crank assembly;

1) fit block side shells in place, oil and lay the crank in place with no trusts. Check it has some end float and can turn (won't be the first person to have a crank ground out of line ........ nor the last!!!). just nip up the bolts, don't torque.

2) Starting from the nose end I fit the shell and main cap, does it still spin?

3) Repeat with the tail cap.

4) Repeat centre cap (not strap if using one). Then add the strap in using one.

If all is OK now I torque everything down, in the same sequence, checking as I go.

If all is OK I measure the end float, select / machine thrusts to suit and then strip and rebuild the motor again with the trusts. Re-oil everything

Now and only now do I fit the pistons to the block and repeat the above proceedure with the big end caps (obviously can't do anything without the full big end assembly so go straight to shells and caps stage). Once I am happy then Torque the rod bolts down and by now I usually need a cup of tea ......

I bit long winded and I'll never break any assembly speed records but I have never had a problem with an engine built this way.

5) Then I go

Every day is a school day ...........

How fast and how expensive ...... the same question...

TRY THIS ITS SIMPLE!!

I have had exactly the same problem before My crank wouldnt turn even without it being tightend!!

Take your crank out and take off the caps. Check the little round lugs which centre the caps. They will be slight crushed or warped! To check put the caps on with your crank or bearings in place and you will be able see the cap hanging over the edge.

Change your lugs and when you are refitting the caps makes sure there sqaure when you tap em on!

Edited by MikeRace on 31st Dec, 2006.

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

eureeka ! 1573 spot on cheers, the lugs were slightly off (fucked) so the cap was pulling slightly off and causing it to nip the crank, i have never heard of this problem before ?

thanks everyone for your help

Roger i will remeber your sequence for future builds !!

______________________________________________________
TRADER HALL OF FAME
BENROSS...MINIMARK..WOLFIE (comic genius).....CARL....MARTPAUL.......AXEL
______________________________________________________
TRADERS OF SHAME
1 user....pm me 4 details

LEGENDS
MikeRace, Mini13

No probs

Cheers

Mike

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

WAHOO!!!

Perhaps they ground the crank 0,10mm(approx .004") then supplied .010" bearings

Metro turbo weekend driver,Mini turbo in the making again!