Re-build issues!!

[coulson1986]

Hi everyone! Im new here.

I am currently rebuilding a 1968 1098cc engine, I have replaced the crank shaft and bearings ect and i have re assembled every thing to the correct torque and lubricated all the nessessary areas but now i cannot turn the egine, it just wont budge i have even tried to turn it by attaching a huge pole and it only moved it ever so slightly. Does anyone know why this might might be?

Thanks

Marc

[kennatt]

Sorry but you will need to start again and at each stage try the engine to see if it turns freely,you will then find out which componant is causing it to bind. The common(Easy mistake) Is replacing the bearing caps in the wrong journal both main and big end. More so with the mains since they are line bored to suit the block and are not interchangable,get them out of place and the engine will bind. Another cause is a bent crank shaft.but not likely unless the engine has siezed at some time .Do you know the history of the engine.At what point did you discover that the engine was bound.That would eliminate some stripping down.Have you fitted the same sized bearing shells has the shaft been reground bit more info required.

[coulson1986]

Hi

thanks for the reply, before the rebuild the big end bearings we worn causing low oil pressure and a horris rumbling sound. The crank i bought was a reground one from the morris minor centre in east sussex. I will check to see if i have fitted the bearings properly hopefully i can solve this issue

Thanks

[kennatt]

it can't be anything else but a bound shaft,theres nothing much else that could cause it,disconnect one at a time and try to turn by hand,it should turn freely,you will soon see where the problem lies and then can sort out why, Its not unknown for the reconner to regrind and then supply the wrong oversized shells,which would lock the shaft solid once torqued up.If you need to slacken them all(Thats all you need to do ) before it free up then I would suspect the wrong shells

[millerman]

1. Remove big ends and mains

2. Replace big-end caps and bearings, using plenty of engine oil, testing that the crank can rotate as you tighten each cap down

3. If crank rotates ok, repeat with big end bearings

This should identify where the problem is

[bmcecosse]

Hope you are also fitting a new oil pump - essential!! And DO NOT use a pole on it!!! You may have done some damage with that... As others have pointed out - it must turn easily by hand. Check every bearing turns as you assemble it. Only the centre main cap can go on the wrong way... But the big end caps MUST be kept with the rod they came off - and must be the right way round on the rod. And of course the rods are handed - so the pistons/rods must go back in the bore they came from.

[coulson1986]

hI! Thanks for your reply,

I kept the pistons ect lined up in order that i took them off (i took photos). just a moment ago i just undid the main bearing caps an everything turned by hand nicley, i then torqued up the center cap and all was good then i torqued up the flywheel end one an then it was rock solid and wouldnt turn so this is where the issue lies, I cqnt get my head round why though.......Sorry but i am an amature

[bmcecosse]

The two end mains can't go on wrong way round - so you had better remove them and check the fitting of the bearing shells in the housings.

[coulson1986]

i have just checked for this an all seems okay.........ish, is it possible that i could be over torqing?

[bmcecosse]

No. Assuming you are not using the long pole. Check the size of the journals. If you slacken/remove the centre and front caps -is the crank still tight when you pull up the rear cap bolts?

[kennatt]

tighten centre and then the front if it still locks up and you are certain that the shells are the right size,then I would suspect a bent shaft. The re ground shaft supplied may have come from an engine that had siezed, which can cause it to warp(Sometimes) difficult to see by eye.Whats the + on the shells, 20, 30,or what,that would give an indication of how bad the shaft was before regrind,which could indicate how much hammer it had taken. Suspect you may be sending it back . You must get it to turn freely by hand,or you will just wreck the bearings ,if it ever turn fast enough to start.

[bmcecosse]

The regrinding process would show up a bent crank - they would need to straighten it before they could do the grind.

[kennatt]

if its been.... re ground.. hence the question of the size of the shells , if standard then it hasn't ,didn't want to start making acusations:(

[IslipMinor]

Can you remove all the main bearing caps and start again with the centre one? Check the centre main shells have been fitted with the small tang on the shell in the groove in the block and cap, and when fitting the centre cap, the two grooves must face each other. Torque up and check for free rotation.

Next fit either the front or rear cap. Make sure the the shell is fitted correctly into the block and cap as above and torque up. Check for free rotation.

Can you take some pictures of the shells in the caps/block?

Wher do you live? There may be someone close by that could help?

[GPO_Van]

Same thing happened to me, locked solid despite keeping all parts oily, (I did not risk too much force trying to turn it though)
First I loosened all the big ends, it then it turned ok, retightened each in turn till it would not turn, everything looked ok on the problem big end to me.
A mechanic friend had a look, but what looked like a dark stain on the cap was in fact carbon built up and slightly under where the old big end shell sat, it was a mechanic friend who spotted it, he rubbed it down torqued it up and all is now fine, engine running fine.
It was just a tiny ridge of hard “carbon like” muck.
Reg

[MarkyB]

Good point, all the surfaces need to be very clean, and unmarked too.
A very small imperfection can cause problems.
If you have the crank out you could do a visual check by holding the appropriate shell on the journal and see if there is even the tiniest gap.

[welshrat]

Agree with Mr B, slightest bit of grit/grime under or on a shell may be creating the problem, I do speak from experience as had not quite grasped how clean all the bits needed to be when rebuilding motors.

[bmcecosse]

You should gently rub the surfaces with well oiled crocus paper before fitting the shells........and of course -degrease the shells!

[kennatt]

any developments