one last bolt

[cadetchris]

having just rebuilt the bottom end of primrose, i have found a problem.

the engine turns over nicely until i tighten the rear bolt on number 1 big end bearing. this causes the engine to seize solid and no matter how much force is applied, it wont budge, loosen the bolt 1/16 of the way back, and it turns over nicely.

not sure why this is happening as i have used buckets of oil on the new bearings in an attempt to avoid this happening.

any ideas why this is occurring?

[mike.perry]

Does No1 piston slide up and down the bore OK?
Have you had the journals reground and fitted the wrong shells on No1?
Are you sure that you have not mixed up the end caps?
Are the shells located in the rods correctly?

[alanworland]

Make sure the parts are spotlessly clean and no burrs or dings on the parts - you might have to measure the journal to establish if it has been ground to the correct size.

[bmcecosse]

As Mike says - double check you have not mixed the caps - or put any on wrong way round. DO NOT try to force the engine round like this and certainly don't try to start it! You say 'rebuilt the bottom end' - what exactly has been done ?

[cadetchris]

i have replaced the crank, big end and main bearings as well as the thrust bearings. so all the bearings are the correct size for this new crank.

as for the caps, i took them off and laid them out in the order they came off and replaced them exactly the same way.

on a lighter note, i have fixed the problem with lots of oil and torquing down each bolt a little at a time, thats fixed it now. however, the engine is quite stiff, but i presume that this is due to the new bearings. should i follow the running in instructions as per the book?

[bmcecosse]

It should NOT be stiff - it should turn over easily. Sure that last cap isn't on wrong way round ? The little tabs on the shells must be adjacent. Also worth taking the shells out and cleaning carefully behind the shells - the seats for the shells must be spotless.

[cadetchris]

fudge, and i had already put the sump on. well, thankfully i hadnt filled it with oil or even made an attempt to start it. ill whip it off and check the caps.

IF, that hasnt cured it, what else could it be?

cannot be the pistons as they where already in the engine and had been since january.