how tight should the crank be after rebuild ?

12th July 2013, 16:24

Okay so got brand new main and big end bearings (genuine citroen) put them in making sure I lubricated all the surfaces in oil,

Got the crank in and rods on and tourqued it all up 65nm for the crank and 35nm for the rod bolts (arp) but can't turn it over freely ?

Any help ?

12th July 2013, 16:35

You say you've got the rods on, I assume the pistons are in.. Possibly with fresh rings?

Edit: also, how hard is it to turn, is it sticking or?

12th July 2013, 16:44

Yeah pistons in also, they are forged low compression, with brand new rings.

The only way I can turn it over is with a screw driver between the bolts for the flywheel and its still hard to turn

12th July 2013, 16:47

I see lol. It will be difficult to turn by hand, the rings will be very tight against the liners causing friction. Without this there would be no compression

12th July 2013, 17:27

Shouldn't really be that tight though to be honest, did you lubricate the cylinder walls?

12th July 2013, 18:06

Yes everything has been covered in oil, confused

12th July 2013, 20:56

You got the bearings in the right way and definatly the correct ones? What size pistons and was the block honed properly?

12th July 2013, 21:23

when ive built fresh engines, they can sometimes a little tight, usually i can just about turn the crank by hand when ive got the pistons in (if i go mental on it lol). did the crank turn freely without the rods attached?

13th July 2013, 00:51

The block has been bored and honed by a company who have been in business for 30 years,

I've undone the rods and the crank moves freely so the problem is in the conrod caps, only thing I can think of is someone has got each on mixed up ? As they are used pistons and rods

13th July 2013, 20:08

If the crank is free moving without the rods connected how easy are the pistons rods to slide up and down in the cylinders. Have you got the rings in the right order and did you check the gap on them before fitting ( ie sliding ring into cylinder on its own and setting it about an inch below surface and checking the gap at joint)
Also did you make sure the bore was done to the piston spec ( if piston is say for a 80mm bore the piston will be 79.xx mm to allow for the piston and rings in bore each piston manufacturer has different specs but if not done right it will mean piston wall gap is too small this if not checked will cause ring bind and possible wall scoring)
And needless to say damned hard to move...

Also have you got the right size big end bearings ? Did you plastigauge them when fitting to make sure they were a correct size? If you have an oversize bearing to make up for wear did the crank get ground for them?

There's lots to think about that you may have misses or not checked right

But ideally the engine with plugs out should rotate reasonably freely with a bar on the crank bolt....
If you have plugs in the compression will slow you a little but the valves will release at some point so still turnable by hand.

14th July 2013, 03:17

Yes the pistons have been bored and honed to the correct size, and rings have been put in the bores and the ring gaps set to 0.0012 onch iirc.

The crank moves freely without the pistons tourqued up so the problem is somewhere in the rods.

Standard size bearings were purchased from bsm citroen aswell

14th July 2013, 18:07

I'd be looking at the big end bearings then
If when not torqued it rotates freely it's the only thing to look at

17th July 2013, 10:57

Okay so I removed everything for the third time cleanned and inspected everything, put it all back together and its one conrod causing all my problems.

Removed it and put the bearings in and tourqued it up to 35nm and its reading 0.45mm under the size of the crank journal. How is this possible ? They are standard rods and genuine citroen bearings.

Anything I can do except buy new rods ?