20 replies to this topic

[kappa]

Hi all,

Basically I am re-building my turbo engine, I have put new big end and main bearings in.

Now I am going to torque it all down, by referring to the Haynes manual.

The crankshaft main nuts states 40lb.ft torque
The conrod main nuts states 35lb.ft torque.

Basically I go to torque it all down and once near the actual torque, I just check the crank turns over by hand, it does but very hard. I torque it down to the actual setting and then go to check if the crank turns over by hand. NO JOY AT ALL?

I have put all my brute force in to it to turn by hand, but does not seem to move at all.

What is the problem here, am I going wrong here, have I messed something up?

All help is really appreciated.

Cheers

Bobby

Edited by kappa, 30 January 2013 - 04:37 PM.

[Artful Dodger]

When you do just the crank up to the right settings is it easy to turn or hard

Ie, is the con rod big ends the issue or is it the crank:P

[kappa]

Yeas it easy to by hand then, but I have not tried it to full torque setting, I say just under the actual torque setting requirement

[sledgehammer]

Slacken the ends - does it still turn ? - if so Torque the mains up & check it still turns easily - if it don't turn - 4th line down

Tighten one end cap at a time , turn in between each cyl - until you get the tight one

strip it - look for any dirt or marks on either the shell or cap / con rod

slacken mains & re tighten one by one until you find the tight one

it only takes a tiny bit of dirt / grit to get in there

all this assumes you have the correct size for the crank - 0 , +10 , +20 +30 , etc ...

... wouldn't be the first time wrong ones packed / sent

Edited by sledgehammer, 30 January 2013 - 04:54 PM.

[Cooperman]

Main bearing cap nuts should be 60 lb.ft and big end nuts should be 40 lb.ft.
Have you fitted the centre main cap the wrong way round?
Are the bearing shells the correct size for the crank diameter?
Have you set the crank end float to 0.0015" to 0.005"?


Now, I have once, and only once, had an A+ 1275 MPI engine where the centre main bearing housing was slightly undersize. It had obviously been like it from new as the old main shells were badly 'graunched' and the new shells were correct as was the re-ground crank. I had to have the centre main line-honed to get it right. It was a late car and I put it down to Rover cheapskate quality control.

Without the rods/pistons installed, fit the crank and 'nip' up the nuts without tightening them. Then torque no.1 main cap and check for easy crank rotation. Then do the same with no.3 assuming the crank rotates OK. If the crank still turns freely do up the centre main and check again. that way you can isolate the fault/problem.

Do that and come back on here and let us know what you find.

Do

[kappa]

Ok will try this now and get back to you guys,

Cheers for the info

Bobby

[Cooperman]

Slacken the ends - does it still turn ? - if so Torque the mains up & check it still turns easily - if it don't turn - 4th line down

Tighten one end cap at a time , turn in between each cyl - until you get the tight one

strip it - look for any dirt or marks on either the shell or cap / con rod

slacken mains & re tighten one by one until you find the tight one

it only takes a tiny bit of dirt / grit to get in there

all this assumes you have the correct size for the crank - 0 , +10 , +20 +30 , etc ...

... wouldn't be the first time wrong ones packed / sent

You just beat me to it. Great minds think alike

[kappa]

Right so I dismantled it all again, and re-fitted it all.
First I done the main caps two on the ends first and checked the crank turns. that is fine.
Then done the main centre main, and that was fine.

Then I went onto the conrods, one at a time. number one was fine, number two slightly harder, number 3 even harder and number 4 and no joy. But when I leave them to the 15lb.ft torque it turns.

[kappa]

Turning all fine now, only when I turn the first go, its a bit hard, then turns over nicely.

Thanks for the advise guys

Bobby

[bully]

it should be free all the time not turn a bit its ok then turn abit more and it gets hard, most likely there is dirt either on the bearing face or between bearing and cap/conrod.
was the crank reground? if it was then it may be a bad job

Edited by bully, 30 January 2013 - 08:08 PM.

[kappa]

No crank has not been reground, just the standard metro turbo crank on there.

[bully]

so does it turn freely then goes stiff then freely again?

[JVA10L]

Have you got the conrods facing the correct way - two face one way and the other two face the opposite.

[Gr4h4m]

Is there not an argument to say during your dry build you should torque all of the caps down, then back them off and do one at a time to make sure the bearings are pushed into and formed the correct shape before spinning the crank, ESP if it's not harderned?


Iirc Des Hammil recommends it in with 4 pot book, as well as checking each of the rods whilst the crank is out of the car to ensure that they are not tight as its much harder to feel a tight rod in the block with everything done up

Main bearing cap nuts should be 60 lb.ft and big end nuts should be 40 lb.ft.
Have you fitted the centre main cap the wrong way round?
Are the bearing shells the correct size for the crank diameter?
Have you set the crank end float to 0.0015" to 0.005"?


Now, I have once, and only once, had an A+ 1275 MPI engine where the centre main bearing housing was slightly undersize. It had obviously been like it from new as the old main shells were badly 'graunched' and the new shells were correct as was the re-ground crank. I had to have the centre main line-honed to get it right. It was a late car and I put it down to Rover cheapskate quality control.

Without the rods/pistons installed, fit the crank and 'nip' up the nuts without tightening them. Then torque no.1 main cap and check for easy crank rotation. Then do the same with no.3 assuming the crank rotates OK. If the crank still turns freely do up the centre main and check again. that way you can isolate the fault/problem.

Do that and come back on here and let us know what you find.

Do

[Cooperman]

If you are new to building engines it's worth remembering that the crank will turn most easily at TDC abd BDC to around 30 degrees either side of that in rotational terms. Then, at halfway up/down the bore, the piston drag will be greatest and the crank will be much harder to rotate, usually needing a screwdriver through the slot at the end of the crankshaft. It seems even harder once the cam and timing gears are installed.

Most people fit the crank first, torquing main no.1 and checking the ease of rotation, then main no.3 and finally the centre main. Then do the big ends in sequence, checking rotation after each one is torqued and remembering that they turn easiest at TDC/BDC. A newly bored engine with new pistons and rings can seem quite tight at mid-stroke, but so long as piston fit and ring gaps were correct then that is no problem.