Dv6fcu wont turn by hand

[1986michaelwatkins]

Hi everyone.

Hope someone can help please? I am rebuilding dv6fcu in peugeot expert. I have followed torque specs when placing bearing caps on. At 10nm on the bearing bolts crank rotates freely. When the 15 m6 bolts are tightened to 8nm and the bearing bolts are backed off 180 degrees and then tightened to 30nm the crank will no longer rotate.

I know that manufacturers torque specs are not always correct, had a previous headache with a bmw. Wondering if anyone has a different tightening sequence that works please?

By the way, new bearings installed, clearances checked and all timing pins removed.

Thanks, Michael

[1986michaelwatkins]

To be clear, the crankshaft housing was defective so a used replacement part has been fitted. After more trial and error, once the bearing bolts are tightened past 10nm the crank will not rotate. Any suggestions welcome, thanks

[PaulC5]

You could fit a cap without the crank and bearings, measure the hole and then compare it to your old housing as it sounds as if the replacement is smaller. Also check the bearing dimensions.

[xantia_v6]

If the bearing clearances have been checked individually, but the crankshaft seizes when all bearing caps are tightened, then I would suspect a bent crankshaft of a warped cylinder block.

What was the failure that caused the original block to be replaced?

[1986michaelwatkins]

Thanks for the answers. The reason for replacing the housing - there was a crack in the old housing. The engine ran fine, just dumped all oil out the crack. I still have the old part, I will compare the two

[1986michaelwatkins]

If anyone else is stuck with this apparently the crank housing is machined to the block. So I have to get the crack repaired or swap the block from the donor engine. Fingers crossed I can get the housing repaired. Thanks again for the input.

[1986michaelwatkins]

So............ I had the old crank housing repaired. Cleaned it up and installed the new bearings. Still locks up when tightening past 10nm, still can not turn by hand. Here are the instructions I am following:

Pre-tighten to 1 daNm

Angular slackening of 180°

Tightening to 3 m.daN

Angular tightening to 140°.

Am I missing something really basic here? Please (haha) help

[1986michaelwatkins]

OK so like everybody else I'm human and I make mistakes. I'm not even ashamed to admit this; turns out that time the cam was pinned, whoops. So if you have a defective crank housing it must be repaired or come with the block. After the repair this one, the original, has worked beautifully. Thanks again.

[Paul-R]

Have a house point for being brave enough to admit it.