Engine strip down and rebuild

**AlfaWorks** · 15-01-12, 17:07

So I got back at my spare bottom end I decided to completely strip it, see what parts need replacing and well check overall condition of everything.

Got the sump off, looks ok from this angle so I carry on deconstructing.

I get the pistons and conrods out and some of the bearings look slightly worn which on the journals look OK, but an engineer will be able to say for sure.

Thje bores look fine, I'll get them re-honed if needed, one shows signs of surface corrosion but no pitting, 3 cylinders are pretty ferfect TBH

OK, now getting the crank out I get a proper shock horror as I am sure this means the end of this crank

I can feel the groves with my fingernails, which isn't good as you cannot grind these cranks!

So I turned to cleaning and stripping the block.

I sort everything into groups to keep it all together.

That will teach me to leave the short block outside for 6 months :o

PS, pistons look gunky, I lined the cylinders with CV grease to protect the bores from corrosion.

Now I have to find out the best way to clean them up!

**AlfaJack** · 15-01-12, 17:11

Hi Brad...as I mentioned on 155.org I have re-ground a crank before so I would think you can get this one done too

**mpampis_** · 15-01-12, 19:56

Your engine look afflicted enough. The day before yesterday I striped mine too for rebuild and I can say that look in excelent condition. even after 340.000 km I can see the X of the honing inside cylinder. I will post my progress too. Every opinion in here is useful for all

**Steve Webb** · 15-01-12, 20:17

Originally Posted by AlfaWorks

I can feel the groves with my fingernails, which isn't good as you cannot grind these cranks!

Never a good sign when you can actually see the damage to the crank from a pic.

Originally Posted by AlfaWorks

That will teach me to leave the short block outside for 6 months :o

Ahh the BMW F1 method of block preparation, apparently works wonders relieving the internal stresses of the block.

**AlfaWorks** · 15-01-12, 20:39

TBH it's more like the metal is stained, but you can feel a slight roughness in the surface.

**AlfaWorks** · 15-01-12, 20:40

Originally Posted by mpampis_

Your engine look afflicted enough. The day before yesterday I striped mine too for rebuild and I can say that look in excelent condition. even after 340.000 km I can see the X of the honing inside cylinder. I will post my progress too. Every opinion in here is useful for all

But this was in half already sitting outside under all weather, mostly rain :o

This is it 6 months ago!

**mpampis_** · 16-01-12, 06:30

That's why. With a good care will be like a new one

**Juan AR155Q4** · 16-01-12, 18:48

Originally Posted by AlfaJack

Hi Brad...as I mentioned on 155.org I have re-ground a crank before so I would think you can get this one done too

Another one here!!!

**AlfaWorks** · 17-01-12, 15:15

Thing is I want to push some serious power out of this thing and the last thing I want is the crank to be the weakest link.

Tough call.....

**Steve Webb** · 17-01-12, 16:55

Originally Posted by AlfaWorks

Thing is I want to push some serious power out of this thing and the last thing I want is the crank to be the weakest link.

Tough call.....

Are you going to be vastly increasing the RPM, if not then I wouldn't worry too much about the stresses on the crank. Increasing flow and boost to get the extra power is going to put far more stress on other components.

**Suzumushi** · 17-01-12, 22:11

Originally Posted by Steve Webb

Are you going to be vastly increasing the RPM, if not then I wouldn't worry too much about the stresses on the crank. Increasing flow and boost to get the extra power is going to put far more stress on other components.

is it common or normal that most of q4 owners has spare engine? and want to rebuild them and get much more power ?

probably forgot to share this info as i also bought spare engine and complete gearbox - and as an extra got the car

waiting for some time and goodies (parts) to rebuild this one...

regards