RB25 conversion Stage 8 - Installing the crankshaft

I finally took delivery of my metal head gasket and big end and main bearings this weekend so I can now carry on with my engine rebuild. Unfortunately I had forgotten to buy a crank oil seal, the camshaft oil seals, the oil pump gasket and the rocker cover gaskets. They are all now on order, and at least this weekend I could reinstall the crank.

I cable tied a piece of cardboard over the cylinder head side of the block just in case I made a mistake and pushed a conrod a bit too hard - I don't want a piston falling through the bore and hitting the floor!

To start I got a tub of engine oil and put the first set of rod and main bearings in. You need to make sure you get the right main bearings - half have an oil feed hole in and half don't. It's the oil feed ones that go in first against the block. All the con-rod bearings are the same so any set will do.



Next get a tube of Graphogen. This does exactly what it says on the packet - I wouldn't put an engine together without it. Smear some of this over the bearings before you press them into the con-rods and the block.




Once the bearings are in, Repeat the process but this time putting the other half of the bearings in to the other half of the con-rods and the crank bracket. Once all the bearings are in place it's time to put the crank in. Make sure the conrods are pointing in the right direction (I pointed 1 and 6 to one side, 2 and 5 to the other side and 3 and 4 upright), and then gently place the crank home.



The next step is to torque the crank down and make sure it turns smoothly. However, I decided to put the other half of the con-rods on and do the bolts up finger tight first, as I didn't want to try turning the crank without the con-rods connected.

Once the con-rod bolts were finger tight I placed the crank bracket onto the crank. I did the bolts up carefully here - working clockwise from centre outwards. This needs to be done in several steps making the bolts a little tighter each time so the tension on the crank is spread evenly. For the final tightening of all the bolts you'll need a torque wrench like the one pictured below, set to 50Nm (37 lb/ft).



The crankshaft should turn nicely once the main bolts are torqued up, check it and make sure there are no tight spots.

Next torque up all the con-rod bolts, doing a turn or 2 on each side of the rod until they are torqued to 15Nm (11 lb/ft). If you're going to buy a torque wrench yourself to do this job make sure it goes this low as many don't!

Once the bolts are torqued they need to be done up a further 60-65 degrees. The best way to do this would be to use an angle wrench, but I didn't have one to hand. It's not hard to guess how far 60 degrees is (think of it as a sixth of one full revolution of the wrench). Once you've done a couple of bolts though you'll be able to do the rest by feel - I found that whilst most needed a 60 degree turn, a couple needed a bit more and a couple needed a bit less.

That's the crank installed! Make sure it turns evenly and without too much effort (obviously a bit of effort is required as you're moving 6 cylinders in their bores!). Here's the crank installed and everything torqued up correctly...




Next weekend I'm hoping to finish building the whole engine, as I should finally have everything I need :o)