Refitting the crank

I got the crankshaft polished at Southern Rebores near Crawley- great job fellas, really like the satin effect on all the journals.

Polished Crank- clearing all oil ways in the crank... 

I cleared the internal oil ways with a compressed air line.

...and in the block, blasting through from the Gallery along the drilling and also from the bearing holes out

I changed the main bearing shells for the new +10s I got from SJSportscars. One thing I noted was that the bearings as fitted weren't quite right. The lower centre should be a plain bearing and the upper centre a plain-with-hole. All the others are groove-with-hole. This motor had a plain-with-hole fitted in the lower position and a groove-with-hole in the centre upper location. This is probably not a serious problem, at least there was a hole to coincide with the bearing oil inlet, but it wasn't right so I got the right bearings for the 907 motor.

Note incorrect plain-with-hole in centre position of MPB

... and incorrect groove with hole in top centre position
in block

I replaced all the shells with those indicated as correct for this motor in the manual:

Note plain bearing in centre lower position (i.e. in MBP)

Note groove with hole in centre upper position (block)

The rear lower shell required a notch to be filed in its upper edge to allow oil to seep through from the bearing to the newly made groove filed in the MBP. This delivers oil to exiting the bearing to lubricate the rear thrust washer. The manual assumes that it will be possible to obtain a specially modified bearing from Lotus for this purpose. - Perhaps once you could, but these are not available at present, so I had no choice but to file the notch myself. There isn't much to go on when it comes to filing this groove as sadly the illustrations in the manual are of limited use. This shell is a groove-with-hole, yet the manual shows it as a plain; furthermore the location boss is on the left, yet the manual shows it on the right - which none of the various combinations actually have in this position. However the dimension given (0.5cm from the location boss) places the notch within the shell groove which makes sense. However there is no indication of how large the notch should be. The size may actually be critical since too large a hole might allow too much oil to exit the bearing, running it too dry and flooding the rear of the motor leading to rear oil seal troubles. Too small a notch would fail to lubricate the thrust washer. The illustration shows the groove as I filed and fitted it in my first attempt. I formed a shallow notch virtually across the centre groove, but thinking about it later, this may well be too large. I decided to fit the bearing whilst I waited for further information. - OK- foolhardy perhaps but at least it gives me a chance to practice assembly and using the sealant in a dry run. 

Note notch filed in bearing groove below alignment guide allowing oil through to newly
made chamfer. I am not absolutely sure that this is the right size so I may end up redoing this.

I applied red engine assembly lube to all the top shells in the block (block inverted) and including the two thrust washers (copper faces outwards)...

Assembly lube on upper shells (block inverted)

...and then laid the crank in the recess- this was a little awkward as you must ensure that both thrust washers remain firmly back in their grooves or they prevent the crank from dropping in squarely.

Thrust washers pressed back into their recess- journal drops in squarely.

Crank in place in block

The next step was to add Red lube to the shells in the MBP before applying PG307 "Gemlok gasket maker" to the mating flanges of the MBP.  The sealant can be applied as a continuous bead or a continuous film. There are no suggestions as to how this should be done but I chose to do the latter ensuring that the sealant passes inboard of all bolt holes. I also applied it around the bearing shells, I don't think its needed as a sealant here, but assuming that the sealant will have some thickness, I didn't want these to mate at a different distance apart from the periphery of the panel, possibly distorting it or pinching the bearings. 

I don't seem to have a picture of this but it wasn't as easy as it sounds since the PG307 is sticky and tends to form lumps. I do suspect I will be redoing this step of the assembly with a modified rear bearing shell- so if that happens at least I will be better prepared to spread the sealant next time.

The manual states that the nuts securing the MBP are 12mm or 8mm- this is not true they are actually 17mm and 10mm. I sorted out the appropriate sockets plus extensions and pre-set two torque wrenches to the correct torque so that all was ready for quick attachment of the MBP. The MBP then fitted smoothly over the block studs.

A word about studs and nuts; I think a perfectionist would use new studs and bolts throughout the block reassembly. This would be very expensive and I suspect unnecessary because, because the existing ones are in very good condition. I cleaned all studs with a brush and chased their threads with an old tap. All nuts and washers were cleaned ultrasonically before being brushed through with pipe-cleaners or tissue. I oiled the threads and torqued it down. The crank still rotated smoothly once the MBP was fitted so that at least is good news.