Engine Rebuild Day 6 - Wednesday July 23

Today I loaded up all the rotating crank parts and the block and delivered them to the machinist.  I am hoping to get them back within 2 weeks.  This will still give me a tight timescale but it should take me only two or three days to get the engine running plus a week running in.  I do have to drill and tap the block to take the new ARP 1/2" studs, which is probably the most time-consuming job left.  I plan to travel the length and breadth of England to get 1,000 miles on the clock before Goodwood.

While the parts are away I'll get everything else ready to drop the motor in.  I have to install the electronic ignition (MSD6AL), change the gearbox primary shaft, check the silencer packing and seal the packing covers, possibly move the fuel pumps and blank off the inside of the side pontoons.  The last two jobs are not absolutely necessary but much easier while the engine is out.

First I can resolve the piston 'problem'.  I had measured the width at the top of the piston which was co-incidentally 3.998" leading me to think they were standard bore, however cast pistons (I am not sure about forged) have a taper  from the skirt to the top of about 30 thou.  The skirt diameter was 4.028", so the undersize was a red herring.

Tonight I thought to change the primary shaft of the gearbox. 

I first drained the oil, the second time recently as I fitted a 0.76 5th gear recently - this now gives me 30 miles per 1,000 revs.  I did try it out before stripping the car and was very pleased with the relaxed motorway cruising.

I have to change this shaft because the original one was made to a non-standard diameter.  This meant a special bearing with a custom holder.  Since I am changing the crank I wanted to get everything back to a regular size.  Chris Cole of Mach 1 transmissions has supplied the replacement shaft but it is overlong to allow for variations in bell-housing depth - it has to be trimmed.

The current shaft is tight in the sleeve joining it to the first motion shaft, probably with LocTite - I will be forced to take the bell-housing off.

On looking at the new bearing and crankshaft I decided that I need the crank back from the machinist before cutting the shaft to length, as they say 'measure twice and cut once'!

I moved to the next job.  As the new engine will be louder, it seems a good idea to check the packing in the silencers now. Also the packing covers leak and I want to try and tidy up the look of the silencers.

I have had trouble getting the button head socket screws out.  Several have rusted in their threads - I shall have to drill them out.  I plan to use brass bolts as I think these are best on exhaust system parts.

I shall omit the central bolts as they are impossible to remove in situ.  This will be important for repacking at a circuit.


I managed to get one cover off, the other one was so noisy drilling the rusted bolts out that I thought to leave it until tomorrow (I want to live in peace with our neighbours).

The packing is still very full and doesn't need changing, I just need to make the covers seal well and be easily removed in the car.

Any ideas for a sealer? (I have tried exhaust putty which just goes hard and leaks again).