With power comes.....broken bits

Another delayed posting.

At Easter brother was driving the sprite home and just as he pulled into the yard 'BANG'. Something let go. On restarting it intermittently apparently was fine and then sounded horrendous. Seemed to correlate with loading the clutch and gearbox so the feeling was has something in the box or clutch let go.

Que me coming home to rip out the engine and box and start tearing her apart.

Bottom end looked good on first inspection, as did clutch system, so started tearing apart the gearbox as had never had her apart more than a cursory look. Ultimately nothing broken but needed a damn good clean inside, selector ball bearings and springs where completely gunged up and explained the savage gear change we had been experiencing.

Still nothing obviously broken so back in she all went...turn her on and....mm that doesn't sound good. Rough as hell, running for 10-20seconds at max. Was as if the timing was completely out. Oh dear, has the crank broken and is it flexing around one of the big end journals and just couldn't see a crack when had the sump off ?

I had to disappear away at this point but when bro came home a few weeks later and had another look it dawned that the number one and two cylinders seemed to be exhausting via the carb, resulting in massive spitback on the number 1 carb and some degree on the number 2. Some investigation resulted in the car running fine...as long as you took off the number 1 plug lead.....mmm...stuck valve?

On taking off the rocker cover it all became clear. The exhaust valve tappet adjuster for cylinder one had sheered clean in half along its oil gallery resulting in no movement of the exhaust valve. oh dear...

We had wondered if something like this may happen as with the thicker cooper S (12g295) head on that hasn't been skimmed the tappet adjusters are at their full expansion with the 948 push rods. Thought was given to just replacing all the adjusters and putting in longer 1275 rods but as times gone on and the bro's buggered off to France I think its time to sit back and reassess.

Whilst a 649 camshaft in a 948 is a lot of fun..its not very practical unless your hill climbing or track racing. So this seems like a good time to tear the engine apart. Get the block line bored for 3 cam bearings (As shes still only on one!), a new fast road/rally cam rather than a full race cam, skim the head to bring the compression up a bit, and a new set of roller rockers to prevent anything letting go and a big expensive blow up occuring.

Basically this means she'll be off the road for awhile whilst we save up and get this all done...but hopefully end up with a far more friendly car at the end of it!

In the mean time there's plenty of other stuff to do so with a few weeks off whilst I await taking up my first job as a real doctor (terrified) I've stripped the period lightweight hardtop down and started repairing the damaged fibreglass.