After 2 days in the garage on the weekend collecting together the accumulated detritus of a lifetime's Triumph fiddling I packed everything remotely useful into my Dad's people carrier. I then slugged it up the motorway to Canley Classics to see Dave Pearson for some help - after contemplating my broken crank and trying to assess how it failed, why it failed and what were the consequences, we came up some explanations. It didn't fail in the main bearing, it failed near the big end but not where you'd expect. The crank had some nice radiuses on the journals and all seemed in order there - it wasn't in the best condition wear wise but nothing that would cause a failure. What we did find was that No 6 piston had touched the cylinder head - this was a zero deck to piston crown set up so you don't need much movement before you get contact. It was hard to see if this contact had occurred because the crank snapped or was this contact there and caused the crank to snap? We'll never really know for sure but what was evident was that the pistons were scrap. I'm not using those awful rods either - they are the late type heavy ones (with a hole in them) and I have a good set of early lighter ones to go in - the replacement set have not been buggered about with either.
Every top ring bar one was broken when I pulled the pistons, this would account for some of the crankcase pressure I had. Now a PI needs good vacuum otherwise it runs over rich so I will carefully gap the rings when it goes back together. The cross drilled crank looks good, it looks like it's never been out of the engine and is factory spec - I'll get the oilways teardropped, and give it a grind and balance. The clutch cover and plate will go round again, the flywheel ring gear is marginal so I'm going to throw a lightened flywheel on it with a new ring. The engine came with alloy front and back plates, I don't think the budget allows for an alloy water pump casing though, would be nice but you can't have it all!
The cam and followers looked OK - one is showing signs of wear so I'll probably just replace that one. The cam isn't anything too lairy but I liked it's nice wide tractable power band and the fact that you can drive it in traffic - I mustn't forget that my wife uses this car on the school run sometimes so it needs to be driveable in traffic! Timing gear looks good and will be re-used with a new chain. As for the head there is plenty of valve seat recession so unleaded seats and some new valves will sort that, the inlets look OK but I haven't stripped it down yet. I have a spare Vitesse big valve head that'll go on eBay to help fund this project - it's not cracked and is ready to fit or be "unleaded".
I'm also taking this opportunity to fix the gearbox, shagged synchro on second means you can beat it if you're not paying attention, rapid down changes are not a good idea. I will also cure the slight oil leak at the front. When I get it home I will tidy up the overdrive and reversing light wiring. I always hate the way this hangs there in a mess so I'll make up some new wires, bind them in loom tape and tidy them up properly.
Once all this is put together with new gaskets and is oil tight I am going to treat it all to synthetic lubrication after a little careful running in and hang the expense!
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