Am I right in thinking Mr G's motor is the one with a plain shell bearing in the centre of the crank, and has in effect a split flywheel?
The other journals have survived, so I hope the cause is found in the crank, otherwise I reckon a new oil pump can be added to the bill.
I'm sure there was an urban myth about Japanese Engines having different size shells, all journals being ground to a finished size which removed the least amount of material.
Swarfy.
That's broadly right, yup. Narrower than the b/ends but (almost) same diameter. Original cranks had round 'flywheeels'. This one was designed by Markus Graef who was a regular poster here (MG), and made by Zanardi in Italy in a batch of 100 (thanks to funding from the Owners' Club) in 2 versions, dynamo and alternator, and has wedge-shaped. The one here was the first prototype, which I was asked to fit and run with before the production run was made available to those who had pre-ordered. A few new ones are still available. The cast iron recipe is the same as was used on TVR car engine cranks, from memory. They are VERY hard, tooling-killers when it comes to grinding and removing metal for balancing, which created a lot of hassle and delay when machining up the blanks. The first engineering company engaged to do the finishing work (in Austria) simply couldn't do it, so we had to move to a Plan B. A not untypical tale of limited production run engineering - but worth it in the end because the result is a top draw item which filled a critical gap in the Unobtainium range. (I remember talking about a similar project for large journal A cranks - but we didn't have the money so it was just a pipedream really.)
The oil arrives from the feed side filter chamber to the middle, then splits for the ends. Had the motor run a few more seconds, the other b/end would have gone, followed probably by the main, which obvs has a much lighter load. Reason was a split oil feed pipe from the tank - ouch. Oil pumps - there are two gear jobs driven off the camshafts - are undamaged. Which is as well, as they're one of the 'hard' parts although luckily I have a few spare pairs.
Interesting about the urban myth on japanese cranks - I'll discuss with T&L Engineering to see what the options are. Obviously the less metal off the better - but these can go down to -60 no problem and Markus designed the angled oil passages from main bearing to the ends a tad deeper than on the originals to provide an extra safety margin after regrinds. In the old days, folk went down to -80 if BMC A series b/end shells were used and a suitable notch cut into the rods (because the locating tabs aren't on the same sides) but I always thought that was stretching things a bit!
(End float is dealt with by car-type thrust washers adjacent the centre main, available after a
l o n g interval in two thicknesses, which allow the use of chunky rollers which last a lifetime both sides.)
