My mate Dave and I have recently rebuilt a Lotus Twin Cam engine for a friend from the Lotuselan.net website. The engine was from her sadly deceased father's Elan Series 3 which she was getting restored to commemorate her father. So Dave and I stepped in to help. The engine's bottom end was quite tired, and we had to have the block rebored and the crank reground. On the top, the head needed new inlet valve seats (oddly the exhaust seats were OK, and new valve guides. Reassembly was pretty straightforward with new shell bearings all round, new pistons and rings and the use of lots of Graphogen on the bearings. We replaced the water pump and timing chain and all the chain sprockets, and up top fitted new valves, ground them in and set the valve clearances. There were a couple of glitches - the rear oil seal holder had a stripped thread in it where one of the sump bolts fitted - an insert solved that. We found the thread in one side of the timing case to head join was also stripped - that was solved with a through bolt. Finally one of the bolt holes in the flywheel where the clutch pressure plate bolted on was threaded - we only found that when we had fitted to the clutch to the flywheel, and it was the last bolt we tried to fit. That meant taking off the clutch and flywheel and getting a proper 'Timesert' insert in it which took a couple of days at our local engineering company. However, otherwise all went smoothly until the new lockdown loomed - the friend was going to collect the engine on Sunday, but we had to arrange for another friend to pick it up on Wednesday to avoid it being locked into Dave's garage for the duration!
Dave and I will be going to see the car once its ready to start up and I'll hopefully have some more notes on it in about 6 months time.
Here is the head before the rebuild - tatty paint but not too bad.
Engine before the stripdown - again tatty, the wrong colour and showing signs of wear
Its upside down but the timing case is on, sump is loosly attached and its all the right colour now! Still need to fit the head mind - note the cable ties keeoping the cam chain out of the way.
And here we are - all done bar the rocker cover. Very enjoyable job - I've built up a few Lotus heads and timing covers over the years and have a couple of 711 blocks so I'll have to build up a tall block TC unit once my new workshop is ready!
Here's one I did earlier - the zero timed Twin Cam for my project Plus 2 sitting in the Spyder chassis with the engine bay nearly ready for its coat of satin black paint.......
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