JerryS

I think this is just a drilling down through the chamber to provide an oil feed to the aux shaft bearing that end. It's blanked off when the housing is bolted into place. I don't have a gasket handy but quickly traced a bit of paper to check: Keeping going Fabian!

Thanks for that description. Wasn’t pictured but that advert said they supply a special extra long tap, your work around sounded good. The last helicoil I did was on a couple of exhaust stud threads. I was hoping to fit longer helicoils than the ones supplied but found the tap couldn’t cut deep enough to the bottom of the hole. I guess at least the head studs have a better chance with the reduced nose where they bottom out. I have a block which had suffered from the head studs corroding in. Got them all out in the end but I'm going to have to revisit the situation. Re gasket/head stud issues - I’d noticed the Northstar engines having similar problems and this radical fix using studs with unequal ends. Not sure if this could be possible with the 9xx block though. https://www.youtube.com/watch?v=wqEj9BKlVEE

Hi Thomas, did you repair this successfully? Just asking as I wondered how feasible it is to repair damaged head stud threads recessed so far down in the block. I recently noticed this insert kit on ebay (in the US). https://www.ebay.co.uk/itm/LOTUS-ESPRIT-907-910-912-ENGINE-M12X1-75-CYLINDER-HEAD-BOLT-STUD-THREAD-REPAIR/153450133860 - Jeremy

Dave I noticed this post on the Lotustalk forum from Tim Engel re crank position for frequency test... https://www.lotustalk.com/threads/timing-belt-tensioning-with-a-snark.470848/#post-5965838

Yes SJs and also just seen PNM have the belts listed...

Do they have to come out Tom? Be good to use new ones in your replacement block. - Jeremy

Don't worry Pete it's not on the way to becoming a coffee table... yet. I made up some odd blanking plates to fit while the block was floating around the workshop. Here's another I made to help marinate the liner joints on my 911 rebuild (can just see the extra long MB studs):

Yes dry sump would make things more flexible. Here's a Sunbeam 911 sump compared to a 912 bottom end:

Lotus Bits should be your first port of call Des. You need the 911 for the correct sump to avoid the chassis crossmember. - Jeremy

Yes maybe a job for a rainy day. My autopsy pics:

Hi Jani, what caused the seizure? I just wondered as I bought a reconditioned alternator that appeared to seize up all by itself. On dismantling I found that too much resin had been used on the internal windings during it's rebuild and this had worked it's way between all the moving parts eventually jamming everything up solid. I managed to file and scrape off the excess and reassembled it and then it was fine. - Jeremy

Here's a pic. I found the 5mm seal was too thick taking up too much of the endfloat on the shaft, but it slimmed down to 4mm ok on some flat emery paper.

I may be able to help you there... Will pm you.

Hi Tom, I've noticed a few 9xx engines on the web (usually fleabay) with different sump mods, usually to put a 907 into a Sunbeam rather than the other way round. What are your plans with the engine?

I remember seeing this post a while back from davetoff re splitting the MBH. Looked like the best way to approach it.