A bit of an update on progress for you all. The last few weeks have been spent solving various conundrums in the engine rebuild project.
The crank has now been sent for harmonic balancing. The workshop I was using (Crewe Engines) closed down, but the guy who did the machining on my block has moved to another company that's a bit closer (Lymm Engine Components). As relayed to you all earlier, they've recommended 'externally balancing' cranks from engines of this age, which means balancing it with all the rotating parts attached - so front pulley and flywheel.
But that threw up a few unknowns for me, so I put off sending it away until I was sure I had all the right parts. The issue is new engine is an earlier block (400 ... G) than the one in the car (446 ... A), but I want to keep all the ancillaries of the later setup, which means meshing two different sets of part numbers together into a combination that fits. A lot of parts you'd think were the same are actually different between the model years, and not all of them will necessarily fit together properly.
I want the new engine setup to have:
- An alternator, which means...
- Long-nose water pump, which means....
- Deep front pulley, which means....
- A big compatibility puzzles to find the right combination of bottom chain wheel and pulley assembly. Both came in different dimensions over the years. (Daunting, I know. Read on...)
And...
- Pre-engaged starter motor, which means...
- Ring-gear with chamfered teeth on the other side (or does it? Read on...)
First issue was solved with a lot of reading. It turns out the change to single-intermediate chainwheel realigned the bottom chain fractionally, so the chainwheel itself is slightly broader. That necessitated a front pulley assembly that is slightly shorter, which is the same assembly fitted to later cars. So I ordered a NOS set of chainwheels of that type, and have taken the pulley off my 446 engine. The two will go together, which is great because that will run with the long-nose water pump and alternator without issue.
So all of that adds up.
All now scavenged from the old engine. Tick
The second problem was the ring-gear. The flywheel has already been skimmed. Had I known in advance, I'd have taken the flywheel off the 446 engine and had that skimmed instead. But that's still inside the bell housing. The issue is the teeth on the flywheel have the chamfered edge on the clutch-side to suit an intertia starter motor, whereas I want to refit a pre-engaged type. I knew I could source a new ring gear (ChrisW offered me a NOS one) but that would need to get that fitted before it could be balanced, which is extra faff. But happily, I discovered my 446 engine doesn't have chamfered teeth on
either side (see below), and I've never had an issue with the pre-engaged starter, so I'm leaving the 400's ringgear as it is. The pre-engaged starter will fire the pinion in from the none-chamfered side, as it currently does on the 446. No issues there. Tick
So with that, the crank went off for balancing....
Next up was the pistons. They're a NOS set of +0.060" Hepolite pistons that I sourced about 10 years ago for £90 (wrongly listed on eBay as "Rover 200" - I think we've all had some bargains from that slip-up!). They came with gudgeon pins, rings and circlips, and instructions. The block has been machined accordingly. Unfortunately one of the pistons has broken compression rings. I discovered this too late in the day, so started the hunt to find them. After many false-starts, I contacted
Cox & Turner in Yeovil, who were able to tell me the precise dimensions from a catalogue within 20 mins (which I verified against a good ring), and had them on the shelf. £25 the pair. They will obviously need gapping appropriately, but that got me out of some very dark woods!
The broken rings:
So with that, the engine project is full steam ahead.
Hope to have it built up by midsummer.
Michael