Quote:
Originally Posted by Laird Scooby
Something you haven't mentioned Alan is whether you've considered the fact that new standard size shells, rings etc may not be right for the engine and are going to hone the cylinders when you replace the rings? Also what if you get part way through the "one day refresh" and find things are out of tolerance? The engine would likely have to still come out then and you also mentioned changing the rear crank oil seal - gearbox needs to be disconnected from the engine to do that.
I've also seen someone do the one-day refresh on a 240 leaving the engine in the car. Took him nearly 2 weeks. All that time the car was up on big axle stands (not commercially available back then, he'd got a colleague to make some up i believe) and by the time he was finished the whole lot was looking wobbly.
I know you are also seeing the "how far do i go with this job" scenario but i think if you decide on set limits (subject to change if you find something that really does need immediate attention) of exactly what you're going to do.
However when all is said and done, it's your choice of how you attack things. Regardless of whether you go for the one day refresh or engine out option, allow double the amount of time you think it will take, there will almost certainly be things that crop up that need more thought and/or parts but the decider for me would be the amount of hassle it is to line up a box on an engine (or vice versa) when one unit is already in the car. It really is so much easier to unite (or split) them outside the car then simply line up three mounting points rather than try to line up the mounting points, the torque covnerter on the flywheel/driveplate, getting the gearbox to slide onto the engine while maintaining the mounting points in position.
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Quote:
Originally Posted by john.wigley
Alan, I sense that you have the 'bit between your teeth' on this one, but I'm inclined to agree with 'L.S.' in his more cautionary approach. As a rule, car engines, on account of, as you said yourself, their lower RPM and more efficient cooling and lubrication systems than their motor-cycle equivalents, do not normally require a bottom end refresh as frequently as I suspect do bikes.
Whilst I'm also very much in favour of preventative maintenance, a case might also be made for 'if it ain't broke, don't fix it'*. On that basis, it could indeed make sense just to replace the rings and shells and leave the big job until later.
I don't have your degree of experience with bikes, being limited mainly to mopeds, scooters and other low capacity machines like the BSA Bantam, but I can remember a time when the need for a top-end overhaul every 10,000 miles was not unusual, with a rebore, new pistons, reground crank and new big ends and mains at 30. Certain cars, like the Riley, didn't even use shells (although a conversion kit was available) but used fragile white metal bearings which required recasting and line-boring.
Regards, John.
*As an aside, a 'bus operator that I knew took preventative maintenance to a whole new level. As part of a national policy, they introduced an 'Annual' service, a requirement of which was to routinely replace all of the vehicle's coolant hoses. Accordingly, OE hoses, which might be expected to last for at least three years, were cut off vehicles - some little more than a year old.
These were replaced with after market items of an inferior quality (to save money (!)) which were found to have a MTBF of 10 months! It was not unknown for one to fail in service, only to be replaced, and cut off and renewed again, a couple of months later, when the vehicle came in for it's 'Annual'.  J. |
Many thanks Dave and John,
I think I had covered all those eventualities in my above Dave. If the work turns out to be more extensive after I've pulled out the pistons I would have lost nothing: the lump would still have to come out anyway. Also I'd mentioned honing the bores in situ (easy on bikes where the barrels come off, but should be possible with the bottom and top of the engine off) - and the rear seal will be done when I swap do the AW71L box job (as I said - probably spring 2023).
Jobs normally take longer than expected, but a one day job becoming a 2 day job wouldn't be much of an issue (but a one week job taking a fortnight would start getting in the way a bit). I'd be doing some of this during the service anyway: dropping the oil and coolant, checking the valve clearances...
Whichever way there will be things that crop up, that is just the nature of older motor cars :-)
You are right that car engines last much longer than do bikes John - they run much faster and are worse cooled and lubricated as you say. I could just leave the RB until something actually goes wrong (like oil consumption goes up, or it starts smoking), there is nothing wrong at the moment. The BofH gives the impression that access via the sump pan is pretty easy - but as I said to Dave above, if it doesn't work out I've lost not a great deal and could still continue on to pull the motor out.
... I'm still very much considering the options. A bit depends on what I think of the AW71L job. I'll collect the auto box from Luke in the coming weeks and will have a better idea about how much work it will be (and the best way of doing it).
:-)