My engine builder used to say "drive it/ride it like the throttle cable is down to a single strand"
He was wrong then...
It'll never run like that and probably glaze the bores... you need pressure and increasing heat, till it will stand full heat after say 1,000 to 1500 miles or so.
As said above correctly, if the bores have been properly cross-hatch honed, and the pistons and rings are correctly sized (check the ring gaps as per works manual down the bores at various places, to give an idea of bore wear and profile) then all will be OK
You couldn't drive an NA Diesel on a whisper of throttle everywhere anyway.
Drive it normally, but gently to start with... but with these provisos:
Heat is a function of throttle position and time...
Heat it can stand needs to be gradually extended, not gently for 1000 miles and then everything
So, can use plenty of throttle for a few seconds initially to get moving, then back off... so it forces rings out so they actually bed in.
Extend the time at larger throttle openings over a period of 500 to 1000 miles, from a few seconds to start with to a minute, then to a couple of minutes etc
Don't cruise at a large throttle setting for long to start with, go up to 50 ior so then lift off and let it settle where it wants with your current level of throttle, say 1/4 or 1/2, or 3/4
Don't use full revs to start with, but quite early, you can for a few seconds if it wants to rev freely, then tens of seconds etc
To restrict heat up hills change down earlier and go up on a lower setting, in,lower gear more slowly
Don't be frightened of it, if you feel you're pushing it's capabilities, lift off and/or change down..
The things to be careful of early are not around town, but on the main road or M-way, try to avoid M-way for a few hundred miles, as this is a low powered engine and always will have to work hard... take the A road.
If into wind or on a climb on M-way, be very aware of the load (throttle position) and every now and again back off for a minute or two where possible and then get back up to speed gently, use downslopes to build up speed and then see if she's happy to hold it on the level...
But every now and again, use some throttle to accelerate briskly, and as time goes on for longer and longer... to start with zip up in 2nd and then 3rd and then take it easy in top... then after a few hundred start giving it a minute or two of good acceleration in top (if that's possible!)
Do not worry too much, just keep it spinning and don't labour it toomuch or for too long, keep changing down if worried, steady as you go, accelerate and then back into top - modulate the throttle, a minute at one setting, then a minute at another. Let it build up speed if it wants to... but don't hold foot on floor for very long till a few hundred miles...
Don't carry heavy loads if you can help it to start with.
Don't idle it for more than a minute or two very early on - drive it or turn it off!
Change oil at 2 or 3 hundred miles, then after another 500 and then after say 1000 and that should be it. Use good quality diesel mineral oil up to 1,000-~1500 miles. Change the filter every time you change the oil
Provided it's been honed and you
don't '
drive like there was nly one strand of throttle cable left', it will soon be going quite well.
Remember, accelerate briskly in the lower gears but change up earlier than usual
Good luck, there should be few hard and fast rules, you have to drive along with the rest of the traffic, it's just hills and M-ways that are a challenge at the very early stages, so avoid where possible in such a low powererd and heavy vehicle. Make sure tyre pressures are corerct too, so it rolls along easily.
I ran a set of rings in nicely in one weekend, but it
was a 1,000 mile weekend... it was going rather well after 500 miles!
