Series 3 Engine turns.....engine seizes.

Ok so it seems to be well and truly seized, as you have already soaked the pistons and bores with oil suggest
Leaving it a couple of days and trying with the starting handle and if no joy I would remove the head for a look see,

You may have been rather unlucky and the engine has stopped at TDC, This means that two pistons are at the top of their stroke and two at the bottom.
With only a little corrosion/old hard carbon in the bore it can be very difficult to get the engine moving now the rods are vertical an have little leverage.
Had an engine like this once and tried all the tricks above but in the end it was head off and whack the high pistons [ block of wood on top ] until they came free. Cleaned it up and wind it over on the starter a good bit, Back together and went on for years.
As Wimblowdriver says a socket and bar on the crank bolt and rock it back and fore. May get it moving after a soak.

Thanks for all the suggestions, will persevere and try the 'rock it' approach!!! Will let you know how I get on?

When it first turned over on the starter how long did you crank it for?...if the plugs are out and its not turning over I'd take the rocker cover off and have a look at the valves maybe a broken dropped valve jamming piston...

What he said ^^^
Take the rocker cover off and see what's happening

We have to acknowledge that the engine was turning over before, I can't see that the bores are too rusty and pistons seized... this is a strange one. Tottot's suggestion above is intriguing and worth thinking about. If it were mine I would be taking the head off and seeing what there is to see: what condition are the bores, are the valves intact and free etc.

Is there any movement at all when you try to lever the ring gear? Even if only a tiny bit?

I'd stick it in reverse and get a couple of mates to try pushing it forward a couple of feet.

Col

When you were starting it with starter motor you probably depressed the clutch, could there be an issue with gearbox. l would try the starter motor again with clutch depressed before taking engine apart.

Have you a cylinder full of coolant?

Just checked and looks/feels dry. I can make out some carbon deposits on the face of the pots at TDC.

Have you removed rocker cover to see if everything looks in order with the valves and rockers and camshaft?

I removed the rocker cover and everything looked in order to me; everything where it should be, springs/rods/arms all present, nice and oily, no corrosion?

BlueAnne said:

I removed the rocker cover and everything looked in order to me; everything where it should be, springs/rods/arms all present, nice and oily, no corrosion?

Click to expand...

Have you tried rocking/pushing it in gear?

Just refitting brake drums at the mo. Once I have them in and wheels on, I will try rocking it. Does it matter which gear I use to rock it?

Use 4th as in this gear the drive is straight down the main shaft.

Cheers guys, will be rocking this weekend, fingers crossed and will keep you updated! Thanks very much for all the advice.

Just a quick update.........Success......she turns!!! Rocking finally worked!!! Thanks for advice all, much appreciated!!

well done