Seized Engine Conundrum

Hello,

First post on this forum. Bit of back story Series 3 with 2.25L Petrol 5 bearing with 36,000 miles. Was running fine but developed a slight miss fire lasting only a few seconds a mile from home after a 35-mile drive. Water temp and oil pressure were normal. Go to start the engine 3 days later and it won’t turn over, with the crank seized solid.

After taking the advice from a few friends and garages and going through all of the easy things(ancillaries, water and oil in the cylinders), came to the conclusion that something must be seized. Jump to the present, I now have the head off with the pistons all out and it's still sized. All parts removed so far in good condition. I can just about turn it with a bit of leverage but it takes everything I've got to do it and compared to my Series 2 which still with good compression is easy. So I'm under the impression that it must now be a main bearing or something in the timing. I'm at the point now where to do any more I will probably need to pull the engine out.

So before I go any further I was wondering if anyone has any wisdom about what it could be?

It was also serviced with new oil, filter and cleaned sump and a few replaced gaskets only 75 miles before.
Is it possible an oil way could be blocked?

Thanks in advance.

I would check the cam followers and cam shaft first, then the timing chest and finally the crank bearings. Presume something’s gone tight so it managed to keep running but once stopped couldn’t budge again

Sounds like it’s an engine out job

But just out of curiosity have you pushed the clutch and tried to turn engine?

Shame cos it looks like a good one.

Welcome

J

A s you have had the sump off you could remove main caps one at a time to check shell bearing then replace
You can also remove timing chain then you c@n turn cam and crank independently see if ones tight
Assume push rods and followers ok ?