Series 2a Crank won’t turn clockwise and is locked

Hello All,
I hope you are well. I have a late series 2a that I have been doing a full restoration on. The car is almost complete and I drove it about 150 miles completely fine. It was leaking a bit of oil from crank seal so replaced that and had to replace the head gasket again due to it over heating slightly and loosing compression. (Hopefully fixed)

I replaced the head gasket and re adjusted the tappets and after doing so she fired into life brilliantly not perfect but not far off. Ran it for about 10 minutes and was adjusting the fuel mixture and she suddenly died.

I tried to restart but no luck. I then tired to turn the dog nut clockwise and it is absolutely locked. It will spin completely smoothly in reverse but as soon as you try and turn it back clockwise it jolts and then locks and is impossible to turn any further.

I have tried a few things. One of the things I tried was loosening the conrod bearing ends as I thought they were locked up. Did this and tried to turn the crank with no luck. I inspected the bearings again but they were replaced when I did a rebuild of the engine and were fairly new. They had light scoring on a few so will replace but the crank still would not turn with them loose.

I then did the same with the crank bearings and they were completely fine I have not removed the crank bearing block closest to the bulkhead as this was too difficult to be removed to easy but loosened it and removed the others and the crank still would not turn.

I have also tired to start it with the clutch engaged encase it was a gearbox issue. Still nothing. Only a click from the starter solenoid.

I am a young novice and I am absolutely puzzled so I would be grateful for any recommendations

Thanks,

Tom.

Something simple like the starter jammed? Easy to check

kermit_rr said:

Something simple like the starter jammed? Easy to check

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Unfortunately not. I removed it and tested it and tried turning the crank with it out and still no luck.

have you checked the distributor? I can't think of anything else that would prevent the engine turning in one direction.
Take the rocker cover off and check they are all moving, i wonder if one of the rollers has given up and is jamming in one direction...

Have you checked the timing chain and tensioner

kermit_rr said:

have you checked the distributor? I can't think of anything else that would prevent the engine turning in one direction.
Take the rocker cover off and check they are all moving, i wonder if one of the rollers has given up and is jamming in one direction...

Click to expand...

I haven’t checked the distributor but I have checked and all the valves move up and down. Should I still check the distributor? Thanks again.

mystery said:

Have you checked the timing chain and tensioner

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No I haven’t perhaps I should check this as well. Although when I took one of the crank bearing block off I looked underneath and the chain looks tight but I don’t know if the chain tensioner could cause the issue?

It didn't run perfectly after you did the gasket and tappets.. how exactly? got to be related...
You say it turns the wrong way ok.. turn the right way it jolts and stops.. something is catching or has come loose/broken, possibly.. I'm thinking something could be binding on the way a sprag clutch does.. so likely cam or cam chain related as the starter is already off
Do the easy things, plugs out.. rocker off.. dizzy out.. do any of those make a difference?

also when you rebuilt the engine did you refit the collar locking grub screw oil pump drive shaft

You may have dropped a socket in there somewhere and locked it up

When you say turns backwards ok.....is that a full turn or you a part turn.