948 Engine rebuild

[rogerowen]

I've got a nice 948 engine to rebuild. I've popped off all the ancilleries and cylinder head. All looks good BUT - if I turn the engine over it turns through about 5 degrees (very easily) then meets strong resistance. I can force it through a complete rotation, bores look absolutely fine, but somethings up. Any ideas?

[mike.perry]

The only sure way to find out is to strip the engine and examine each part as you remove it.

[kennatt]

At this stage it matters not,its on the progressive REBUILD,that at each stage the engine should turn easily by hand that is if you are doing a full strip and rebuild not just sticking shells into it.Allthough it would be handy to know where the tightness is, just check at each stage of dismantling.

[rogerowen]

Good advice, thanks. Given the lump has sat for over 30 years -it's probably not suprising that something's a bit sticky somewhere .

[JOWETTJAVELIN]

Of key importance is LUBRICATION. Fresh engine oil must be used copiously on every bearing before assembly and in the bores when fitting the pistons.

[beero]

If it has sat for 30 years it could be corrosion in the bores. Your best bet is to take it apart.

[rogerowen]

Good point, but bores look excellent. No oil in the sump - so I'm wondering if shells are dry>?

[beero]

Sorry, didn't read your first post properly where you said head off, bores good!!
Has someone taken it apart before and put the shells back in wrong way round or wrong order?

[bmcecosse]

Don't force it round - whip the sump off and inspect the centre main and the big ends to see the general condition.

[rogerowen]

Sorry, didn't read your first post properly where you said head off, bores good!!
Has someone taken it apart before and put the shells back in wrong way round or wrong order?

That's a possibility . Had that happen before with an MG Midget engine (Triumph 1500). It was one end cap reassembled 180 degrees out!!!

[rogerowen]

Don't force it round - whip the sump off and inspect the centre main and the big ends to see the general condition.

Good thinking. I've just aquired an engine stand which is something I've not used before, Not sure if one is supposed to attach the engine with flywheel on or off. Also slightly nervous about the stress tat would be imposed on the rear plate - maybe that comes off before mounting the engine.

[bmcecosse]

Engine stand is useless - more trouble than it's worth - use an old table/desk. Much easier/safer access. Certainly DO NOT attach it on the backplate - it will bend........... and you need the backplate off anyway.

[rogerowen]

Engine stand is useless - more trouble than it's worth - use an old table/desk. Much easier/safer access. Certainly DO NOT attach it on the backplate - it will bend........... and you need the backplate off anyway.

Thanks. I'm not thinking straight - too many mince pies!