[teflonbilly]

The rust has only formed since the last time the engine was run so is a red herring in terms of the extent of any damage.

The photos aren't the best quality so it's hard to say but why do you think the block might be scrap?

 

[teflonbilly]

I thought it might be scrap due to rust, but yes, like you say it's just surface rust.
Thanks for reminding me about the thin liners, forgot all about them, so that rules out a rebore.
I'm now hoping a hone and new piston rings should be enough.
If the bores have worn to much I'll see if I can get them relined.

From the symptoms you described I think the liners are fine. My best advice would be to get the liners checked anyway for cracks. Always worth getting the head pressure tested when it's off the car. If that's all ok and both the cylinder head and engine block surfaces are good then it should be a straightforward rebuild. There are several possible reasons why the head bolts had varying levels of torque but the most likely reason is that it was rebuilt by someone who had no idea what they were doing.

 

[teflonbilly]

So what should I have done?

I would have given the cylinders a good coating of oil and turned the engine over by hand a few times to sweep the bores with the pistons, then ensure a thin film of oil was left to stop them rusting up again anytime soon.

 

[teflonbilly]

I bought the car spares or repair for a grand and by the time it was collected, trailered to the Midlands, diagnosed and head off, a month went by so the lubing piston boat has sailed.
At the end of the day, I am were I am and i need advice on what to do now, not what I should've done with insight a month back.
Imo the block needs relining, but would be nice to know if it can be honed?

I understand your frustration but all I did was answer your question!

 

[teflonbilly]

I've rebuilt a few engines so aware of the cost which is why relining is preferred route as a I can keep pistons and just fit new rings.
Apologies Teflon if I sound frustrated, I'm not, I just don't understand how barring the engine over will get rid of those rust pits. If a gentle rub with some emery paper exposed them, then IMO scraping them with piston ring would also do the same.
Either way it would leave pits and comprise new rings.
I've now removed everything from the block and will try lowering it and sliding it under the wheel arch the next week. There's a machine shop nearby in Daventry that might be able to re-line. If worse comes to worse, there's a good used block on eBay for £230

I'm not an expert and have only rebuilt a couple of engines myself. My suggestion was based on the fact that you are unlikely to be able to remove the rust pits full stop but I think the engine will still run fine even with them present. My concern about the emery paper was that it would destroy the honing pattern. A sweep of the piston would remove any rust on the surface of the cylinder wall whilst not affecting the honing.

 

[teflonbilly]

Thats far worse! The rust will likely be dragged up and down causing vertical scoring and damage to rings and pistons. The only course of action is a light hone or carful diagonal rub down with fine abrasive medium. Trouble is you cannot see or get to lower bores. But once rusting has caused pitting, the bore is really none serviceable. I would not be happy using those bores anymore, Will likely have blowby issues.

If it was heavily rusted up such as having had pools of coolant left in cast iron lined cylinders for months then you might be right, but the rust in the photos is really no different to what forms in any engine that is left for some time without running. Provided there isn’t any significant damage these engines will almost always start up and run fine, and at a much higher speed than turning over by hand.