Surface rust inside engine block

[Tophutt]

I’ve taken off sump, cleaned up gasket surfaces put back sump lose fitting as was expecting to take off again to repaint. Live got the bloody way n rtn to job a few weeks later. Sump had half a cup of water inside, plus surface rust on underside of crank etc. Am I likely to have ruined the internals? I was thinking magnet in the sump, regular oil change n might just get away with it. Or do I risk damaging engine,oil pump failure etc?

[Colin Lindsay]

Surface rust over a few weeks won't have eaten into anything sufficiently to cause real damage, but make sure it's all gone, and oil everything well, before you start up again. The visible bits of crank don't do anything; it's the bits inside the bearings etc that do the work and there should have been at least some residual oil there to keep moisture out. Just make sure there's no water in the bores when you turn it over as it won't compress and could damage anything it pushes against.

[johny]

Agree with Colin but thats some amount of condensation! Will you have a quick peak at the crank bearings and thrusts while youve got the sump off or have they been changed recently?

[dougbgt6]

I once snapped a crank in my daily driver, an old mini. At that time you could get an exchange crank for half the price of a new one, but the old one had to be in fair condition and one piece. So I went to the dump and found an up ended mini engine, for some reason the sump was off and the endcaps on the mains and big ends were off. All I had to do was lift it out, the bearings were red rusty but it would do for the exchange. Paid £5, took it home and then thought "Better clean it up!"  Having done that it didn't look too bad so mic'd it up and it was OK, certainly within spec. Reassembled the engine and the car ran another 5 years and it wasn't the crank that did for it in the end, side swiped on a roundabout.

Doug

[JohnD]

Clean and wire wool the rusted areas, then treat with phosphoric acid.    This leaves a hard, insoluble layer of phosphate on the surface where any remaining rust was, better than a coat of paint!

A magnet will catch any remaining rust particles, and tiny wear particles - good practice anyway.  But not loose, sump plug with bonded in magnet best.

John

Edited April 21 by JohnD

[johny]

Dont think a magnet will help much with rust but no worry as the oil filter will do the job. Then perhaps renew the filter at the next oil change rather than leave it to the next? 

[Pete Lewis]

a question  where on earth did the cupfull of water come from to get in the sump

it /doubt   wont be condensation 

light staining a rub with an oily rag .......you need to see the state of cranks left outside to normalise 

i nice big magnet taped to the oil filter always seems agood idea 

Pete

[JohnD]

Thank you, Johnny!  I always assumed the iron.oxide was magnetic!    EDAScHD!

John

[PeteH]

Ferric oxide red is largely non magnetic. Black is (magnetite). 
 

Pete

[JohnD]

Hence the name, I presume!

[Tophutt]

Thanks all, I’ll have a look at crank thrusts n bearings. I am a bit surprised at the amount of water also, esp as system was drained long time ago so I can only assume was from condensation. It’s been so rainy for so long, everywheres basically damp if not sealed. There’s no way water can to inside of engine block, was all running fine before I started working on it.

[micklewis]

blocked breather or cracked block can induce high amounts of condensation within the block .

check breather , change oil and monitor .

fyi   rust inside the block was probably there long before it was machined !!

 

 

mick