Was doing a head gasket due to the usual K series. Have done a few before but must have not had my Weetabix!
Took off head and had it skimmed. To have head skimmed you need to remove both cams/cam carriers/all head gear apart from valves and springs.
Reassembled and started engine. All OK apart from an oil leak from a cam oil seal on the front (pulley) end of the engine. Running at a fair rate down front of engine. Agghhh! Need to dissasemble some of it!!
Had to remove drive belts, cam belt and exhaust cam pulley, found seal was not fitted tight enough and lip was bent under seal spring, rectified and then wanted to test it would be OK without assembling the whole thing in case it still leaked.
Key part - Therefore, left off cam cover fronts and BOTTOM PULLEY(drives PAS and Alternator) has a long bolt, which goes through heavy pulley and through small toothed pulley which drives cam belt. Therefore this cam pulley is sandwiched between the big ancillary drive pulley and the engine. Therefore so is the cam belt!!!
Did not know and started engine without this big pulley on. It ran for a few seconds before the drive pulley probably wobbled a little and through off belt - thus stopping very quickly with the cam belt flying off the bottom pulley and the engine making a nasty noise.
DOH!! I thought I would get away with changing a few valves.
Went out on a night on the sauce to cheer me up before more dissasembly the next day. Took head off to find 4 nr valves had snapped around 25mm up the stems and turned upside down in pistons 1 and 2. Therefore pistons had smashed valves against head. OK, thought I may need a new head. After an age I managed to remove the valves from being embedded in the pistons. Luckily they had not gone the whole way through!! However, they had pressed large holes by their stems into the top of the pistons.
However, piston Nr 2 did not look right in the bore, notwithstanding the deep holes in it from the valve stems. Turned crank so it was at TDC - Oh dear. One side of it is 25mm above liner, other side is 25 mm below - bent con rod!!!!!!
At this point I knew it was a new lump so I thought I would "have a go at trying to bend it back" - succeeded but a large crack appeared down the liner!!!
Well and truly screwed!!!!
Reason therefore my stuppidity/lapse of concentration and lightweight K series ally pistons and con rods!!!
Have now changed engine but have been on holiday so have not tested properly yet!!