Help with 520i engine overhaul. just fried it going 210 kph and oil pump seized

[aabdelhamid]

I just fried my engine, going at 210 kph and the oil pump seized, the engine sounds like a tractor now.
I am planning and overhaul next week. Do you have any instruction and precautions I can use to start this process as well as fitting and torquing tips. I am truly worried about paying too much money for this job and not getting the best quality. I need the instructions in detail please.

[E34-520iSE]

I rebuilt my M20 2ltr block myself a couple of years back so I know a fair bit about it. I can give you as much detail as you need - no problem. I gotta ask though, would it not be easier/cheaper/quicker to get another engine? My block rebuild cost £1200 UK, I could have had a decent engine for £300 or less. If you really are set to rebuild then give me a shout. Have you got somewhere you can keep the car while the engine's out?

Cheers,

Shaun

[Gene in NC]

I vote for used engine. I call such sources "involuntary and unscheduled organ donations" Rebuilding a locked up engine should be left to nla antiques.

[E34-520iSE]

Absolutely! 'If I knew then what I know now' I'd have just dropped another engine in. Would have saved me a fortune...........

Cheers,

Shaun

[Kai@e34.de]

broken rocker arm or worn conrod bearing i guess

[E34-520iSE]

Same thing can happen when the oil doesn't get changed and the black goo fills all the crank journal oil holes - fantastic! Somewhere around here I have one of my old conrod bearings from when my engine went crank! I'll try and dig it out and take a pic. The middle of the shell is about as thin as a piece of paper - made a sort of knocketty knock knock knock sound before removal.

Cheers,

Shaun

[Kai@e34.de]

from the moment on you HEAR this knocking, your crankshaft (low end) is damaged. it's insufficient to change the conrod bearings only.

[E34-520iSE]

Exactly Kai! This is why I'd recommend the guy getting another engine at this point. It cost me big ££££ to get my crankshaft reground and new oversize bearings obtained, and that was just to repair the block. If his valves, cam etc have been starved of oil then it's time to go off and cry somewhere. So, as to maybe help him decide his engine's fate - What would be the point where you'd say the M20 engine is scrap?

Cheers,

Shaun

[Kai@e34.de]

hard to say. depends on how much you've to pay for an used M20 and in which condition your current M20 is.
if it's only a broken rocker arm -> doesn't matter.