95 M3 engine destruction/overhaul

[99MPower]

As some of you know, I've moved into the San Diego area. I primarily work on E30/E36/E46 stuff (E36 most well known, but I've done a couple 24valve E30 swaps, E46 valve timing stuff, etc)

Just wanted to share the current project.

This "customer" brought the car to me today because he was told it had dropped a valve. Motor didnt turn over all the way, but we didnt know if it just needed a new cylinder head, entire motor, or what.

This is what we found














We are in the process of sourcing a s52. This was an s50 from a 95 M3. I believe the initial cause was a bad valve retainer at 6000rpm (according to owner). Valve rips through retainer, drops into combustion chamber, eats valve, jams valve head into cylinder head after eating piston, and valve stem gets bent in half and wedged into the intake manifold.

New motor will get a proper refreshing for track/auto-x duty, and some other maintenance while we are in there (one of my powdercoated, reinforced front subframes, new clutch, rod bearings, dual pickup oil pan, fresh cylinder head with upgraded retainers, and all the gaskets/parts to go with it.

I'll try to keep this updated as I work on the car this week, and get the "new" motor this weekend.

Enjoy, and let me know if u need any work done on your track/weekend toy.

Calvin

[Crazy 13immer]

Dude, Calvin I didn't know you moved to SD! That's awesome! I'll have to look you up next time I'm down in the area.

-Paul

[shervinguy]

ughh im so scared of this happening to my 95, how hard is it to change the valve retainers before they bust?

[99MPower]

ughh im so scared of this happening to my 95, how hard is it to change the valve retainers before they bust?

ideally you do a HG and pull the cylinder head. Have the machine shop deck it, pressure test it, clean it, and then a full valve job (3 angle valve job, new valve seals, and when they reassemble, have them install a set of reinforced VAC retainers)

Not too bad, worst part is the machine shop and labor (having it done as a "side job" definitely helps keep cost down though. I know a good person )

PM me if u want more info

[IamHanSolo]

PM sent!

[99MPower]

folded valve stem



prepping the wiring harness



get that shiet out of the way



where did it go?



there it is



transmission/clutch removed



Engine on the engine stand, and I'm done for the night




driveshaft, exhaust, wiring all removed, and got the engine/trans out. Pretty good day.

Tomorrow is tear down, and clean up. Owner has been searching for a good s52 motor to start prepping

until the next update

[99MPower]

new 120k s52 out of a 99 M3 automatic on the engine stand



wiring harness all removed



manifold removed so I can strip the remainder



cleaned up, and oil filter housing removed (euro oil filter housing going on)



coils all removed, valve cover about to come off



front about to get started



thermostat housing off, valve cover off, vanos/cams ready to come off



vanos off



where did the cylinder head go?



pan off, ready for oil pump, oil pan upgrades (z3 2.8 pickup tube, baffled oil pan, rod bearings)