Official BMW Video

[digger]

Official BMW m20 video disassembly and reassembly. looks like a B23

https://www.youtube.com/watch?v=sfx3...ature=youtu.be

[zaq123]

nice find. One can use CC and select auto translate for English CC

[dnguyen1963]

Wish I have some of those tools...

[D.Martijn]

Haha also just found this video on youtube. Great info on removing the rocker shafts!

[zaq123]

Haha also just found this video on youtube. Great info on removing the rocker shafts!

Yeap, they come out by hand nicely. Sometimes one needs to deburr spots where rocker retainer clips are sitting. It makes me cringe when someone knocks those things out with a hammer etc Sent from my iPhone using Tapatalk

[D.Martijn]

Yeap, they come out by hand nicely. Sometimes one needs to deburr spots where rocker retainer clips are sitting. It makes me cringe when someone knocks those things out with a hammer etc Sent from my iPhone using Tapatalk

Indeed, I needed to buy new shafts since the previous owner mushroomed the shafts when installing...
I was able to assemble the head without hammering them in as well.

[ForcedFirebird]

I haven't watched the video, but also have dealt with mushroomed rocker shafts. It's because people try to remove them while there is still spring tension on them. Haven't watched the video yet, but I just slide the rockers off the lobes while turning the camshaft and they remove pretty easily. As zaq said, too, I use a tiny file and remove any burrs on the retaining spring slots. Also helps a lot if you clean the head first, carbon build up is enough to make some difficult to remove.

[zaq123]

removing/installing those shafts is like putting Rubik's cube together....yes you can brake it and hope it will go together but it's not how it was designed to be solved

[ForcedFirebird]

I am a lame dad. Took me a bit to catch on to the solve the cube matrix, but went around the house and solved them all in one night, several Christmases ago. Lol

Much like the '78 Datsun truck I bought for $300 in 1996. It was my first top end rebuild - that turned into - rebuild everything - a $300 truck that was probably $1k all in..... If we only knew now.... dang nabbit, get off my lawn.

[digger]

There is an equivalent M30 video.

https://youtu.be/NVQWfhYpjRE

i like the fixture they use to disassemble / assemble the valve train. i'm not sure how the valves don't smash into each other though

[ForcedFirebird]

M30 had a unique design with 4 rocker shafts. Again, didn't watch the video, but they do take a bit more enginuity for a DIY'er. The spring tension cannot be released on all rockers at once since the external spring clips and retainers are too close to the head casting bosses.

Albeit, once a shop has setup for a particular cylinder head, repeatability is moot.

Similar to the 24v head fixture/tool, there are work-arounds with competent machinists.

[Victell]

This video should be archived here on R3V

[digger]

M30 had a unique design with 4 rocker shafts. Again, didn't watch the video, but they do take a bit more enginuity for a DIY'er. The spring tension cannot be released on all rockers at once since the external spring clips and retainers are too close to the head casting bosses.

Albeit, once a shop has setup for a particular cylinder head, repeatability is moot.

Similar to the 24v head fixture/tool, there are work-arounds with competent machinists.

i don't understand how it works on an M30, pushing the valve down lifts the pad end of the rocker to enable the cam to slide in but the inlet and exhaust valves will clash? atleast on an M20 you cant lift both valves to max lift at same time as they clash into each other

[ForcedFirebird]

i don't understand how it works on an M30, pushing the valve down lifts the pad end of the rocker to enable the cam to slide in but the inlet and exhaust valves will clash? atleast on an M20 you cant lift both valves to max lift at same time as they clash into each other

They way I do it, cam comes out last, and goes in first just like m20. On m20 you can rotate the cam as you slide the rockers off the cam lobes - once that happens, the shafts slide out one end or the other. The m30 has circlips and washers to hold rockers in place which inhibit the rockers from sliding enough to release all rockers - you will always end up with at least one rocker still in tension. So, what I do is get enough rockers off one half of the shaft and pull them out, rather than push them through. The m30 has threaded plugs on the end of the shaft halves, so they can be removed and bolt threaded in to be able to grab.

Just scanned the m30 video, interesting in your thought about the valves hitting. I am in the process of building another m30 head, can easily check how far they can open before hitting each other, but my guess is the fixture only opens the valves enough to clear the cam lobes.

Also interesting that they use a rubber tipped punch and hammer in the video.

EDIT: Video was playing as the post was loading, saw the valve seat cutters they are using, and happen to have the very same set lol.

[digger]

i'd think you'd need to get them to max lift.