Rocker Lever Broken on a M20 :(

[Mordan]

Hey

look what I found when opening the head cover

http://www.mordan.biz/bmw/valves_2.jpg
http://www.mordan.biz/bmw/valves_3.jpg
http://www.mordan.biz/bmw/culbuteur_broken.jpg

Have you ever seen that on a 180 000 km (120k) M20?

How to best repair this? Can you do that without dropping the head cylinder?

Thx

[Jon K]

Yeah that repair isn't too bad and its very common. I believe you remove the rocker bar and install a new rocker. Someone will know more about it but don't worry you're not alone. It actually doesn't damage anything really - your intake valve wasn't opening so no fuel or air was in that cylinder. That means you shouldn't have burnt a valve or anything.

[Pwr2spare]

The samething happened to me a few years ago on my M20. On the drivers side but more in the middle, thus having to take the head off. Since your break is on the rocker towards the front you may be able to slide the rocker arm shaft towards the rear of the engine and put in a new one. Good luck.

[Mordan]

The samething happened to me a few years ago on my M20. On the drivers side but more in the middle, thus having to take the head off. Since your break is on the rocker towards the front you may be able to slide the rocker arm shaft towards the rear of the engine and put in a new one. Good luck.

yep we tried it but not enough room to shift the rocker arm shaft

my mechanics wants to remove the distribution, radiator and some of the front grills and slide the rocker arm shaft out of the cylinder head. I'm a bit scared about that.

[Mordan]

Hey

A friend showed me this and he had a borken rocker lever :(

http://www.kalendaar.com/pifoubmw/photos/bmw/6enligne_net/moteur/web_M30_culbu_hs.JPG

http://www.kalendaar.com/pifoubmw/photos/bmw/6enligne_net/moteur/web_M30_piston_HS.JPG

http://www.kalendaar.com/pifoubmw/photos/bmw/6enligne_net/moteur/web_M30_soupape_HS.JPG

I don't think that's my condition. Because the oil is clean, no metal in it

[E34-520iSE]

There's two ways to repair that. One is to remove the head and fix it with the head off, the other way is to loosen the engine mounts, jack the engine up, remove the bonnet, rad, cam belt & pulley wheel etc,slacken all the rockers off on that shaft, pull the locking t-piece out of the slot and attempt to slide/pull the rocker shaft out of the head. They are a tight fit in the head and won't come out without a fight though, so be aware you may need to find a good rocker shaft to replace the old one that could be damaged. It's up to you which way you do it, but if it was me doing it I would just take the head off.

HTH,

Shaun M

[Ferret]

http://www.kalendaar.com/pifoubmw/photos/bmw/6enligne_net/moteur/web_M30_piston_HS.JPG

That looks scarily like my cylender number 3 on my old M50 right before it went to the great scrapyard in the sky!

[Mordan]

There's two ways to repair that. One is to remove the head and fix it with the head off, the other way is to loosen the engine mounts, jack the engine up, remove the bonnet, rad, cam belt & pulley wheel etc,slacken all the rockers off on that shaft, pull the locking t-piece out of the slot and attempt to slide/pull the rocker shaft out of the head. They are a tight fit in the head and won't come out without a fight though, so be aware you may need to find a good rocker shaft to replace the old one that could be damaged. It's up to you which way you do it, but if it was me doing it I would just take the head off.

HTH,

Shaun M

thx bro. I'm tempted to do that as well. I don't feel it good otherwise. will I need to put a new head gasket because I removed the head?

[Ferret]

thx bro. I'm tempted to do that as well. I don't feel it good otherwise. will I need to put a new head gasket because I removed the head?

Yeah you'll need a new HG and new bolts if it's the first time it's been done - the bolts will be old and may be starting to go brittle...

I agree the best way to do this is to take the head off - that way you'll know 100% what condition the cylenders are in inside the engine....

[E34-520iSE]

Yeah you'll need a new HG and new bolts if it's the first time it's been done - the bolts will be old and may be starting to go brittle...

I agree the best way to do this is to take the head off - that way you'll know 100% what condition the cylenders are in inside the engine....

Yep, new bolts, new head gasket, and while it's off you should replace the cam belt & tensioner too, for peace of mind. It just depends how much money you want to sink into the car to keep it running. Of course I'd be biased and say keep it running at all costs, just so I know I haven't got the only one in the UK lol!

Good luck,

Shaun M

[Martin in Bellevue]

July at the track, late afternoon. Kept going just a bit faster throught the front chicane and downshifting while traversing the cones; my bad. The ireland regrind was grooved, and the other rockers weren't wearing right.
Did you pull the rocker retaining clips before taking the pictures? If they were missing, the rockers would break at the valve end. Not a huge project to pull the head to replace the rocker. If doing it on the cheap, just pull the head, then extrack that 1 rocker shaft enough to replace that rocker.
I ended up with a new schrick 284, rockers & hardware, mls head gasket and head studs, valves and springs.
http://e28-535i.com/upload/m30shrick.JPG
http://e28-535i.com/upload/m30mlsStuds.JPG
http://e28-535i.com/upload/regrindJIwear.JPG
http://e28-535i.com/upload/rockBrokem30.JPG

[E34-520iSE]

Oh yeah, I never looked that closely - where are the retaining clips Mordan?

Shaun M

[Mordan]

Did you pull the rocker retaining clips before taking the pictures?


yea the clips were all there at the right place. We removed them before taking the pictures. Well observed though :) Nice pictures of yours.

I already bought the cam belt and tensioner and water pump... so I guess I will now also buy the gasket set and bolts and change lots of things all at the same time.

[Mordan]

http://www.mordan.biz/bmw/valves_2.jpg


as a reminder, before the car was shaking in idle, blue smoke and white smoke +loss of power.

and I'm happy today as I have good news guys. my M20 is up and running again. but what bloody mess it was to remove the rocker shaft without removing the cylinder head!!! First, the shaft was slightly bent where the broken arm was. Shaft would not slide out by hand. Then my old rocker shaft did not have the screw thing to remove it with the special BMW tool my mecano got from a friend. sorry no pictures. So he had to drill in the shaft. remove it with special BMW tool and remove with a magnet the crap in the cylinder head, finally reinstall the new shaft. valves clearances were set cold at 0,25mm
new water pump and new belt. the old water pump was shaky on its axle.

Anyways when we first started it, the motor was noiseless. nice humming. lots lots of blue smoke at first. but then no more blue smoke. :) nothing :).the car does not shake anymore. and I swear I could not hear any tac tac tac.
However, after a test drive and a few high revs with engine hot and high speeds, we got back to the garage. the engine runs really great. I'm very happy. I'm just bothered that the tac tac tac tac came back after our test drive. The mechanics says to wait 1k miles as the new rocker arm might still not be happy in its new position. he says maybe something with the old camshaft.

My question is do valve clearances can change over a test drive for some reasons?

What's your experience on this?

[DaveVoorhis]

A warmed-up M20 normally has a bit of even, fairly soft valve-train clatter, but if you've got a loud CLACK! CLACK! CLACK! it's unlikely to get better in 1k unless there's a sticky valve that loosens up real soon. And if it doesn't loosen up real soon, like in a few revs, it'll burn. I'd be inclined to open it up and see if a valve adjuster has slipped, or there's some other problem.

[Mordan]

A warmed-up M20 normally has a bit of even, fairly soft valve-train clatter, but if you've got a loud CLACK! CLACK! CLACK! it's unlikely to get better in 1k unless there's a sticky valve that loosens up real soon. And if it doesn't loosen up real soon, like in a few revs, it'll burn. I'd be inclined to open it up and see if a valve adjuster has slipped, or there's some other problem.

no no no it is not THAT loud :) it would be more like "fairly soft valve-train clatter"

[DaveVoorhis]

no no no it is not THAT loud :) it would be more like "fairly soft valve-train clatter"
Sounds like nothing to worry about, especially if it's even and regular.

[E34-520iSE]

I adjusted my valves about a year ago. For the first few miles they were as silent as a grave. After a 550 mile round trip to N. Wales the 'tick tick tick' noise was back, not loud, just 'there'! I gave up and left it alone - it's still running great.

I thought you might have had bother getting that rocker shaft out with the head in the car - they stick in the guide holes and are a swine to slide out. At least you got it fixed though - nice one!

Cheers,

Shaun M

[Mordan]

This is not finished. now the engine goes

............ tac tac tac tac tac tac

............ tac tac tac tac tac tac

............ tac tac tac tac tac tac

we need to bring the head out :(

some valve seats are ****ed. THAT IS WHY the rocker arm was broken in the first place!!!

[xaviervp]

maybe not the cyl head but timming chain sprocket needs to come off so you can remove the bar where all the rockers are installed to replace the rocker that broke
I would carefuly inspect all of them and replace any that look like they could have hairline cracks.

put it all toghether and adjust your valves and your ready to rumble.

[Mordan]

maybe not the cyl head but timming chain sprocket needs to come off so you can remove the bar where all the rockers are installed to replace the rocker that broke
I would carefuly inspect all of them and replace any that look like they could have hairline cracks.

put it all toghether and adjust your valves and your ready to rumble.

thx mate. that's what we did. I rumbled one day. Next day, the valve seats of some valves were ****ed. blah. all this work down the drain. cylinder head is be to cand hecked somewhere.
M20 rocker arm broken = cylinder head out. valve seats and guides ****ed up

[allerston]

i will tell you from my experience it is much better to just repair or replace while the head is off. at least then you will have piece of mind. that you would not have the same problem again.

[whiskychaser]

thx mate. that's what we did. I rumbled one day. Next day, the valve seats of some valves were ****ed. blah. all this work down the drain. cylinder head is be to cand hecked somewhere.
M20 rocker arm broken = cylinder head out. valve seats and guides ****ed up
I had a 'coming together' and got away with 12 bent inlet valves. No damage to guides or the pistons. If you havent had the head off yet look on the bright side. It could have kicked a leg out of bed

[E34-520iSE]

I had a 'coming together' and got away with 12 bent inlet valves. No damage to guides or the pistons. If you havent had the head off yet look on the bright side. It could have kicked a leg out of bed

Yep that would have been 'The end'

[SilverFive90]

I'm replacing my engine. I was going to go thru all of that, but found a pretty decent used engine at www.bmrparts.com. I don't know how much peace of mind I'll have in the end....as I like to keep everything original, but I'm dumb and forgot to get timing belt service...blew up the valve and couldn't start the car. I had the same broken lever/arm....

Hope the fared well, I'm about 2500 bucks down, but it's my daily driver and in great shape otherwise....so its hard for me to give it up of better yet find another one I trust...so good luck!

[Mordan]

pesky timing belts.. sorry to hear that. :( how many miles since last change before it broke?

did it break at the start up? if so, just rebuild the cylinder head and you will be fine provided the pistons are ok.

by the way doing all the work myself, it cost me 1000 euros to do the whole job

[ahlem]

I'm doing the same job on a 325is from 1989. I had broken castings so the head has to be replaced. I was under the impression that the 525 motor and the 325 motor were the same. I noticed that you have different head bolts. Anyone familiar with this? 50,000 miles between timing belts UNLESS the car sat for a long time without much use. I only have 120k miles and the timing belt was changed at 60k.