replacing #1 rocker

[jeffnhiscars]

I give up

[downforce22]

Since we agree you can't drive the rocker shaft to the rear with the head on that leaves driving it towards the front as per above. Are you saying you can tap a socket and or extension from the rear of the head when its still on the car ?

Yes, a small socket to get the shaft started and then an extension or two to get it further until you can slide it out by hand.

[jeffnhiscars]

how common are broken rocker arms on the m20's? i've heard of this before.

Common enough. Besides broken timing belts being an obvious cause, my understanding is that they break from a combination of metal fatigue & high revving. One suggestion is to grind smooth the stress risers under the eccentric & the other is to go with HD rockers from IE.

Having just repaired the damage from a PO's broken TB, I will say that all the piston damage was where the rockers did NOT break so if you are not racing or going to FI, I'd stay with stock rockers.

Just my $.02

[peytonracer4]

how common are broken rocker arms on the m20's? i've heard of this before.

[jeffnhiscars]

Once you pull the head plug(the black rubber pieces that seal the head) you have enough room to fit a 13mm socket in the space and tap it out a bit. Then you can fit the entension or two in there to tap it further until you can slide it out by hand.

Since we agree you can't drive the rocker shaft to the rear with the head on that leaves driving it towards the front as per above. Are you saying you can tap a socket and or extension from the rear of the head when its still on the car ?

[downforce22]

Having just reman'ed & installed a replacement head after the PO broke a timing belt I know how to remove rocker shafts.

The OP specifically mentioned cyl 1 rockers with the head attached which would require driving the shaft towards the firewall which I see as not possible. That was the basis of my question which remains open.

True, what I am saying is you must remove all 6 rockers to get to that cylinder's rocker by sliding the shaft out the front of the car. It is obviously not possible to slide the shaft through the firewall, there is not enough room for that. Hence my posts above with the procedure to remove them all. It really isn't hard with the head on the car.

[jeffnhiscars]

Once you pull the head plug(the black rubber pieces that seal the head) you have enough room to fit a 13mm socket in the space and tap it out a bit. Then you can fit the entension or two in there to tap it further until you can slide it out by hand. Make sure to clean the grease off as that helps sliding it out.

If you turn the camshaft so cylinder 6 is engaged all 5 others are not and you can tap it out. Thanks why keeping the belt on is helpful because it allows you to turn the cam without throwing off the timing and damaging the engine. There is a good write up here: (you need to take off the cam bolt so you can take off the rotor piece, but the cam gear stays held in place. You do this so you can slide the rocker shaft out between the cam gear with the Tbelt still on. Remember to but the bolt back on and only turn it clockwise when trying to turn the cam)

http://www.e30zone.net/e30zonewiki/i..._Cylinder_Head

Having just reman'ed & installed a replacement head after the PO broke a timing belt I know how to remove rocker shafts.

The OP specifically mentioned cyl 1 rockers with the head attached which would require driving the shaft towards the firewall which I see as not possible. That was the basis of my question which remains open.

[downforce22]

I'm missing something here. How do you drive the shaft anywhere with the head being an inch from the firewall ?

Once you pull the head plug(the black rubber pieces that seal the head) you have enough room to fit a 13mm socket in the space and tap it out a bit. Then you can fit the entension or two in there to tap it further until you can slide it out by hand. Make sure to clean the grease off as that helps sliding it out.

If you turn the camshaft so cylinder 6 is engaged all 5 others are not and you can tap it out. Thanks why keeping the belt on is helpful because it allows you to turn the cam without throwing off the timing and damaging the engine. There is a good write up here: (you need to take off the cam bolt so you can take off the rotor piece, but the cam gear stays held in place. You do this so you can slide the rocker shaft out between the cam gear with the Tbelt still on. Remember to but the bolt back on and only turn it clockwise when trying to turn the cam)

http://www.e30zone.net/e30zonewiki/index.php/Stripping_and_Rebuilding_an_M20_Cylinder_Head

[jeffnhiscars]

I'm missing something here. How do you drive the shaft anywhere with the head being an inch from the firewall ?

[bastianshaw]

A broken rocker won't do any damage to a valve or a rod.

I wouldn't recommend driving it though unless you disconnect the injector on that cylinder.

this idea intrigues me...

[MR 325]

A broken rocker won't do any damage to a valve or a rod.

I wouldn't recommend driving it though unless you disconnect the injector on that cylinder.

[SpecM]

That's cylinder 1

Sent from my Vortex using Tapatalk 2

[bastianshaw]

Ok i pulled the VC and its the #6 exhaust rocker arm:



now what? im picking up a busted head tomorrow to practice on and to get another rocker arm.

can you bend a rod driving w a valve closed?

[bastianshaw]

Not true. :ohsnap:
I just replaced #1 rocker on intake by sliding the rocker shaft out front toward the radiator removing all 6 rockers to get to number 1. I replaced a couple worn ones on cylinders 5 and 4 in the process.

You can remove the radiator and should be able to move the engine around to get the shaft out. I also did it with the timing gear and belt on, just removed the plastic cover on the timing gear. This was on a 325iX so the motor mounts may be slightly different placement but the principal is the same. It took me an afternoon. I would suggest going to a junkyard and getting a spare head if you can for cheap so you know how the rocker/clips/rocker shafts go together and practicing removing the rockers on the junk head before doing it on yours.

Here is a simple DIY http://e30technic.com/forum/showthre...adjustment-DIY

I would suggest a few things.

-If you have the timing belt on you can turn the cam without damaging anything. This allows you to remove the rocker retaining clips and slide them off the cam which lessens the force on the rocker shaft allowing you to pull/slide it out easier.
-Be careful not to mushroom the shaft as you tap it out of place. I used a quarter inch drive extension, it worked great.
-While you have the fan off and finish the rocker do the valve adjustment as you can turn the cam with the crank without moving the car/lifting the car.
-The most annoying thing was having to drain some of the coolant hoses/radiator and fit it back together with coolant dripping on you. I didn't drain the block of coolant and suggest you don't either.

It seems intimidating, just be careful and pay attention and your vert will be running smoothly once again.

And as for your question above, no the rocker breaks and the spring returns the valve to closed position. The rocker is therefore a fail-safe that protects the engine from further damage. The rockers were designed to break where they do to protect the engine from damaging itself.

NICE POST
thanks

[downforce22]

on #1 and #6, you can replace the broken rocker without moving the engine, just pull out the rocker shaft plugs and tap it backward/forward. On 2-5, you'll have to pull the head.

Not true. :ohsnap:
I just replaced #1 rocker on intake by sliding the rocker shaft out front toward the radiator removing all 6 rockers to get to number 1. I replaced a couple worn ones on cylinders 5 and 4 in the process.

You can remove the radiator and should be able to move the engine around to get the shaft out. I also did it with the timing gear and belt on, just removed the plastic cover on the timing gear. This was on a 325iX so the motor mounts may be slightly different placement but the principal is the same. It took me an afternoon. I would suggest going to a junkyard and getting a spare head if you can for cheap so you know how the rocker/clips/rocker shafts go together and practicing removing the rockers on the junk head before doing it on yours.

Here is a simple DIY http://e30technic.com/forum/showthre...adjustment-DIY

I would suggest a few things.

-If you have the timing belt on you can turn the cam without damaging anything. This allows you to remove the rocker retaining clips and slide them off the cam which lessens the force on the rocker shaft allowing you to pull/slide it out easier.
-Be careful not to mushroom the shaft as you tap it out of place. I used a quarter inch drive extension, it worked great.
-While you have the fan off and finish the rocker do the valve adjustment as you can turn the cam with the crank without moving the car/lifting the car.
-The most annoying thing was having to drain some of the coolant hoses/radiator and fit it back together with coolant dripping on you. I didn't drain the block of coolant and suggest you don't either.

It seems intimidating, just be careful and pay attention and your vert will be running smoothly once again.

And as for your question above, no the rocker breaks and the spring returns the valve to closed position. The rocker is therefore a fail-safe that protects the engine from further damage. The rockers were designed to break where they do to protect the engine from damaging itself.