M20 rocker arm replacement.

[Nine468]

Hi.
My car/engine has broken a rocker arm.
Ive removed the cam cover and found the offending article.
Its a inlet rocker.
Im after a guide on how to replace the rocker arm with the engine still in the car, IE without removing the head.
Ive managed to move all the rockers along the rocker shaft so the shaft is not under tension, but im stumped at the point of removing the rocker shaft.
Ive also removed the wedge shaped bar at the front of the rocker shaft.
Ive removed the rad and all other bits from the front of the engine, and can see the end of the rocker shaft through the cam sprocket. Unfortunately it doesn't have any threads in the end to fit a slide hammer on.
Is there any other way of getting the rocker shaft out.?
Im hoping somebody here has done this job, and can help me out...
Thanks.

[e30topless]

It's a delicate job ! You need to use grips with a cloth to protect the shaft.... if you mark it in the slightest it will NOT go through the next rocker or head journal !
I have done it many times while the engine is warm, it's much easier ...

Sadly Snapped rockers on the inlet suggest poor oil feed or blocked oil spray bar from a poorly maintained or thrashed car, it's only a matter of time before it happens again... if you are keeping the car then remove the head and refurbish it

[Nine468]

Thanks for the help.
Unfortunately the engine isn't warm....and cannot now be warmed up...
The head has been refurbed , in fact its only covered approx 1600 miles.
The reason for the snapped arm is ,, its a race car, and I think, I might've "buzzed" it when on a track day, changing down.

So when you use the grips, do you then try and twist the rocker shaft to release it from its journals, whilst at the same time pushing towards the front of the engine.

[e21jps]

sometimes they move easy (as they should) and sometimes they can be a real bitch, just try to twist it back and forth while sliding it along and as mentioned dont grab the shaft too tight and be REALLY careful you dont mark it or you will have no chance of getting it out, i use a little piece of a leather glove. Dont hammer or try to wedge it out i have seen a lot of heads with the piece of alloy that goes over the shaft broken or welded. once its free you might be able to GENTLY lever it along with a screwdriver. Lastly if it seems to jam on one if the rockers or holes in the head then look at the little slots that hold the keeper clips in place they sometimes develop a little burr on one end, can easily be removed with a bit or fine emery paper or wet and dry. Doing that first usually makes life a WHOLE lot more fun and it should almost slide out by hand

The worst case is that someone has previously beaten on it badly and has flared the end of the shaft slightly, if thats the case then give up straight away and pull the head its not that big a job. Then you might be able to slide it out the other way, you can often carefully linish off the flared part

[Nine468]

Thanks folks for the help and advice.
Unfortunately it was that stuck ive had no option but to remove the head...
Once the head was off I managed to fix it in about 10 mins...
Just a couple of hours to replace the head now.....

[AardHawk]

I always find that you need to get the rocker shaft scrupulously clean, with no brown residue.