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Replacing M30 engine Rocker


Steve VH

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I suspect if you loosen the head bolts then you’ll not be able to torque it back down properly. 
 

From memory 2 of the shafts come out the back of the head so you won’t have space to pull them out. Not sure either of the timing chain case will hinder access too. 

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If the head has not been off before - or for a long time - I'd bite the bullet and remove the head. It's not a bad job on an E28, two or three hours. Leave the inlet manifold behind and pull the head off with the exhaust manifold.

 

With it off you will undoubtedly find corrosion that needs alloy welding and you can do other stuff like replace all the exhaust manifold studs. If the cam is good, a set of 12 new rockers (febi seem best), new shafts and stem seals. Some machine shops will take a scruffy old cylinder head and turn it around for a few hundred. Remember that the four rockers shafts are not interchangeable and fit a certain way. They can also be a right bastard to remove. The cam oil spray bar must be fitted with the little arrow notch facing forwards, and always use new banjo bolts. Don't reuse the old ones as they will work loose and never, ever use threadlock as it will congeal inside the oil hole.

 

Do it all in one hit and it'll be good forever. 

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I will probably have to farm this job out, 30 yrs ago in my twenties I did a cylinder head gasket on my Capri, an Essex V6, and took me a week, now being the wrong side of 50 the old back isn't up to a week of being bent over a bonnet. It's a shame as the engine was running sweet as a nut till the rocker shoe broke off.

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From memory, yes in theory you can remove the front two rocker shafts with the head in-situ, but not if the radiator is in place. As mentioned, M30 head removal is straightforward enough (I'm currently in the throes of it with my E24...) so thats by far the best option, all things considered.

You'll almost certainly break an exhaust stud or two getting it out, so plan ahead for this. 

Spraying all the manifold fastenings with penetrating oil every day for a week prior to removal will better your chances.  

Just wanted to Echo what Sir anthony put about the oil spray bar, too- oil starvation as a result of loose banjo bolts/blockages are usually why rockers break in the first place! New ones with the correct locking compound are crucial, and are pence from the dealer, part no. 11421738621

Good luck, let us know how you get on

Edited by Undernutter
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On 02/03/2023 at 11:29, Undernutter said:

From memory, yes in theory you can remove the front two rocker shafts with the head in-situ, but not if the radiator is in place. As mentioned, M30 head removal is straightforward enough (I'm currently in the throes of it with my E24...) so thats by far the best option, all things considered.

You'll almost certainly break an exhaust stud or two getting it out, so plan ahead for this. 

Spraying all the manifold fastenings with penetrating oil every day for a week prior to removal will better your chances.  

Just wanted to Echo what Sir anthony put about the oil spray bar, too- oil starvation as a result of loose banjo bolts/blockages are usually why rockers break in the first place! New ones with the correct locking compound are crucial, and are pence from the dealer, part no. 11421738621

Good luck, let us know how you get on

But in removing the front inlet rocker shaft, you would still need to remove 3? cylinder head bolts seeing they interlock with the rocker shaft,?

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I was looking at some old pictures of my cylinder head but couldn’t see the rocker shafts out of the car. But are they notched? I can’t recall how they are retained in head. If not you might not need to pull the head bolts?

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7 hours ago, duncan-uk said:

I was looking at some old pictures of my cylinder head but couldn’t see the rocker shafts out of the car. But are they notched? I can’t recall how they are retained in head. If not you might not need to pull the head bolts?

As far as  I'm aware the notches in the rocker shaft line up with the cylinder head bolts and interlock, the cylinder head bolts prevent the rocker shaft from working its way lose, even though the shaft is probably an interference fit in the cylinder head housing.

Does anyone know different?

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Just now, Steve VH said:

As far as  I'm aware the notches in the rocker shaft line up with the cylinder head bolts and interlock, the cylinder head bolts prevent the rocker shaft from working its way lose, even though the shaft is probably an interference fit in the cylinder head housings.

There are holes in the camshaft gear, that lined up, would allow the shafts to be extracted without removing the camshaft gear wheel.

Does anyone know different?

 

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On 25/02/2023 at 20:45, Steve VH said:

I will probably have to farm this job out, 30 yrs ago in my twenties I did a cylinder head gasket on my Capri, an Essex V6, and took me a week, now being the wrong side of 50 the old back isn't up to a week of being bent over a bonnet. It's a shame as the engine was running sweet as a nut till the rocker shoe broke off.

Where are you based?

I'm in Sheffield/Notts. 

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5 hours ago, Sir Anthony Regents Park said:

It can be fixed! It must be 20 years - maybe more - since I did an E28 head job. I did an E34 535i around 2010 but I still remember the various details. 

 

It depends on £££ and how far you want to go. If the cam is worn it can get very expensive very quickly. It's repair v reconditioning. 

Looking at a repair more than recon, the cam is spot on, car is currently on my drive and Sorned, while I decide what to do, presumably if you took it on I would need to find a way of getting it over to you, a cost, plus your time.  D974YPH 

I bought it in 2011 for £600 as a weekend hobby car before E28 prices went up, being a tight arse, I'm not wanting to spend loads to get it right.

 

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