Rocker & Shaft Removal

[Wes]

Hi
Is it possible to remove the Rockers, Springs & Rocker Shaft without unbolting the pedestals ie not loosening the head? I have very noisy tappets, despite setting up correctly, but what looks/feels like worm shaft/rockers. I have a good replacement set but would rather not have to loosen the head, just undo the split pin and carefully pull out?.
Thanks

[svenedin]

Yes you have to undo the split pin but you also have to undo the locking screw in one of the rocker pedestals. The locking screw is prevented from turning by a plate on the top of the pedestal. The earlier design plate is secured in place by both the rocker pedestal nut AND a head nut. The latest design is only secured by a pedestal nut only. So you will probably have to release the tension on one head stud nut.

Take photographs and carefully note the order of shims, springs and rockers to aid reassembly. To make things easier, adjust the rocker clearances so that they are very large and the rockers can easily be slid out of the way. You may as well check the pushrods for problems whilst you are there, especially noting if the cups are worn or the rods are bent. They must be replaced in the same position so examine one at a time. Also examine the rockers for wear where they contact the valve stem.

Stephen

[philthehill]

The later rocker shafts have the securing peg in No:2 pillar not No:1. This was changed because there was a tendency for the rocker shaft to break around No:1 pillar. You may have to end up loosening two head studs if that is the case. Make sure that the oil transfer pillar is in the right place. You may have to replace the pillar or drill a transfer passage to suit.
In many cases it is the shaft that is worn and the rocker bushes remain serviceable.
BL replaced the 3/8"-5/16" plate so that only the 5/16" section remained to lock the peg and is more than suitable for the task. Shortening the locking plate is acceptable.
If your rocker adjusting screws are waisted and have the oil transfer passage drilled through the ball end they need to be changed to the non waisted type as it was found that the waisted type broke at the waist. BMC discarded the waisted adjusting screw and the need for additional oil for the rockers, push rods and cam followers as it was found that there is more than sufficient oil circulating around the engine. See photo below of waisted adjustment screw. The early 1/4" rocker threads clean up nicely with a BSCY thread tap without removing any metal.

Waisted adjustment screw.JPG (67.89 KiB) Viewed 1693 times

[svenedin]

Further to what Phil says: here you can see the locking peg in pedestal number 2 with the type of locking plate that is full length and is held in place by both a head stud nut and a pedestal stud nut. Also a picture of the shorter locking plate which you can buy from Minispares (and others I am sure) part number 2A259. The shorter plate is only held on by a pedestal stud nut.

Stephen

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[philthehill]

https://www.minispares.com/2a259-rocker-post-lockplate

[Wes]

Thank you all for your great insights. This also tells mt why I've read about the lock plate on pedestal #1 and the the spare rocker assembly I've been given has the lock nut on pedestal #1. Thanks. Good tip about slackening off the adjusters. Just need the courage to get it in bits and the garage temp to fall!

[svenedin]

You should be OK. Just take some good photographs so you can remember the order parts were in. If the rockers don't line up properly (assuming they did before) you've misassembled. You will probably find that the rocker shaft is very worn where the rocker bushes sat. As Phil said, it is usually the shaft that wears out, not the bush. Sometimes the shaft is very excessively worn because it was not receiving oil. The oil for the rocker shaft goes up through a hole in the base of pedestal number 1 that lines up with a hole in the cylinder head. It can happen that the wrong pedestal was fitted in position 1 and then no oil gets to the rocker shaft or that the holes were blocked by crud. A heavy duty rocker shaft is also available. https://www.minispares.com/c-aeg399-roc ... heavy-duty

If I was doing it, I would remove pillar 1 completely so I can check the oiling holes and poke them clear with wire. Not doing this risks ruining your new parts from insufficient oil.

Note in the pictures the earlier type of rocker adjuster screw that has an oiling hole. These were deleted as they were prone to breakage.

Stephen

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[Wes]

The assembly i have is second hand but i can feel little/no play in the rockers on the shaft so was intending in replacing all but the pillers. Good call re the oil ways though. thanks

[oliver90owner]

Hi
Is it possible to remove the Rockers, Springs & Rocker Shaft without unbolting the pedestals ie not loosening the head? I have very noisy tappets, despite setting up correctly, but what looks/feels like worm shaft/rockers. I have a good replacement set but would rather not have to loosen the head, just undo the split pin and carefully pull out?.
Thanks

It may be quite likely that, if you used feeler gauges, the settings are too loose - as the feelers bridge the wear at the rockers. An alternative method of adjustment is better, if this is the case.

[svenedin]

Hi
Is it possible to remove the Rockers, Springs & Rocker Shaft without unbolting the pedestals ie not loosening the head? I have very noisy tappets, despite setting up correctly, but what looks/feels like worm shaft/rockers. I have a good replacement set but would rather not have to loosen the head, just undo the split pin and carefully pull out?.
Thanks

It may be quite likely that, if you used feeler gauges, the settings are too loose - as the feelers bridge the wear at the rockers. An alternative method of adjustment is better, if this is the case.

Yes. This is where a Clickadjust tool is useful. The OP says he is going to use a second hand assembly presumably including different rockers? Examine these carefully for wear where the rocker contacts the valve stem.

PS: it is quite normal for increased rocker clatter at start up with a cold engine. As the gaps narrow when the engine heats up this should quieten down. Other noises such as squeaking are not normal and suggest oil starvation. The old mechanic who taught me the basics on Saturday mornings 40 years ago said a well adjusted A-series engine should sound like a Singer sewing machine.

Stephen

[oliver90owner]

I was aware that he wrote he was going to use another assembly. Maybe my point was too subtle that it was missed? The alternative may be worn just as much as the one in present use - if the problem is that of setting the clearances. KISS Principle in operation. If it ain’t broke (or the fix may be no better) why fix it? Checking first is always best before jumping in unnecessarily.

[Wes]

Its not just noisy at start up. When i set tappet the gaps i noticed a lot of movement of the rockers on the shaft. At a club run someone commented on the noise and asked if the gaps were set and i said yes. It was this person who offered me the s/h assembly and it was looking at this that made me realise that all the rocker movement i currently have isn't correct, something has become worn. BTW this isn't my first Minor/BMC car so i'm used to tappets, their noise and their adjustment.

[Wes]

but it has been 35 years since my last A series