Morris Minor Owners Club

Just set the tappets for the first time on my newly acquired 1098 traveller. I noticed that the rocker arms were a tad loose on the shaft(?) i.e. i could jiggle them a bit, not up and down, but side to side. Is this normal? or have i got worn rocker arms and/or a worn rocker shaft? Thanks

and by side t side i mean pivoting about the point where the shaft goes through the rocker arm. its like the bore of the arm is 10 thou' bigger than the shaft.

If you have concerns just replace the rocker shaft which is a relatively easy job to do. It is rare for the rocker arm bushes to wear.
Use the search facility for information as regards shaft replacement.
It should be noted that the securing peg for the rocker shaft has now been moved to pedestal No: 2 and the pedestal must have the oilway drilled through its centre or the pedestals rearranged to suit the new shaft.

Thanks I'll take e look

Ah so you cant just remove the rocker shaft and its 4 clamps, its a job with the head off right?

You can just remove the rocker shaft only. The problem with removing the rocker shaft only is the locking washer for the locking peg. You cannot remove the locking peg without removing the locking washer.
To remove the locking washer you have to undo a 3/8" UNF nut which holds the head and rocker shaft pedestal down and a 5/16" UNF nut which holds the rocker shaft pedestal down.
If you are prepared to take a risk to the head gasket with undoing just the 3/8" nut holding the head down and the 5/16" nut holding the rocker pedestal down you can remove the locking washer and go on to remove the rocker shaft.
I would drain the coolant if you decide to take the risk. I would say that the risk of head gasket failure after one head nut is removed is very low.
You then slacken right off the tappet adjusters which allows you to disengage the push rods.
Remove the rocker shaft locking peg and then remove the split pin from the rear of the rocker shaft. Then slowly draw the rocker shaft forward out of the rocker pedestals. Note the arrangement of the washers and springs so that you can put them back in the right order.
Once the old shaft is out fit the new shaft in reverse order.
Fit the locking peg.
The only snag with the above is that if the locking peg has been and/or is to be transferred to No: 2 pillar you are going to have to undo the nuts on pedestal No: 1 and No: 2 which is not a good idea and you should replace the head gasket.
Once you have assembled the rocker shaft the peg locking washer can be shortened by removing the 3/8" end of the locking washer so that the locking peg washer is then secured by the 5/16" UNF nut/washer. BMC/BL did a similar modification to the peg locking washer but made the mistake of retaining the 3/8" end of the locking washer. Once you have modified the peg locking washer you can remove the rocker shaft without compromising the head gasket.
When ever the peg locking washer is disturbed I always recommend that the locking washer is modified as above.
An interesting fact regarding the rocker shaft - early rocker shafts has a screwed plug in one end which could be removed and the inside of the rocker shaft cleaned. Later shafts just had a pressed in bungs at both ends.
Later shafts because they are hardened cannot be internally threaded and a screwed plug fitted.
Phil

Phil

Must be having a thicko moment but don't understand...

" BMC/BL did a similar modification to the peg locking washer but made the mistake of retaining the 3/8" end of the locking washer "

Does that mean that they left the locking plate secured under the head bolt not the pedastal nut ??

John ;-)

Correct.
They should have used the 5/16" stud/nut for securing the rocker shaft securing peg.
This is what BMC/BL came up with:-
https://www.somerfordmini.co.uk/plate-s ... stal-74-on
It should have been the other way around with a 5/16" hole instead of the 3/8" hole.
The 5/16" hole is more than adequate to hold the securing peg in place/stop the peg unscrewing.
An original top plate can be easily modified to suit the 5/16" pedestal stud. A plain washer can be fitted under the 3/8" spring washer/nut.
Phil

Thanks for the insight Phil. I think i'm just going to play the "if it ain't broke" card i think Leave it until i need to replace Head Gasket.

I wouldn’t.

They may not be broken but the shaft (at least) is past its service life.

If they are that loose, you may need to check the lifting surfaces on the rockers.

Otherwise, setting valve clearances may not be as accurate as one might expect.