Morris Minor Owners Club

Noted whilst fettling the rocker alignment this morning and worth a mention:-
The oil transfer hole through No: 1 rocker pillar is on the centre line between the two stud holes. The oil transfer hole through the 940 head where it meets the bottom of No: 1 rocker pillar is not - it is biased towards the centre of the head.
Even though the bottom of the pillar oil transfer hole is countersunk to counteract the offset it still badly shrouds the hole in the head so restricting the flow of oil to the rocker shaft assy.
To allow for the maximum transfer of oil between head and rocker pillar I have had to relieve the hole in the bottom of the No: 1 pillar towards the hole in the head.
I have checked the two spare 940 heads I have and the position of the oil transfer hole in the head are both slightly different.
It is worth checking when assembling the engine top end that the two holes align (even if you have to relieve the bottom of the pillar) otherwise the flow of oil to the rocker assembly may be compromised.
It cannot be taken for granted that the holes align so allowing the max flow of oil.
Phil

Phil,
Good tip Phil,
I am rebuilding a 1275 engine and have a 940 head on the bench at the moment so I will check this afternoon to see what I find.
Regards
Declan

Declan
A photo of the No: 1 rocker pillar with relieving towards the black mark.
The non sintered and sintered rocker pillars both have the oil feed passage/hole on the centre line of the pillar so both types of pillar can be affected.
Phil
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Phil,
I found exactly the same but the outer diameter of the pillar block towards the centre of the head lines up with the outer diameter of the smaller hole in the head so in my case -not shrouded. I will have to machine the pillars to align the rockers with the valves which I had to when I fitted the 940 to the 1098 engine.
Regards
Declan

Declan
Thanks for coming back.
As I said above - the two heads I have (ex 1275cc Midget & 1275cc 'A' Plus) the oil holes are orientated/positioned slightly differently to each other.
As regards rocker shaft pillars - general comments / observations:-
The holes through the pillar (11/32" for 5/16" stud & 13/32" for 3/8" stud) allow for a little sideways movement of the pillar which could result in some shrouding the oil transfer hole.
A little engineering blue on the head rocker pillar seat and when the pillar is removed from its pre final assembled position it should show any shrouding of the oil way by the pillar.
If there is a need to machine the pillars to get the non sintered rockers over the valves I would recommend using the early Minor ones stamped with forging numbers 12A210 & 12A211. The Cooper 'S' rocker pillar is based upon the same steel forging so the early Minor one can be machined with confidence. They are the ones I am using.
They are slightly narrower around the 3/8" stud hole as well and turn up a treat.
The sintered pillars when turned - end up with a rough rubbing face no matter how sharp the cutting tool is or in the case of sintered pillars was.
To enable the alignment I would recommend the use of the old style forged or pressed steel rockers with the side bosses as the sintered rockers (with flat sides throughout their length) will not slide into any machined recess and the thickness of the metal around 3/8" stud cannot be reduced on the 12A210 & 12A211 pillars, especially as it is already slightly thinner than the sintered pillar.
If using the later 'A' Plus cylinder head nuts with bottom flange you may have to reduce the diameter of the nut bottom flange as the adjuster end of a deeply recessed rocker will or may foul the nut flange when it moves through the operating arc.
I hope that the above is of help.
Phil

Thanks Phil,
In the first and second photo you can see the location of the hole in the head. I am lucky enough to have the head with the pressed steel rockers. The pillars have no forging number so they could be the sintered one's and you can see the misalignment in the third photo. I still have the original Minor head stashed away so will check to see whether the pillars are sintered or not and pick out the best rockers.
Regards
Declan[frame][/frame][frame][/frame]
Misalignment[frame][/frame][frame][/frame]

Declan
Many thanks for the photos.
In your 1st photo you can clearly see that the oil feed hole is off centre to the two stud holes and that is where any miss-alignment of the countersink or relieving in the bottom of No: 1 rocker pillar could restrict the oil flow to the rocker shaft and rockers.
The pillars in your 2nd & 3rd photos are the sintered type; and those are the type that I had no luck in getting a good finish on the new rubbing surface between rocker and pillar.
I have managed to get an extra 5 thou clearance between the rocker adjuster end and the pillar by smoothing down and polishing the flat on the pillar (12A210/12A211) adjacent to the 3/8" stud hole (no need to do both sides/flats) - so now have 25 thou working clearance between the adjuster end of the rocker and pillar which is more than adequate.
As the rockers have been moved I am having to turn up new spacers to go between the rockers as I do not use the original springs.
I have posted photos on here http://www.mmoc.org.uk/viewtopic.php?f= ... start=20od
The rockers are now placed directly centre over the top of the valve stem.
As an aside there are three types of rocker pillar used on the 'A' Series ex works - they are:-
The aluminium pillar type - best put in the bin.
The forged steel type - fitted to early 'A' series and the Cooper variants.
The sintered steel - adequate for most applications.
In the picture (a poor scan) below - the two pillars, left and centre are sintered and the one on the right is forged steel and they are the ones I am using. You can see the forging/part numbers at the bottom of the pillar. Easily identifiable by the double waisted top.


Phil[frame][/frame]

Phil,
I just tried machining the no. 1 sintered pillar. The finish is not perfect but not rough and certainly usable. If you coat the surface with oil on the final passes and up the speed, it does make a difference rather than a dry cut.
Regards
Declan



Set up
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Closer[frame][/frame]Before the clean up[frame][/frame]
Then wire brushed with a high speed mini drill[frame][/frame]
Same procedure pillar no. 2[frame][/frame]
etc etc....very enjoyable work on a rainy day like today!

Declan
Many thanks for the photos.
They are looking good.
I tried cutting the sintered pillars with a sharpened tool steel cutter and cutting oil.
Cutting oil ended up all over the front window of the shed.
I may decide to turn up a mandrel as you are using which will enable me to up the turning speed as that big heavy independent 4 jaw chuck does not like going too fast.
Phil

philthehill wrote:Declan
Many thanks for the photos.
They are looking good.
I tried cutting the sintered pillars with a sharpened tool steel cutter and cutting oil.
Cutting oil ended up all over the front window of the shed.
I may decide to turn up a mandrel as you are using which will enable me to up the turning speed as that big heavy independent 4 jaw chuck does not like going too fast.
Phil

Certainly worth doing and it's a lot easier. I made the mandrel from 15mm PVC and it's fine. I don't have an independent 4 jaw chuck.
One thing I did notice is that pillars No 1,3 &4 are identical although on 3&4 the oil holes are not used. I wonder why they did that-probably trying to save costs or to prevent people from getting pillars mixed up if there were no holes to the head on 3&4. The rocker shaft on that head pictured above is very badly worn so a new one is on the cards. I see minispares has an improved version with a greater wall thickness and not much dearer than the standard one. I hope I won't have to replace the rockers as well.
Regards
Declan

The wear is generally all in the shaft - the rockers are usually fine. I wouldn't worry about 'extra wall thickness' unless using super strong springs / high lift cam.

Thanks Roy,
Then I'll go for the standard rocker shaft. I have no idea what cam I have but it certainly looks fairly newish. I doubt if it is the original Midget cam. There is nothing stamped on it to help identify it. I could measure the lobe height and the timing once installed. The crank also looked good but I did have to get the block bored out to 0.040". Just got it back from the machine shop.

Regards
Declan[frame][/frame][frame][/frame][frame][/frame]