A-series 1098 rebuild video (also blocked breather)

[svenedin]

A friend sent me a link to this long (nearly an hour) professional rebuild video of a Morris Minor 1098cc engine.

I thought it may be of interest.

If you do not want to watch the whole video there is a particularly interesting bit at around the 23 minute mark. It concerns the older style breather pipe on the tappet chest cover which is completely blocked with years of crud. Since questions about oil leaks are so frequent and the breathing system is so important in this respect I just thought this illustrated the issue very well.


Stephen

https://www.youtube.com/watch?app=deskt ... 8rPIQlp98n

[rocco]

Thanks for sharing, that was a really good video and will be a good reference for myself and anyone else who does a rebuild.

[svenedin]

Thank you Rocco. I did think of you when I posted this and I am glad it was informative.

For the non-engineer like me the video did show that there is an awful lot involved in the proper overhaul of an engine. Just seeing the premises and how many different areas of the workshop there are was fascinating. I noticed that the rooms become cleaner and cleaner the further on the engine overhaul goes. The primary survey/stripdown area is rather dirty but the final assembly area is spotlessly clean like an operating theatre!

I was interested to see how the rockers with bushes were honed to a perfect fit on the rocker shaft as well as many other things.

One tiny thing I noticed was that in the fully reassembled engine the engine steady bracket was fitted upside down.

It really is a remarkable engine the humble A-series.


Stephen

[philthehill]

I may have missed it but was there a reference/comment regarding to moving the No: 1 rocker shaft pillar to the No: 2 position and any issues that may occur?
The rocker shaft being used in the rebuild was the later type with the locating peg moved to No: 2 position.
The peg was moved by BMC because of occurrences of rocker shaft failure around No:1 pillar because of the number of holes required in the rocker shaft.
When the locating peg is moved to No:2 position it requires No: 1 pillar to have a vertical oil transfer hole/gallery so that oil can get from the head to the rocker shaft.
I always use the after market thick wall rocker shafts when rebuilding the rocker assys. The thicker wall of the shaft gives me a bit more assurance that the rocker shaft is not going to fail.

[svenedin]

I don't think he mentions moving the pedestal but he does mention the pedestal locking screw and shows the oil way in the rocker shaft.

When my cylinder head was rebuilt last year it had the thicker wall rocker shaft

Stephen

[svenedin]

Cylinder head with oil way to rocker shaft pedestal arrowed (cylinder 1 position/front of engine)

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Thicker wall type rocker shaft

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Rocker assembly top view showing locking pedestal in position 2 (this pedestal does not have an oil way hole in the base see bottom picture. I think this is because it is a later pedestal)

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Rocker assembly bottom view

IMG_9338.jpeg (1.24 MiB) Viewed 212 times

[svenedin]

Earlier arrangement with locking pedestal in position 1. Note that these are earlier pedestals (note different shape) and in this case, the locking pedestal DOES have an oil hole in the bottom. It has to as it is in position 1 here and that is where the oil way is in the cylinder head.

IMG_8997.jpeg (2.81 MiB) Viewed 208 times

[rocco]

Why do all the pedestals in those photos have oil holes in them if the head only has one?

I would like to have seen the acid bath the guy used. You're right about the cleanliness, not going be as easy for a hobby mechanic but that's part of the challenge. The machines that these workshops have run in to the hundreds of thousands.

I think I'll need to use exchange/remanufactured parts but hopefully, the engine I will get next month won't need so much expensive work and I can just clean and rebuild it

[philthehill]

Because it is easier to have a pedestal with oil transfer hole under one part number than have several variations of pedestals with different part numbers. The extra hole is not expensive to produce.
The 'bull head' pedestals in the photo above were made in alloy (chuck them in the scrap bin even though some list them as competition pedestals - no way!!!) and steel. The steel 'bull head' pedestals are the best (as fitted to the Cooper S) and can be machined to allow the rocker hammer end to fit central over the valve stem. With the sintered steel pedestal/rocker machining is unable to be carried out to centralise the rocker. The width of the sintered rocker is what allows it to fit anywhere over the head of the valve stem.

[svenedin]

Phill can you explain what the different type of pedestals are please? I don't understand which are the bull head type you refer to.

In my pictures, the type of pedestal in my picture of the old oily cylinder head prior to refurbishment I did throw away the pedestals as scrap. The rebuilt rocker assembly has later steel pedestals. However, I am not sure whether this is exactly what you mean?

Stephen

[philthehill]

If you look down onto the top of the pedestals in the photo immediately above - the impression is of looking down at a bulls head.
They were produced in both alloy and forged steel - not sintered. They have scalloped sides which allows for some metal to be removed for rocker alignment.
The sintered steel rockers have plain sides and a non shaped top surface. Unfortunately they cannot be machined to allow centralisation of the rocker on the top of the valve stem.
There are some after market steel - not sintered rocker pillars that look like and are shaped like the sintered pillars.
Below is a forged steel bulls head rocker pillar being machined by me to allow centralisation of the rocker over the valve stem.

Rocker pillar machining 2.jpg (77.8 KiB) Viewed 118 times

Once you have machined the pillars you can assemble the rockers as in the photo below - all rocker arms central to the valve stem. The rockers are after market items and the springs are replaced with steel spacers/shims.

Rockers 2.JPG (1.48 MiB) Viewed 115 times