Ariel Owners Motorcycle Club

Thanks you, Nev I'm going to check on the rocker boxes on saturday. You helped me a lot. By the way the picture above is from an old ebay auction, not my rocker box.
Regards
Chris

MN
My guess at the thickness of the hardened washer may have to be confirmed. I will measure one when I get the chance. Nev

I am going to jump in here as I also appear to have an odd mix of parts on my '39 VH.

Christain....looking at the photo of your assembly it looks as though you may already have the 945A washer in place. The clearance at the other end looks similar to mine. My exhaust side assembly has 0.055 inch clearance and the inlet side 0.035 clearance. The rocker levers /arm assemblies are both the same length and my distance washers are 0.123 thick (with a bevel on one side of the hole) so the 20 thou difference must be in the rocker box castings.

This is what I can work out:

1938 to 1947 : (cast part numbers in brackets)
Rocker housings: 845-38 (A7 617) and 850-38 (A7 618)
Rocker spindles: 895-38 (A7 621)
Rocker levers: 911-38 (A7 620) and 921-38 (A7 619)
Distance washer at oil feed end of spindle: 945A-31(A7 28)

No parts list found for 1948-50 so I do not know when the following part numbers first changed.

1951:
Rockers housings: same as earlier models
Rocker spindle: 895-49 (A7 621A)...different
Rocker levers: same as earlier models
Distance piece: same as earlier models
Rocker spring: 905-52 / K79-47...addition

1952 /53:
Rockers housings: same as earlier models
Rocker spindle: 895-38 (as 38-47 models ...is this a mis-print?)
Rocker levers:as earlier models
Distance washer and spring both listed

1954: As per 1951 parts list

The only difference between the 38-47 setup and 51 onward appears to be the rocker spindle and the addition of the spring (the distance washer was still being used). The other photo Christian posted apparently shows the later setup, with a distance washer AND a spring.

I think the wider diameter end section of the later spindles may have a slightly shorter length and this provides the extra space required for the spring to be fitted ....the spring protrudes slightly into the cast boss on that side. My reasoning for this opinion is that a spring had been fitted to my exhaust spindle in addition to the distance washer. However, as mine was an earlier spindle, this had moved my spindle outwards. The spring was totally coil-bound and the rocker arm stiff to move. Two thick fibre washers had been used to seal the spindle.

The distance washer aligns the rocker arm/lever correctly...if it was omitted the assembly would move sideways and the pushrod / valve alignment would be out by about 1/8 inch. I can only assume that the spring was added later on to reduce the sideplay seen in my and Christian's setup and stop any noise that occurred due to that clearance, the change in spindle allowed for this.

In my case I think I will just use some shim washers on the opposite end of the spindle to the distance washer to give about 5 thou of play.

Of course I could be wrong and if so maybe someone will put me straight. It would be handy if anyone has a later spindle which could be compared with an earlier one.

Cheers
Alan

I Think I have both lengths of shaft sitting dismantled . The large dia of the shaft should end up just below the surface of the rocker box on the spark plug side. where the cover screw seals it off. I had better measure the different lengths of shaft. I think the variation is in the length of the ground surface the rocker runs on. I'm tied up at the moment but will do it soon if someone else doesn't. You don't need a lot of end float. A couple of thou would be adequate. A bit more won't hurt but you might hear it. I have found one that binds when the oil acorn nut was tightened so worth checking before assembly as you can't check it after.. Nev

With the early rocker box the end float is actually set, or more correctly stated, can be reduced by the screw in the end of the shaft. If you loosen the screw too much you eliminate all clearance and lock the rocker arms.
With the later shaft there is more movement available and I adjust the screw to centralise the oil hole in the banjo. The spring then takes up the extra clearance.
Below is a photo of both shafts together. As already stated by others the rocker boxes and rocker arms are the same through different models.
David

David....yes your second photo shows what I thought must be the case i.e the shorter length of the larger diameter section.
I am interested to read your description of adjustment. The owners manual says fully tighten the acorn nut first [to pull the shaft hard up against the washer/casting boss] and only then tighten the cap screw. I can see that the owners manual method could cause the wider diameter of the shaft to pinch /press against the rocker arm but only if the hardened washer was too thin. Your method would eliminate any 'pinching' in those cases but would point to there being wear somewhere in the assembly?

Can you, or anyone else, comment on the bevel on one side of the clearance washer...should this be towards the shaft or the case? In my view there seems no point in it being against the case. If it is towards the rocker arm it would allow oil to seep from between the spindle and end of the rocker arm in order to lubricate the washer/rocker arm rubbing faces.

Cheers
Alan

You were right Alan, the washer was there. I didn't remember and didn't notice it on my photo. It's a bit difficult at the moment because I moved to the next city and my workshop is about 1 hour away

I dismantled, cleaned and measured both rocker boxes today. On the exhaust side I found the oil seal screw fully tightened and fixed with loctite or something. There was also an additional washer pressed into the rocker box between the large diameter section of the spindle to hold some kind of rubber. I guess an selfmade oil seal? (unfortunately forgot to take a photo) This stuff was strong enough to prevent the dome nut from fixing the distance washer and caused the clearence.

After cleaning and putting everything back together I now have a clearence of 0.006"
The distance washer thickness measures 0.126"

I'm going to attach new gaskets and hopefully get the engine running on the next saturday or sunday.
Thanks again
Regards
Christian

Edit: There is a slight difference in the rocker box casting of the inlet compared to the exhaust of about 0,012". The spindles and rockers both measure the same.

I have just reassembled both my rockers as per the owners manual .......i.e tighten acorn nut fully in order to pull the smaller shoulder on the spindle tight against the washer / casting boss. The slot in the larger diameter end of the shaft is presumably there so that you can a piece of flat metal / large screwdriver to prevent the shaft turning as you fully tighten the acorn nut.

As Christian I now have 0.006 inch clearance / endfloat on both rocker arms. I see that doing in this way pulls the beveled end of the wider diameter section through the cast boss slightly and, as Nev says, the outer end is just below the level of the casting. I think the previous owner had tightened the 'blanking' screw first and then nipped up the acorn's. This had resulted in the excessive clearance I had.

I also found that my spindles were a tight fit in the casting...heating the casting before assembly made fitting the spindles and getting them fully seated easy.





Cheers
Alan

Alan
That shaft is well sunk into the rocker box and goes to show just how much the end clearance can be varied by loosening or tightening the adjustment screw.
When it comes to the shafts with the spring there is also a big range of movement. I set the shaft to centralise the oil hole within the banjo, and the spring takes up the end clearance from there.
I have just checked a couple of my end clearance hardened washers and they do not have any bevel although I am certain that I have bevelled washers in a running bike.
David

I can't believe the "adjustment screw" is an adjustment screw!
The spindle shall sit tight in its house without moving around or rotating. That can be acheived only by tightening the acorns nut fully up.
If the spindle can move, it will soon be loose in the house.
Afterwards you close the hole in the spindle with the "adjustment screw", so oil is not spilled all over the place.