Washers under Cylinder head stud nuts or not?

Hi All,

I started a new thread to the previous one on the studs being a bit short. Now interested in washers.....I lead a sad life...

Thanks very much for all the replies to " Commando cylinder head studs too short?' .
Please remember we are all Norton owner trying to sort out the issues left to us by our forebears.
Some of the correspondence was a little rude towards each other. Please show respect for each other.

I have had a fiddle with my head.....

- The studs I have a are little longer than the specification kindly given to me by Andover Norton
- The rear stud in the Commando engine I built 24 years ago nearly comes though the long nut
- Amazingly I put the rear nut on with no washer and the chamfered side towards the head.
- There is just about 1/4" to about 5/16" of thread exposed for both the sleeve nuts and the long read nut.

- I am using a composite gasket so the gasket thickness is not the problem
- There is plenty of room to put the head on with longer studs
- It is the pushrod which cause the difficulty in putting the head on
- With the rockers slackened off and with elastic bands it is fairly easy to put the head on

- The holes in the head will allow a longer threaded portion on the head end of the stud without bottoming in the hole
- The space when putting on the head will allow about 1/4' of extra thread for the nuts
- I have ordered some bolts which I will get made into longer studs.
- I will let you know how I get on......to be continued

Now....the subject of washers seems rather interesting....hopefully I will have some
space to fit washers if I want to.......comments gratefully received....

Thanks
Staytite

I got a set of barrel nuts from RGM and they came with beveled washers, pretty much like what was on originally. That's for the early 750. The 850 may be different, I bet if you went on the Old Britts site and looked at their parts lists you could figure it out.

Dave
69S

Flat washers are to provide a consistent surface friction from which a torque specification can provide the correct tension. In most cases, washers act as a lubricant.

Ditto that.

For example, the ARP line of high performance studs/bolts is a system that comes with polished surface hardened washers and a moly based lubricant.

Hi All,

It seems strange to me that washers are specified for the cylinder head bolts (four next to spark plugs)
and for the nuts on the front studs that poke up from the barrels near the push rod tunnes, but not for
the studs that poke down ie for the long rear nut between the carb inlets and not for the sleeve nuts at
the front of the barrels.

Anybody know why this is?

Thanks
Staytite

Staytite said:

It seems strange to me that washers are specified for the cylinder head bolts (four next to spark plugs)
and for the nuts on the front studs that poke up from the barrels near the push rod tunnes, but not for
the studs that poke down ie for the long rear nut between the carb inlets and not for the sleeve nuts at
the front of the barrels.

Anybody know why this is?

Click to expand...

Presumably it's because the three nuts on the downward facing studs tighten against the hard cast iron barrel-not the alloy head.

The original norton washers are fairly good and correct size.
Many butchered bikes I have worked on had thinner and wrong size generic washers that crush/deform the aluminum head.
Since I have had to replace so many washers, I bought thick hardened washers to support the load better and not redamage the repaired head surfaces.
They work for the BSA A-10's also :mrgreen:

ludwig said:

Or lack of space ?

Click to expand...

Possibly, however if there's room for a hexagon nut then logically there should be room for a washer.

ludwig said:

They used washers under the flange nuts from these very same barrels ( sharp side down btw ..)

Click to expand...

Only 2 washers for 5/16" studs/nuts appear to be listed for (some?/all?) Dominator barrel base flanges. BSA and Triumph do not list base flange nut washers for all fasteners either. My T140V for instance, had/has no washers under its larger diameter base flange nuts.

ludwig said:

ps : still waiting for your pictures..

Click to expand...

Yes, and with that attitude you WILL be waiting a long while. There is a reason why no photos have been posted (by me) as yet, which I won't bother going into the details here.

ludwig said:

LAB : you can blame my 'attitude' on my unhappy youth .. Do you want me to say 'please' or shall I just beg you on my knees ?
You now what ? I'll send you a free headgasket if you pull a stud out .
How does that sound ?

Click to expand...

I find I must repeat what I said one more time: "There is a reason why no photos have been posted (by me) as yet,"-so you will have to wait, if I can be bothered at all.

ludwig said:

L.A.B. said:

.. if there's room for a hexagon nut then logically there should be room for a washer.

Click to expand...

Ok , i think frased it wrong .
I mean lack of space on the studs : not enough available length .
With everything STD and the stud screwed in the head as deep as it will go , the nr of effective threads can be as little as 4 .
I'll try to be clear : from the moment the nut is engaged , you can count 4 full turns before the nut touches the barrel . May be 5 if you are lucky .
From an engineering point of view , this is a bare minimum and thus there is no room for a washer .
The use of a washer here can be arguable , but if you do use one , it should be at least 2 mm thick steel . not some generic stamped washer . AND make shure it falls into the machined recess .
This is one reason why I use longer studs . The main reason is that I want them as deep as possible in the head .
When tightening these nuts , more than half of the aplied torque can be lost in friction of the nutface , plus an aditional amount in thread friction .
The workshop manual says nothing about lubing the threads , but i believe that at least the nutface shoud be slightly lubed .
The reason for lubing threads is that the aplied torque should stretch the stud/bolt , instead of twisting it .
Of course the real problem here is that these studs can not hold their tension , bu that is discussed in another thread .

LAB : you can blame my 'attitude' on my unhappy youth .. Do you want me to say 'please' or shall I just beg you on my knees ?
You now what ? I'll send you a free headgasket if you pull a stud out .
How does that sound ?

Click to expand...

Well said.

Hi All,

Thanks for the replies.

I am new to this so might have a go at posting a few photos later.

I have taken some bolts to a local engineering firm to make them into longer studs.

I have measured the holes in the head as 0.8" So will have studs made:
- Head end = 20tpi of 0.60"
- Center section of 0.75" (as original
- Nut end = 26tpi of 0.90"

This should allow more thread in the head.
Same non threaded centre section
More thread for nuts and possible machined washers.

I think the longer studs will not cause too much problem during fitting the head.

Thanks
Staytite