Cylinder head for spigotted barrells

:lol:
Now I feel better too!
Maybe I won't need to take my 63 head off... right now anyway. I'm quite busy with the build of my 88SS and 65 atlas engine. I've currently got about 7 cranks on the go and been pulling bearings left and right. Over 20 bearings in the parts wash tank and 4 new NTN NJ306E C3 be here next week. :mrgreen:
After those two are together I need to put my combat engine back together and in the bike all by april 15th ...bike season here in new england.
 
I've just measured the height, excluding spigot, of my '64 650SS barrel at 4.560" (+/-0.003")
The spigot height varies from 0.144" to 0.159"
Cheers
Rob
 
texasSlick said:
Ooops! I made a typo. 4.90 should have been 4.590. I made an edit to my previous post.

I dont think 0.040 makes much difference, thus we can take spigotted and non-spigotted as the same height.. Then can we tell Piero to mill off his spigots with no fear?

Slick
Click to expand...
Hi Slick.
I will use spigotted barrells and head together.
But is good to know that i can mill the spigots and use as a flat type.
Thank you.
Pieto
 
Hi
I thought the reason to change from a spigot to no spigot was it helped reduce oil leaks at the head cylinder join.
Is this true, or just a Norton urban myth?
Thanks
 
ERRATA: I jsut discovered my calipers are out of calibration! The dimensions I posted above are in error. I have re-measured with another pair of calipers.

The height of my Atlas barrel is 4.565 and spigot height measures from 0.130 to 0.145. These numbers are more in line with that posted by others.

Sorry for any inconvenience.

Slick
 
dynodave said:
72 combat/ shorter lifter bores to accommodate 2S cam
Click to expand...

Sorry,
but i think that the combat lifters are the same of the all other commando.
I have ever listen that the combat pushrod are shorter; i think they are long like all the other.
Maybe.
Ciao
Piero
 
Norton46 said:
Hi
I thought the reason to change from a spigot to no spigot was it helped reduce oil leaks at the head cylinder join.
Is this true, or just a Norton urban myth?
Thanks
Click to expand...

The cylinder head gasket should have sealed in the oil. (!).
They didn't generally leak there, out of the showroom...

I'd have thought that getting rid of those silly spigots would have simplified the manufacturing,
by a complete order of magnitude !
And, if the cylinders show any sign of warping, how do you surface something back to flat with
a pair of spigots in the way...

It must be said that Nortons experience with manx race bikes was that deeply spigotted heads (and cylinders) gave a much more rigid engine assembly, and this considerably aided sustainable power outputs.
Hence sticking with this for 15 years in the dommies....
 
On this topic, with the impending reassembly of my (spigotted head) '64 650SS...
I am about to have the mating surfaces of the head and barrel checked and if necessary milled to flatness (as well as having the valves and seats cut)
In preparation for this I have noted:
The recess in the head for the spigot varies from 0.104" to 0.138"
The copper head gasket thickness is 0.037"(+/- 0.0005")
The spigot heights on the barrel varies from 0.135" to 0.158"
In the worst position the spigot would prevent the compression of the head gasket by 0.005"
I am contemplating having the spigot height also milled to a maximum height of 0.140"

Is this a problem that anyone else has encountered - and if so, what did you do about it?
Cheers
Rob
 
"Is this a problem that anyone else has encountered - and if so, what did you do about it?"

Just came back from a brief measuring session.

Cleaned minor carbon out of the squish band of the heads and measureably improved the results.
The pix of your head in the beginning of this thread is in need of cleaning

knocked height off the spigots by scraping carbon and rust off the spigot tops with a 12" scale. Improved measurement 5-6 thou, now .138-.142"
 
robs ss said:
The recess in the head for the spigot varies from 0.104" to 0.138"
The copper head gasket thickness is 0.037"(+/- 0.0005")
The spigot heights on the barrel varies from 0.135" to 0.158"
In the worst position the spigot would prevent the compression of the head gasket by 0.005"
I am contemplating having the spigot height also milled to a maximum height of 0.140"

Is this a problem that anyone else has encountered - and if so, what did you do about it?
Cheers
Rob
Click to expand...

I have contemplated this possibility after I discovered the large variation in spigot height in my own barrels. Unfortunately, my head is out for rebuild and I cannot measure recess in my head for comparison. When I once measured combustion chamber volumes, I took the recess at 0.125", but I was not being critical of any variation.

I think you have brought up a good point.

You might try the following before milling the spigots:

Seat the head on the barrels without a head gasket. Lightly tap it down, then check for any rocking. Next poke a thickness gauge into gap all around. Compare your max and min thickness gauge readings with head gasket.

Keep in mind some compression of head gasket must be a available.

Slick
 
pierodn said:
Ciao.
Spigotted barrell use the same head gasket of flat cylinders?
Thanks,
Piero
Click to expand...

No. Visit AN website .... they show part numbers for both composite and copper head gaskets for spigot and non spigotted.

Slick
 
Just read thingo on Manganese Bronze by out of AMC - to ' Norton Matchless ' . This is when they deletted the spigot set up - and introduced improved oiling set up . 1966 ( Oct ?? )
 

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