Hymn to the 1928 Model C

User avatar
Vincent.vanGinneke
Holder of a Platinum Anorak
Holder of a Platinum Anorak
Posts: 4294
Joined: Sat Apr 09, 2011 12:14 am
Location: "The Dutch Branch"
Contact:

Re: Hymn to the 1928 Model C

Post by Vincent.vanGinneke »

Dents can be knocked out, so....
I've made up a impact slide hammer thing for inside the tube :)
calibrated ! o.k. maybe numbering it was over the top :lol:
slagpen stuur  (1).jpg
Idea is to heat up the part in the handlebar's curve where the dent sits.
Hmmm, it works...sort off.
The rounded nose on the impact part needs some 'fine tuning' :D
slagpen stuur  (2).jpg
slagpen stuur  (3).jpg
ehhh, the one on the left it is.
User avatar
Vincent.vanGinneke
Holder of a Platinum Anorak
Holder of a Platinum Anorak
Posts: 4294
Joined: Sat Apr 09, 2011 12:14 am
Location: "The Dutch Branch"
Contact:

Re: Hymn to the 1928 Model C

Post by Vincent.vanGinneke »

I wanted to grind in the seal between cylinderhead and barrel.
But...
a.t.m. head and barrel make contact on the outer rim.
And there is a gap between top of the barrel and head inside the combustion chamber.
So I made up a copper gasket to fill that gap .
Contacted Karol about it if this was a good idea, he told me yes.
But , how where these cylinderhead / barrel joints originally ?
If I use the outer rim as the seal, (which is wider then that inner rim) does that gap inside present a problem ?
Anyone any clue ?
1928 copper ring in head.jpg
20220426_162814.jpg
User avatar
cmfalco
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 472
Joined: Fri Apr 07, 2017 4:53 pm
Location: U.S.
Contact:

Re: Hymn to the 1928 Model C

Post by cmfalco »

Vincent, for what it's worth, the head of my 1928 Model C seats against the rim that projects from the cylinder/sleeve, rather than against the outer surface that you seem to be the case on your engine. This results in the ~0.007" gap that you can see in the photograph.
ArielHeadGap.jpg
You mentioned in an earlier post that you installed a new sleeve, so it must project above the top of the fins by slightly less than the original one in my bike.

If it were mine, I would carefully measure the projection of the sleeve, and the depth of the inner ring on the head that should seal against it. The difference will be the height of the space between the two (I know that you know this). If you make a head gasket for the outer ring, no matter how thin you make it, it will increase that gap. My concern would be the sharp edges on either side of that gap might get hot enough to cause pre-ignition issues.

Ideally, I think it would be better to make a copper "head gasket" to sit on the inner ring, rather than seal the head against the outer ring. Depending on the height of the measured/calculated gap, this might or might not be easy. However, if the measured gap is small enough, Cu shim stock could be quickly and accurately cut with scissors.
User avatar
adrie.degraaff
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 3275
Joined: Sun Feb 27, 2011 10:07 am
Location: Holland
Contact:

Re: Hymn to the 1928 Model C

Post by adrie.degraaff »

I have found prewar Ariels with both inner and outer copper gaskets, the fourvalve Ariel heads will brake if using the inner copper gasket due to the tension of the headbolts.
User avatar
Vincent.vanGinneke
Holder of a Platinum Anorak
Holder of a Platinum Anorak
Posts: 4294
Joined: Sat Apr 09, 2011 12:14 am
Location: "The Dutch Branch"
Contact:

Re: Hymn to the 1928 Model C

Post by Vincent.vanGinneke »

Thanks Charles and Adrie for your comments.
I'll measure it all up and see if I can do this 'double gasket' version.
Must be pretty precise otherwise one of them hangs in there free.

copper gasket by Karol.jpg
This outer gasket is made by Karol and friends.
I'll make just a circle as the outer rim on the cylinder I have does not sit in the same level as the bolt hole part.
:)
User avatar
cmfalco
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 472
Joined: Fri Apr 07, 2017 4:53 pm
Location: U.S.
Contact:

Re: Hymn to the 1928 Model C

Post by cmfalco »

Vincent.vanGinneke wrote: Fri Apr 29, 2022 8:51 amMust be pretty precise otherwise one of them hangs in there free.
For exactly that reason I'd argue against a double gasket. Even if the face of the liner projection were precisely parallel with both the inner and outer rings of the head, as well as with the outer ring of the cylinder, and you were able to make the thicknesses of both gaskets to within better than 0.001" of what they needed to be, would the "crush" of such thin sheets of Cu be enough to seal both rings through the full 360-degrees.

If the inner ring seals the interface between the head an projection, the outer ring does nothing, as evidenced by the fact I don't have anything on the outer ring of my engine. This also shows that an outer ring isn't needed to provide support since the cast iron is strong enough to resist bending. Considering all of this, along with the odds against all four surfaces being precisely parallel with each other, and it suggests to me either only using an outer gasket and hoping there are no pre-ignition consequences of the resulting gap, or making an inner gasket and only using it.
User avatar
Vincent.vanGinneke
Holder of a Platinum Anorak
Holder of a Platinum Anorak
Posts: 4294
Joined: Sat Apr 09, 2011 12:14 am
Location: "The Dutch Branch"
Contact:

Re: Hymn to the 1928 Model C

Post by Vincent.vanGinneke »

Thanks Charles, inner copper ring it's going to be .

next question;
I am going to use the Amal pictured and want to fabricate a inlet manifold.
What is the distance from valve stem to needle on a '28 OHV ?
carb distance piece  (2).jpg
I have a alloy bar to make one from :
carb distance piece  (1).jpg
and : would it be o.k. to fit a fyber washer under the valve spring bottom collar?
I know they are used in alloy heads for quieter running, but does it make sense in a iron head ?
carb distance piece  (2) - kopie.jpg
Simon.Gardiner
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1670
Joined: Tue Aug 02, 2011 11:37 pm
Location: South West (Bristol-ish)
Contact:

Re: Hymn to the 1928 Model C

Post by Simon.Gardiner »

All my iron heads (early '50s singles) have had hallite washers in the gasket sets (bought from Writers in the 1970s) to go between the valve spring collar and the cylinder head.
My understanding is that it's to do with reducing the heat fed back into the valve spring.

SG
Web admin (webmaster@arielownersmcc.com)

'55 Huntmaster, '56 VH, ' 51 VH, '62 Arrow, '80 R100RT, '00 Sprint ST (now with a new Arrow project, and just now those 4-stroke Ariel parts can't even make one running bike...)
User avatar
cmfalco
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 472
Joined: Fri Apr 07, 2017 4:53 pm
Location: U.S.
Contact:

Re: Hymn to the 1928 Model C

Post by cmfalco »

To save wear and tear on your calculator, I held a somewhat flexible ruler with a metric scale against the spacer on my 1928 Ariel.
ArielCarbSpacer.jpg
However, if you want more precision, the metal itself (not counting the gaskets at either end) measures exactly 1.250". The extra piece of metal next to the carburetor is a ~1.2 mm-thick drip tray from a BSA A10 to keep gasoline from falling on the magneto. I also extended the bottom end of that drip tray sideways to deflect any gasoline that might fall from the float chamber.

I don't know if my carburetor spacer is original, but it is the one that came with my bike and I have no complaints whatever with how the bike runs with it in place. Also, for what it's worth, my bike came without insulating washers for the valve springs and I didn't add any when I rebuilt the engine.
User avatar
Vincent.vanGinneke
Holder of a Platinum Anorak
Holder of a Platinum Anorak
Posts: 4294
Joined: Sat Apr 09, 2011 12:14 am
Location: "The Dutch Branch"
Contact:

Re: Hymn to the 1928 Model C

Post by Vincent.vanGinneke »

Hello Simon, thanks.
Hallite, that was the name. I'll fit a pair.
To keep heat away from the springs, that's a very good reason!
I thought they where there because of noise, but that -ofcourse- is a 21st century approach :D

32mm for the manifold, and I'll have enough left from my bit of material to make another if need be.
thanks Charles .
That drip tray is also a handy thing..
Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests