RAM Pin

[1stab]

I may be re-inventing the wheel for those of you in the know but I just had to share.

I had the tremendous fortune of acquiring a RAM that seemed to have never entered the water. The inside was absolutely spotless. The chrome was clean and looked NOS. I gleefully disassembled the reg and soaked the metal parts in Bryan's Blue Mystery solution, (great stuff). Fast forward -- As I opened the air to tune the Internal Pressure, the needle on the gauge didn't move. Could it be the new Conshelf HP seat? I didn't think so. So I took the Channel Lok wrench to the yoke tire and slooowly bled the air. I disassembled the nozzle and checked all the parts. Everything seemed fine. Maybe the seat was binding on the inner walls? I polished the inside of the nozzle with a very mild abrasive. I cleaned everything and reassembled the reg -- turned on the air. Again, it locked up. Then it hit me. I had bought 2 new blue Conshelf seats and Bryan even provided the pins. When I received the pins, I disassembled another RAM, threw the new seat in there, and while the reg was disassembled, measured the pin with a caliper and cut the 2 new pins to match. I gave myself a little margin, taped some electric tape on the pin, and chucked it in a hand drill. Then with a metal file, I worked the tip as it spun, keeping it rounded, until I came close to the final length. I then switched to an emery board with varying roughness, going from rough to fine. Checking frequently with the caliper I was able to match the length of the original pin exactly. I now had 2 extra pins.

The pin in the nozzle that was locking up was too short!

I disassembled the reg, again, and threw in the pin that I had cut to size. I compared the pin that came with this reg with the new one, and it was quite short. Maybe that's why the original owner seemingly never used it? I turned on the air and all was well in the world. I set my IP to 140 at 300 psi tank pressure and checked again at 3000psi.

I can't wait to try it.

[luis]

The receiving hole in the new seats is deeper than in the old HP seats. That is why you need a longer pin than what it had with the original 1970's or 60's seat.

You can always check it by assembling the nozzle with all its parts including the pin and the pin holder. The mushroom looking pin holder should be lifted from the nozzle body and you should be able to push it in with your thumb easily. This is opening the first stage valve. By doing this you are checking that everything is moving freely. In the case of the Royal, you can even do this with tank pressure in the first stage, but I am not recommending you do that.

The distance from the edge of the mushroom looking pin holder to the base of the nozzle body I think it is about .01" to .015", but I can't remember. It is hard to measure because the pin holder tends to rock on top of the pin.

[Bryan]

We should have a section called "Things I wish I would have known" The 1st time I used Conshelf parts I did the exact same thing except I had a dozen new pins and I went to all the trouble to make a little jig to put them in so I could cut them straight and quickly without measuring them. After the 1st regulator I stood around going.....WHAT THE HEY IS WRONG HERE!!! Needless to say I had cut them all too short and ended up ruining a dozen good pins.
Luis is right on the money as usual.

[1stab]

Now I know. Thank you gentlemen.

I had, "It's too good to be true" syndrome because this reg is in great condition. I was thinking that something had to be wrong with this reg for me to get it. The thought that I had acquired a "perfect" RAM with a defective nozzle was enough for me to abandon hope for a few days and mope around in a bath robe with a bottle of Ole #7. Well, pretty close.

I now understand just a little more of how a reg works and that little things like pin length make a big difference. I will definitely use the, "Mr. Luis" method (thank you) in the future before tightening things up.

Don't laugh but I am writing these things down and keeping the info together with my tools and stuff so that if (when) I kick the bucket, my offspring will have plenty to keep them busy!

[luis]

The approximate pin length required for the new HP seats is around 0.635" according to the measurements I took a wile back.

[1stab]

Awesome! Thank you, Sir, for the measurement. I'll write that one down.

I didn't really bother measuring the pin when I should have. I compared the pins that I had cut and grinded down with a file and then finer and finer grades of sandpaper, to the pin that worked. When the needle on the caliper stopped on the line for which I was looking, I stopped polishing.

Now that I have the length/measurement, if I get another RAM, I won't have to take apart one that is already up and running!

[1stab]

My caliper reads off 15.7 mm.

My English caliper is downstairs and I'm too lazy to get it right now.

[luis]

15.7 mm = 0.618"

The pin I measured was 0.017" longer, I don't know what say

[1stab]

You're right. I noticed that too. I went back to the original pin to see if I messed up but it measures 15.7mm exactly. And all three regs with that size pin work fine from 300 to 3000psi cylinder pressure.

Maybe there's a bit of a margin?

The next pin I get, I will try .635" I would imagine that one would want the pin as long as possible before getting leaks.

What say you?

[duckbill]

15.7 mm = 0.618"

The pin I measured was 0.017" longer, I don't know what say

Isn't the pin he is measuring a standard RAM pin, not a modified pin for the blue Coonshelf seat with the deeper center?
Maybe I'm missing something, or maybe this is the solution to the difference. Dunno.

[luis]

I just measured one of the old short pins at its length is around 0.482".

You can tell them apart even if they are not side by side.

I had some of the 0.635 pins that USD made. I think they were used in some of the last Royals made. I am not sure about that. I just bought the pins as spare parts. Since the length is perfect with the new seats. I just keep on cutting the long to pins to match.