Please help ID SP 1st stage.

[ozziworld]

I just got the reg on the left. Which I can't seem to positively identify. My old MK5 is on the right.

It is a lot heavier than my MK5.

4 LP swivel port is longer than on the MK5.

It has a very heavy yoke marked 3000psi. My MK5 also marked 3000psi but with lighter yoke.

It has 2HP ports. One is bigger than usual.

The biggest difference is the weight which I think is the yoke.

Appreciate any help identifying this 1st stage.

 

[Luis H]

It is just a newer Mk-5. The weight difference as you suspected is due to the newer heavier yoke.

That Mk-5 has the small ambient chamber holes. The chamber was designed to be filed with silicone grease and the holes was supposed to help keep the grease in place.

The HP ports are also the newer 7/16" ports used now for HP hoses.

 

[ozziworld]

Thanks Luis.

 

[Ed Palma]

Ozzie, re the HP ports in the later mk5, did you mean both were bigger on one compared to the other, or were the ports on the same reg of different sizes?

 

[Fishpie]

Early MK5's had a single 3/8" HP port. The later ones had 2 7/16" HP ports.
I don't know of any reg that has both 3/8 and 7/16 HP ports.

 

[ozziworld]

The heavier one has both 3/8 and 7/16 HP ports. The lighter one has just one 3/8 HP port.

 

[ozziworld]

Ooops! My mistake. It is two 7/16ths HP ports. Not one of each. The Port plug was misleading. Removed the plugs today to fit a spg. Sorry about that.