I just purchased a variable speed pool pump. I want to add a surge protector because of the electronics on it.
I don't have any room in my main service panel, (Murray R256EB1A).
So thought i would replace my old timer box with a sub panel at pump itself, about 100 ft away. My feed wire is UF 12-2 with ground so there is no neutral wire, 240 V.
My questions are:
1) Best way to make room in Main panel and add surge protector?
2) Would it be better/easier to just add a surge protector in the sub panel?
Is it possible to install a surge protector without having neutral wire in the sub panel?
Can i install a GFCI breaker in the sub panel with no neutral wire? Would the breaker and GFCI connect to ground
instead?
The sub panel would feed the pool pump, 240V and a deck that only has couple lights on it.

I have considered putting Quadplex breaker in Main and combining 2 breakers to free up a 20A breaker to attach a surge protector to but have not found one compatible with my panel.

I think Murray is now Eaton. There may be a Challenger breaker "classified" for that panel.

I am not sure about how those breakers are listed but I see surge protectors double lugged to an existing 240v load if they are listed for 2 wires.

Murray was bought by Siemens & was sold by them for a number of years, but was discontinued, Siemens breakers are the listed choice, Eaton CL is UL classified for many competitive makes, it's more expensive then Eaton BR, which is not classified for competitive makes.

OK thanks for covering me. I am old and I tend to put all of those "stab" panels in one boat. I also have trouble remembering who bought who.

Good to know they use Siemems. OP can get them anywhere. No luck on seeing anyone on their website say you can use 2 wires on a terminal. I looked at a breaker too. Not on the label.
If there is plenty of room in the panel you could pigtail the conductors coming from the smallest 240 a breaker you have and be legal.

Right, these breakers don't allow 2 wires. I plan on pigtailing a surge protector as you suggested.
I also plan on swapping out the upper 20A breaker, this feeds the pool pump, and replace it with a GFCI breaker.
Is it ok to put the surge protector on a GFCI breaker or will it cause problems?
Other option is:
I have a 30A breaker on lowest left I could put surge protector on, will a surge protector be effective on a bottom? Or should I swap these positions, even though it would mean another splice in panel, if I need to use this one?

I would stay away from the GFCI. The 30 should work tho. Mine is on with the water heater. I am not sure a few extra inches of bus will affect the surge protection enough to matter. Try to keep the ground lead as short and straight as possible tho. You certainly don't want a loop in it.

Think i have solved my surge protector problem, my panel will accept Square D Homeline breakers. They are rated for 2 wires. I didn't realize the Homeline series was capable of this. So gonna replace one of my old breakers with Square D and add surge protector to that.

I also want to put a GFCI breaker on at least one end of this circuit to pump. Wire that feeds pump is 12/2 with ground. Could i put 30A gfci breaker in main and 20A standard breaker in sub panel? And still have protection?
Is it possible to have gfci breaker at sub with only the 12/2 w/ground?

Are the SqD breakers actually "classified" for a Murray panel? It might be worth checking that out. I know SqD had a real dust up with Cuttler Hammer over the Challenger breakers in SqD panels and it might seem a little disingenuous for them to go back to U/L and look for the OK to put their breakers in someone else's panel.
Just because they "work" and they probably do, doesn't mean they are legal.
As for your other question about the GFCI in a 240 only panel (no neutral) you would have to look at the manufacturer's instructions. That set up was pretty normal with computer room panels. They did not bring the neutral to the panel. The insulated, grounded wire was reidentified green and it was the isolated ground. I suppose you could hook the white wire from the breaker to the ground bus and the GFCI would "work" as intended but the instructions should be your guide.
You could go the other way and use the 30a in the main panel and exploit the tap rule, using the 20a as down stream overload protection. That would also provide GFCI protection to the feeder.

Yes, on inside of panel door lists Square D Hom breakers as suitable.
And thanks for info on GFCI. I believe i will go the route you mention at end of your comment.