Simonton left window dbl coil balancer

I honestly can't say for sure. Your pictures don't tell me much, I'm afraid. Did the Series 160 springs at least fit? I just want to be sure these are the right springs to begin with. Can you also tell me the weight of your sash? And just to confirm, there are two springs used on either side, correct?

I'm afraid that number doesn't tell me the weight of the sash. I'll need you to remove it from the window and put it on a scale, then let me know what you get. Without any old stamps to go by on your one spring, this is the only way we can determine what would work.

Hmm... well, the way you have it, the combination of springs would support 18 pounds. This would work just the same as our S160-4. Each of these carries 4.5 pounds, so four working together (two on each side) can also support a sash of 18 pounds.

Now, this is a bit heavier than what you have, but could still work. Two S160-3 (3.5 pounds) and two S160-4 (4.5) might be better, since that combo can carry 16 pounds. Ultimately, it's up to you.