This is my study of time in Judges. Here are all the hits on the word "years". I removed all the passages that were not needed for our calculations.

Judg:3:8: Therefore the anger of the LORD was hot against Israel, and he sold them into the hand of Chushan-rishathaim king of Mesopotamia: and the children of Israel served Chushan-rishathaim eight years.
8 years.

Judg:3:11: And the land had rest forty years. And Othniel the son of Kenaz died.
40 years.

Judg:3:14: So the children of Israel served Eglon the king of Moab eighteen years.
18 years.

Judg:3:30: So Moab was subdued that day under the hand of Israel. And the land had rest fourscore years.
80 years.

Judg:4:3: And the children of Israel cried unto the LORD: for he had nine hundred chariots of iron; and twenty years he mightily oppressed the children of Israel.
20 years.

Judg:5:31: So let all thine enemies perish, O LORD: but let them that love him be as the sun when he goeth forth in his might. And the land had rest forty years.
40 years.

Judg:6:1: And the children of Israel did evil in the sight of the LORD: and the LORD delivered them into the hand of Midian seven years.
7 years.

Judg:8:28: Thus was Midian subdued before the children of Israel, so that they lifted up their heads no more. And the country was in quietness forty years in the days of Gideon.
40 years.

Judg:9:22: When Abimelech had reigned three years over Israel,
3 years.

Judg:10:2: And he judged Israel twenty and three years, and died, and was buried in Shamir.
23 years.

Judg:10:3: And after him arose Jair, a Gileadite, and judged Israel twenty and two years.
22 years.

Judg:10:8: And that year they vexed and oppressed the children of Israel: eighteen years, all the children of Israel that were on the other side Jordan in the land of the Amorites, which is in Gilead.
18 years.

Judg:12:7: And Jephthah judged Israel six years. Then died Jephthah the Gileadite, and was buried in one of the cities of Gilead.
6 years.

Judg:12:9: And he had thirty sons, and thirty daughters, whom he sent abroad, and took in thirty daughters from abroad for his sons. And he judged Israel seven years.
7 years.

Judg:12:11: And after him Elon, a Zebulonite, judged Israel; and he judged Israel ten years.
10 years.

Judg:12:14: And he had forty sons and thirty nephews, that rode on threescore and ten ass colts: and he judged Israel eight years.
8 years.

Judg:13:1: And the children of Israel did evil again in the sight of the LORD; and the LORD delivered them into the hand of the Philistines forty years.
40 years.

Judg:15:20: And he judged Israel in the days of the Philistines twenty years.
20 years.

Judges seems to be pretty much in a chronological order. This makes it easy to figure the number of years it covers. I calculate 410 years. Now we take that and add it to our 2860 years; from our previous studies.

2860 + 410 = 3270 years