diff --git a/src/allmydata/test/test_checker.py b/src/allmydata/test/test_checker.py
index ad9b4be39..c3851285c 100644
--- a/src/allmydata/test/test_checker.py
+++ b/src/allmydata/test/test_checker.py
@@ -393,4 +393,4 @@ class TooParallel(GridTestMixin, unittest.TestCase):
         d.addBoth(_clean_up)
         return d
 
-    test_immutable.timeout = 40
+    test_immutable.timeout = 80