diff --git a/tests/riscof/sail_cSim/riscof_sail_cSim.py b/tests/riscof/sail_cSim/riscof_sail_cSim.py
index b34425f72..972b838e1 100644
--- a/tests/riscof/sail_cSim/riscof_sail_cSim.py
+++ b/tests/riscof/sail_cSim/riscof_sail_cSim.py
@@ -130,4 +130,5 @@ class sail_cSim(pluginTemplate):
             make.add_target(execute)
 #        make.execute_all(self.work_dir)
 # DH 7/26/22 increase timeout so sim will finish on slow machines
-        make.execute_all(self.work_dir, timeout = 1800)
+# DH 5/17/23 increase timeout to 3600 seconds
+        make.execute_all(self.work_dir, timeout = 3600)
diff --git a/tests/riscof/spike/riscof_spike.py b/tests/riscof/spike/riscof_spike.py
index 67c88b6ab..4a5b68b96 100644
--- a/tests/riscof/spike/riscof_spike.py
+++ b/tests/riscof/spike/riscof_spike.py
@@ -191,7 +191,8 @@ class spike(pluginTemplate):
       # parallel using the make command set above.
       #make.execute_all(self.work_dir)
       # DH 7/26/22 increase timeout to 1800 seconds so sim will finish on slow machines
-      make.execute_all(self.work_dir, timeout = 1800) 
+      # DH 5/17/23 increase timeout to 3600 seconds
+      make.execute_all(self.work_dir, timeout = 3600) 
 
 
       # if target runs are not required then we simply exit as this point after running all