diff --git a/cirq-google/cirq_google/cloud/quantum_v1alpha1/services/quantum_engine_service/transports/grpc.py b/cirq-google/cirq_google/cloud/quantum_v1alpha1/services/quantum_engine_service/transports/grpc.py
index 5658f4293da..42854490b78 100644
--- a/cirq-google/cirq_google/cloud/quantum_v1alpha1/services/quantum_engine_service/transports/grpc.py
+++ b/cirq-google/cirq_google/cloud/quantum_v1alpha1/services/quantum_engine_service/transports/grpc.py
@@ -169,8 +169,9 @@ def __init__(
                 ssl_credentials=self._ssl_channel_credentials,
                 quota_project_id=quota_project_id,
                 options=[
-                    ("grpc.max_send_message_length", -1),
-                    ("grpc.max_receive_message_length", -1),
+                    ('grpc.max_send_message_length', 20 * 1024 * 1024),  # 20MiB
+                    ('grpc.max_receive_message_length', -1),  # unlimited
+                    ('grpc.max_metadata_length', 10 * 1024 * 1024),  # 10MiB
                 ],
             )
 
diff --git a/cirq-google/cirq_google/cloud/quantum_v1alpha1/services/quantum_engine_service/transports/grpc_asyncio.py b/cirq-google/cirq_google/cloud/quantum_v1alpha1/services/quantum_engine_service/transports/grpc_asyncio.py
index 56b4bfd59a2..8223fec9e6d 100644
--- a/cirq-google/cirq_google/cloud/quantum_v1alpha1/services/quantum_engine_service/transports/grpc_asyncio.py
+++ b/cirq-google/cirq_google/cloud/quantum_v1alpha1/services/quantum_engine_service/transports/grpc_asyncio.py
@@ -214,8 +214,9 @@ def __init__(
                 ssl_credentials=self._ssl_channel_credentials,
                 quota_project_id=quota_project_id,
                 options=[
-                    ("grpc.max_send_message_length", -1),
-                    ("grpc.max_receive_message_length", -1),
+                    ('grpc.max_send_message_length', 20 * 1024 * 1024),  # 20MiB
+                    ('grpc.max_receive_message_length', -1),  # unlimited
+                    ('grpc.max_metadata_length', 10 * 1024 * 1024),  # 10MiB
                 ],
             )
 
diff --git a/cirq-google/cirq_google/engine/stream_manager.py b/cirq-google/cirq_google/engine/stream_manager.py
index 52b42a7f5ab..dc00c14309a 100644
--- a/cirq-google/cirq_google/engine/stream_manager.py
+++ b/cirq-google/cirq_google/engine/stream_manager.py
@@ -123,7 +123,7 @@ async def _make_request_queue(self) -> asyncio.Queue[Optional[quantum.QuantumRun
 
         If `None` is put into the queue, the request iterator will stop.
         """
-        return asyncio.Queue()
+        return asyncio.Queue(maxsize=100)
 
     def submit(
         self, project_name: str, program: quantum.QuantumProgram, job: quantum.QuantumJob