diff --git a/sync/src/synchronization_client.rs b/sync/src/synchronization_client.rs
index d09967a0..8bc2a201 100644
--- a/sync/src/synchronization_client.rs
+++ b/sync/src/synchronization_client.rs
@@ -20,7 +20,7 @@ use synchronization_chain::{Chain, ChainRef, BlockState, HeadersIntersection};
 use synchronization_chain::{Information as ChainInformation};
 use verification::{ChainVerifier, Error as VerificationError, Verify};
 use synchronization_executor::{Task, TaskExecutor};
-use synchronization_manager::{manage_synchronization_peers, manage_unknown_orphaned_blocks, MANAGEMENT_INTERVAL_MS};
+use synchronization_manager::{manage_synchronization_peers, manage_unknown_orphaned_blocks, MANAGEMENT_INTERVAL_MS, ManagePeersConfig, ManageUnknownBlocksConfig};
 use hash_queue::HashPosition;
 use time;
 use std::time::Duration;
@@ -468,6 +468,8 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 		// TODO: start management worker only when synchronization is started
 		//       currently impossible because there is no way to call Interval::new with Remote && Handle is not-Send
 		{
+			let peers_config = ManagePeersConfig::default();
+			let unknown_config = ManageUnknownBlocksConfig::default();
 			let csync = Arc::downgrade(&sync);
 			let mut sync = sync.lock();
 			let management_worker = Interval::new(Duration::from_millis(MANAGEMENT_INTERVAL_MS), handle)
@@ -479,7 +481,7 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 					};
 					let mut client = client.lock();
 					if client.state.is_synchronizing() || client.state.is_nearly_saturated() {
-						let blocks_to_request = manage_synchronization_peers(&mut client.peers);
+						let blocks_to_request = manage_synchronization_peers(&peers_config, &mut client.peers);
 						// if no peers left => we are saturated
 						if !client.peers.any() {
 							client.switch_to_saturated_state(false);
@@ -487,7 +489,7 @@ impl<T> SynchronizationClient<T> where T: TaskExecutor {
 							client.execute_synchronization_tasks(blocks_to_request);
 						}
 
-						if let Some(orphans_to_remove) = manage_unknown_orphaned_blocks(&mut client.unknown_blocks) {
+						if let Some(orphans_to_remove) = manage_unknown_orphaned_blocks(&unknown_config, &mut client.unknown_blocks) {
 							client.remove_orphaned_blocks(orphans_to_remove.into_iter().collect());
 						}
 					}
diff --git a/sync/src/synchronization_manager.rs b/sync/src/synchronization_manager.rs
index 11240129..6ad954eb 100644
--- a/sync/src/synchronization_manager.rs
+++ b/sync/src/synchronization_manager.rs
@@ -6,32 +6,63 @@ use primitives::hash::H256;
 /// Management interval (in ms)
 pub const MANAGEMENT_INTERVAL_MS: u64 = 10 * 1000;
 /// Response time to decrease peer score
-const PEER_FAILURE_INTERVAL_S: f64 = 5f64;
+const DEFAULT_PEER_FAILURE_INTERVAL_MS: u32 = 5 * 1000;
 /// Unknown orphan block removal time
-const UNKNOWN_BLOCK_REMOVAL_TIME_S: f64 = 20f64 * 60f64;
+const DEFAULT_UNKNOWN_BLOCK_REMOVAL_TIME_MS: u32 = 20 * 60 * 1000;
 /// Maximal number of orphaned blocks
-const UNKNOWN_BLOCKS_MAX_LEN: usize = 16;
+const DEFAULT_UNKNOWN_BLOCKS_MAX_LEN: usize = 16;
+
+/// Peers management configuration
+pub struct ManagePeersConfig {
+	/// Time interval (in milliseconds) to wait answer from the peer before penalizing && reexecuting tasks
+	pub failure_interval_ms: u32,
+}
+
+impl Default for ManagePeersConfig {
+	fn default() -> Self {
+		ManagePeersConfig {
+			failure_interval_ms: DEFAULT_PEER_FAILURE_INTERVAL_MS,
+		}
+	}
+}
+
+/// Unknown blocks management configuration
+pub struct ManageUnknownBlocksConfig {
+	/// Time interval (in milliseconds) to wait before removing unknown blocks from in-memory pool
+	pub removal_time_ms: u32,
+	/// Maximal # of unknown blocks in the in-memory pool
+	pub max_number: usize,
+}
+
+impl Default for ManageUnknownBlocksConfig {
+	fn default() -> Self {
+		ManageUnknownBlocksConfig {
+			removal_time_ms: DEFAULT_UNKNOWN_BLOCK_REMOVAL_TIME_MS,
+			max_number: DEFAULT_UNKNOWN_BLOCKS_MAX_LEN,
+		}
+	}
+}
 
 /// Manage stalled synchronization peers tasks
-pub fn manage_synchronization_peers(peers: &mut Peers) -> Option<Vec<H256>> {
+pub fn manage_synchronization_peers(config: &ManagePeersConfig, peers: &mut Peers) -> Option<Vec<H256>> {
 	let mut blocks_to_request: Vec<H256> = Vec::new();
 	let now = precise_time_s();
 	// reset tasks for peers, which has not responded during given period
 	for (worst_peer_index, worst_peer_time) in peers.worst_peers() {
 		// check if peer has not responded within given time
-		let time_diff = worst_peer_time - now;
-		if time_diff <= PEER_FAILURE_INTERVAL_S {
+		let time_diff = now - worst_peer_time;
+		if time_diff <= config.failure_interval_ms as f64 / 1000f64 {
 			break;
 		}
 
 		// decrease score && move to the idle queue
-		trace!(target: "sync", "Failed to get response from peer#{} in {} seconds", worst_peer_index, time_diff);
+		warn!(target: "sync", "Failed to get response from peer#{} in {} seconds", worst_peer_index, time_diff);
 		let peer_tasks = peers.reset_tasks(worst_peer_index);
 		blocks_to_request.extend(peer_tasks);
 
 		// if peer failed many times => forget it
 		if peers.on_peer_failure(worst_peer_index) {
-			trace!(target: "sync", "Too many failures for peer#{}. Excluding from synchronization", worst_peer_index);
+			warn!(target: "sync", "Too many failures for peer#{}. Excluding from synchronization", worst_peer_index);
 		}
 	}
 
@@ -39,9 +70,9 @@ pub fn manage_synchronization_peers(peers: &mut Peers) -> Option<Vec<H256>> {
 }
 
 /// Manage unknown orphaned blocks
-pub fn manage_unknown_orphaned_blocks(unknown_blocks: &mut LinkedHashMap<H256, f64>) -> Option<Vec<H256>> {
+pub fn manage_unknown_orphaned_blocks(config: &ManageUnknownBlocksConfig, unknown_blocks: &mut LinkedHashMap<H256, f64>) -> Option<Vec<H256>> {
 	let mut unknown_to_remove: Vec<H256> = Vec::new();
-	let mut remove_num = if unknown_blocks.len() > UNKNOWN_BLOCKS_MAX_LEN { UNKNOWN_BLOCKS_MAX_LEN - unknown_blocks.len() } else { 0 };
+	let mut remove_num = if unknown_blocks.len() > config.max_number { unknown_blocks.len() - config.max_number } else { 0 };
 	let now = precise_time_s();
 	for (hash, time) in unknown_blocks.iter() {
 		// remove oldest blocks if there are more unknown blocks that we can hold in memory
@@ -52,8 +83,8 @@ pub fn manage_unknown_orphaned_blocks(unknown_blocks: &mut LinkedHashMap<H256, f
 		}
 
 		// check if block is unknown for too long
-		let time_diff = time - now;
-		if time_diff <= UNKNOWN_BLOCK_REMOVAL_TIME_S {
+		let time_diff = now - time;
+		if time_diff <= config.removal_time_ms as f64 / 1000f64 {
 			break;
 		}
 		unknown_to_remove.push(hash.clone());
@@ -66,3 +97,73 @@ pub fn manage_unknown_orphaned_blocks(unknown_blocks: &mut LinkedHashMap<H256, f
 
 	if unknown_to_remove.is_empty() { None } else { Some(unknown_to_remove) }
 }
+
+#[cfg(test)]
+mod tests {
+	use time::precise_time_s;
+	use linked_hash_map::LinkedHashMap;
+	use super::{ManagePeersConfig, ManageUnknownBlocksConfig, manage_synchronization_peers, manage_unknown_orphaned_blocks};
+	use synchronization_peers::Peers;
+	use primitives::hash::H256;
+
+	#[test]
+	fn manage_good_peer() {
+		let config = ManagePeersConfig { failure_interval_ms: 1000, };
+		let mut peers = Peers::new();
+		peers.on_blocks_requested(1, &vec![H256::from(0), H256::from(1)]);
+		peers.on_block_received(1, &H256::from(0));
+		assert_eq!(manage_synchronization_peers(&config, &mut peers), None);
+		assert_eq!(peers.idle_peers(), vec![]);
+	}
+
+	#[test]
+	fn manage_bad_peers() {
+		use std::thread::sleep;
+		use std::time::Duration;
+		let config = ManagePeersConfig { failure_interval_ms: 0, };
+		let mut peers = Peers::new();
+		peers.on_blocks_requested(1, &vec![H256::from(0)]);
+		peers.on_blocks_requested(2, &vec![H256::from(1)]);
+		sleep(Duration::from_millis(1));
+
+		let managed_tasks = manage_synchronization_peers(&config, &mut peers).expect("managed tasks");
+		assert!(managed_tasks.contains(&H256::from(0)));
+		assert!(managed_tasks.contains(&H256::from(1)));
+		let idle_peers = peers.idle_peers();
+		assert_eq!(2, idle_peers.len());
+		assert!(idle_peers.contains(&1));
+		assert!(idle_peers.contains(&2));
+	}
+
+	#[test]
+	fn manage_unknown_blocks_good() {
+		let config = ManageUnknownBlocksConfig { removal_time_ms: 1000, max_number: 100 };
+		let mut unknown_blocks: LinkedHashMap<H256, f64> = LinkedHashMap::new();
+		unknown_blocks.insert(H256::from(0), precise_time_s());
+		assert_eq!(manage_unknown_orphaned_blocks(&config, &mut unknown_blocks), None);
+		assert_eq!(unknown_blocks.len(), 1);
+	}
+
+	#[test]
+	fn manage_unknown_blocks_by_time() {
+		use std::thread::sleep;
+		use std::time::Duration;
+		let config = ManageUnknownBlocksConfig { removal_time_ms: 0, max_number: 100 };
+		let mut unknown_blocks: LinkedHashMap<H256, f64> = LinkedHashMap::new();
+		unknown_blocks.insert(H256::from(0), precise_time_s());
+		sleep(Duration::from_millis(1));
+
+		assert_eq!(manage_unknown_orphaned_blocks(&config, &mut unknown_blocks), Some(vec![H256::from(0)]));
+		assert_eq!(unknown_blocks.len(), 0);
+	}
+
+	#[test]
+	fn manage_unknown_blocks_by_max_number() {
+		let config = ManageUnknownBlocksConfig { removal_time_ms: 100, max_number: 1 };
+		let mut unknown_blocks: LinkedHashMap<H256, f64> = LinkedHashMap::new();
+		unknown_blocks.insert(H256::from(0), precise_time_s());
+		unknown_blocks.insert(H256::from(1), precise_time_s());
+		assert_eq!(manage_unknown_orphaned_blocks(&config, &mut unknown_blocks), Some(vec![H256::from(0)]));
+		assert_eq!(unknown_blocks.len(), 1);
+	}
+}