diff --git a/lib/stateManager.js b/lib/stateManager.js
index f606d80a4b..833eb046e6 100644
--- a/lib/stateManager.js
+++ b/lib/stateManager.js
@@ -14,16 +14,15 @@ module.exports = StateManager
 function StateManager (opts = {}) {
   var self = this
 
-  self.trie = opts.trie || new Trie()
-
   var common = opts.common
   if (!common) {
     common = new Common('mainnet', 'byzantium')
   }
   self._common = common
 
+  self._trie = opts.trie || new Trie()
   self._storageTries = {} // the storage trie cache
-  self.cache = new Cache(self.trie)
+  self._cache = new Cache(self._trie)
   self._touched = new Set()
   self._touchedStack = []
   self._checkpointCount = 0
@@ -32,13 +31,13 @@ function StateManager (opts = {}) {
 var proto = StateManager.prototype
 
 proto.copy = function () {
-  return new StateManager({ trie: this.trie.copy() })
+  return new StateManager({ trie: this._trie.copy() })
 }
 
 // gets the account from the cache, or triggers a lookup and stores
 // the result in the cache
 proto.getAccount = function (address, cb) {
-  this.cache.getOrLoad(address, cb)
+  this._cache.getOrLoad(address, cb)
 }
 
 // saves the account
@@ -47,9 +46,9 @@ proto.putAccount = function (address, account, cb) {
   // TODO: dont save newly created accounts that have no balance
   // if (toAccount.balance.toString('hex') === '00') {
   // if they have money or a non-zero nonce or code, then write to tree
-  self.cache.put(address, account)
+  self._cache.put(address, account)
   self._touched.add(address.toString('hex'))
-  // self.trie.put(addressHex, account.serialize(), cb)
+  // self._trie.put(addressHex, account.serialize(), cb)
   cb()
 }
 
@@ -84,7 +83,7 @@ proto.putContractCode = function (address, value, cb) {
       return cb(err)
     }
     // TODO: setCode use trie.setRaw which creates a storage leak
-    account.setCode(self.trie, value, function (err) {
+    account.setCode(self._trie, value, function (err) {
       if (err) {
         return cb(err)
       }
@@ -100,7 +99,7 @@ proto.getContractCode = function (address, cb) {
     if (err) {
       return cb(err)
     }
-    account.getCode(self.trie, cb)
+    account.getCode(self._trie, cb)
   })
 }
 
@@ -112,7 +111,7 @@ proto._lookupStorageTrie = function (address, cb) {
     if (err) {
       return cb(err)
     }
-    var storageTrie = self.trie.copy()
+    var storageTrie = self._trie.copy()
     storageTrie.root = account.stateRoot
     storageTrie._checkpoints = []
     cb(null, storageTrie)
@@ -161,7 +160,7 @@ proto._modifyContractStorage = function (address, modifyTrie, cb) {
       // update storage cache
       self._storageTries[address.toString('hex')] = storageTrie
       // update contract stateRoot
-      var contract = self.cache.get(address)
+      var contract = self._cache.get(address)
       contract.stateRoot = storageTrie.root
       self.putAccount(address, contract, cb)
       self._touched.add(address.toString('hex'))
@@ -196,8 +195,8 @@ proto.clearContractStorage = function (address, cb) {
 //
 proto.checkpoint = function () {
   var self = this
-  self.trie.checkpoint()
-  self.cache.checkpoint()
+  self._trie.checkpoint()
+  self._cache.checkpoint()
   self._touchedStack.push(new Set([...self._touched]))
   self._checkpointCount++
 }
@@ -205,13 +204,13 @@ proto.checkpoint = function () {
 proto.commit = function (cb) {
   var self = this
   // setup trie checkpointing
-  self.trie.commit(function () {
+  self._trie.commit(function () {
     // setup cache checkpointing
-    self.cache.commit()
+    self._cache.commit()
     self._touchedStack.pop()
     self._checkpointCount--
 
-    if (self._checkpointCount === 0) self.cache.flush(cb)
+    if (self._checkpointCount === 0) self._cache.flush(cb)
     else cb()
   })
 }
@@ -219,40 +218,37 @@ proto.commit = function (cb) {
 proto.revert = function (cb) {
   var self = this
   // setup trie checkpointing
-  self.trie.revert()
+  self._trie.revert()
   // setup cache checkpointing
-  self.cache.revert()
+  self._cache.revert()
   self._storageTries = {}
   self._touched = self._touchedStack.pop()
   self._checkpointCount--
 
-  if (self._checkpointCount === 0) self.cache.flush(cb)
+  if (self._checkpointCount === 0) self._cache.flush(cb)
   else cb()
 }
 
-//
-// cache stuff
-//
 proto.getStateRoot = function (cb) {
   var self = this
-  self.cache.flush(function (err) {
+  self._cache.flush(function (err) {
     if (err) {
       return cb(err)
     }
-    var stateRoot = self.trie.root
+    var stateRoot = self._trie.root
     cb(null, stateRoot)
   })
 }
 
 proto.setStateRoot = function (stateRoot, cb) {
   var self = this
-  self.cache.flush(function (err) {
+  self._cache.flush(function (err) {
     if (err) { return cb(err) }
-    self.trie.checkRoot(stateRoot, function (err, hasRoot) {
+    self._trie.checkRoot(stateRoot, function (err, hasRoot) {
       if (err || !hasRoot) {
         cb(err || new Error('State trie does not contain state root'))
       } else {
-        self.trie.root = stateRoot
+        self._trie.root = stateRoot
         cb()
       }
     })
@@ -278,7 +274,7 @@ proto.dumpStorage = function (address, cb) {
 
 proto.hasGenesisState = function (cb) {
   const root = this._common.genesis().stateRoot
-  this.trie.checkRoot(root, cb)
+  this._trie.checkRoot(root, cb)
 }
 
 proto.generateCanonicalGenesis = function (cb) {
@@ -300,7 +296,7 @@ proto.generateGenesis = function (initState, cb) {
     var account = new Account()
     account.balance = new BN(initState[address]).toArrayLike(Buffer)
     address = Buffer.from(address, 'hex')
-    self.trie.put(address, account.serialize(), done)
+    self._trie.put(address, account.serialize(), done)
   }, cb)
 }
 
@@ -327,7 +323,7 @@ proto.cleanupTouchedAccounts = function (cb) {
       }
 
       if (empty) {
-        self.cache.del(address)
+        self._cache.del(address)
       }
       next(null)
     })
diff --git a/tests/api/index.js b/tests/api/index.js
index 26e3e10921..1f569f234a 100644
--- a/tests/api/index.js
+++ b/tests/api/index.js
@@ -11,14 +11,14 @@ tape('VM with fake blockchain', (t) => {
   t.test('should insantiate without params', (st) => {
     const vm = new VM()
     st.ok(vm.stateManager)
-    st.deepEqual(vm.stateManager.trie.root, util.KECCAK256_RLP, 'it has default trie')
+    st.deepEqual(vm.stateManager._trie.root, util.KECCAK256_RLP, 'it has default trie')
     st.ok(vm.blockchain.fake, 'it has fake blockchain by default')
     st.end()
   })
 
   t.test('should be able to activate precompiles', (st) => {
     let vm = new VM({ activatePrecompiles: true })
-    st.notEqual(vm.stateManager.trie.root, util.KECCAK256_RLP, 'it has different root')
+    st.notEqual(vm.stateManager._trie.root, util.KECCAK256_RLP, 'it has different root')
     st.end()
   })
 
@@ -47,7 +47,7 @@ tape('VM with fake blockchain', (t) => {
 tape('VM with blockchain', (t) => {
   t.test('should instantiate', (st) => {
     const vm = setupVM()
-    st.deepEqual(vm.stateManager.trie.root, util.KECCAK256_RLP, 'it has default trie')
+    st.deepEqual(vm.stateManager._trie.root, util.KECCAK256_RLP, 'it has default trie')
     st.notOk(vm.stateManager.fake, 'it doesn\'t have fake blockchain')
     st.end()
   })
@@ -74,7 +74,7 @@ tape('VM with blockchain', (t) => {
     )
 
     const setupPreP = promisify(setupPreConditions)
-    await setupPreP(vm.stateManager.trie, testData)
+    await setupPreP(vm.stateManager._trie, testData)
 
     vm.runBlock = (block, cb) => cb(new Error('test'))
     runBlockchainP(vm)
@@ -101,7 +101,7 @@ tape('VM with blockchain', (t) => {
     )
 
     const setupPreP = promisify(setupPreConditions)
-    await setupPreP(vm.stateManager.trie, testData)
+    await setupPreP(vm.stateManager._trie, testData)
 
     await runBlockchainP(vm)
 
diff --git a/tests/api/runBlock.js b/tests/api/runBlock.js
index 1920376b35..47b8b68068 100644
--- a/tests/api/runBlock.js
+++ b/tests/api/runBlock.js
@@ -122,7 +122,7 @@ tape('should fail when runCall fails', async (t) => {
   // which always returns an error.
   // runTx is a full implementation that works.
   suite.vm.runTx = runTx
-  await suite.p.runBlock({ block, root: suite.vm.stateManager.trie.root })
+  await suite.p.runBlock({ block, root: suite.vm.stateManager._trie.root })
     .then(() => t.fail('should have returned error'))
     .catch((e) => t.equal(e.message, 'test'))
 
@@ -137,15 +137,15 @@ tape('should run valid block', async (t) => {
   const block = new Block(util.rlp.decode(suite.data.blocks[0].rlp))
 
   const setupPreP = promisify(setupPreConditions)
-  await setupPreP(suite.vm.stateManager.trie, suite.data)
+  await setupPreP(suite.vm.stateManager._trie, suite.data)
 
   t.equal(
-    suite.vm.stateManager.trie.root.toString('hex'),
+    suite.vm.stateManager._trie.root.toString('hex'),
     genesis.header.stateRoot.toString('hex'),
     'genesis state root should match calculated state root'
   )
 
-  let res = await suite.p.runBlock({ block, root: suite.vm.stateManager.trie.root })
+  let res = await suite.p.runBlock({ block, root: suite.vm.stateManager._trie.root })
   t.error(res.error, 'runBlock shouldn\'t have returned error')
   t.equal(res.results[0].gasUsed.toString('hex'), '5208', 'actual gas used should equal blockHeader gasUsed')
 
diff --git a/tests/api/stateManager.js b/tests/api/stateManager.js
index 839ed5129e..172790d862 100644
--- a/tests/api/stateManager.js
+++ b/tests/api/stateManager.js
@@ -8,7 +8,7 @@ tape('StateManager', (t) => {
   t.test('should instantiate', (st) => {
     const stateManager = new StateManager()
 
-    st.deepEqual(stateManager.trie.root, util.KECCAK256_RLP, 'it has default root')
+    st.deepEqual(stateManager._trie.root, util.KECCAK256_RLP, 'it has default root')
     stateManager.getStateRoot((err, res) => {
       st.error(err, 'getStateRoot returns no error')
       st.deepEqual(res, util.KECCAK256_RLP, 'it has default root')
@@ -33,13 +33,13 @@ tape('StateManager', (t) => {
 
     st.equal(res.balance.toString('hex'), 'fff384')
 
-    stateManager.cache.clear()
+    stateManager._cache.clear()
 
     res = await promisify(stateManager.getAccount.bind(stateManager))(
       'a94f5374fce5edbc8e2a8697c15331677e6ebf0b'
     )
 
-    st.equal(stateManager.cache._cache.keys[0], 'a94f5374fce5edbc8e2a8697c15331677e6ebf0b')
+    st.equal(stateManager._cache._cache.keys[0], 'a94f5374fce5edbc8e2a8697c15331677e6ebf0b')
 
     st.end()
   })