diff --git a/vvp/delay.cc b/vvp/delay.cc
index ac751f860..66a22a4c6 100644
--- a/vvp/delay.cc
+++ b/vvp/delay.cc
@@ -135,6 +135,17 @@ vvp_fun_delay::vvp_fun_delay(vvp_net_t*n, vvp_bit4_t init, const vvp_delay_t&d)
       cur_real_ = 0.0;
       list_ = 0;
       initial_ = true;
+	// Calculate the values used when converting variable delays
+	// to simulation time units.
+      struct __vpiScope*scope = vpip_peek_current_scope();
+
+      int pow = scope->time_units - scope->time_precision;
+      round_ = 1;
+      for (int lp = 0; lp < pow; lp += 1) round_ *= 10;
+
+      pow = scope->time_precision - vpip_get_time_precision();
+      scale_ = 1;
+      for (int lp = 0; lp < pow; lp += 1) scale_ *= 10;
 }
 
 vvp_fun_delay::~vvp_fun_delay()
@@ -176,8 +187,12 @@ void vvp_fun_delay::recv_vec4(vvp_net_ptr_t port, const vvp_vector4_t&bit)
       if (port.port() > 0) {
 	      // Get the integer value of the bit vector, or 0 if
 	      // there are X or Z bits.
-	    unsigned long val = 0;
-	    vector4_to_value(bit, val);
+	    vvp_time64_t bval = 0;
+	      // The following does not work correctly for negative values.
+	      // They should be sign extended to 64 bits (1364-2001 9.7.1).
+	    vector4_to_value(bit, bval);
+	      // Integer values do not need to be rounded so just scale them.
+	    vvp_time64_t val = bval * round_ * scale_;
 
 	    switch (port.port()) {
 		case 1:
@@ -272,9 +287,17 @@ void vvp_fun_delay::recv_real(vvp_net_ptr_t port, double bit)
       if (port.port() > 0) {
 	    /* If the port is not 0, then this is a delay value that
 	    should be rounded and converted to an integer delay. */
-	    unsigned long long val = 0;
-	    if (bit > 0)
-		  val = (unsigned long long) (bit+0.5);
+	    vvp_time64_t val = 0;
+	    if (bit > -0.5) {
+		  val = (vvp_time64_t) (bit * round_ +0.5) * scale_;
+	    } else if (bit != bit) {
+		    // For a NaN we use the default (0).
+	    } else {
+		  vvp_vector4_t vec4(8*sizeof(vvp_time64_t), bit);
+		  vvp_time64_t bval = 0;
+		  vector4_to_value(vec4, bval);
+		  val = bval * round_ * scale_;
+	    }
 
 	    switch (port.port()) {
 		case 1:
diff --git a/vvp/delay.h b/vvp/delay.h
index 20fa617e9..d886f0c94 100644
--- a/vvp/delay.h
+++ b/vvp/delay.h
@@ -106,6 +106,7 @@ class vvp_fun_delay  : public vvp_net_fun_t, private vvp_gen_event_s {
       vvp_vector4_t cur_vec4_;
       vvp_vector8_t cur_vec8_;
       double cur_real_;
+      vvp_time64_t round_, scale_; // Needed to scale variable time values.
 
       struct event_ *list_;
       void enqueue_(struct event_*cur)
diff --git a/vvp/vvp_net.cc b/vvp/vvp_net.cc
index fa869bf0a..af7402245 100644
--- a/vvp/vvp_net.cc
+++ b/vvp/vvp_net.cc
@@ -1156,7 +1156,9 @@ bool vector4_to_value(const vvp_vector4_t&vec, long&val,
       long msk = 1;
       bool rc_flag = true;
 
-      for (unsigned idx = 0 ;  idx < vec.size() ;  idx += 1) {
+      unsigned size = vec.size();
+      if (size > 8*sizeof(val)) size = 8*sizeof(val);
+      for (unsigned idx = 0 ;  idx < size ;  idx += 1) {
 	    switch (vec.value(idx)) {
 		case BIT4_0:
 		  break;
@@ -1187,7 +1189,34 @@ bool vector4_to_value(const vvp_vector4_t&vec, unsigned long&val)
       unsigned long res = 0;
       unsigned long msk = 1;
 
-      for (unsigned idx = 0 ;  idx < vec.size() ;  idx += 1) {
+      unsigned size = vec.size();
+      if (size > 8*sizeof(val)) size = 8*sizeof(val);
+      for (unsigned idx = 0 ;  idx < size ;  idx += 1) {
+	    switch (vec.value(idx)) {
+		case BIT4_0:
+		  break;
+		case BIT4_1:
+		  res |= msk;
+		  break;
+		default:
+		  return false;
+	    }
+
+	    msk <<= 1UL;
+      }
+
+      val = res;
+      return true;
+}
+
+bool vector4_to_value(const vvp_vector4_t&vec, vvp_time64_t&val)
+{
+      vvp_time64_t res = 0;
+      vvp_time64_t msk = 1;
+
+      unsigned size = vec.size();
+      if (size > 8*sizeof(val)) size = 8*sizeof(val);
+      for (unsigned idx = 0 ;  idx < size ;  idx += 1) {
 	    switch (vec.value(idx)) {
 		case BIT4_0:
 		  break;
diff --git a/vvp/vvp_net.h b/vvp/vvp_net.h
index b9b3bfb6c..9313df469 100644
--- a/vvp/vvp_net.h
+++ b/vvp/vvp_net.h
@@ -394,6 +394,7 @@ template <class T> extern T coerce_to_width(const T&that, unsigned width);
  */
 extern bool vector4_to_value(const vvp_vector4_t&a, long&val, bool is_signed, bool is_arithmetic =true);
 extern bool vector4_to_value(const vvp_vector4_t&a, unsigned long&val);
+extern bool vector4_to_value(const vvp_vector4_t&a, vvp_time64_t&val);
 extern bool vector4_to_value(const vvp_vector4_t&a, double&val, bool is_signed);
 
 /*