diff --git a/dev-python/pypy3/pypy3-5.9.0.ebuild b/dev-python/pypy3/pypy3-5.9.0-r1.ebuild
similarity index 99%
rename from dev-python/pypy3/pypy3-5.9.0.ebuild
rename to dev-python/pypy3/pypy3-5.9.0-r1.ebuild
index 1fe12fc2c5235..a1892572aacb9 100644
--- a/dev-python/pypy3/pypy3-5.9.0.ebuild
+++ b/dev-python/pypy3/pypy3-5.9.0-r1.ebuild
@@ -210,6 +210,8 @@ src_install() {
 	doexe pypy3-c libpypy3-c.so
 	pax-mark m "${ED%/}${dest}/pypy3-c" "${ED%/}${dest}/libpypy3-c.so"
 	insinto "${dest}"
+	# preserve mtimes to avoid obsoleting caches
+	insopts -p
 	doins -r include lib_pypy lib-python
 	dosym ../$(get_libdir)/pypy3/pypy3-c /usr/bin/pypy3
 	dodoc README.rst
diff --git a/dev-python/pypy3/pypy3-9999.ebuild b/dev-python/pypy3/pypy3-9999.ebuild
index 1369c84d3fc9b..ff2a3ff800ed4 100644
--- a/dev-python/pypy3/pypy3-9999.ebuild
+++ b/dev-python/pypy3/pypy3-9999.ebuild
@@ -237,6 +237,8 @@ src_install() {
 	doexe pypy3-c libpypy3-c.so
 	pax-mark m "${ED%/}${dest}/pypy3-c" "${ED%/}${dest}/libpypy3-c.so"
 	insinto "${dest}"
+	# preserve mtimes to avoid obsoleting caches
+	insopts -p
 	doins -r include lib_pypy lib-python
 	dosym ../$(get_libdir)/pypy3/pypy3-c /usr/bin/pypy3
 	dodoc README.rst