# Blacktop SR20DET compression test readings...need help! **URL:** \ **Category:** SON240sx Automotive\ **Created:** [October 13, 2007, 7:39pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235 "2007-10-13T19:39:51Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![kingtut](https://avatars.discourse-cdn.com/v4/letter/k/c2a13f/32.png) [@kingtut](https://forums.speedlife.net/u/kingtut)\ **Post date:** [October 13, 2007, 7:39pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/1 "2007-10-13T19:39:51Z")
i went to go look at a hatch with a stock s13 blacktop and the owner and i performed a compression test. The results are as follows: Cylinder # 1 = 130psi Cylinder # 2 = 140psi Cylinder # 3 = 140psi Cylinder # 4 = 135psi I’m not too sure whether these readings are too low or not according to s13 sr20det specs…im having trouble finding it on the internet…so if anyone knows what the compression should be…or range from…please let me know ---
**Author:** ![spooolin](https://avatars.discourse-cdn.com/v4/letter/s/48db29/32.png) [@spooolin](https://forums.speedlife.net/u/spooolin)\ **Post date:** [October 13, 2007, 8:08pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/2 "2007-10-13T20:08:40Z")
thats fairly low yes… im guessing it should be around the 150-160psi mark ---
**Author:** ![kingtut](https://avatars.discourse-cdn.com/v4/letter/k/c2a13f/32.png) [@kingtut](https://forums.speedlife.net/u/kingtut)\ **Post date:** [October 13, 2007, 8:53pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/3 "2007-10-13T20:53:14Z")
thanks…its most likely the head gasket if their all low…or all piston rings are fried…but i have a question…should you be cranking until the needle stays stationary?.. ---
**Author:** ![R33](https://avatars.discourse-cdn.com/v4/letter/r/5f8ce5/32.png) [@R33](https://forums.speedlife.net/u/R33)\ **Post date:** [October 13, 2007, 10:06pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/4 "2007-10-13T22:06:20Z")
> [@Parting out 05 wrb wrx](https://forums.speedlife.net/t/parting-out-05-wrb-wrx/14463/9): > > thanks…its most likely the head gasket if their all low…or all piston rings are fried…but i have a question…should you be cranking until the needle stays stationary?.. yeah keep cranking till the needle doesnt move ---
**Author:** ![robbbby](https://avatars.discourse-cdn.com/v4/letter/r/b19c9b/32.png) [@robbbby](https://forums.speedlife.net/u/robbbby)\ **Post date:** [October 13, 2007, 10:55pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/5 "2007-10-13T22:55:40Z")
Was the engine warmed up? Did you hold the throttle open while cranking? And you aren’t supposed to keep cranking, you should only have to turn it over 3-4 times to get agood reading. ---
**Author:** ![slipperysilvia](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/slipperysilvia/32/5485_2.png) [@slipperysilvia](https://forums.speedlife.net/u/slipperysilvia)\ **Post date:** [October 14, 2007, 6:41am UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/6 "2007-10-14T06:41:27Z")
thats not to bad…if it was cold and sitting for a long time those #"s are ok… open the throttle body while cranking, and also pour a small drop of oil in each cylinder just to seal the piston rings…i bet they are dry cuz its been sitting for ages… Dont put more then a drop of oil, the comp#"s should never go above 155-160… ---
**Author:** ![seth](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/seth/32/3175_2.png) [@seth](https://forums.speedlife.net/u/seth)\ **Post date:** [October 14, 2007, 6:47am UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/7 "2007-10-14T06:47:22Z")
^ nod nod ---
**Author:** ![kingtut](https://avatars.discourse-cdn.com/v4/letter/k/c2a13f/32.png) [@kingtut](https://forums.speedlife.net/u/kingtut)\ **Post date:** [October 14, 2007, 1:16pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/8 "2007-10-14T13:16:04Z")
yea i don’t think we kept the throttle open…and it was warm because it was idling for a while and i drove it for a little bit…if throttle was closed and engine was warm…are those numbers ok? ---
**Author:** ![nwmrkt](https://avatars.discourse-cdn.com/v4/letter/n/aca169/32.png) [@nwmrkt](https://forums.speedlife.net/u/nwmrkt)\ **Post date:** [October 14, 2007, 2:06pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/9 "2007-10-14T14:06:23Z")
what should you do if your engine was sitting for sometime in the cold ie garage? ---
**Author:** ![kingtut](https://avatars.discourse-cdn.com/v4/letter/k/c2a13f/32.png) [@kingtut](https://forums.speedlife.net/u/kingtut)\ **Post date:** [October 14, 2007, 3:21pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/10 "2007-10-14T15:21:09Z")
drive it so it warms up then take the test…back to my original question, are those numbers ok if throttle was closed and engine was warm? ---
**Author:** ![robbbby](https://avatars.discourse-cdn.com/v4/letter/r/b19c9b/32.png) [@robbbby](https://forums.speedlife.net/u/robbbby)\ **Post date:** [October 14, 2007, 3:27pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/11 "2007-10-14T15:27:56Z")
> [@kingtut"](#): > > yea i don’t think we kept the throttle open…and it was warm because it was idling for a while and i drove it for a little bit…if throttle was closed and engine was warm…are those numbers ok? Redo it with the throttle held open. And do it without oil, putting oil in defeats the purpose of checking compression since your engine doesn’t run with oil in the combustion chamber in the first place. ---
**Author:** ![kingtut](https://avatars.discourse-cdn.com/v4/letter/k/c2a13f/32.png) [@kingtut](https://forums.speedlife.net/u/kingtut)\ **Post date:** [October 14, 2007, 3:43pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/12 "2007-10-14T15:43:11Z")
see the thing is…it isn’t my car…i went to check it out…and i dont want to ask the owner to redo for me…thats why i was asking if the throttle is closed and i get the values i got…does that sound about right? ---
**Author:** ![pearlS13](https://avatars.discourse-cdn.com/v4/letter/p/e68b1a/32.png) [@pearlS13](https://forums.speedlife.net/u/pearlS13)\ **Post date:** [October 14, 2007, 4:26pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/13 "2007-10-14T16:26:37Z")
The numbers are getting on the low side but are still in spec according to the fsm. The important thing here is that the numbers are pretty even across the board so I wouldn’t worry too much. ---
**Author:** ![kingtut](https://avatars.discourse-cdn.com/v4/letter/k/c2a13f/32.png) [@kingtut](https://forums.speedlife.net/u/kingtut)\ **Post date:** [October 14, 2007, 6:12pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/14 "2007-10-14T18:12:05Z")
sounds good…i was just concerned about the readings because if i do get the car and up the boost on stock internals i don’t want to risk damaging my motor at all ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex034/uploads/speedlife/original/2X/b/b7170c8eddc0b95ece6b88172b2f416a08489a45.png) [@system](https://forums.speedlife.net/u/system)\ **Post date:** [October 15, 2007, 8:18am UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/15 "2007-10-15T08:18:45Z")
> [@This Is Some Cool Shit...](https://forums.speedlife.net/t/this-is-some-cool-shit/14469/3): > > ^ nod nod lol so true, “seal the rings” ---
**Author:** ![slipperysilvia](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/slipperysilvia/32/5485_2.png) [@slipperysilvia](https://forums.speedlife.net/u/slipperysilvia)\ **Post date:** [October 15, 2007, 11:57am UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/16 "2007-10-15T11:57:32Z")
yea, you will notice that when motors sit for a while, its bad to turn them over without pouring a drop of oil into the top of the cylinder to make sure its wet…otherwise, u can score the walls… The best way is to wet them a tiny bit, turn over the motor 5-10 times, and then do the comp test so u know for sure there is no more oil in the cylinder, and the walls are glazed with oil. ---
**Author:** ![kingtut](https://avatars.discourse-cdn.com/v4/letter/k/c2a13f/32.png) [@kingtut](https://forums.speedlife.net/u/kingtut)\ **Post date:** [October 15, 2007, 5:24pm UTC](https://forums.speedlife.net/t/blacktop-sr20det-compression-test-readings-need-help/110235/17 "2007-10-15T17:24:41Z")
great…thanks varuun and thank you to everybody that helped on this thread