I recently did a compression test on my ls and the results were as follows,
#1 - 175
#2 - 180
#3 - 180
#4 - 160ish

Ive been feeling like my car does not have the power it once had, before I put the engine in, I did a complete rebuild, so I dont understand why compression on cylinder #4 would read that low. Is it possible the low compression in cylinder #4, although not way off but enough to cause concern, could cause the engine to noticeably hold back? I have been looking for smoke and checking the oil regularly, and no problems there. I figured the rings could still be seating but its been 1000 miles. The car just feels like overall throttle response is non existent, for example if I mash the gas in 3rd doing 60 (I have a gsr tranny BTW) the car isnt going anywhere, where as it used to be the car would take off. I did blow the first tranny that was in the car when it was still running great and pulling hard due to an improperly sealed casing that binded all the gears after unknowingly leaking fluid. After the car sat for a month, I finally got a new tranny and put it in and tranny has no problems of any sort, but the car doesnt pull like it did with the old tranny, is it possible the trannys, although both gsr, would make a difference? Im really stumped here, and trying to narrow down the possible causes of my engine lag. Im about to do a valve adjustment next, it sounds like my valves are tapping a little, which could cause a loss in compression.

 

Start off with the basics and go from there. Do a valve adjustment, check your ignition timing, check/replace your distributor cap and rotor, maybe plugs and wires as well. You'll probably find something there, if not do a leak down test and see if anything comes up.

 

The whole distributor is new as well as plugs and wires, is it possible my valve timing could be off?

 

possibly, it's just one more thing you can check.

 

i'd say that ur timing is off what's ur full build and what type cams do u have and are u using cam gears.

 

Its all internally stock, but I did notice today the belt seems to have some slack in it, so im thinking it may have jumped teeth.

 

Alright, checked the timing and it was dead on, and I did another compression test that put down some different numbers (engine was good and hot, the first test the engine was warm) #1 - 182, #2 - 175, #3 - 182, #4 - 173. Valve adjustment is next, cause car is still feeling sluggish.