cylinder compression 90 chev 305

[roonie]

what should the cylinder compression be on my 90 chev with a 305.I did a dry test and ended up with 75 lbs.at each hole.that seems a bit low to me.what would it have been from day one.runs nice but using some oil.have already done valve seals.no longer puffs apon starting.thanks

[tirefryer93]

You are right, 75 lbs is low. Stock should be anywhere from 130-150. My inclination is that your rings are worn, which is reasonable because of your loss of oil and low compression. Unless you want to give the engine a partial (or entire) rebuild, I suggest using some engine flush in your oil, drain it, then add a new change of Valvoline (best thing for chevys) and try a quart of additive such as Restore or similar. That should help seal the cylinder walls better and give you some better numbers on the compression gauge.

[Fireplug]

The main thing about a compression test is that they are all about the same reading. 75psi is low but if its running good and does not burn a lot of oil then run it.