What is a good compression reading for an sr20

[240sx23]

Just curious lmk thanks

[EsChassisLove]

Not sure but mines 170, 170, 155, 170 after a rebuild and 9:1 compression.

I can't imagine anything under 140 being too good even if its consistent numbers with all the cylinders.

Edit-pretty positive this has been covered before.

[clutch187]

i know all cylinders should be +or- 14 psi of each other. most will probably say time for another rebuild

i accidently responded to EsChassisLove thinking he was the OP, sorry

[jr_ss]

Factory spec is 156psi, with 128psi being the minimum. 14psi difference between cylinders is the max allowable per the FSM. The important part is that they are consistent between cylinders. There are many variables that can create comp differences, rings, valves, and head gaskets are the most common. A leak down test will give you a better idea of how healthy your engine is.

[jr_ss]

I can't imagine anything under 140 being too good even if its consistent numbers with all the cylinders.

This varies, lower compression motors aren't going to yield high comp numbers. Changes in head gasket thickness, piston compression ratio's and ring gaps will all play a role in different comp readings. Just because it "reads low" doesn't mean it's in bad shape.

[Kingtal0n]

most important thing is that they are all very similar to each other. if one cylinder is notably lower than the others that is an indication that something is wrong. could be anything- from a piece of carbon stuck in a valve, to a broken piston ring.