Lethalwx69

I have a LQ4, new block, rods, pistons, and rings. I took my time and made sure everything was oriented correctly, while assembling the shortblock. I just got my head gaskets in so I put those on. I then decide to put a spark plug in each cylinder and give it a couple turns. So I turn the crank maybe a 1/4 turn when I started to feel some resistance, and then pssst!!! Air is leaking passed the rings, it scared me at first, but I figured it was because the rings haven't seated. I tried another cylinder same thing happened. I don't have a gauge so I just went by feel. Is this normal?

Pb Foot

iTrader: (2)

The piston rings do not create an airtight seal. At rpm the pressure does not have as much time to leak down. Normal operation

JRENIGAR

iTrader: (37)

If the system is primed up with oil then remove the plugs and install a comp checker. Jump power to the starter and check the comp the correct way. Report back what the readings are.

96capricemgr

iTrader: (1)

Who knows what pre break in compression should be on his setup?

VandykeT/A

Any engine will have that psst sound when you turn the motor over by hand with plugs in it.

svede1212

iTrader: (3)

Combustion forces the compression ring out to seal

RockinWs6

Its normal, all engines leak down about 10%.

Lethalwx69

Thanks for all the info.

I'll do that for sure when I get the engine back in.

96capricemgr

iTrader: (1)

Agreed it sounds normal, my last post was more a challenge for those say to do a test