rebuilt engine and now no compression

[shawny2087]

hi i am rebuilding my 1992 talon 6bolt block cause all the compression was leaking past the rings also the gas. so ive put new rings on and also honed the cylinders i also put on new clevite main and rod bearings and gaskets and what not. i got all the stuff from SBR so i know its not the parts. i also got my rebuilt SBR head today and i bolted it up and i still have it on the stand without the oil pan on yet and i turned the crank by hand and all i got from all 4 cylinders was a little over 30psi and i could hear the compression hissing from the crankcase why would it do the with new rings the bores are good. is it just cause the engine is out or what? and help would be wounderful thanx

 

[engineman100]

hi i am rebuilding my 1992 talon 6bolt block cause all the compression was leaking past the rings also the gas. so ive put new rings on and also honed the cylinders i also put on new clevite main and rod bearings and gaskets and what not. i got all the stuff from SBR so i know its not the parts. i also got my rebuilt SBR head today and i bolted it up and i still have it on the stand without the oil pan on yet and i turned the crank by hand and all i got from all 4 cylinders was a little over 30psi and i could hear the compression hissing from the crankcase why would it do the with new rings the bores are good. is it just cause the engine is out or what? and help would be wounderful thanx

turning by hand will not give you the same results as with the starter, it is called swept volume and RPM.
make sure the timing is installed correctly
thanks Engineman100

 

[turboguy25]

Ya you cant be turning that crank by hand that dosent have any where near the torque the starter has. Also the compression might be a few psi low until breakin. Why dont you do a Cylinder Leakage test that would be better ,than do one ofter breakin. Also did you steager the ring eng gaps so they dont line up?

 

[shawny2087]

okay i see. but i just didnt wany to get the engine in and have to pull it all back out cause leaking compression is what i pulled it out for in the first place. i havent even heard the car run cause i bought it not running and yes i did stager the ring end gaps cause i know that will cause leak. but dont the rings turn at all while the engine it moving??

 

[shawny2087]

okay i see. but i just didnt wany to get the engine in and have to pull it all back out cause leaking compression is what i pulled it out for in the first place. i havent even heard the car run cause i bought it not running and yes i did stager the ring end gaps cause i know that will cause leak. but dont the rings turn at all while the engine it moving??

 

[shawny2087]

okay im now getting about 60-70 psi by hand but i understand what you guys are saying but should i be hearing the hissing from the crankcase when the pistons are compressing? thanx