Zero Compression

[Chain_skipper]

I have a 4.3 v6 that I replaced main bearings in as well as gaskets. I didn't run it last summer because the starter was bad. Got a new starter on and have a no start condition. I am checking the compression and I get no reading from the gauge, like no movement at all. I replaced the head gaskets when I reassembled, so I'm pretty sure those are good. The piston rings are the ones that were in there before the bearing replacement, and they were fine before, so I left them in. I checked the timing last night on the gears and that is spot on as well. Somebody suggested hanging valves, so I readjusted the lash to 3/4 of a turn past zero, and still nothing. This one has me stumped, so I'm throwing it out to anybody who can offer insight. Thanks in advance.

 

[Bt Doctur]

is your 4.3 3/4 past zero or torqued to 20/Ft.lbs

 

[scoflaw]

0 on all 6 holes ? Sounds like a faulty tool, stick your thumb over the hole and try spinning it

 

[Chain_skipper]

I torqued it 3/4 of a turn past when the pushrod would no longer turn.

 

[Bt Doctur]

i realize that but some v6`s are torqued not adjusted

 

[Scott Danforth]

I torqued it 3/4 of a turn past when the pushrod would no longer turn.

its 3/4 turn past zero lash (up/down movement). not 3/4 turn past when they stop rotating. the valve are partially open long before the push rods stop spinning with your fingers.

back them off and start over.

 

[Chain_skipper]

Yes, it is a 1990 model year 4.3. S/N 0C665406. I haven't really found an exact process for valve lash, it seems everything I find says something different.

 

[Bt Doctur]

according to manual 25 that should be you the rocker arm nuts are torqued to 22 /Ft.Lbs no adjusting . Set cylinder at TDC and torque

 

[Bt Doctur]

 

[Chain_skipper]

I'm assuming I need to make sure the valves are closed when I set that torque spec?

 

[Bt Doctur]

I set each cylinder at TDC .Watch the valve train to see when the intake vale opens and then closes now your on compression and both valves will be closed, torque and move to the next cylinder

 

[Chain_skipper]

I will do that tonight then. I wish I had known it was that east to start with. Hopefully I can report back with healthy compression.