73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Mr84c10 on August 26, 2011, 08:03:43 pm
-
So today I was working on my truck and while it was running heard a tapping sound pop valve cover off and lifter was so loose I could have pull it off so I try to tight all em down that were loose and mainly all were loose.... I started wit cylinder 1 and went from there motor only has 2 k on it is a rebuilt 350 60 over before it would crank up on a dime now I don't any fire and it back fire on me twice.... anybody tell me what I did wrong???
Sent from my SCH-I500 using Tapatalk
-
There is a proper sequence to tightening rockers....
Just tightening the "loose" ones is a good way to introduce your piston to your valves...
-
I tight all of em... and what you mean by introduce my valves to my piston.... and what would be correct way
Sent from my SCH-I500 using Tapatalk
-
I meant other way around my bad
Sent from my SCH-I500 using Tapatalk
-
Start here...
http://www.classiccarauto.com/impala/how_to/adjust_valves.shtml
-
Just cranking them all up will bend push rods, break rocker arms, could leave the valve open to long and slam the piston up into the valve.
-
Start motor with vc off, get them to the point where they barely click then go a half a turn. Assuming this is hydro lifties
-
Oh ok thanks guys ill try this either Saturday or Sunday and get bk wit y'all....
Sent from my SCH-I500 using Tapatalk
-
Start motor with vc off, get them to the point where they barely click then go a half a turn. Assuming this is hydro lifties
Or do it the right way
-
You can set the valves INITIALLY with the engine off, and in a particular order or prcedure, but even when thats done, you have to set them later with the engine running.
to do it more cleanly, since you're supposed to do it while its running, is get an old valve cover and cut the top off it and that will catch the oil from running out of the head all over everything. there are also some clips to have to clip on the rocker arm to keep oil from squirting up and out all over the place too, but i cant remember what theyre called.
If you tightened them all up without rotating the engine at all, probably some are too tight and not letting the valves close all the way, so you get backfires when an intake valve is open and a spark plug fires.
Introducing the valves to the pistons means the valves hand down too far and at the wrong time and the piston hits the valve crushing and or bending both.
-
thats not how youre supposed to do it.
-
thats not how youre supposed to do it.
What do u suggest then
Sent from my SCH-I500 using Tapatalk
-
get a SBC rebuild book and follow the directions. IIRC youre supposed to rotate the motor to TDC tighten intake valve to spec, rotate it a little, repeat for exhaust then do it all over again for the remaining 7 cylinders.
Id check on youtube to see if there is info, but a book will have more info
-
Beastie, the way I did it was bring the piston to TDC compression stroke, so both valves are closed. Turn the push rod with your fingers and tighten the nut until the push rod stops turning theb turn it another 1/2 turn. Then bring the next piston to TDC compression and repeat. Some people aay turn it 3/4 turn, but 1/2 worked for me.
-
i was close
-
Adjusting rockers with the engine running is the least accurate method and can cause serious engine damage if done incorrectly.
Adjust them according to the service manual or if it's an aftermarket cam use their recommended procedure. For an SBC or BBC a simple method is start on #1 TDCC and adjust I & E to zero lash plus 3/4 - 1 full turn. Rotate the crank 90° and repeat in the firing order #8 - 4 - 3 - 6 -5 -7 - 2