rocker arms + valves on a 3.8

[smithtim]

Hi all I am doing a basic head gasket and I have a question about the instaltion when I did the rocker arms - valve adjustment I think I did a sloppy job...

now everything is back together the enginge turns but does not get combustion... could this be caused by the valves being out of adjustment?? I hear of people saying valves out of adjustment makes the car run rough or whatever but could it totally stop the enginge from getting combustion?

thank you in advance for any help


Tim


p.s. before I did the work the enginge did run fine and the only problme was the head gasket went... but even after that happened the enginge did run (codes said running on 5 cylinders only with a constant misfire of 6th - turned out the leake on the head gasket was by that cylinder)

[WickEdSix9838]

Re: rocker arms + valves on a 3.8

The rockers on the 3.8 are not adjustable. They seat solid on the aluminum pedestal. You might look elsewhere for you lack of compression.

[CDNFB]

Re: rocker arms + valves on a 3.8

Need some more clairity here. Is it a lack of compression (no pressure build), or no combustion (no fire in the hole)????

[slow6]

Re: rocker arms + valves on a 3.8

check compression, check fuel, check ignition
Lance is definately right, our rocker arms are non-adjustables! yeay
Sounds like you messed with the valves

Torque to 132 in/lbs, then rotate 90*! Youre done

[smithtim]

Re: rocker arms + valves on a 3.8

Sounds like you messed with the valves

when I put the rockers on I just felt the push rods for no play (like you would for usual zero lash) then turned the nut an extra 3/4 turn... would this affect the valves? maybee it is tow tight and won't allow them to open/close correctly??

I will losen them and then put them to the 132 in/lbs +90degrees and see what happens.. also when I do this does it matter about setting certain valves in #1 TDC and others is #0 TDC... or can I just do them in any postion?

[slow6]

Re: rocker arms + valves on a 3.8

any position
dont think it would matter as long as you dont have them tooo tight but IDK

[BLLDOGG]

Re: rocker arms + valves on a 3.8

it doesn't matter the position of the pistons. just tighten properly and down to spec

[UDLOSE98]

Re: rocker arms + valves on a 3.8

tell me what you find.....that sounds like my car right now.

[caspernicus]

Re: rocker arms + valves on a 3.8

When you pull your plugs for the compression test, check and see if there is
gas on them. That'll rule out fuel delivery being a problem.

[BLLDOGG]

Re: rocker arms + valves on a 3.8

he could have injectors not pulsing. anything is possible

[slow6]

Re: rocker arms + valves on a 3.8

When you pull your plugs for the compression test, check and see if there is
gas on them. That'll rule out fuel delivery being a problem.

he could have low fuel pressure from something being clogged
cant totally rule it out :spank: but yes you're right, check to see if there is fuel on them

[smithtim]

Re: rocker arms + valves on a 3.8

off hand I can't tell... when I turn the key the motor turns and sounds like it wants to fire but doesn't quite get it:(

I will run a compression test and post the results

ran the compression test.. 150 on the rear cylinder but 30 on the front cylinder ( din't get time to do the middle one as the wife wanted dinner)... anyways I want to belvie that somehow one of my vlaves are stuck open due to the rocker nuts beign to tight.. but then in all reality I think that most likely there is some lower end damage there, perhaps slipped piston ring from when the head gasket blew... what do you guys think??

thanks for all of your time looking at this + helping me out it is apprachiated


Tim

[slow6]

Re: rocker arms + valves on a 3.8

(while doing a compression test - keep an eye on the needle!!!)
a healthy engine should build compression rapidly

If you crank it once, is it low pressure on the 1st and just GRADUALLY building pressure after? sounds like maybe piston rings

If you crank it once and theres low pressure on the 1st, but hardly anything on the next strokes indicates bad valves or busted head gasket

a wet compression test will also tell you if its a bad piston ring - put oil in the cylinder.. crank it once..it should build alot of pressure quick on 1 stroke (more so than dry)

A Leak Down test is the best way to diagnose a cylinder!!
I'm sorry for your loss

[smithtim]

Re: rocker arms + valves on a 3.8

(while doing a compression test - keep an eye on the needle!!!)
a healthy engine should build compression rapidly

If you crank it once, is it low pressure on the 1st and just GRADUALLY building pressure after? sounds like maybe piston rings

If you crank it once and theres low pressure on the 1st, but hardly anything on the next strokes indicates bad valves or busted head gasket

a wet compression test will also tell you if its a bad piston ring - put oil in the cylinder.. crank it once..it should build alot of pressure quick on 1 stroke (more so than dry)

A Leak Down test is the best way to diagnose a cylinder!!
I'm sorry for your loss

thanks for all of the usefull info it is much apprachaited. :)
when I crancked it initally it went to about 40 then on the second, third stokes it went upto about 50 and sounded like it wanted to bulid some more after that but never got past 50-55; so that sounds like teh causes you listed for bad piston.. will try a leake down test

Just to clarify if I do the leake down I should physcially put oil into the cylinder (on top of the piston) and see if it seeps down past the piston or if it stays on top of the piston in the cylinder??



p.s. tryign not to think of it as a loss as I got 145K out of her and have already purcased a new car to drive to work a few months ago; so trying to think of it now as a project car and something to do in the grage... just wish it was a 69 firebird, maybee one day