Adjusting Valves
Thread Starter
Member
Joined: Nov 2007
Posts: 155
Likes: 0
From: Cordova, TN
Car: 1989 Pontiac Formula 350
Engine: 350 tpi
Transmission: 700
Axle/Gears: 3.27
Adjusting Valves
I know this has been gone over to death but I have to ask about it once again. I have installed some 1.6 roller tip rockers and thought I was doing the adjustment correctly but the engine idles high (1.5k) and misses when I accelerate......bad miss.
The method I was using was turning the engine and when the #1 exhaust pushrod started to push up against the rocker I stopped and adjusted the #1 intake rocker by tightening the nut until I felt resistance in the pushrod and then added another 1/2 turn of the wrench before tightening up the allen lock. Then rotate the engine again until the #1 intake pushrod pushes up and makes the rocker press down on the spring then just before the pushrod goes all the way back down(rocker just about to stop pressing the spring) I adjusted the exhaust rocker the same as the intake.
DO I have a reading comprehension problem and screwed up the instructions or is there something else I am missing???
Thanks
The method I was using was turning the engine and when the #1 exhaust pushrod started to push up against the rocker I stopped and adjusted the #1 intake rocker by tightening the nut until I felt resistance in the pushrod and then added another 1/2 turn of the wrench before tightening up the allen lock. Then rotate the engine again until the #1 intake pushrod pushes up and makes the rocker press down on the spring then just before the pushrod goes all the way back down(rocker just about to stop pressing the spring) I adjusted the exhaust rocker the same as the intake.
DO I have a reading comprehension problem and screwed up the instructions or is there something else I am missing???
Thanks
Joined: Mar 2000
Posts: 43,187
Likes: 46
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
That is the "right" way to get the cam in the right position for the adjustment of each rocker. With hydraulic lifters, you usually don't have to go to that detail for each cylinder to get them adjusted. But, that method puts the lifter on the "heal" of the lobe when you adjust it.
Sometimes the "resistance in the pushrod" method leads to overtightening. I prefer to call it "zero lash", in which case you need to distinguish between gap(s) between the lifter-pushrod-rocker-valve (> zero lash) and depressing the lifter plunger. But to me, that's easier than determining "resistance" to pushrod rotation.
Sometimes the "resistance in the pushrod" method leads to overtightening. I prefer to call it "zero lash", in which case you need to distinguish between gap(s) between the lifter-pushrod-rocker-valve (> zero lash) and depressing the lifter plunger. But to me, that's easier than determining "resistance" to pushrod rotation.
Thread Starter
Member
Joined: Nov 2007
Posts: 155
Likes: 0
From: Cordova, TN
Car: 1989 Pontiac Formula 350
Engine: 350 tpi
Transmission: 700
Axle/Gears: 3.27
Re: Adjusting Valves
OK I have found what is causing the noise and it wasn't the lash setting.
The self aligning tabs are smacking the retainers and marring up the tabs mostly on the exhaust rockers. Everything is stock except for the rockers.
Should I order upgraded retainers that would clear?
Measure pushrods to see if I may need a little longer?
For this supposedly simple mod to go into such a headache is ridiculous.
The self aligning tabs are smacking the retainers and marring up the tabs mostly on the exhaust rockers. Everything is stock except for the rockers.
Should I order upgraded retainers that would clear?
Measure pushrods to see if I may need a little longer?
For this supposedly simple mod to go into such a headache is ridiculous.
Thread Starter
Member
Joined: Nov 2007
Posts: 155
Likes: 0
From: Cordova, TN
Car: 1989 Pontiac Formula 350
Engine: 350 tpi
Transmission: 700
Axle/Gears: 3.27
Re: Adjusting Valves
Here are some pics to make it easier to understand what I am seeing. First the rockers on the retainers. Then the rocker SA tabs. Then a pic of the two retainers with the intake on the left and exhaust on the right.




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