# Adjusting Valves on a 389



## steveo (Mar 29, 2010)

Can someone tell me how to adjust the valves on a 389. Thanks


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## johnnylightning03 (Nov 27, 2007)

if it a stock hydraulic cam, you just torque down the rocker arm nuts to spec (18-20 ft lbs), they are zero lash. i belive if you back them off a bit (1/2 turn or so) you can get a few more rpms before valve float. a royal bobcat trick i think. anyone?


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## Thumpin455 (Feb 17, 2010)

If you back them off you need to have poly locks on them, that means taller valve covers. The stock nuts arent locking in any way, they have a shoulder on the bottom that hits the stud and allows them to be tightened. If its a stock valve train with a hydraulic cam then you just torque them down.

If its a solid cam, then its a different ball game and you better get good with feeler gauges and a remote starter switch.


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## jetstang (Nov 5, 2008)

OK, my 70 350 doesn't have crimped nuts, which I just found out. My 75 400 w/6X-4 heads has posi locks, and I've adjusted the valves trying to get rid of a tick, found 2 dead cam lobes.
So, you can make the earlier cams adjustable with posi locks or crimped nuts. Then, did Pontiac make the valvetrains adjustable later on, as is my 400? I guess I have owned Pontiacs, but did a lot more Chevy work, so assumed all Pontiacs were also adjustable. All my motors have screw in studs and guide plates, is this normal?


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## geeteeohguy (Feb 2, 2008)

Stevo, google the Jim Hand article about adjusting valves, and do it that way. They get tightened to 20 pounds, BUT ONLY WITH THE PISTON AT TDC IN THAT CYLINDER. Then, you TIGHTEN the nut another half turn and go to the next cylinder. The Hand method tells you which cyls are at TDC at the same time, so you can do the whole thing in about 15 m inutes. Works like a charm. BUT. ONLY TIGHTEN., Never loosen. As stated above, the nuts are one-time deals, unless you use poly locks. I have poly locks on my '65, with the stock valve covers, and no issues at all. On the '67, I installed BBC screw in studs and went that way (low compression heads), Jetstang: screw in studs and guidplates mean the heads are high performance heads. Most HP Poncho heads are that way, including stock '67 up GTO heads.


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## jetstang (Nov 5, 2008)

My 350 2 barrel heads have screw in studs and guide plates. Hmm, guess I need to run the numbers on them, but the machine shop said they were nothing special after a $400 rebuild-new guides and hardened seats.


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## Rukee (Feb 8, 2007)

I've never been able to use the torque method of adjusting the valves.
Turn the motor over till TDC on the cyl your working on, loosen the rocker arm, tighten the rocker arm nut while spinning the push rod in your fingers. Just at the point when the push rod becomes tightened and you can't spin it, tighten the nut an additional 1/2 turn. Repeat for the other rocker arm. Then repeat for the other cyl's. 
They also make some clips you can put on the rocker arms to stop the oil from slinging all over and then you adjust them while the motor is running loosening each rocker till it just starts to tick, then tighten till it just stops, then tighten an additional 1/2 turn.


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## geeteeohguy (Feb 2, 2008)

Rukee, I did it your way for 25 years, but you have to be mechanically inclined and have a "feel" for the drag on the pushrods when they spin, etc. It works great. It was the only way I felt comfortable with it. Then I saw the Jim Hand method in an article, and decided to try it 2 years ago when I put new heads on the '67. It was super fast, oil-stain and splash free, and worked like a charm. Before this, I've never really trusted the "just torque 'em down" edict. I'm a believer now, though. Whatever works is what's important...The one's in my '65 were done "by feel" almost 30 years ago and remain silent and trouble free, even with a big cam.


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## 68greengoat (Sep 15, 2005)

Jeff, can you post up a link to the article? I searched it and came up with this: http://www.classicfirebird.com/hand/jhand7.html , but I can't display the page or www.classicfirebird.com for that matter......

It would be appreciated, at least by me......


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## geeteeohguy (Feb 2, 2008)

Sorry, GG. No go on this end. Tried, but was not able to.


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## 66tempestGT (Nov 28, 2009)

Jim Hand Article #7


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## 66tempestGT (Nov 28, 2009)

you can adjust the valves this way with even with the engine out of the car. then just pop it in and fire it up.


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## Rukee (Feb 8, 2007)

66tempestGT said:


> Jim Hand Article #7


wtf? In one breath he says they are non adjustable and to tighten to 20 foot pounds and then at the end he says to adjust them exactly like I said how to do it. 
Which is it??


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## 66tempestGT (Nov 28, 2009)

when he says they are non adjustable he means that they are "designed" to be tightened to twenty and forget about it. if you are looking for more performance then you can do it differently. 
"This assumes the rest of the engine can live at the increased speed, and that increased RPM might help performance. We have found that the larger Pontiac engines generally run quicker when shifted at a relatively low RPM."


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## 66tempestGT (Nov 28, 2009)

his "sequence" can be used with stock valvetrain as well as crazy solid roller cams. If your engine is stock, which is what i keep seeing everybody recomend ( 068, 068, 068, blah, blah, blah) then tighten them like factory and walk away. if you are looking for more and your engine can take it then do them his way. or disregard years of R&D and dyno time and do it your way.


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## 68greengoat (Sep 15, 2005)

geeteeohguy said:


> Sorry, GG. No go on this end. Tried, but was not able to.


Thanks for tryin', Jeff......



66tempestGT said:


> Jim Hand Article #7


This worked...... Thanks....... Not going to read it now, I have other issues I need to discuss...


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## steveo (Mar 29, 2010)

thanks for all the information...we're gonna give it a try tomorrow night. All the hints were greatly appreciated.


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## jetstang (Nov 5, 2008)

When you tighten them all down to 20 lbs you are assuming that all the lifters are in the middle of there travel. When you hot lash them, when running you back off til they clack, tighten til they don't clack and then 1/4 turn. Then you know that all the lifters are adjusted exactly the same and it frees the valve train up and won't float the valves as early as it would in the torque down mode. For my base line I turn the motor 1/4 turn at a time, tighten all loose rockers until the push rod gets light pressure between the rocker and lifter, rotate it another 1/4 turn and tighten again, continue until all pushrods have been adjusted, start it then hotlash it. That is the easiest way to do it and works for me and not much thinking. Also, if one valve on a cylinder is open, you can adjust the other knowing it's on the flat of the cam. I would run SBC lock nuts as stated in the article, that is cheap insurance so the nut doesn't back off at an inopertune time.


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## Rukee (Feb 8, 2007)

The lifter actually has 1 full turn of adjustment and you can fine tune your cam with it. The guys running 1/4 turn at the rocker will get a few more rpms before the valves float with a little less bottom end. Best for high speed runs.
Running at 1/2 turn will slightly increase valve lift helping bottom end at the expense of a lower red line. I don't rev that hard and am more looking for bottom end grunt so I run at the 1/2 turn on the rockers. I would not recomend more then 1/2 turn.


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## jetstang (Nov 5, 2008)

I haven't lost any bottom end with the 1/4 turn, but at a 1/4 turn they will need adjusting sooner with wear, or bad oil. Bottom end is all about advance curve kits in your distributor. Back in 82, in highschool with my 455 66 Tempest, I put a set of Sorrenson cross cut points and an advance curve kit in. With the heavy springs it dogged out of the hole, with the light springs it was a tire shreader, all the diference in the world. I don't know what todays gas will do with all the initial advance, ping like hell I suppose. Pontiacs make power down low, so all in worked and made a lot of power. I was a hero in highschool with my 2 barrel 455 with a 70 GTO rear w/3.55 gears, that car smoked almost everyone I came up against, but I didn't race grown ups with "real" cars.
Oh, that reminds me, maybe I have a kill story for the other thread, funny as hell. Or, I'll give the cliff note version here:
1984, Buddy had a 70 442 w/455, paid $1000 for it, me, 66 Tempest 455, paid $450, we are on a 3 lane going to the capital in Madison, 70 Cutlass pulls up between us with a full roll cage and two mid 20's guys in it (grown ups), drag strip ready. Game on, light turns green and my buddy and I both smoked the Cutlass and left him by a couple car lengths, my buddy nosed me. Guys in the Cutlass didn't even look at us at the next light, guess there 350 with a cam was no match for CID!!


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