Rocker Adjustment Help Quick!

kpack5982 · Apr 13, 2007

I'm retightening my rockers (pedestal mount) and a couple of them on the driver side will tighten down to 18ft/lbs but there is still play, like for instance you can still push on the rocker and it moves a little? Is this normal? I think I need shims but I'm not sure. Can someone give me an answer quickly?

white_97_GT · Apr 13, 2007

how long has it been since you ran your engine? if its been a while your lifters will not have any oil in them and you may need to prime it

Bullitt347 · Apr 13, 2007

The "little bit" of movement may be that you are pushing the pushrod into the lifter a bit. The pushrod can push the plunger of the lifter as much as .100 if the lifter is not pumped up with oil. With a standard adjustment the pushrod sets into the lifter about half of that or .050, so if the lifter has bleed down then it is possible for you to move the rocker arm a "little bit". This is normal.

white_97_GT · Apr 13, 2007

^^^ yeah, what he said

kpack5982 · Apr 14, 2007

so when some of the rockers have a little bit of play that is ok and others seem to sit on the valve stem that is ok too or should I need some shims for that?

back2fox · Apr 14, 2007

Need more info. Is this stock, or modified cam, heads?

86bluecobra · Apr 14, 2007

well some of the valves will be open or slightly open so some rockers will be tight. Odds are you lifters are just bled down. Why exactly are you adjusting your rockers anyways? did you do some internal mod?

87Mustang351 · Apr 15, 2007

i put new cam and lifters in, stayed with my 1.6RR and push rods, and i start the motor run it for a minute or 2 and then some of them come loose, readjust n come loose again, i dont know whats goin on?

86bluecobra · Apr 15, 2007

87Mustang351 said:
i put new cam and lifters in, stayed with my 1.6RR and push rods, and i start the motor run it for a minute or 2 and then some of them come loose, readjust n come loose again, i dont know whats goin on?

I think whats going on is your pushrods are 2 short. Either that or your nuts that are holding your rockers are cooked and they are backing off. But if you installed a new cam you really should check for proper pushrod length again.

OK I'll try to explain why. A cam lobe can only be so big around before they grind it so that you get the proper lift. Say a stock cam has that cam lobe perfectally in the center of the cam. With that position they can get .400 lift (just a number i'm using for the purpose of my explaination). Now that lift is gotten by leaving one point of the circle radius there as they grind away all the other metal to form a lobe. Now if you want say .500 lift you need to move the circle up .100 on the shaft. Thus offsetting the lobe on the camshaft. It is no longer in the center but off set. Now imagine your lifter and push rod moving on that lobe. Yes at max lift everything is tight but as the lobe moves around to the bottom of the lobe or the valve closed position the lifter/push rod is now .100 to short (remember the lobe was moved up .100). Thats why when changing cams you really should check pushrod length again in order to get the correct ones. I hope this helped.

back2fox · Apr 15, 2007

When I changed cams I had to go with 6.4 pushrods and shim kit. My RR loosened up a little after breakin but I didn't torque them down enough because I wasn't sure if they would clear the valve covers. I retorqued them down 24ft lbs and now they are nice and tight.

Here is a quick way to check your pushrods. Check the #1 cylinder pushrods with the engine at TDC. While you tighten down the rocker, rotate the pushrod at the same time. If you are able to get your rocker tight without feeling any resistance on the pushrod than your pushrods are too short.

Black1987Stang · Apr 15, 2007

my thoughts same as first 2 guys, i thought they got torqued to 25 or so ft lbs tho....

87Mustang351 · Apr 15, 2007

another problem i could have is i didnt torque them, i will have to try this

86bluecobra · Apr 15, 2007

87Mustang351 said:
another problem i could have is i didnt torque them, i will have to try this

tsk tsk.

white_97_GT · Apr 15, 2007

i was under the impression once they were tight enough to get a considerable drag on the pushrod while turing it, tighten another quarter turn, is this not correct for pedistal mount rr's?

Black1987Stang · Apr 16, 2007

white_97_GT said:
i was under the impression once they were tight enough to get a considerable drag on the pushrod while turing it, tighten another quarter turn, is this not correct for pedistal mount rr's?

nah thats the rule for stud mounted rockers.....you can go 1/4, 1/2 turn, whatever you think is best for your application also

Pedestal, you just tighten em all down to I believe 25-30 ft lbs (according to one of my manuals) and you're set......as long as the heads haven't been milled, valve job done, anything to alter the valvetrain from stock. I just converted to studs so I don't have to worry about shims and all that, plus studs are stronger, etc....

86bluecobra · Apr 16, 2007

white_97_GT said:
i was under the impression once they were tight enough to get a considerable drag on the pushrod while turing it, tighten another quarter turn, is this not correct for pedistal mount rr's?

I also thought this the first time I worked on my F-150. Started it up sounded fine but they all came loose. So i reread my manual and say I was doing just what you said there and on earlier f-150's and bronco's you did do that but on my 92 302 you need to torque to 25 ft/lbs.

white_97_GT · Apr 17, 2007

ill have to try that i guess, because i did the 'old school' method, and they come loose after rotating the engine a few times with a ratchet, usually just the exhaust side though

Rocker Adjustment Help Quick!

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Yeah, it was pretty stiff, but eventually a buddy

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