loose rockers

butch27 · June 21, 2009, 04:09:12 PM

I adjusted all of the rockers on a 302 Ford (hydraulic) then when I ran the engine twice for about 15 min. the ones on the left bank ONLY loosened up. Any ideas why? Thanks

chimp koose · June 21, 2009, 07:33:22 PM

press in rocker studs. You may have too much valve spring for them . Also check that you are not running the rockers against the stud. If you have too much lift for the rockers ,the end of the rocker slot will hit the stud and try to lift it out. This will also happen when you run too long of a pushrod . Ford changed pushrod length for the windsor engines by about .100" after I think 1970 ,when they went to the positive stop rocker adjustment. If you run earlier heads with the longer pushrod you will have troubles.

wayne petty · June 21, 2009, 09:05:58 PM

you might also use a ruler or straight edge across the top of the rocker arm studs... to see if they have pulled up.... and along the sides of the studs near the top to see if they have bent over..

you can also use a bent paper clip to use as a feeler to see if the rocker slot is touching the stud with the rocker at full lift...

are the threads on the studs worn more on one head than the other?

i have run across this... the nuts were tight on one head.. and almost no grip from the new lock nuts on the other do to the reduced diameter of the threads... the old mechanical locking nuts tore the threads off the outside of the stud...

what kind of rocker arm nuts?

? new , used... not nylocks... there are several designs of nuts also.. some with a collar that is crimped in.. others that have the top wedged in so it looks like a rounded triangle..

what is the overall length of the push rods... some small block ford push rods can be had in +.060 and -.060 lengths.. along with standard...

one more thing... are the valve springs nearing coil bind...

? or are the valve guides sticking up too far and the bottom of the spring retainers pounding on them....

were the rockers adjusted like a chevy...

butch27 · June 21, 2009, 10:12:22 PM

Stock rockers on a 1978 Ford 302 engine. Stock springs valves etc.

butch27 · June 21, 2009, 10:13:42 PM

OH- And the stock style elongated hole lock nuts.

wayne petty · June 21, 2009, 10:16:45 PM

i was thinking that you might check the clearances....

there are a lot of different stock parts... some will work some won't ...

and .. you don't have to post twice... there is an edit post link when you are logged in.. you can go in and edit within an hour...

jaybee · June 21, 2009, 10:35:34 PM

A lot of the Fords are adjustable only by changing pushrod lengths, the rockers don't have locking nuts. Possible you have one of those?

wayne petty · June 22, 2009, 01:56:10 AM

does your rocker arms look like this??/ cast iron... half circle steel ball , nut...

later versions have bolts to hold the rocker arm fulcrums down in a steel channel....

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/04/b7/21/medium/0900c1528004b721.gif

with reduced thread diameter verses stud diameter??//

if so they are nonadjustable and get torqued tight... valve adjustments are done with different length pushrods... or thin washers under the nut to tighten the adjustment...

this is what the later rocker arms look like....

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/04/b7/22/medium/0900c1528004b722.gif

the only really adjustable versions have a single diameter stud and thread size....

there are ways to adjust the non adjustable types...but they still need to be tight..