Converting mid 80s sbf heads to adjustable rockers

[junkyardjeff]

The rebuilt mid 80s 351 I have in my 55 sunliner has a couple rockers that make noise when good and hot now that I stepped up the gears some so can those heads be converted to adjustable rockers,I did not notice the noisy rockers last year on the trip to Daytona but this year with the motor spinning a little faster I heard them. Since the motor is going to be replaced with a Y block in a couple years I need a quick and somewhat inexpensive fix for the time being and was thinking adjustable rockers would be the best way.

[wayne petty]

are these pedestal mounted rockers..

that mount in a steel channel or in slots milled on the top of the head ??

using rocker arm stands like these...

http://contentinfo.autozone.com/znetcs/product-info/en/US/mel/MRM-1776/image/4/

when i need to tighten the valve lash up on these.. i either replace the rocker arm fulcrum.. as it might be worn..    or grind the base down slightly.. this moves the rocker arm closer to the cam .. a little goes a LONG way here.  and you have to be sure that you take the same amount off all the way around..

you will also want to inspect the inside of the rocker arm.. to check for wear...

if you have a spare junk valve cover you can cut a flap that open along the center of the valve cover.. but bending it up to catch any oil splash..  you can glue the gasket to this.. so you can install it on either side to examine the rocker arm movement while the engine is running..

if you have rocker are  stud mounted rockers.. with a half moon shaped fulcrum.. you can add a thin brass washer from the plumbing section of the hardware store.. used on old style supply tubes under the nuts on angle stops..   that is just about the perfect size and thickness to take up a little valve lash..

this is what the angle stop supply tube washers look like.. and where they go...  when you use them in plumbing..

http://onsaleproductstoredlzlqq.tk/images/Westbrass-D150X-04---1-Piece--1-2--IPS-Inlet-Cross-Handle-Angle-Stop-and-Riser-with-3-8--x-12--Supply-Tube_341126.jpg

here is a better image of what i like to use..

http://images.bizrate.com/resize?sq=140&uid=857916062

don't worry about them being brass.. there is almost NO movement between the top of the rocker arm ball fulcrum  and the rocker arm nut..


please examine the amount each rocker arm moves in relation to the others..   that you don't have a cam going flat..  that the push rods are spinning then stopping.. only in one direction..  spinning then stopping ..

if the push rods spin one way . then the other.. you have a bad cam and lifters.. where the bottom of the lifter has gotten eaten away.. and its not rubbing on a single small line of contact on the tapered cam lobe.. but rubbing all the way across the cam lobe where it would be impossible to get any oil between the components ..


this is more than you ask for....

there are also on some rail or groove mounted ford rocker arms.. various thicknesses of shims to change the lifter preload..

grinding the bottom off the fulcrum is a dirt cheep easy way to adjust the rockers /lifter preload on these...

[junkyardjeff]

Its got the newer style rockers and I wondered about the cam since about the time I broke the motor in the zinc was being reduced and new nothing about it but I have been driving it for over 4 years.  After I get a couple other projects done this winter I will pull the valve covers and put each cylinder on tdc and see which ones are loose and inspect the parts,I presumed all the rockers were new but who knows as I heard nothing but horror stories about the shop that built the motor after I bought it.

[junkyardjeff]

I shorted the cylinders one at a time and the noise did not change so its something on the top end,I dont want to spend a bunch of money on it since its going to be replaced with a Y block in a couple years.  I will need it to be able to go to Daytona and back probably one more time but will find out what it is after I get my 2wd bronco finished and 66 F250 back togather unless it gets warm enough I can work outside.

[chimp koose]

If you have non adjustable rockers ,the rocker stud will have a taper under the threaded part that goes larger than the threaded diameter. Toss a washer or two under the adjuster nut on top of the fulcrum and you should be able to adjust them further down.The non adjustable ones were supposed to be torqued to 18 ft/lb I believe but you will now be able to adjust them. Just make sure the rocker studs arent working their way out of the head, I had a set of 351W heads that were bad enough like that that I had to use screw in studs. If you are near 300# open pressure on valve spring you might consider screw in studs.