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Old 07-22-2005, 10:44 PM
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289/302 valve adjustment

Ok here goes. I bought a 65 comet caliente that was suppose to have a 289 in it. I have been having some valve tapping noise and my chrome valve covers were more rust then chrome so I bought a new set of valve covers and planned on adjusting my valves when I changed them out. First thing I noticed was that the heads had 302 cast in them between two of the valve springs. Im guessing that means that the heads are 302's. It could be the whole engine is a 302. It runs strong and has alot more pep then I thought a 289 would have. The main problem is that my rockers are loose but the nuts are tightened down as far as they will go. The studs are larger at the bottom then the top. The holes the pushrods go through are perfectly round. And the point where the valve stem meets the rocker arm has a rail on each side to keep it from slipping off. My question is how do I get rid of the loose rockers.

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Old 07-22-2005, 10:54 PM
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loose rockers

I have had success by replacing the pushrods and rockers (along with the balls that sit in the rocker. 302s have the valves set by tightening the nuts all the way down.
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Old 07-23-2005, 01:58 AM
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Early small-block Ford engines had adjustable valves that could be tightened to zero lash, then another 3/4-turn. Later ones had a non-adjustable valve train, and this is probably what you have. Comp Cams makes a set of lock-nuts and beveled spacers that can be used to convert to an adjustable valve train.

http://www.compcams.com/Technical/Cu...ML/315-319.asp (scroll down about 3/4 of the way to Adjusting Kit)
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Old 07-23-2005, 03:13 AM
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i believe around 1987 ford started using pedestal mount rockers on their windsor heads, which are tightened down all the way (5/16-16 bolts) with shims to take up the slack. early windsor cylinder heads were stud mounted rockers that you could adjust. crane makes a pedestal-to-stud conversion that just bolts in and uses stock length pushrods. you can use roller rockers with it too, going away from the pedestal mount rockers altogether. you just cant too radical of a cam profile, nor can you spin the rpm too high....
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Old 07-23-2005, 06:12 AM
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Thanks for the quick replys guys. I found the kit that jimfulco gave me. From what im looking at it seems that a thick washer on each stud would do the trick. This may sound a litte "shade tree" but I dont intend to race the car. Somewhere in the back of my mind I remember seeing something like this on a SBC. I may head out to the junkyard and look at some heads and see what I can come up with. Thanks again guys.
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Old 07-23-2005, 08:15 AM
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Quote:
Originally Posted by Wooky71

First thing I noticed was that the heads had 302 cast in them between two of the valve springs. Im guessing that means that the heads are 302's. It could be the whole engine is a 302. It runs strong and has alot more pep then I thought a 289 would have. The main problem is that my rockers are loose but the nuts are tightened down as far as they will go. The studs are larger at the bottom then the top. The holes the pushrods go through are perfectly round. And the point where the valve stem meets the rocker arm has a rail on each side to keep it from slipping off. My question is how do I get rid of the loose rockers.
Quote:
Rocker arm with close-tolerance pushrod slot

289 engines built before mid-1966 and all 289 HP engines use a conventional stud mounted rocker arm. The rocker arm is held in alignment with the valve stem by a close tolerance pushrod slot machined into the cylinder head. These engines use hardened pushrods. This scheme is fully adjustable and may be used successfully with mechanical cams.

Rail-type rocker arm with loose fit pushrod hole

289 engines built after mid-1966 and 302 engines use a rail-type rocker arm. These rocker arms have ears that extend downward, forming a rail or channel over the valve stem. This rail maintains proper alignment. The pushrod passes through a loose tolerance hole in the cylinder head, resulting in a cheaper assembly. At high RPM, however, these rockers can jump the track, loosing alignment with the valve stem and resulting in potentially serious engine damage. These engines do not require hardened pushrods. This scheme was fully adjustable until 1970 when the studs were changed to incorporate a positive stop. The rocker arm nut is no longer used to adjust the valve clearance. Rather it is simply tightened down. Longer or shorter pushrods are selected to adjust the clearance. Since these are non-adjustable they can not be used with mechanical cams.
You actually have to identify the year of production of the cylinder head to know how to assemble the valvetrain correctly. It sounds like the previous owner just threw extra parts into it without thinking. You have the Positive Stop studs so therefore valve adjustment is accomplished by correct length pushrods.

Even with the use of the COMP CAMS KIT, I would worry about having the correct pushrod length for proper geometry.

CAUTION! Old Guy Passing Through...
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Old 07-23-2005, 08:55 AM
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289 valve adgustmnt

you most likely have the rail rockers which are not adjustable, as you have been told. in my experiance the rail type are very poor, you will find the end of your valves worn plus rockers worn as the rail vertuly limites the lubrication to the valve stem and rockers. get a set of the early heads and hardened push rods, or latter heads with pedistal mounted with stamped rockers. by playing with washers to compensat for wear next thing is the cam , if not already. will fail. good luck
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Old 07-23-2005, 02:59 PM
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As the old guy passing through said (sorry Gary, you started it ), It sounds like the parts were just thrown together. If it is a 289 and they put later non adjustable (these are different than the bolt on type) heads on it the pushrods are probably the wrong length, the 2 heads used different length push rods. From the description you gave these are not the later fulcrum rockers that will benefit from shims. Shims will not only be waste of your cash, they will do nothing (not even fit) for these heads. The positive stop studs, have as you described, a "swollen" stud part way down that limits how much you can move the rocker down. The fulcrum style that came later are attached with a bolt and are aligned by the notch in the head that the fulcrum rest in. These are the type that can use the shim set, not the kind you've described. Listen to the old guy, and this younger more handsome guy . I see after looking at the link, the kit described is for the pedestal style, so it would work, but have to agree with Gary regarding pushrod length even when those are used.
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Old 07-23-2005, 11:10 PM
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[QUOTE=Wooky71] From what im looking at it seems that a thick washer on each stud would do the trick.QUOTE]

That was my first thought (although I was thinking about a Pontiac at the time). Note that the inner diameter of the Comp spacer is stepped, not straight. Also, you might find that your stock rocker nuts are not lock-nuts, and will unscrew during vibration.
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Old 07-24-2005, 12:07 AM
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However you do it, whatever parts you have or end up with,
you want a certain amount of preload on the hydraulic lifters.

Crane & Comp both recommend .020 to .060 preload.

Here's how I did mine. You may not have to get quite
so fussy on measuring, but if you do a good job your
motor will run better and last longer.

http://www.lincolnsonline.com/article78.html
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