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Roller tip rocker arm problems...

broncoman6524

broncoman6524

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I bought a set of PRW 1.6 ratio roller tip rockers at the local car show.

Installed them via instructions. Which were, bring valve to closed position, remove, install new rocker, nut and ball thingy, then tighten the nut down. The whole time waiting to not be able to spin the pushrod. Once that happened it said give 1/2 more turn tightening. We did that, started up first try, ran like a top....for a day.

Next day had the re-adjust 3-4 rockers, the tips were slipping off and pushing onto the spring/keeper instead of the valve tip. Tightened them up and it worked great for another 2 days.

Today it ran fine on the way to school, as we left i noticed it was starting to tick, drove it gently to work and home. Turns out the rocker slung off the spring and it bent the pushrod:mad:. Installed a new pushrod, adjusted it correctly. Started it up, and about 30 seconds later it slipped to the side, kept repeating this. Gave up and called my neighbor, he said that the nut is probaly screwed and is backin off. So i put one of my old nuts over the new one, and its stayed in place for now.


I'm basically looking at buying a new set of nuts correct?

Or, somebody else at the car show said that I may have too "short" of pushrods, since I increased the rocker arm ratio. Could this also be the culprate?
 
Sounds like you need to replace the nuts. They are locknuts and are only supposed to be used once.

I actually had mine on and off a few times (dealing with valve springs issues :rolleyes:) and eventually the nuts started backing off on my rockers. Replaced them and the problem went away.
 
If the rockers are coming off the tip of the valve, it sounds like you may have removed self-aligning rocker arms and replaced them with old-school non-self aligning roller rockers.
On the original rocker arms, where the arm seats on the valve tip, are the faces smooth side to side or are there "notches" bent into the sides of the face--sort of "U" shaped?? If so, those are self aligning rockers and the rockers you have will not function correctly unless you install pushrod guide plates. Another way to tell is to look at the hole in the cylinder head where the pushrod comes through. If the hole is round and approx 7/16" diameter the heads are set up for the self-aligning rockers. If the hole is oval and approx 5/16" on the narrow side (fits pushrod rather tightly in that area) then the head is not set up for self-aligners.
The reason I suspect this is even if the rocker nuts are backing off, the arm should still remain on the valve tip. With it swinging off like you state makes me wonder if the holes in the head for the pushrod are the bigger variety for self-aligners. In the early years GM used the pushrods for rocker arm alignment--locate the pushrod fore/aft and the rocker will always be on top of the valve. In later years, GM went to self aligning rocker arms where the "U" channel in the end of the rocker arm is what aligned the rocker on the valve tip, thus the bigger and round holes for the pushrods to go through the head.
Might be worth a look.
 
mosesburb said:
If the rockers are coming off the tip of the valve, it sounds like you may have removed self-aligning rocker arms and replaced them with old-school non-self aligning roller rockers.
Click to expand...

Ding Ding Ding, We have a winner here.
 
dyeager535 said:
You do realize the spec is "zero lash" not zero rotation, right?
Click to expand...

Yes I mis-typed it, unless im still wrong, it said to tighen the arm while twisting the pushrod once you can't give another 1/2 turn.


And the heads are set up for self-aligning rockers, the old rockers have the "u" and the holes are big enough to "wobble" the push rod in.

Because pictures always help...

Stock arm. The new arms have the indentation for the pushrod, but not for the valve tip (obviously)
100_4903.jpg

Whole head, as far as i can see it is just the first 2 cylinders that are giving me problems. (2,4)
100_4904.jpg

Cyl 2 Or is it OK for the tips to be not centered?
100_4905.jpg

Cyl 4 the one with double nuts in the one that bent a rod yesterday. As you can see it backed off again.:mad:
100_4906.jpg
 
broncoman6524 said:
Yes I mis-typed it, unless im still wrong, it said to tighen the arm while twisting the pushrod once you can't give another 1/2 turn.


And the heads are set up for self-aligning rockers, the old rockers have the "u" and the holes are big enough to "wobble" the push rod in.
Click to expand...

You should tighten the rocker down until you can feel resistance in the pushrod and then 1/2 to 1 turn after that.

You have old style (non self aligning rockers) on heads that need self aligning rockers, that is the reason your rockers are falling off the valve.
 
Those heads don't have provisions for guideplates (they need to use self aligning rocker arms). You need to get rockers like these.

The rockers need to have the little tabs on the sides to keep the rocker on the valve.
 
38377k5 said:
You should tighten the rocker down until you can feel resistance in the pushrod and then 1/2 to 1 turn after that.
Click to expand...

Just to make sure it's crystal clear, we are talking about the moment you feel drag on the pushrod as you turn it. You may need to loosen the nut up and then tighten again to make sure you are feeling it right, but the hydraulic lifter seat moves very easily if not full of oil, you can easily go too tight.

Pushrod should spin freely as you tighten the rocker nut, then when you feel extremely light drag on it, stop, then rotate the final 1/2-1 turn.

Make sure the nut on that one rocker didn't strip the stud threads or pull the stud loose.
 
You actually got lucky. Sometimes when the rocker slips off the stem and starts running on the retainer it can release the keepers and drop a valve :doah:
 
MaxPF said:
You actually got lucky. Sometimes when the rocker slips off the stem and starts running on the retainer it can release the keepers and drop a valve :doah:
Click to expand...

This was my first though after I pulled the valve cover. And the first time it was sitting on the spring, not even near the stem or keepers.:eek1:
 
In order to use those guide plates, you would have to remove the cylinder heads, pull the rocker studs out, machine the stud bosses and tap for screw in studs and guide plates and reinstall the cylinder heads.

Much cheaper to just buy the correct rockers.

You are lucky you did not bend a valve or two.
 
x2, much easier to replace a bent pushrod, than a bent valve. Also less likely to kill your piston and head.
 
I'm concidering myslef lucky... VERY.

The stock ones are on now, rollers are sitting in their box.

Thanks guys, for helpin me with this and explaining they were wrong before i killed this motor.:bow:
 
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