It appears that the rocker arm is hitting the support. This is the best pic I could get. It's hard to see, but the notch is actually shaped like a step. There are two dents in the support. I bolted support back on and it doesn't look like the arm can come down that far with the pushrod in contact with the rocker arm. Am I wrong about that?
Thus is the front rocker support and both exhaust and intake have the stepped notches.
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Here's another pic. You can see where the arm is digging in. [attach=0]
I'll take it apart this morning.
I assume those are OEM supports and rocker arms? So if I see it correct, the arm is hitting when the valve closes?
Yes Brian. Here is a better pic after I took it apart. [attach=0]
It's not quite as bad as I thought, what I thought was the last step,is actually the way the plate is machined. Alright to relieve this area a bit with a round file?
Have you had a recent valve job on those heads? Have the rocker stands been machined on their base in an attempt to correct the valve geometry? How is the end play with the rocker in the rocker stand?
valves were done a couple of years ago. I'm running an Andrews 48. Should geometry have been looked into with a mild increase in lift. The end play is in spec. Around .014 on both rockers.
[attach=0,msg1296614]
this is what the inserts looked like when I pushed them out. It's almost like the support was loose( it wasn't). Neither one of the shafts came out easily. I checked support plate on glass and it's flat.
you don't need corrected geometry running that cam.
If you have a dremel tool and a bit for it...just hit it the rocker arm with it to remove a little bit of the material until you have clearance. I wouldn't think you would have to remove much material off the rocker arm at the contact point to get the needed clearance.
Thanks ray. I'll just remove material until the dent disappears. I'm just wondering how it could of happened. When it's bolted up and pushrods are in base circle, the arms don't look they could move that far down. I guess cylinder growth,lifter bleed down and pushrod flex could contribute. I purchased a used set and they have the same marks in them. :idunno:
The reason I asked about a valve job was to rule out a sunken valve. That may be able to be confirmed by measuring the protrusion.
With the bushings, you can't move the the bases over to avoid contact but you could shim the rocker. this would be dependent somewhat on how well centered your pushrod is in the tube. I personally feel grinding is not a fix, it's a compromise. there must be a cause and therefore a proper correction.
you have to watch closely for this. I have seen this same thing drive guys nuts because they were chasing a ticking noise. When the valve is all the way down is when it usually happens. You have to look closely at each rocker arm as you roll the engine over to make sure the arm doesn't touch the support or a spring collar at any time. All four rocker arms should be checked for clearance.
Quote from: No Cents on May 12, 2019, 08:42:45 AM
you have to watch closely for this. I have seen this same thing drive guys nuts because they were chasing a ticking noise. When the valve is all the way down is when it usually happens. You have to look closely at each rocker arm as you roll the engine over to make sure the arm doesn't touch the support or a spring collar at any time. All four rocker arms should be checked for clearance.
I get what you are saying. That's why I also mentioned checking the protrusion. I haven't actually noticed how close the average clearance is across a set to comment on that.
Like you, I locked my rocker shafts with grub screws rather than rocker lockers (before they were created) and then positioned the stands in the sweet spots to put the valve contact centered on the valve tip and the pushrod centered in the tube before torquing them down. All the other clearances like the rockers / stand casting were OK.
Quote from: Chippitt68 on May 12, 2019, 08:08:22 AM
this is what the inserts looked like when I pushed them out.
That's normal for the Rockout inserts. They deform on installation, that's what locks the shaft in place :up:
FWIW I looked at my collection of supports here... every one of then has those notches. My guess is I did it flopping the rocker arms around checking for noise... maybe you did too? :wink:
I considered that. I feel like you'd have to be a little rough to put a gouge in the support plate. It may be the case.
You can always roll the engine over slowly and check for clearance. It would be nice if it was caused as John says.
I had to blow the pic up to see the notch, I'm with John and it occurring when the arms flop around, mind a little buff in that area with a Dremel/File ain't going to hurt any.
I've an appointment with the Eye Surgeon this arvo so maybe I'll see better later in the week. :SM:
(https://i.imgur.com/hY5pp93.png)
I checked my OE rockers this winter when I noticed some pitting. Mine had the mark also.