Rocker arm wear pattern

-

DartVadar

Well-Known Member
Joined
Apr 3, 2013
Messages
1,293
Reaction score
39
Location
Alberta
So i was mocking up my rocker gear on my 360 and was looking at the wear on the valve tips to check the geometry.

I have an la 360, so it has a shaft rocker system, and I am running comp ultra pro magnum rocker arms. I noticed that the pattern is biased towards the exhaust. It looks closer in the picture, but I have about ~90 thou till the end of the valve, so its not going to roll off, but I still would think it would be better to have it centered, especially since I am running a solid roller cam.

I would think that lash caps would help, and I should have room for them, I just got pushrods, but I have some adjustment to still use them and lash caps. Is this wear pattern bad? or should I check again with the lash caps?
 

Attachments

  • IMG_3235.jpg
    41.8 KB · Views: 888
A thin shim under the rocker shaft all the way across would center that up a little more. I think you would be fine the way it is. I personally would try and center them more. May save a little wear on the valve guides. Just my opinion.
 
While others may disagree, if the others are not any worse than what's in the picture, I'm calling that acceptable. The roller tip will do nothing but move inboard of the position noted, plus, it's close enough to the center of the valve tip that it's certainly not going to fall off the edge. JMO. I am sure others will vary.
 
That looks identical to my sweep with indy rhs heads and harland sharp rockers. I asked the same question and only got one response that said it's not good.
 

Attachments

  • image.jpg
    30.3 KB · Views: 722
I was thinking it wasn't too big of a deal, but know that it wouldn't hurt to try and center it If I can. And wouldnt shimming the shaft move the pattern further out anyways?

I'm interested in this as well. Do you know the length of pushrod you are using
I dont remember off the top of my head but I have it written down. They are custom smith bros pushrods.

Is that rocker shaft stand cracked?
Nope It is not. It kinda does look like it in the picture, but they are good heads. They were like that when I got them.
 
I was thinking it wasn't too big of a deal, but know that it wouldn't hurt to try and center it If I can. And wouldnt shimming the shaft move the pattern further out anyways?

Yes. Adding shims will move the wipe pattern toward the exhaust side of the valve. Installing valve stem shims or milling the pedestals lower will move the pattern toward the intake.

I had this issue when I built my 340 with CC rockers (Pic 1). Mocked up 3 different sets of factory heads and they all were to close to the edge for me. I chose to not run valve stem spacers and gave up on the comp rockers. I talked to Mike at MRL and explained my issue and he recommended I put a set of Hughes rockers on. I bought them from Mike and the geometry was perfect (Pic 2).
 

Attachments

  • comp cams roller contact area.jpg
    56.1 KB · Views: 618
  • hughes rocker contact 1.jpg
    52.1 KB · Views: 625
A fellow member told me about a guy b3 racing engines, he has you take some measurments and machines custom shaft cradles that are suppose to center the roller and create a better sweep, it's like $180. I might go that route just out of curiosity.
 
I got some custom shims from a seller on Ebay for under 50 bucks that moved the rocker shaft on my slant head for better pattern. It might have been B3, I cannot remember. All I had to do was provide him with one measurement taken with a dial caliper and he did the rest. He got it spot on. But as said, I don't think it's a huge issue. Factory stuff comes that bad or worse and runs for how many hundreds of thousands miles?
 
New rocker arms are definitely not in the budget, so I will be using the comps, they are brand new too. Also they are the only ones that fit around my springs (they are 1.52 inches in diameter).

Ill try the lash caps, if those help ill use em and leave it at that, but if not, I will just leave it as is I guess.
 
I would not run the engine with that pattern , you will experience valve and guide problems in short order. Lash caps would help spread the load but the Hughes rockers would probably be perfect. I think I would throw a set of crower lash caps on it and check the pattern again.
 
I took pictures of the roller travel at 1/2, full and closed. The lash cap helped a bit, it seems to be centered at zero lift, it just moves forward as it opens the valve. They are 60 thou lash caps I believe, I just borrowed one somebody had lying around.

Sorry if its hard to see, I had a really hard time taking clear pictures for some reason. Also I had to mark the travel on the lash cap as it was hard to see.
 

Attachments

  • IMG_3259.jpg
    25.5 KB · Views: 543
  • IMG_3262.jpg
    27 KB · Views: 539
  • IMG_3264.jpg
    31.5 KB · Views: 564
  • IMG_3263.jpg
    26.2 KB · Views: 576
  • IMG_3267.jpg
    23.6 KB · Views: 571
  • IMG_3266.jpg
    28.2 KB · Views: 557
  • IMG_3265.jpg
    26.8 KB · Views: 571
I got some custom shims from a seller on Ebay for under 50 bucks that moved the rocker shaft on my slant head for better pattern. It might have been B3, I cannot remember. All I had to do was provide him with one measurement taken with a dial caliper and he did the rest. He got it spot on. But as said, I don't think it's a huge issue. Factory stuff comes that bad or worse and runs for how many hundreds of thousands miles?

Wouldnt shims move it the wrong way in my case? and yeah thats very true, I remember the geometry on this engine when I yanked it out of a truck last year, was pretty bad.
 
Wouldnt shims move it the wrong way in my case? and yeah thats very true, I remember the geometry on this engine when I yanked it out of a truck last year, was pretty bad.

No. The shims I am talking about are designed to move the shaft toward or away from the valves. Whichever you need.
 
1st choice Hughes rockers , 2nd choice lash caps , it always comes down to dollars and cents. I would be alright with the pattern on the caps just make sure your adjustments are correct. Crower make caps in .060 and .080 or .090 I believe.
 
Shims are available from hughes too, use them. ~35$, it corrects your problem.
 
I was messing around with different thicknesses of lash caps and I think I centered the wear pattern pretty good, still slightly towards the exhaust, but doesn't seem as wide. This is with a 80 thou lash cap.

Only problem is I don't have very much adjustment in the rocker arms. My pushrods have ball/ball ends so wouldn't it be good that I got the adjuster very close to the body of the rocker arms? Without lash caps I had about a thread and a half of the adjuster sticking out, now I have only a bit of one. Nothing will bind like pushrod with a cup end though.

Also note that the wear pattern on the other lash cap earlier in the thread is wider than it looks, I had to colour it in with a sharpie because you couldn't see it and didn't get it wide enough.
 

Attachments

  • IMG_3306.jpg
    29.2 KB · Views: 336
-
Back
Top