Keep an eye on those aluminum rockers (Some can be troublesome)
08-13-2010, 12:23 PM
#1
Keep an eye on those aluminum rockers (Some can be troublesome) Long story short, my aluminum roller rockers are failing because the spring clips are much harder than the aluminum rocker body material. Now, these are CAT SBC rockers modified to fit the LS1/LS6, but, the mod to use them has nothing to do w/ the problem.
The hardened bearing retainer clip cuts into the rocker body material which has resulted in either the end of the retaining clip snapping off or the rocker shaft to walk into the rocker.
Again, if your aluminum rockers have hardened material, likely a bearing housing, that rests against the retaining clip, then you won't have this problem. However, if there is aluminum against the clip, it will fail eventually.
It's worth removing the valve covers to have a look.
NOTE: I did not have this problem w/ the PRW 1.8 rockers that I had been using before the cam swap. The PRW's have hardened material against the retaining clips. Have only had the problem w/ the modified CAT 1.7 roller rockers.
NOTE 2: Am gonna tack weld the stock bearing retainers to the stock rocker so that they don't pop off & release needle bearings. Stock failure was the reason that I went to the roller rockers to begin with. The stock rocker body is ductile iron & the retainers/covers are stainless. So, the tack weld will hold to the iron & overlap the stainless to hold the clip/retainer in place.
The hardened bearing retainer clip cuts into the rocker body material which has resulted in either the end of the retaining clip snapping off or the rocker shaft to walk into the rocker.
Again, if your aluminum rockers have hardened material, likely a bearing housing, that rests against the retaining clip, then you won't have this problem. However, if there is aluminum against the clip, it will fail eventually.
It's worth removing the valve covers to have a look.
NOTE: I did not have this problem w/ the PRW 1.8 rockers that I had been using before the cam swap. The PRW's have hardened material against the retaining clips. Have only had the problem w/ the modified CAT 1.7 roller rockers.
NOTE 2: Am gonna tack weld the stock bearing retainers to the stock rocker so that they don't pop off & release needle bearings. Stock failure was the reason that I went to the roller rockers to begin with. The stock rocker body is ductile iron & the retainers/covers are stainless. So, the tack weld will hold to the iron & overlap the stainless to hold the clip/retainer in place.
08-13-2010, 06:22 PM
#5
AFR 205 heads & Comp cam. There is nothing stock about the engine. I don't like stock rockers because when used w/ heavy springs, the bearing retainers pop off. Yes, this has happened to me. Am going back to try the stock rockers, w/ welded retainers, as of today. We will see how they hold up.
Can't use a thrust washer behind the clips. There is no room. Also, found one of the shafts, clip & all, was walking through the rocker body. Guess the press fit of the inner rocker pivot shaft to rocker body wasn't tight enough.
Best & most reliable rocker I've used are aluminum PRW's. You know...the cheap ones that the "convincing internet crowd" won't use? The ones I have are 1.8's, too much ratio & lift for the XER lobes. So, am gonna see how the welded stockers do. If the stockers fail again (don't see how they can), will buy some 1.7 PRW's.
Can't use a thrust washer behind the clips. There is no room. Also, found one of the shafts, clip & all, was walking through the rocker body. Guess the press fit of the inner rocker pivot shaft to rocker body wasn't tight enough.
Best & most reliable rocker I've used are aluminum PRW's. You know...the cheap ones that the "convincing internet crowd" won't use? The ones I have are 1.8's, too much ratio & lift for the XER lobes. So, am gonna see how the welded stockers do. If the stockers fail again (don't see how they can), will buy some 1.7 PRW's.
08-13-2010, 06:26 PM
#6
AFR 205 heads & Comp cam. There is nothing stock about the engine. I don't like stock rockers because when used w/ heavy springs, the bearing retainers pop off. Yes, this has happened to me. Am going back to try the stock rockers, w/ welded retainers, as of today. We will see how they hold up.
Best & most reliable rocker I've used are aluminum PRW's.
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08-13-2010, 06:50 PM
#8
AFR 205's can run a stock rocker just fine. Bearings do pop out, but it's few and far between. I've built 100's of engines so far and have yet to have this happen to me. 1 time, doesn't mean it'll happen every time. The trunion upgrade fixes that.
That's an opinion, not a proven fact.
That's an opinion, not a proven fact.
Yes, it's an opinion based on my experience. It was stated in response to your "internet myth/follower" comment.
Yah, trunnion upgrade is expensive/over priced. IMO, the tacked retainers will do a similar job. As noted, my dual springs popped a retainer in less than 200 miles. Yes, the valve train geometry is set up correctly.
Another issue w/ stockers is the wide valve wipe pattern. The design of the stock contact radius coupled w/ the motion of the stock rocker makes a wider wipe pattern than an aftermarket adjustable rocker. There is a huge difference between the two.
08-13-2010, 06:53 PM
#9
I will post some pics. Yes, was using guide plates. It's a design flaw in this particular manufacturers rocker. The edge of the retainer clip can contact the aluminum rocker body. Once it contacts, it digs in & either brakes the tip of the clip off or pulls the shaft into the rocker body.
08-13-2010, 07:19 PM
#10
Here are the pics. While taking the pics, realized that the shaft walked first & then the clip tip broke off. All of the shafts were walking. I just found the first two that broke retainer tips. So, it's definitely a design issue.
First pic 009 shows the shaft as it is pushing out the opposite side of the rocker. Smallest to largest... the smallest diameter is the inner shaft. The next stepped diameter is actually the retainer. The largest diameter is the outer shaft sticking through the rocker body.
Second pic 004 is a pic of a pen pointing to the protruding outer shaft
Third pic 002 shows a broken retainer tab. There should be two ears w/ holes for the c-clip tool used to expand the clip/retainer when installing or removing. One of the ears w/ a hole in it has broken off. (Found both broken tabs stuck to the drain plug magnet in the oil pan.
Fourth pic 011 shows how I tack welded the stock retainers to make sure that they don't pop off.
First pic 009 shows the shaft as it is pushing out the opposite side of the rocker. Smallest to largest... the smallest diameter is the inner shaft. The next stepped diameter is actually the retainer. The largest diameter is the outer shaft sticking through the rocker body.
Second pic 004 is a pic of a pen pointing to the protruding outer shaft
Third pic 002 shows a broken retainer tab. There should be two ears w/ holes for the c-clip tool used to expand the clip/retainer when installing or removing. One of the ears w/ a hole in it has broken off. (Found both broken tabs stuck to the drain plug magnet in the oil pan.
Fourth pic 011 shows how I tack welded the stock retainers to make sure that they don't pop off.
08-14-2010, 09:46 AM
#12
That's good to hear. I corrected myself as to the clip to aluminum thing. The actual issue is that the steel outer race/shaft that is pressed into the aluminum rocker body is walking out. Apparently, the press fit is not tight enough between the steel & aluminum. Most, if not all of mine were walking out. It looks like the issue is w/ this manufacturer only. Although, as is the point of this thread, everyone w/ aluminum rockers should check to make sure that the inner steel shaft/race is not walking out of the aluminum rocker body.
