Posted a month ago about one rocker turning black. Replaced the ball and jam nut and was good to go when I checked last yesterday. Then today, cruising on the freeway at my 3500 RPM... snap crackle pop! Busted a rocker stud clean off, and have 5 black rockers now, and the rocker that was black before, isn't the one that broke!

http://www.thirdgen.org/techbb2/attachment.php?s=&postid=2070854

http://www.thirdgen.org/techbb2/attachment.php?s=&postid=2070858

http://www.thirdgen.org/techbb2/attachment.php?s=&postid=2070862

Talking to a good friend of mine, it's possible I might be shooting oil OVER the rocker... but then again, these rockers have 5000 miles on them, and it's not good. Doubt comp will even discount a new set or set of full rollers.

is it breaking parts on the exhaust side? looks like that one got pretty hot, and the exhaust side will be naturally hotter.
what kind of pivot balls are you using? some have lubricating grooves, some don't.
what kind of studs are you running?

and why aren't you running full rollers yet?

the ball pivot for the rocker arm, does it have grooves cut in it?

What is the operating temperature of the motor, read with What gauge, and how is the line/routed. What type of gauge as well (mechanical or electrical)?

What Oil are you using? Did you ever check the pushrods to see if all the holes were clean/free of debris?

Pushrods were brand new, blown out, and they all pass oil through the rocker. The swivel balls have the 4 anti galling lube slits the rocker arms/balls/jam nuts were in the kit from Comp.

I have two guages, both electrical, one in the head the other in the manifold... the head reads about 187 cruising, the manifold reads 180ish cruising.

Some of the dark ones are on exhaust valves some aren't.

Using 10W30 Havoline. The engine doesn't use any oil, and it's the oil I was told to run by my machine shop.

Paul,
More than likely it is how the tip of the pushrod fits in the rocker.
Some pushrods, the welded ball ones especially seem to shut the oil off to those rockers in particular.
I have seen this a number of times & for that reason I do not use them any more at all.

I believe what happens is the radius in the rockers is either misformed or the rocker & pushrod tip fit without leaving a space at the top of the pushrod which will shut off the oil.
We have had a few of failures on the dyno & in one case we just stuck a stock rocker in place of the Comp & it cured the problem with the same pushrod??

Comp says they have never heard of a problem (imagine that :rolleyes: ) but did say it might be caused by the rocker ball being to tight on the stud or possibly a bad pushrod or too much spring??

Would have to dig up the specs on the spring, but it's what Harold told me to run with the cam in sig. I'm using Comp Magnum pushrods.

Unfortunatly on these protopline heads, with the dia springs I am running, stock rockers wouldn't fit, they would hit the retainer... thus I got these. These pivot balls slid right off the studs.

I didn't have trouble with these for the 3000 miles they were on my engine before the rebuild. The difference now, is the cam, pushrods, springs, oil pump (Melling 55 with upgraded spring).

What should I do? Are the full rockers good investments? Will they do the same?

With the engine idling, everypushrod was spitting oil, but it didn't shoot out, it just poured out and down the rocker....

That's pretty much what they are supposed to do but they could still be limiting oil at higher rpms if the tip is touching in the middle as the only time you will get oil is when the holes line up.

Really can't tell you what the problem is for a fact, all I know is what I have seen with some rockers & pushrod combos & so I just don't use the rockers any more & no longer have a problem. I have only seen it with the Comp rockers??
Lots of folks run them with no problem as have I but a few problem ones without an explanation that makes sense is enough for me not to use them anymore.
I have never had this problem with stock rockers or full rollers regardless of whose pushrods I used.
BTW, what pushrod are you using? Also, look at the rocker where the pushrod rides & see if there are wear marks in the middle or center or if it is on the radius away from the tip of the pushrod where the hole is.

Here is a picture of the underside of the rockers and the pushrod tip. The pushrods are Comp Magnums, and I the geometery was perfectly centered on the valve stem. I was cruising at about 3800rpm when this happened... (3.73's, 25" tires, no overdrive, 70mph speed limit!).

I looked at all the rockers still on the car, and I could see 90% of the pushrod hole, through the rocker hole... so I'm fairly confident it gets more than enough oil. The question is, is it bypassing the rocker and lubricating the valve cover walls? lol.

The rocker on the left is an overheater, and the one on the right is the one that broke off.

http://memimage.cardomain.net/member_img_a/331508_119_full.jpg

What kind of open pressure do you think your springs are at? With the kind of lift you are running, it is possible that the open pressure exceeds the recommended pressure for a ball/socket type of rocker arm pivot. I think comp says something like 350 lbs. max.(?) The fact that you had several thousand miles on these rockers before switching cams and springs leads me to believe that spring open pressure might be too high. Also make sure that you are not running into a coil bind situation, if you are on the edge it could cause rocker failure. If coil bind is not at fault, I would recomend changing to a full roller rocker arm.

I gotta think that your spring pressure is too much..

I went with .050" taller keepers to take some pressure off the Manton PN 2454 springs Competiton Products sells that I decided to use with my CC 282S solid cam and their Magnum rockers.

Take your valve spring "pounds/inch" rating and multiply it by your lift and then add it to your springs recommended installed seat pressure and that should give you the max. lift pressure.

See if you aren't either right below 350 pounds or maybe over it...

Otherwise pull a spring AND go have it checked by a good Machine Shop..

pdq67

Harold told me to get the Lunati 73100 dual springs the specs on the sheet are as follows:

-1.450" outer diameter
-.730" ID
-1.850 Seat load height, load=125 (Actually installed at 1.8)
-1.250 Open load height, load=325
-Coild Bind 1.110
-Max lift = .680
-Rate 333

Cam lift with 1.6 rockers is 544/.566 . I think your forula with it installed at 1.85 comes out to 313.4lbs/in max lift. You guys are right, I checked my rocker paperwork and it says 350 max pressure. And still have .124 before coil bind.


Definatly going with the Pro Magnum Full rollers, really wanting to know if it's a stuff happens thing, or if its faulty parts, or something I did wrong before I was to call comp or not.

Paul,
Assuming everything was checked,, at 1.800" you are at about 140 on the seat which is a little high but should not a problem & about 330 open on the exhaust which again should not be a problem so,,,
Either you have some "problem rockers" which we all know can't happen :D or the rockers don't like the pressure Comp says they will handle.

Will I need taller studs than stock studs for the full roller rockers with the poly locks? My friend with an AFR roller 383 had to get taller studs to engage the polylock enough, and I don't know if that applies to my tappet engine, and should I expect my pushrod geometery to change?

I'm not sure how the stud is measured,
From the base where the stud meets the head, to the top thread my old stud is 1.75"long. Threads are 15/16"long. The 2nd picture in the post shows how much stud was left after lash was set. I do have the tall style valve covers.

Here are specs on arp studs at summit:


ARP-134-7101
Base Thread Size 7/16-14 in.
Rocker Arm Nut Thread Size 3/8-24 in.
Guideplate Locator Shank Yes
Rocker Arm Nut Thread Length (in) 0.800
Effective Stud Length (in) 1.750
Base Thread Length (in) 0.700

ARP-134-7104
Base Thread Size 7/16-14 in.
Rocker Arm Nut Thread Size 3/8-24 in.
Guideplate Locator Shank Yes
Rocker Arm Nut Thread Length (in) 1.000
Effective Stud Length (in) 1.895
Base Thread Length (in) 0.710

Got the Pro Magnum full rollers tonight. For those who are Comp Elitists...... the rockers didn't come with lube or any kind of paperwork (instructions).

Not that I need any, but polylocks can be kind of confusing! I lubed em up, poured oil over the top, and went for a drive. Put about 15 miles on them, pulled the covers and it looks like everything is getting poper oil! Think the polylocks may help if I was overshooting the rocker.


These are 10 times quieter than the roller tip rockers were! Can't complain about that!