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Rovker Arm Failure... Help!!!

E

elks

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So I got my motor together ran it through break in and was on my 2nd tank of gas (130 miles) and then a little loss of power and a knock. Pull the valve covers and find 2 rocker arms as below. They were a cheaper set of Roller Rockers, and the 2 that failed were next to each other in Cylinder #1. The rest looked ok the push rods were factory rods and looked good.

Engine specs in general are: SBC 350, Comp Cam that is built for lower end torque and power weaker top end. Can't remember the exact number off had but one more aggressive than a RV cam. The cam and lifter were brand new from comp cams. The heads are a set of world products sportsman 2 heads with valaves/springs etc.

All seemed to be adjusted properly!

Here are my questions:

1. What would cause this?
2. How should I replace?
3. Do I need to worry about the lifters? I have accounted for all pieces.

4. What should I replace with? I am looking at doing new push rods and rocker arms. Again the motor has only been ran through a break in and about 150 miles.

Let me know what you think and thanks for all the help!!!

 
to much travel / lift and to small a slot for rocking motion on stud .

cheep as crap .

are your heads set for gide plates for the pushrods ? if not I think you need a set that was self aligning . shims on each side for the roller. non self aligning if I recall require gide plates to keep every thing inline and not twist in there motion of travel .

fyi you didn't get roller rockers. you got roller tip rockers.

pic of my comp cam units. scored for under 175 new off ebay few years ago when I needed them .

350 tbi motor build 004.jpg
 
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agreed with Brett /\ on this....inspect the valve tips for the rockers running off the edges, the pushrods for galling or flat spotting on the tips, and the slots on the rockers to see if they were binding at full lift. You should check each valve after finding that.
replacement of quality pieces is a good idea...Looks like China **** to me.
 
You might also check for coil bind on the springs or retainer hitting on the guide, but on those heads with those springs, I really doubt that cam has enough lift to do that.
 
right, those heads are usually put together for at least .570 lift.


What rocker ratio are those rockers?
They say you need to elongate the head pudhrod holes for 1.6 rockers.
 
Up dates with better info!!!

COMP Cam for 2,000-6000 RPM 230/230 and .480/.480

That is the cam I am running. And the heads are actually the SR Torquer HEads here:

http://www.worldcastings.com/produc...ds/world-products-s-r-torquer-iron-heads.html


So far I see no scaring on any of the other rocker arms and no mark on the valves.

1 of the rods was flat at tip.

I am looking to order new rods and rocker arms. What should I get?

This was my first engine rebuild. So I am still learning!!!!

So which rocker arms and rods? Do I need a rod that is stock or one a little longer?

Thanks a bunch...
 
Probably counterfeit rockers.....

I just read an article in HotRod (?) about this. MSD and Comp Cams have had huge problems with Chinese knock-offs of their stuff.

If you bought these off eBay at a "too good to be true" price, you most certainly got Chinese knock-offs.

Buy from a reputable source. You can try contacting Comp Camps directly. They are always on the lookout for counterfeit sellers so maybe they'll hook you up with some genuine parts in exchange for information about where these knockoffs came from??? :thinking:


-G
 
OK.... So looked over all the valve tips and the other rockers. No major concerns there. The valves all look good. Of the rocker arms (which are going to the trash) 1 other showed a mark in the slot. We have removed all rocker arms. Later today we will take off intake and inspect each lifter separately.

What should I be looking for on the lifter? Again I had 1 push rod that had a flat tip. None were bent.

I am wanting to go with all new push rods, and rocker arms.

What should I buy for this set up considering it is not hugely built? Should I just run OEM style rockers and rods? Or something else?

I can afford better quality now and do not mind spending a couple hundred to get this set up right!
 
When I built mine, the Comp Cams Pro Magnum rocker series weren't incredibly expensive, and they are steel, which I liked. 10 years or so later, still working fine. Not a lot of spring pressure or RPM's over 4500 in my truck, but I'm not concerned with them lasting no matter what.

There might be others out there, at the time they were the only ones with that offering.

All sorts here: http://www.summitracing.com/search/...nless-steel?SortBy=DisplayPrice&SortOrder=Asc and http://www.summitracing.com/search/...moly-steel?SortBy=DisplayPrice&SortOrder=Desc
 
So if I went with these:
COMP Cams Ultra Pro Magnum XD Roller Rocker Arms 1804-8

http://www.summitracing.com/parts/cca-1804-8/overview/make/chevrolet

What ratio should I get? Should I order the rocker arms first then check length measurement for the rods before ordering?

I see that they are not self aligning. How would they align then? What do I need to accomplish this?

THanks I am reading and learning stuff I sohuld have the first time aorund.

Do I really need rollers? What advantage do they have over standard rockers?
 
So according to WP page on the head specs. I need to stick with a 1.5 rocker arms as a 1.6 will require elongation of the push rods holes.

So can I go with these since they are roller tips and self centering? Assuming I have the 3/8 stud?

Thanks again.
 
Can't really comment on those arms particularly, but if running stock centerbolt valve covers, full rollers require some trimming of the valve cover to clear the rocker trunnion. It's not much, or hard, nor does it affect anything, it's just a tiny bit more work. No idea what diameter studs you have, the head page doesn't list them that I see.

Stock ratio is 1.5, not sure why you'd want to go with anymore than that unless your application demands it, and those heads note you have to do some grinding to make higher ratio rockers work right.

Alignment is dictated by the valve/retainer arrangement. If it's the "Vortec" style valve, the rocker arm is designed such that it keeps the rocker (and thus pushrod) inline. If the valve/retainer is the earlier style, they require guideplates. From what I can tell from the pictures, those LOOK like they are setup for self aligning rockers, but that's a guess.

Based on what I know from back when I put my motor together, you don't want to use self-aligning rockers on valves/retainers not designed for that setup. Not sure if you can use guideplates and non-self aligning rockers on the newer valve setup, but I assume yes, if pushrod length is made sure to be correct.

Edit: you beat me to some of it. The ones you linked are for 7/16" studs. Additionally, you need to find out what rocker arm style the heads require.

Edit Edit: And before someone beats me up over it, you could most likely just use stock stamped rocker arms that are probably 5 times less expensive. The "gains" from roller rockers are almost nothing. But if you like cool stuff, in building an engine, all steel full roller rockers are cool. :)
 
Yup those are the cheap procomp roller rockers I think. I bought those when i did my vortec swap and head the same thing happen. I ended up breaking 5 of them. On one of them the pin that holds the roller tip on broke in half and was laying on the head. Summit gave me full credit towards new ones, so I bought the comp stamped steal ones like youre looking at and havent had any problems since. :waytogo:
 
That sucks. When redid my top end I used crane roller tip rockers. 1.6 lift fit fine but mine are stock corvette heads. Used edelbrock duel spring valve springs though. Definitely get some quality parts from reputable source this time.
 
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