Ok, I actually feel pretty relieved right now. Yesterday, I had just turned 800 miles on my new heads/cam setup when all of the sudden, I started hearing a loud "clacking" noise coming from the engine. Fortunately, I was just getting off the freeway so I immediately turned into a gas station and shut her down. The car only ran for a minute or so, and a quick look at the guages showed oil pressure at 40 and temp was normal. I then had the car towed home. I was REALLY bummed--figured I spun a bearing.

Today I was looking over the engine and noticed a large bump on the rear of my drivers side valve cover. Took it off and the #7 exhaust rocker fell out. Turns out my 9/16 rocker stud had broken off in the rocker nut . The "keeper" was still in the rocker nut. The rocker and pushrod look fine.

So, what would cause this? I have pro magnums with comp r's and had set my lash at 1/16. Could this have been caused from the rocker being set too loose or tight? Also, the two pieces of the stud are not matching up. I've found 3 small pieces of thread around the #7 valve springs--can't find any more with my magnetic pickup tool. I'm pretty sure the other pieces went down the rear oil passageway. Which leads me to my main question--Should I pull the intake to check for metal and to examine the lifter, or do I try to "flush" any debris out by pouring a bunch of oil on that side of the engine (I'll be changing the oil/filter regardless). Obviously, I would rather NOT pull the intake, but then again, I don't want to pay for a rebuild later on. Thanks for your suggestions....

 

I had the same happen on #5 intake, caused by a bad Comp4 (pn 875) hyd lifter. It snapped the rocker stud, you mentioned 9/16 rocker stud snapped on yours, think you meant 7/16 which is what I have. I was running 1.7 RRs though not 1.6s. I'd recommend a stud girdle for starters, but more concerning is the unrecovered metal shavings, etc. The return passages should just bring it down to the oil pan though. Don't blame you for not wanting to see the engine builder before it's necessary.

 

Yea, meant 7/16--how could a bad lifter cause a stud to break? Ever since I put the engine back together, I have noticed a ticking sound on that side of the engine. I relashed everything but still had the noise--figured it was an exhaust leak, now I'm thinking defective comp r . Also, what's a stud girdle??

 

The stud itself could have been defective...I believe this to be my failure mode. I examined the break line under a microscope and I could see a cresent shaped area that was a different color than the rest of the stud "grain". Mine had 30K miles on it befire it failed; the rest of the set is still going strong 10K miles later.

 

TTT for the night crew . Still don't understand how a lifter could cause this, or how I could determine if my lifter is bad.......

 

I am with OBE sounds like a bad bolt.

 

ttt