broken rocker

**soulaudio** · 10-11-2007, 08:32 AM

I was driving home from work one day with the cruise set @ 80mph when i heard a loud lifter type ticking coming from me engine and the check engine light was flashing. I drove home 3 miles and tore off the valve cover. What i found was that the roller bearings from my rocker arm on cyl. 5 exhaust had come out of the arm assembly and i had a broken valve spring also. I have comp. dual springs so the valve was still up so i installed a good rocker arm and did a compression test. Much to my demise i have no compression in that cylinder. I have a mti x1 cam, hardened comp pushrods, and the comp springs along with titanium keepers. My question is what went wrong? I wasn't running the engine hard, and have had the cam/springs installed for at least 20,000 miles. Also what is the chances that i have damaged the piston? I know it is probably 50/50. I had went to the strip the weekend before, but i had driven at least 500 miles after that without any problem. Thanks

**cam99** · 10-11-2007, 02:37 PM

Originally Posted by soulaudio

I was driving home from work one day with the cruise set @ 80mph when i heard a loud lifter type ticking coming from me engine and the check engine light was flashing. I drove home 3 miles and tore off the valve cover. What i found was that the roller bearings from my rocker arm on cyl. 5 exhaust had come out of the arm assembly and i had a broken valve spring also. I have comp. dual springs so the valve was still up so i installed a good rocker arm and did a compression test. Much to my demise i have no compression in that cylinder. I have a mti x1 cam, hardened comp pushrods, and the comp springs along with titanium keepers. My question is what went wrong? I wasn't running the engine hard, and have had the cam/springs installed for at least 20,000 miles. Also what is the chances that i have damaged the piston? I know it is probably 50/50. I had went to the strip the weekend before, but i had driven at least 500 miles after that without any problem. Thanks

Bad luck I suppose, things do break ....
So if the valves are seating properly now that you've put a new rocker on, 100% chance are that you put a hole in the piston. Good Luck.

**soulaudio** · 10-11-2007, 05:50 PM

I'm pretty sure that i have a bent valve. My question is the possibility of the valve putting a hole in the piston when it made contact. I wasn't running it hard like i said, maybe like 1700 rpm or so. Thanks for the input though.

**vettenuts** · 10-12-2007, 04:53 PM

Stock rockers? Unfortunately, the stock rockers were designed with lower spring pressures and lower lift cams. I have been an advocate of aftermarket rockers for a long time and have taken crap for it, but the fact of the matter is GM designed the valve train for lower spring loads and as you build it up you put a lot more stress on it. The wipe pattern of the rockers is very wide as well and I think guys are going be having guide issues in the future as well. Either go with a set of correctly setup aftermarkets or get yours rebuilt by Harland.

**slims00ls1z28** · 10-15-2007, 05:27 AM

Originally Posted by soulaudio

I'm pretty sure that i have a bent valve. My question is the possibility of the valve putting a hole in the piston when it made contact. I wasn't running it hard like i said, maybe like 1700 rpm or so. Thanks for the input though.

Mine let go at about that RPM as well. Only difference is the head broke off the valve, piston shattered and cylinder wall toasted. I was doing only 45 so speed does not always determine the problem especially if something detrimental happened previously. Piston will shatter before it actually puts a hole in it. Every last exhaust valve in mine hit the pistons and all of them have dimples but only that one broke. What are the specs on the cam? If its rather large and one of the springs on it is broke theres a good possibility that the valve floated making contact either now or earlier but just decided to go pop. Wish I would have broke a rocker I might still have an engine.