A friend and I took a blast last night and broke a valve spring retainer and dropped the valve. The cam is a Thunder Racing 220 on a 114 lobe center with 1.8 Harland Sharp rockers that makes it just under .600 lift. The springs are 918 blue stripes and the retainers are stock. Is this a common problem? I have never heard of a broken retainer. The spring is fine, but the retainer shatterd. I am now concerned about my .560 lift cam and the stock retainers on my car.

 

Were the rockers checked for proper clearance on the retainers? Sounds like the rockers could have been coming into contact with the valve retainer causing it to stress and break.

 

Eek. I was under the impression that running 1.8 rockers and tr220 or bigger was a bad idea. Thunder Racing says on their page they don't suggest it.

"Thunder Racing Custom Camshaft - 220/220 .553/.553 114 LSA 1500-6500 RPM Power Band. Computer Tuning Required with automatic transmission cars. A very well balanced camshaft that makes excellent power across the entire RPM range. Due to the fast ramp rate of this camshaft, the use of 1.8 rockers is not recommended."

And to answer your question, that is not common. I too think there was interference somewhere with the rockers.

 

Ditto that.