it turns out the lifter on the #1 intake valve broke in half.....anyone ever hear of this before??? what causes it???

454 I had a lifter break on me last year the bottom of the lifter had a small groove like the old GM lifters did and I started the engine and heard a snap noise pulled the valve cover off and found a loose rocker pulled the intake and the piece under the groove had broke off. Comp told me to eat it . Any lifter you use you can check on a surface plate for crown and rockwell. If you need these numbers I've got them . Best of luck Laz Mesa

Check your spring pressure?? Also you might have to much lift on the cam to run a flat tappet type lifter set up. Glad you didn't hand greande it.

Good luck in future. Ruben's racing came in CA has really good lifter sets for really cheap. I don't know where they come from, but I tried a set a while back and they are working well. I think I paid $50 a set for them. It was worth the experiment.

Don't know the specific cam specs, cam by crane..lifters also. Motor is built back to stock 420hp specs. bottow 1/3 is where lifter actually broke, sounds similar to your experience laz mesa.

I would like to see that, can you post a Pic?

If it is stock specs then there is no porblem with springs or cam. Only thing I can dream of is maybe rockers were a little to tight and putting excessive pressure on lifters. On hydraulic, I always use 1/4 turn from 0.

Good luck next time. Glad you have a warranty.

i would like to see a pic too, i'll see if i can't get one from the engine builder....he'll give me the old pieces if i want them.....once he finds them!

Make sure that he does. They are in there somewhere. They usually hide in the coolers or lines, and when you think your back in the clear, WHAMMO, they come back to haunt you and blow up your next engine for you.

About a year ago, one of the car mags had an article about GM's special facility where they were hand assembling the Corvette Z06 and Cadillac hi-per engines. The article stated that they coated all the critical moving parts with "GM Camshaft and Lifter Prelube" (p/n 12345501) before firing the motors. They shipped them with Mobil 1 Synthetic in the crankcase. A 4 oz. bottle of the prelube is about $8 and my local GM dealers don't always have it in stock. They tell me that they often use the old standby-EOS. About the same time, I believe it was Hot Rod Magazine had an excellent article on cam failures. As I recall,for flat tappet cams especially, they recommended EOS in the crankcase until the first oil change. After that,they recommended a bottle of the Prelube to offset the concerns about ZDDP. Anyone interestested might do a Google search as my old memory ain't too good. I've been adding two bottles of the prelube to each of my 800SC's for two seasons now. 170 hours since a Sterling rebuild and the valve covers have never been off. Just tryin' to help....