A friend of mine is having to take his car back into the shop because after he put about 600 miles on the engine that was rebuilt (327) it started making a loud rattle type noise. Well, when he took it back in the shop the head mechanic told him they had to redo all the "Rockers"....could someone please explain to me why this would happen and what the shop people would have to do to correct the problem? And also, whats to say this couldn't happen again? Is my friend possibly getting a the ole royal sh_ft? The owner of the shop did tell my friend they wouldn't charge him anything to fix the problem, and would make it good.

Sometimes the stock type rocker nuts can back themselves if they have been adjusted a few times or if they get reused. Also if he is running roller rockers and poly locks they might be coming lose. Or if he is running a solid cam his lash might be losening. Coulda wiped a cam lobe possibley http://www.chevelles.com/forum/frown.gifKinda hard to tell without knowing what kind of valvetrain he has. The shops explination sounds like it could be correct.

Maybe there is someone close that can give a listen for a brewski? http://www.chevelles.com/forum/smile.gif

Thanks for the information. I didn't understand everything you tlked about but I got the jist of the idea. At least the "Brewsky" part.....JL

It's not uncommon to have to readjust the rockers with a performance cam, even hydraulics. It's not that common with a stock cam. Most of the time a stock hydraulic cam is preloaded about 1 turn on the adjusting nut. Usually a performance cam is preloaded about 1/8 to 1/2 turn. As the parts lap in, the preload can become less. With 1 turn, there is enough preload to allow for this. With only 1/2 turn or less the valves can start clattering.

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Pat Kelley
66 El Camino, daily driver
67 El Camino, STRIP/street (7.392, 92.70, 1.63 60', 1/8 mile) 355 powered
Pat's Page (Dynamic Compression Ratio Calculator, car specs, Spark plug reading info) (http://cochise.uia.net/pkelley2/)

Thank you Pat...I think I understand what your explaining. But I'm really not so sure if there is a cam in the engine or not. All I know is the engine is a '68 #'s match 327 and is running around 300 horsepower right now with all the stuff my friends put on the engine. What all that is I really don't know. I'm not really that versed on the mechanical end. But I'm learning!! Thanks again.

http://www.chevelles.com/techref/ftecref17.html

Maybe this will help you understand things a bit more? Its some interesting reading any way if you are bored.

Holy cow!! There's definately allot more there than meets the eye thats for sure! I'll keep that reading material and re-read it again and hopefully some of it will sink in after awhile...who knows, I may just learn something afterall!

this might be a bit more helpfull too
http://www.chevelles.com/forum/Forum4/HTML/009839.html
http://www.chevelles.com/forum/Forum9/HTML/010793.html

If you do a search here in the perf or engin forum on adjusting lifters or setting preload or adjusting rockers you will come up with all kinds of stuff.

That how stuff works. com usually helps too. I finally figured out how a rotary worked from them http://www.chevelles.com/forum/redface.gif

Thanks for all your help guys, and also thanks for the reading material also. I should learn alot hopefully.