I'm new to the forum and recently just purchased a '75 280Z with a built 302 V8. I apologize in advance, this post may be long.
After about a month of ownership I noticed a ticking coming from the engine that was pretty pronounced. I suspected a lifter or that a general tune up was needed. The car runs very strong, and has not had any performance issues that I can detect, but I also don't have anything to compare it to.
Fast forward to this week. I dropped the car off with a local hot rod shop to go through the heads and adjust the valves, etc. Once the valve covers were off, the guy noticed there was a small metal ring down in the head just laying between the valve springs. It was determined it dropped out of the valve cover gasket, as the gasket had 6 small ringed shims where the bolts go through to attach to the head. His theory is someone removed the valve covers and then tried to re-use the gaskets and while pushing the bolt back through the hole it dislodged the ring into the head.
He says he also found one that was cut in half upon further inspection; as well as metal on the underside of the valve cover. He also noticed there were more shims missing from the valve cover gasket and he suspects they went through the oil drain back holes in the head and dropped down into the engine. He sent me a picture of the ring he found, but by the time I got to the shop, he had thrown all the rings away from both gaskets.
He is telling me now that I should pull the engine and have it rebuilt because he suspects this material floated through the engine to the crank and bearings and will cause me issues in the future. He said I could pull the engine myself and bring it to him and it would probably cost around $700-800 to rebuild. If he pulls the engine it will cost anywhere from $1,700 to $2,500.
My question is, should I be worried if these rings went down the oil drain holes? Don't those holes go straight back to the oil pan, where they wouldn't be able to be sucked back into the engine? I plan to drain the oil through a filter and see if I catch any shavings. I want to be catious, but I also don't want to needlessly rebuild the engine. I haven't had valve covers off since I owned it until now, and the previous owner owned it for 2 years with no issue, so if someone pushed these rings into the engine accidentally, they would have been there for a while.