friend of mine was at the shop the other day and his car (99 z24) was sitting outside idling hot. i was standing next to it and at an idle you can hear a soft rattling sound that sounds internal, i was just wondering if any of you are familiar with this, we popped the hood and tried to listen for the sound with a scope but it just seems to come from somewhere in the head, possibly the timing chain housing? the noise is hard to describe its barely audible like a soft knocking/rattling and you cant hear it over the engine at anything above an idle? any help would be appreciated hes pretty worried about it
i agree... my rod bearing ticked slightly above idle for 2 years before it finally spun and produced a full rod knock
ok thanks guys, ill let him know, if it makes any difference his is only at idle, anything above and it goes away, he described the sound as " almost like a chain rattling quietly inside the block"?
perhaps his timing chain tensioner is about to crap out?
Sounds like a lifter to me.. I've never heard a soft nock or tick come from a rod. However sound does travel well in these motors.
i had a very soft knock (Sounded like a quiet tick) from a rod bearing...
i had it for two years, you wouldn't hear it at all at idle, you'd start hearing it at 1500, and it get faster (but not louder) at higher rpms...
then a lifter exploded and bent a valve... i replaced the entire valve-train ... new head with new springs, valves, retainers, keepers --- secret cams with new housings and lifters. Nothing was reused except the fuel injectors and manifolds. The tick persisted until it turned in to a full rod knock. The tear down showed a cyl 3 rod spin, no other damage to any other internal.
That's just it when I heard mine it wasn't till under load or at higher rpms. When I had bad lifteers it was at idle and all rpms but never sounded like a hard knock.
ive never heard lifter tick... Ive had a few explode over the past few motors, and when they go... they go... without much warning besides a few misfires prior...
