LOUD ticking

[sil80drifter]

Here's my story: Did the chain swap, guides were still fine, but I replaced the passenger's side one anyway, tensioner was fine too, replaced anyway, and left the chain, because it never really needs replacement, especially not after 40k miles. Replaced the oil pump with a 280ZX oil pump. Result: Oil pressure is now normal, no "start-up rattle" or audible rocker/valve tick. So the oil pump helped.

The "rattling" that was present between 2k and 3k rpms under LOW THROTTLE ONLY, turned out to be.... PING! Can you believe this?! I've been pinging for a good week! I did an injector replacement recently, put in 460cc instead of the old 270cc, because I'm going turbo soon, and tuned them with the SAFC. Well technically, 40% of 460cc is ~270cc, so I initially just put -40% all across the board, BUT! As I've been trying to figure out the nature fo the rattle, and it's disappearing under WOT (at any rpms when it would usually be present otherwise), and thought about how even 460cc injectors can't flow too much at idle and low rpms, since other cars have them and they don't seem to have idle problems (i.e.: the RX-7 they are from originally), I figured that I should try to rich-en the low throttle map. I did, and went with around -12% between 1000 and 3000 rpms... and the pign is gone.

I cannot believe how long the engine took this abuse, considering I've driven it to work for a couple of hundred miles with this condition present. I think my scenario is prety specific, and the rattle I had is not timing chain/rocker arm/valve related, but I just thought I'd share, so others can maybe learn from my experience. I did fix the start-up rattle though, for which the new oil pump was great help.

sil80