weird noise coming from my 89 240 PLEASE HELP!

[driftiteasy0113]

OK,whenever i start up my car in the morn and when its been sitting there for a little while it makes this weird almost chattering farty type noise,it happens when im coming down from high rpm's as well.i though maybe not enough oil was getting to my head so i replaced my oil pump but it still does it.i have no idea what it is,anybody have this problem too??any help would be appriciated

[CrypticScorpio]

its a stab in the dark but have you checked ur exhaust for crap in it, also is you heatshield over your exhaust coming loose? stabs in the dark but ive noticed in my buddys cavalier when he downshifts the exaust makes a farting clinking noise and we know its the "cat", it like "Br-kling kling ding king"

[driftiteasy0113]

thanks bro ill definetly check that out

[Jay240X4X4]

Sounds to me that it may be your timing chain tensioner & guides. Your guides are probably chewed up, this usually starts to happen after 100K mi. To do it right you have to completly take the engine out. If you don't you'll most likely damage your oil pick up screen. When my 240 started doing it all the metal & plastic shavings caused a spun bearing. I would recomend replacing the timing chain tensioner, chain, & guides. And if your ride has high miles it's probably time for a rebuild. That what I did with my 2nd 240 , I learned my lesson from the first one that blew up because of it. Better safe that sorry.