LUVTruck.com

Just bought an 1980 Chevy Luv as kinda a toy. Problem is the engine makes a bad noise half throttle and above. At idle is sounds like the day it was new. Get on the gas and it sounds like a rod is knocking. If it was, then how come it is quiet half the time. Just wondering if anyone has an idea as to what is going on here? Thanks. Adam

it is possible for it not to knock til it gets higher rpm's.
or when it has a load on it.

check the timing or the cam chain.If it is an auto check the flex plate too, they can make a hell of a noise.

Could be a "duh" kind of maybe .... but check not only the timing, but maybe replace the points. I felt kind of stupid when I figured out THIS one. I was having a similiar oddness about a week ago... but I had the additional delight of backfiring (shoulda seen the natives freeze with fear or duck & cover whenever THAT happened! ). Picked up points at a CarQuest for $5.50 and had the timing adjusted as well.... and she's back to purring like a kitten.

If you have a test light,hook it to a good ground & while you have it knocking probe the spark plug wires one at a time-if your knock goes away or changes tone you should be able to pinpoint which cylinder may have a rod knock. or if you dont have a test light you can do it the old fashioned way & pull one wire at a time