kaotik_good

i have a 98 Z28 i got a set of stage 3 heads (milled 30/1000s) for it and got em installed, it ran great for like 2 days then i got this loud engine knocking. i was positive i had it narrowed down to lifters replaced the lifters and thought well hell im in there anyway cam time. so now i got xer273 (581/592-224/230-114) and cc850-16 hyd roller lifters. when i start it up (takes alot of proding to get it started) it still makes this loud knocking. is there any way at that this could be a result of not tunning after the much larger heads? could this be why its still making the knocking? is there any chance that good tunning could correct this?

thanks in advance for all the help

00TAProject

You are still knocking after Top end work....I am not a master Mech, but I would believe that your problem is bottom end....It you are knocking then I would say you are bound to or about to loose a rod.....Anyone else think the same?

pekkaz

Running very lean can damage piston and cylinder due to overheating and detonation though you should have seen it when you replaced the lifters. If it's louder under load then it could be piston skirt and louder when you lift throttle, typical to rod bearing. If it's not constant at piston speed, main bearing.

Here's how my knocking cylinder looked like .. had to be re-sleeved.