Originally Posted By: dlundblad
Originally Posted By: Zaedock
Jeep engines are an inherently noisy design. They are mass produced cast iron block and head with non adjustable valve trains. If the OP's engine only makes a bit of noise for a few moments when cold, he should consider himself lucky.
First off, I meant minutes rather than moments. Its always quiet immediately upon start up for about 20 seconds, (this tells me my ADBV is working) then the tick starts for 1-2 minutes at idle. I imagine the time is less if I just get in and drive. I'm always easy on a cold engine btw.
While it seems to be a fairly common issue on the web, I have yet to hear a 4.0 tick like mine on start up. Of all the 4.0s I've heard fire up in parking lots, they were all tick free. Heck, my dads Renix 4.0 is quieter than mine with the exception of the exhaust.
I understand they aren't as quiet running as say a late model Civic, but the ticking is just plain odd. I guess some Jeeps have it.. some don't. I need to replace the valve cover gasket and PCV. Maybe once the cover is off, I can feel for loose lifters. Either way they don't seem to hurt anything besides my mental health.
Precisely why I don't believe it's an oil flow issue as another poster stated. It is more likely an issue with a lifter or again, a rocker arm.
I can't tell you how many Jeep engines I have built for myself, friends, and customers over the years. One thing that has always blown me away is the variance of the stock rocker arm ratio and geometry.
I'll agree on the Renix engines being the quietest. My kid's '89 XJ is quiet as a mouse and as the body nears retirement, I may keep the chassis for another buggy build or zap in some new body panels and keep motoring on.
That reminds me of a customers 1998 TJ. It's super clean with a Clayton long arm on 33's, but with only 75,XXX miles on it, sounds like a flippn' sewing machine.