|
Post by neil on Apr 11, 2012 17:17:12 GMT -5
One of the most common things for the jeep I-6 is the ticking at idle or sometimes at load. Generally new lifters will solve the problem for a time, but it would be in the best intrest to look at rebuilding the head along with them. Valve and lifter tap are caused from multiple points of contact. Worn valve springs can lead to valve float at higher rpms. Plugged oil holes in the pushrods can leave inadequate oiling of the head in general. Worn valve guides can lead to sticking valves. Colapsed lifters make a nasty racket because the pushrod is not kept tight to the rocker arm. A failing lifter will tend to have a specific rpm at which it becomes noticeable. Low oil pressure at idle can be a contributing factor, but then you probably have worn main and rod bearings. Sometimes adding lifter pre-load by increasing push-rod length will quiet them down. Not too much to worry about if it is just at idle though. Before hydraulic lifters, every motor sounded that way. Never refrain from posting a question in Tech assist, somebody will be glad to help you out
|
|
Lou
Moderator
Injanir
Posts: 577
|
Post by Lou on Apr 11, 2012 17:24:02 GMT -5
Good stuff Neil.
I know my 4.0L I6 has had a slight knock at idle but goes away when you increase the RPM's. I have 303,000+ miles on mine and its still going strong. I have replaced the oil pump, timing chain, valve job done but I've never replaced the rockers, pushrods, lifters or cam. That may solve my problem but I just can't justify tearing a strong running motor down.
|
|