AMC Eagle Den Forum

The Mighty 258 => General Service and Diagnosis => Topic started by: kajsdf on December 15, 2011, 08:52:47 PM

Title: engine clicking
Post by: kajsdf on December 15, 2011, 08:52:47 PM
i attempted to diagnose this previously, which led me to replace the timing set, but the noise still hasn't gone away.  i am now thinking it is lifter/rocker noise, but i am not sure.

i experience an intermittent ticking noise which is faster/slower depending on rpm.  at slow speeds it is a light ticking, at higher speeds it sounds closer to a woodpecker tapping on a tree.  i tried to get a video to capture the sound.  it is faint, but audible in the video:

http://youtu.be/kqIrVtIraE0

i plan to do the 4.0 swap very soon and have a second car i can drive if this is going to wreck my engine if i leave it untouched.

Title: Re: engine clicking
Post by: milliard431 on December 15, 2011, 09:45:04 PM
Is that the sound it makes when you have an intake manifold leak? When you listen under the hood you can't hear it but when driving you can.
Title: Re: engine clicking
Post by: GRONK on December 15, 2011, 09:51:30 PM
Sounds like an exhause manifold leak.  The smaller the leak, the louder the ticking.

Tighten everything down.
Title: Re: engine clicking
Post by: AMC of Houston on December 15, 2011, 10:47:30 PM
Well, could also be worn out rocker stands.  I had to replace mine at the 170,000-mile mark.
Title: Re: engine clicking
Post by: kajsdf on December 15, 2011, 11:05:59 PM
it's got 90k miles, is worn out rockers likely?  i'll be replacing everything when i do the head swap anyway but in the meantime i'll check to make sure everything's tightened down
Title: Re: engine clicking
Post by: eaglebeek on December 15, 2011, 11:48:19 PM
Kajsdf...Does your ticking noise occur while accelerating and does it stop when you're coasting? :eagle:
Title: Re: engine clicking
Post by: kajsdf on December 15, 2011, 11:53:54 PM
it usually starts when coasting, and now that you mention it i can't remember it ever happening while accelerating
Title: Re: engine clicking
Post by: eaglebeek on December 16, 2011, 12:09:29 AM
Quote from: kajsdf on December 15, 2011, 11:53:54 PM
it usually starts when coasting, and now that you mention it i can't remember it ever happening while accelerating
Strange noises while coasting seem to point to to a vacuum leak...coasting with throttle off is when the engine develops highest vacuum.

Vacuum leaks can occur through the intake manifold gasket, the carburetor base gasket, or the various hoses that pervade the engine compartment of an Eagle.

One way to find such leaks is to spray starting fluid in the area of a suspected vacuum leak while the engine is running. If engine rpm changes then you have found your vacuum leak. Careful when doing this...you don't want sparks or other ignition sources nearby while you do this.





Title: Re: engine clicking
Post by: kajsdf on December 16, 2011, 12:25:43 AM
i replaced all the vac lines i could find except the 4x4 lines.  it sounds like it's coming from the drivers side which would make sense if it was a manifold leak
Title: Re: engine clicking
Post by: kajsdf on December 16, 2011, 01:10:04 AM
running without the valve cover sounds like an awful mess!
Title: Re: engine clicking
Post by: AMCKen on December 16, 2011, 01:46:09 AM
Quote from: kajsdf on December 16, 2011, 01:10:04 AM
running without the valve cover sounds like an awful mess!

Start with a warm engine. Then you won't have the fast idle cam in the works.
Or a cold engine if it will run at base idle. I've fixed a few tickers by lower the rocker arm pivots to tighten up the valve train. Remove the pivots and file 5-15 thousandths off the bottom where they butt against the head. Slipping a feeler guage inbetween the valve stem and rocker with the engine idling can help pinpoint which is the loose one.

I have been tempted in the past to mangle a spare cover by taking the top side off leaving the vertical sides to help contain the oil in cases like this.
Title: Re: engine clicking
Post by: kajsdf on December 16, 2011, 01:35:39 PM
found a few bolts needing tightening on the exhaust/intake manifolds.  i will road test a little later to be sure but this may have solved it.  i'll check the lifters next if this didn't work.

related note, i am going to pick up the head swap equipment today, so it won't be an issue much longer if it happens to be the lifters  ;D
Title: Re: engine clicking
Post by: carnuck on December 18, 2011, 12:26:07 AM
If you have a dry rocker, it will clack. I tap on the pushrod end of the rocker with the motor running to pop loose anything stuck in the lifter. They usually start pumping oil quickly after that.
Title: Re: engine clicking
Post by: Jurjen on December 18, 2011, 08:20:01 AM
What about the flexplate, easy to inspect and they seem prone to cracking.
Title: Re: engine clicking
Post by: kajsdf on December 18, 2011, 07:50:12 PM
didn't think of that.  need to pull transmission to check, right?
Title: Re: engine clicking
Post by: WoodenBirdOfPrey on December 18, 2011, 08:20:36 PM
No, just take the inspection plate off if it's still there.  That'll give you enough room to see part of the flexplate and ring gear.  Turn it over manually with a breaker bar on the other end of the crank, or just bump the starter a few times to see all the way around the flexplate.  Mine was pretty obviously cracked all the way around the middle so it was immediately apparent.

Mine did it worst at idle and sometimes when i'd get off the throttle I could hear it.  It was definitely not a steady sound, sometimes it was there and sometimes it wasnt. 
Title: Re: engine clicking
Post by: kajsdf on December 23, 2011, 12:56:09 AM
flexplate was actually in good shape.  i'll check with the valve cover off soon.