Is this possible?

[Snakeyes_Tx]

I know, I'm trying to be a little of a miser here.. but I'm trying to not overfix a problem.

I *think* I have rod bearing noise. #6 or #8 to be more specific.

Here's what makes me believe it MIGHT not be.

* I have good oil pressure bigtime
* As long as the timings set right, I have tons of power
* Gas mileage is still around 220 miles to a tank
* Noise not getting any worse and I still drive it semi-hard from time to time

I did a compression test but the gauge *may* have been faulty.

I used a timing light and set this sucker at 13 degrees BTDC. The sticker on the cowl says to. I still have an occasional miss. Every once in a while when it's cold outside, my cruise control will freak out, but I think that's due to a CTO opening and closing because I'm running too cool a thermostat.

It still pings all over the throttle.. sometimes full, sometimes only half, sometimes only a quarter I usually find a sweet spot on the pedal to make it stop though.

I'm wondering if the noise I hear in the block might just be a light ping due to poor timing at idle?

Maybe I just need to replace the timing chain, EGR valve, and some vaccum lines?

If this is the case then I have a little to play with.. maybe just go new intake and carb and cam and lifters since I'm in there doing the timing chain! :D

[killroy]

Befor I did my engine work, I would get the engine ping, mostly under torque, we've got some realy lousy gas here in Colorado, reg octain runs around 85, I would have to run mid to high, high being only 91, to keep it from doing it. have not done to much her since the work so I don't have a lot to compair. don't know if this helps, but thought I'd share.

[Crazy_Jeepman]

It is possible to maintain good oil pressure with a bad rod bearing, just not very likely is all, especialy at idle. If I suspect a bad rod: at a idle pull one plug wire off if the knock changes tempo or pitch it is either the rod or wrist pin on that cylinder. Do this on all the cylinders. this is an old trick and works well. Compression tests and setting the timming will not detect a bad rod, nor will it tell you if it is or not. A wrist pin could be very likely if the knock is more to the top of the block, rod knock really should be easy to pick up at the oil pan. ;)

[Snakeyes_Tx]

Well, every once in a while the noise will come and go... sounds like a REALLY quiet diesel engine at the bottom near the rear of the oilpan area... and it's not consistant.. just every now and then! That's why I'm a bit confused! smile.gif

[Crazy_Jeepman]

Well It sounds like a mystery noise to me. I will guarantee that a rod knocking will not go away or be intermittant, or occasional. (Yes I am aware I spelled most of those big words WRONG) So if I were you I would be :D and poke around till you find the noise.

[andy d]

that mill is 19yrs. its old enough to smoke :D . the rig needs to be babied along. the knock could be a bunch of things. sounds are hard to diagnose over the 'net.SE why dontcha run up to my house tomorrow after work and we'll take it for a ride :D

[Snakeyes_Tx]

http://www.contrabandent.com/pez/contrib/edoom/spacecraft.gif

Lemme have myself shipped this way so it'd be worthwhile! :D It'd take the cost of repair just in gas to get up that far, and while I'm up there, I'd have to pay a little visit to my buddy in Lowell.

[Antelope]

I think I had that same at least similar noise coming from my engine (you described really well I could never quite put into words (quiet diesel)). Notice I said had, it's now in the shop and I'm deciding if I want to dump about $3,600 plus options into it.... I don't know if the noise was related to my engine cooking or not but it probably was (it was a very late nite). I say drive it till it won't drive anymore!

[gbarrett]

I'm dealing with a light "ticking" also. Mine is a bad cam / lifter combo. I've replaced the lifters, but the cam seems to be wearing the lifters down to the point that the push rods tap against the rocker arms. I'm probably going to swap out the cam as the engine looks like it has been rebuilt or at least re-ringed. I only hope the cam bearings were changed at that time - I'd hate to spend the money on a decent cam only to have it wear out early because of old bearings.

By the way - any reasonable cam suggestions? My GW is a daily driver, not a lot of off-road stuff.

Thanks,

Greg

[64Trvlr]

Snake
You still haven't changed the thermostat?
:cool:

[jeepbob]

I would suspect a bad cam and lifters, I have not found an AMC motor with more than 70000 miles that had good cam in it. They will wear to the point that they are almost round. Even my 65000 mile 304 had lobes that were no longer in spec and some of the lifters were dished. It was still a good, smooth running motor that all the bearings (cam,rods, & mains)were still in spec with good oil pressure but the cam was junk.

[Snakeyes_Tx]

That would be a huge relief actually.. here's my issue then.

Would it make that funky dieseling noise at idle? The noise seems more prominent at the bottom half of the motor, not up top.

I'd like to go ahead and change the cam, lifters, pushrods, and at-least the intake for now. I could afford that most likely. Guess I should do the timing chain too while I'm in there, but I'm gonna be stuck with that 2150 I just rebuilt for a while.

[ November 15, 2001: Message edited by: Snakeyes_Tx ]

[Crazy_Jeepman]

This is just a real wild idea but maybe your heat riser valve on the passenger side exaughst manifold is stuck shut. These can make a noise, as it restricts the exaughst on that side and could be only noticed at an idle. Worth checking I would think. ;)