Before I get too far, I just wanted to say that I would post a video, but my phone can’t pick it up with my exhaust. You can hear it clearly in person, but not with a phone (go figure right?)

Anyway, this sound isn’t a clanging or banging like a spun bearing, or a ticking like bad lifters, but it’s more of a rattle like somethings loose inside of the engine. It doesn’t start until the engine gets up to temp, and you can hear it clearly when you pull up next to someone when you’re at a stop light.

I put my little stethoscope around to try and find out where it is, and without snapping the belt or getting my hand caught in the fan, I figured out it was potentially coming from the front end. Which is where the most important component is, the timing chain. My guess is that’s probably stretched out too much and it’s hitting the timing cover.

Is there anything else that can make this rattle sound, like something else that’s loose? And how much would it hurt to do a timing chain at 290k on my little tractor motor?

 

Common engine rattles include lifter noise, bad engine mounts, and flex plate/torque converter bolts. Obviously, look for other loose bolts, but those are the most common ones I know of. Also, I've seen accessory pulleys cause a rattle, so maybe take the belt off and spin them.

Almost forgot about the crank pulley. If the rubber is starting to separate, that can cause it too.

 

Ill check those sometime tomorrow when I flush the whole cooling system. Found lots of rust in my coolant so that’s fun.

Anyway, not ruling out bad/stuck lifters, but the sound is too un-rhythmic to be valve train related. I just did my VCG, and the inside of my engine is pristine, no junk or anything. Now i’m not saying that my lifters are fine, they may be worn out, but i’ve seen clogged lifters that are filled with sludge cause noise in other OHV engines, and since I had no sludge anywhere (including the bottom end when I did my OPG), and I even checked to make sure the rocker arms weren’t loose. I’ve been debating about changing the lifters because it’s so easy on the 4 cylinder (and since they’re so cheap), but i’m worried about how it could be the timing chain. I know there’s a way to check to see if there’s slack in the chain, but I forgot about how to do it because it’s been so long since I last did it.

Actually, now that I think about it, I remember when my belt snapped because of all the leaking oil, I checked every pulley for play because that’s what I thought happened, but turns out it was just oil soaked.

I’ll try to take a better video without my exhaust drowning everything out, but as of now, i’m leaning towards the timing chain being loose.

 

I’ve figured it out finally.

It’s the lifters.

If I put a stethoscope on the passengers side of the block where the lifter valley is, I can hear the exact same noise coming from the lifters that I can hear outside of my Jeep. My best assumption is that they’ve worn down on the sides of the lifters and sort of “clatter” around in there. The noise hasn’t got any worse since I made this thread, but I’ll get them replaced regardless. And maybe throw in some Harland Sharp Roller Rockers as well. Maybe give my 4 angry squirrels a reason to be slightly more angry

 

Try some seafoam. Project Farm on YouTube did a video on seafoam in an old ranger. Made a heck of a difference.

 

I’ve been meaning to do that, but I keep forgetting to put some in to replace a bit of the oil. I did do it with MMO, and it seemed to make a difference until I drained it out with the oil

 

 

marvels works well..add 1 qt with next oil change...dumb question but you do know that the head has to come off to replace lifters.....lots of money if your not doing it yourself...see you got the 4...might not be so bad..probably 75 lbs lighter and half the bolts

 

The 4 cylinder in my old TJ needed gas one time and I decided it wasn't worth the money, so I swapped it with a 4.0.

 

first off, it was NEVER a tractor motor!!

Secondly, lifters can be removed from a 4 cylinder with the head in place.

 

Thats a nice option..

 

And, the 4 cylinder was prone to piston slap.......

 

Yup. I don’t mind taking the head off, but it makes it easier when you can just snag them out of the valley.

I’m going to do the pushrods, lifters, and a set of a Harland Sharp roller rockers, 1.7:1 ratio. Figured since i’m doing it, might as well give me a reason to upgrade something

 

Hope the cam isn't worn.

 

Before I do anything with the new parts, I'll take a boroscope and stick it down there to look at the cam lobes and look for any scoring or dents or anything but a smooth finish, within reason. If anything is found, ill put this project back on the back burner until I can get a new chain, gasket, cam, and balancer. And maybe a radiator since I have to take that out