Heard some rod knock at 2500-3000rpm and pulled over 1/4 mile later and towed home.

Dropped oil pan and all of the rod bearing caps equally have a little wiggle front to back but no wiggle side to side or up and down, none are sitting totally loose, if that makes sense.

How do I go about checking them? Can I remove them all at once to check the rod bearings or do I need to do 1 at a time? Do I order a set of rod bearings or do I need to measure the clearance for each one and order a specific rod bearing for each one?

Any advice greatly appreciated!

 

Which engine, how many miles, how long have you owned it or been driving it? All the caps loose would be actually unbelievable. Just put a wrench on each nut or screw (I don't know whether the fasteners are nuts and bolts or capscrews) and put a little unfasten torque on it. Is it/they loose too? Maybe your "wiggle" is describing the bearing clearance. You can't move 'em up and down cuz they are connected to the piston through the gudgeon pin which runs with almost no clearance, and the cylinder rings friction is going to resist your up and down pressures.

How do you know that the sound you have described as a rod bearing knock is coming from a rod? There are a number of potential "knock" sound sources in the engine area.

 

I wonder of Jakez is talking about connecting rod thrust clearance? http://web.archive.org/web/201004010...ine/9cylin.pdf The spec is 0.16 – 0.26 mm, with a maximum of 0.30 mm. I'm not sure I would experience something as small as 0.26mm as even "a little wiggle."

 

Whoops sorry, its a 1993 4x4 pickup 22RE. Something over 300k miles.

Its not valve noise, I know what that sounds like. Its a rattle/knock sound that happens under load or revving in neutral between 2500-3000rpm.

When I took the oil pan off to see if the rod caps (maybe its the bearing caps not rod caps? I thought they were the same thing, I will verify) were loose I can wiggle/slide them back and forth (toward the front and back of the truck). Basically wiggling sideways on the rod bearings. Are the caps supposed to be able to move at all?

 

These are the caps I'm talking about. Wiggle just a hair in the direction of the arrows

 

afaik, very slight movement fore & aft (axial?) is normal (along the journal), but radial movement would be bad.

 

This would be more helpful before you pulled the pan, but when running you could pull each plug wire to see which cyl the knock was coming from and then look at that bearing. The fore-aft movement of the rods, if within spec, is not a problem. Now that you’ve pulled the pan, i think you are going to have to inspect each bearing and look for a worn or damaged one. If the crank looks OK and the bearings are not say, .5mm over, i would put a new set of standard sized bearings in and go. If they are oversized, it means the engine has been rebuilt and then i would put that size in. Use plastigage(green) to check the clearance. And oil or assembly lube when you install the new bearings. I would inspect/install one at a time. Doing this on your back under the truck sucks!

 

Your photo is of rod bearing caps ("connecting rod"). You also have crank bearing caps.

I know you were just using an expression, but a human hair is usually 0.017 mm to 0.180mm https://en.wikipedia.org/wiki/Hair%27s_breadth. So wiggling a bigger "hair" is right in the middle of the spec.

 

Ok got a video uploaded, and apparently there IS some up and down play in the first connecting rod up front at least

 

Yeah... that's a problem.
but, the good news is you caught it before it grenaded the whole motor.

 

Well, I think I finally understand the term "spun a rod bearing"?

Any suggestions on how to proceed from here?

 

It's not clear from the images that the bearing has spun.

Let's see the bearing shells. What do their retaining ears look like; how's about their inner surfaces and the condition of the crank journal????

 

What's the condition of the rod journal on the crankshaft?

 

Sorry here is a more clear picture, looks like the bearings have spun a couple centimeters and the oil hole does not line up so I am unsure on the proper way to get these out without harming anything

 

Push the rod and piston up a few inches. Pull the bearings off the crank. It’s just held on there by the oil film.

wipe the oil off the crank with something lint-free. Take more pictures of the bearing surface and crank journal.

 

Melrose is in the right track bro...
you might get by with just new bearings.

 

Not much to lose at this point, anyway...

 

Before you go further, cover the rod bolts with pieces of soft tubing so you don't score the crankshaft journals

 

This bastard bearing will not budge! Tried wd40 and compressed air and pushing and pulling and pushing while pulling. Is it safe to torch this sucker a bit?

 

Crank is toast. might be salvagable with undersize re-grind.

A rebuilt 22re is in your future.