Just about to remove the rod end caps on my 3.0 and found I can wiggle every one of them by hand with only one of them showing less movment than the others. One of the caps is darker than the others usually indicating high tempratures right?
Crank seems to be rock steady. So, should I be able to move a rod cap by hand?

Original reason for pulling the block was knocking.

 

NO...

There's your knocking...

 

Holy crap! So if the rod caps move, what else should I think about replacing? Crank bearings? Cant move that thing at all.

 

Removed first rod end. Bearings are toast and crankshaft has grooves. I suppose a replacement crank kit then?

 

sounds like full rebuild time.

I would recommend tearing apart the block and measuring everything. Make sure nothing's warped or grooved, especially the bearing journals.

If all the rod caps are loose, there's little hope for the main journals being ok. That's a lot of excess movement that the block wasn't designed to handle.

I'd say at the very least you want to replace all the bearings, mains and rods. And while you're at it you might as well put in new piston rings and get the block honed. The guy I took my race engine to only charged $10/cylinder to hone so it won't be too expensive. I took it to him bare though.

 

wow... just wow. no way in hades should the rod caps be able to be moved by hand....

It's probable that with the loose rod bearings, the crank bearings were starving for oil and are toast. You may be able to get away with having the crank turned, but not likely considering the throw journals have grooves.
And while you've got it apart have the rods checked too- if the studs did stretch, they'll need replaced.

 

Since crank has to come out, just overhaul the engine. I STRONGLY recommend you take the block to your local machine shop and see if the engine can be salvaged by just honing the block and turning the crank. Caution here, the engine has left and right side pistons. Once a crank bearing gets destroyed, that piston will bang the aluminum head and possibly crack it. I've been down this road already. So, a shop can best advise your next course of action and costs. They can also do your heads and set the valve clearances, something you will play hell with trying to accomplish in your garage. And, only install Hastings iron rings if you just do the hone option.

My $0.02, been there, done that...

 

It would likely be cheaper to buy a used 3.0, and rebuild that, rather than machining the original.

Or buy a used 3.4



I once took apart a motor to find that one of the rod bearings had disintegrated, giving the piston enough movement to slap the head repeatedly. warped the head, and increased the volume of the swirl chamber

 

Well, front to back (along the crank length) was in spec, but side to side was at 0.030. Bearings where thin and grooved. Crank is grooved - I can feel it with my fingernail. Rod looks clean and smooth, as does the cap. I went and bought a complete crank kit with rods and mains for $223. I cannot find any evidence of material in the block. There was oil pressure as there is plenty of oil up around the camshafts.
I'm trying not to open this thing up as the heads are sealed great. I cant see any damage to the cylinder walls except for some very minor scuffing, but I can still see the original hone marks.
Turns out that just 2 of the bearings are out of spec. I did not expect to be able to move them along the length of the crank but apparently, according to several engine builders, this is normal and expected.

 

well, I misunderstood you. I thought you could like twist the rod caps without moving the rod like they were loose, not slide them back and forth along the journal. it is normal to have some axial play in the bearings.
If you replace the rods, you'll have to pull the head since the pistons have to go out and back in the top.
so it kinda sounds like only the crank needs work, and you need new bearings.

 

I spoke with a Toyota tech today who said I could slide the pistons back in from the bottom which is an awesome result!

 

well... what do you need us for?

 

Hah, well, tripple checked to see if you can install pistons from the underneath, and well, you can not. The heads do have to come off.
Which gasket manufacturer is recommended? I really didnt want to split this as it has no leaks or top end issues.

 

I would only use Toyota head gaskets on the 3.0.

You could just install the bearings/crank and not change the rods. Wouldn't have to mess with the top end.