Testing piston rings with water

If you have a 75% leak on a valve seat or even a valve seal it’s gonna be very evident, like a burned valve or cracked valve seal. If it the head gasket it will also pretty evident as to where the leak is across the cylinder head. 75% is a lot. Good luck and keep us posted as to your findings.

 

The valve seals (bottom, at the combustion chamber) don't look too bad (no obvious crack or gap around the seal) but there is quite a bit of carbon buildup. But if the seal is leaking (like I am pretty much 100% sure it does), it is hard to tell by looking.

 

Is that just a shadow on the valve?

 

Also if I had taken the time to pull the cylinder head imo I definitely wouldn’t put back on looking like that but then that means doing both sides.

 

Put the cylinder at TDC and fill it with 30-40 psi air pressure. Listen to the exhaust, the intake and pull the oil cap and listen to the crank case. You should also pull the plugs for the adjacent cylinders and listen there too. There's way better ways than using water.

 

I think so, I will tell you exactly at 4 EST because until then I have water draining through the middle intake valves (24 hrs, to see how much it leaked over that time, then will do the same on others)

I am almost positive it is because if not, I wouldn't only be leaking 25% on that cylinder

 

Looking like what, carbonized? Of course I will clean it.

You think it's bad to clean only one side?

 

water????

 

Most of the engine is aluminum

 

If it were mine, I’d pull the other head and send them to a reputable shop for port polish 3 angle valve job. Have them check the springs, replacing if needed, replace the valve seals. Then go in with new head gaskets and arp bolts or studs.

Of course torque in 3 steps, for example IF the spec is 75 ft lb, go finger tight, 25, 50, 75. You might be able to find a torque sequence. Meaning do this one first, that one second and so forth.

There was a guy not far from me, Dan Paramore, he had a shop DPR. He did a outstanding work. Last I heard he moved into a new shop that got broken into. He might have shut down after.

My hats off to you for tackling a big job like this. I have the ability but not the ambition.

 

But, the cylinder sleeves aren't.

 

Imo. I wouldn’t do just one side. Definitely gonna be carbon buildup on the backs of the valves. To clean properly you need to pull the valves but at that point it would be dumb not to both sides and clean the valves and seats, new seals etc. even a complete valve job at a machine shop. I mean if both your shoes had holes you would by a new pair and only wear one new one. With one head off you might as well pull the other and get it done properly. But hey that’s me.

 

Too much work. I only took this head out because I had a cylinder leak on that side. The other side doesn't have a leak.

I appreciate your suggestion but it's easy for you to say because you don't do the work... hey, why don't you replace the whole roof on your house? LOL

 

The other shoe doesn't have holes.

 

Doing the rings and valves now, while the engine is already apart half way, is the smart thing to do. Drop the diff and then the oil pan. Trying to locate one leak point now is just asking for doing this again when you put it back together. Also, when you did the leak down test you should have identified the leak path then. It's quite obvious on a leak that large by just listening for the air sound through the exhaust manifold, intake manifold or crankcase (via oil filler).

 

It should be in the original post that I felt air flow coming through the manifold, which means leaking through the intake valves but I want to test other possibilities.

As far as coming through the crankcase, I wish that option had existed but much of the engine was off, including the timing cover so through a hole that large i couldn't really sense anything.

 

How hard is it to drop the differential? I have never done it before. I've done what I'm doing now (cylinder heads + valve overhaul) once before, 6 years ago

 

If you don't know how much leakage is OK and how much is not, what will water leaking by the rings and valves show you? Lapping valves with significant mileage on them doesn't sound like something that would work. Lapping is more of a new valve/seat break in thing and it's not usually needed for modern stuff. If you can get most of the water out, it probably won't hurt anything. Any small amount left in the engine will have thoroughly oil coated parts to isolate it from steel/iron and turn to steam after the first start once its up to temp and probably go through the PCV valve pretty quick. It still seems like doing everything while it's this far apart is the smart thing to do. How many miles on the engine?

 

160K

 

I've never done it on a Toyota, but I would think pulling the CV axles and then the fwd driveshaft, plus any electrical/vent lines, would be the only requirements before unbolting it from the chassis. I have a 3rd gen FSM that I can get the procedure from if you want. Should be very similar to the 2nd Gen stuff. Can you get the oil pan off without removing anything else besides front diff? It's been a while since I've had a 2nd Gen.

@ 160k, it almost seems negligent to not do full rings and heads job.