Should I replace the head on my 3rz?

keakar you the man! Thanks for all the info. I'm pretty broke, so I'm going to just replace the valves on cylinder #2. I'm gonna go ahead and see if I can borrow a friends leak down tester, so I can see what's up with cylinder #3, which was slightly low. When you say I need to lap every valve you mean all 16?

 

yep, you don't do a half assed job with these things, you do them as a set so if you lap valves you lap all 16.

also after lapping the valve clearances will change so you will need to check every tappet disk thickness and buy new ones to get the correct valve clearances. not a big deal but takes time to order them so its not a 1 day thing and plan to spend at least a week fooling with the head

 

Sounds good. I was going to adjust all the valves anyways. Should I just go ahead and order all new valves? Or just re-use the ones on the good cylinders?

 

first find out if you even need any new valves, just because they aren't sealing doesn't mean you need new valves and sometimes they don't seal from deposit buildup so take them out, clean and inspect then if there is no obvious damage to the matting surface just relap them. its rare to need to replace a valve unless its bent or the shaft shows noticeable wear in which case the valve guide needs replacing as well.

remove the cam and tappets with the spring caps and put everything in a separate clearly marked ziplock bag so later everything goes back in the exact same spot.

then take out the bad valves one at a time (bag those parts seperately) and inspect for signs of wear on the valve shaft and any pitting or imperfections on the matting surface. if you see pitting or imperfections on matting surface buy a new valve, if you see wear on the valve shaft then you need to pay a shop to replace all the valve guides so you may as well put the head back together and just let them do it all since there isn't much price difference at that point.

 

now the disclaimer about my advice:
im sure mechanics are cringing at this advice telling a novice to go for it without knowing what he is doing because there is so much more you "should" know to do this job such as knowing if something is good or bad or what sort of wear is "ok" to reuse and when to toss it out just by looking at it, but for a guy on a budget just trying to get it running again, a less them professional do it yourself head rebuild should be fine to get back to where you were before you had issues.

post pictures on anything you aren't sure about and we can help you make those decisions

just remember, you wont know if you can do it all yourself or if something is worn to the point you will need a shop to recondition the heads until you get into it.

also once you see what you have to work with you still may need to get a salvage yard head and relap that one to use if yours has more wear then expected and needs everything.

so short answer, yes you might get a cheap fix out of it but only after you get into it will you know and no matter what, its great experience doing this yourself to learn.

this should help you:
https://www.youtube.com/watch?v=c_-n20Op1j0

 

Couldn't find any 3RZ locally, so quick question guys-if I R/R the head (and maybe pay a shop to rebuild it if needed) do I need a full gasket kit or can I get away with just buying a headgasket and head bolts?

 

yes you could get by without the kit, but think about it, what gaskets will you not be using from the whole gasket set kit? by the time you buy every gasket and seal separately you will be spending more then if you just bought the kit.

exhaust and intake gaskets, valve cover gaskets and seals, thermostat and water pump, throttle body and EGR, so the only thing your getting in a full gasket set that you aren't using is oil pan gasket and crank seals

 

every single gasket that is included in a head set is used when replacing/rebuilding the head. you may not need the collector gasket, but every other gasket should be replaced as well. i recommend you get the headset and not forget to take the valve stem seals out to give to the machinists so they can properly rebuild the head.

 

How often do the valves need to be adjusted on these engines? I have over 220k on mine. Never been done before. You can do it by just removing the valve cover right?

 

OK I am in the process of doing this same thing but on my #4 piston. My compression was only 30 psi. 170 on 1,2and 3. Before you start tearing up the head and blaming a bad exhaust valve check to see if its a bad head gasket.

Clue #1. Have you over heated the engine. Have you had to add radiator fluid.

Put #3 piston at tdc in the compression stroke Take the compression tester and remove the valve core that is at the bottom of the hose. This will allow you to blow air in both directions. Then install the hose to #3 piston. Hook up a compreson to the other end of the hose and send some air into #3 piston. Open your radiator cap and watch for bubbles. If you get bubbles. It's a head gasket not a burnt valve.

 

Is the rest of your truck in good shape? If the body, transmission etc are all in good shape i would look at saving up for a rebuilt motor or dropping in a low mileage motor.

 

It's highly unlikely that it's the head gasket. Truck has never overheated or ran hot. I've never had to add coolant. Coolant is always super clean and so is the oil. The only issue I had with the cooling system is a small crack on the plastic end cap of the radiator, which I found and replaced quickly. If for some freak reason it was the head gasket, I'm pulling the head anyways and will be able to visually inspect the gasket.

I added oil to the piston with low compression and it didn't increase my pressure values. This combined with my CEL code have led me to believe that it's a burnt exhaust valve. The rest of the truck is in great condition, but I don't want to dump a ton of money into it since it won't be worth it financially.

And there are a few threads on how to adjust valve clearances on these engines. It sounds like a royal pain in the ass, but I'm pretty sure that's the culprit for my 220k motor. If I could find a sub 150k motor locally for under $500 I'd jump on it, but I've been keeping an eye out for a few months and haven't seen anything.

 

Try to presurise the piston if you can before you pull the head. I had a 0304 code and oil and radiator was clean. I found a tread here where a guy had a small water leak into the piston and would not fire off. If you do the pressurisation test you can rule that out. I never thought overheat my engine either. It only takes a little water to stop ignition.

 

@DukesTaco has a good idea!!! if you remove the spark plug to the bad cylinder and pressurize it, you'll notice air either pushing coolant into the reservoir(bad head gasket), the exhaust (burnt exhaust valve), or the throttle body (bad intake valve). it's also possible to get air coming out of the engine's oil cap signifying either a bad head gasket, or bad rings. try this first!

you just gotta figure out at what degree of the stroke the bad cylinder is supposed to be completely sealed and test at that point.

 

Here is my head gasket blown out between 3 and 4. The #4 piston is nice and clean because it has been firing of with a little water. The valves on #4 look brand new as well from the water in the mix.
Do the pressurisation check on your #3 piston. It might not be a burnt valve after all. The machine shop quoted me $375 to shim and lap the valves and resurface the heads.

 

a semi-related story. i was doing a minimal R&R on a toyota camry 4cyl head. so i washed it, removed the cams, pressure tested it, then did a vacuum test on the valves. 5/8 ports failed. usually means needing to lap/grind/cut the seats and valves. customer didn't want to pay that much. so instead, after inspecting and finding the seats and valves were just really dirty from carbon build up, i removed each valve and just wire wheeled them with a die grinder til all the carbon buildup came off. all 8 ports passed after with 40hg vacuum.

 

You need to bring the piston that you are testing to TDC. Then back it up just a little right before detonatio. The intake and exhaust valve should be closed and have no blow-by. If its a head gasket it will get bubbles in the radiator.

 

I don't understand the people in here saying replace the whole engine for a bad valve. A 3rz head comes off fantastically easy and a valve job isn't going to run more than $200. I paid $425 for a whole head R&R including welding up some cracks in addition to new valves. I didn't want to roll the dice on a $600 drop in Chinese head of unknown quality.

This way you know what you are getting and aren't rolling the dice on a used engine and a shop to put it in if you aren't comfortable. People leave out the cost of driving/shipping an engine too. Then there is a cost of your time. Time to locate a suitable engine, drive time plus time in the shop if it takes them a while to get the motor in. The mileage on the bottom end shouldn't be an issue if the oil has been changed. At 320k I still had crosshatch marks from the original hone.

 

My experience as well. I did that once, will never do it again. You'll end up chasing money spent with more money.

It's either a complete rebuild or replace the motor with another good one.

 

I don't get that at all.


Say you blow a HG at 120k or have a tagged valve because they were never adjusted. No sense in touching the bottom end if all it needs is head work. Unless you like watching money burn for fun

Even at 200-300k, how many people have you ever heard from that spin a bearing or have rings go to hell? It just doesn't happen on 2/3rz or a 5vz. The bottom ends are stout.