2.7L 3RZ engine health troubleshooting and diagnostics ADVICE NEEDED

Ok, 3614 is the stock size and 3600 is a larger canister. You can check the specs online to be certain. Walmart carries the fram ultra synthetic, which is actually a really nice filter.

 

Yeah they’re bad. It’s on my list.

 

Valve Clearances:
Cyl 1, 2, and 3 exhaust valves are far too tight by as much as .005 inches out of spec. Cyl 4 intake valves are also tight. Cyl 4 exhaust is OK and Cyl 1, 2, and 3 intake are OK, but some are at the minimum spec. I was only able to remove a few shims to check their thickness. It was simply impossible for whatever reason to remove any other shims, so I am going to remove the camshafts to finish the shim measurements, unless someone tries to stop me.

My plan:
Replace shims as needed and see if it improves cylinder compression in Cylinders 1, 2, and 3. Considering replacement for intake shims that are at minimum spec while I'm at it to be proactive.

Help needed:
Will this effort be in vain ad a waste of time? At this point, should I just go ahead and remove the cylinder head to inspect and lap or replace the valves? Or is that getting too ahead of myself? I can't physically see the valves to see if they're bad or not. If I do need to remove the head, I'm assuming I should replace the head gasket to be safe. Do I need to have a machine shop resurface the head too? If so, when looking for a machine shop, what am I looking for and what kinds of questions should I ask to ensure I'm getting what I need?

Bonus footage:
I cleaned the valve cover, it was covered in black grime. It looks good now. I also fixed the stripped valve cover bolt. I drilled and tapped the original threads and replaced all bolts with flanged M6x1.0 bolts from Advance Auto parts. (I haven't installed them yet). If there's a problem with it later, I have a helicoil for backup. I have a new valve cover gasket, grommets, and spark plug tube grommets to install when done.

 

Did your fix require lapping, replacing, or just reshimming the valve?

 

Replaced.

 

Nice work. I would pursue your place as described, unless you have good reason to remove the head. Removing the head could open a new can of worms, while getting the valve clearances in spec could solve your issue.

If I’m wrong, getting back to where you are now, with the valve cover removed, isn’t too terribly difficult. Worst case is that clearances change for whatever reason after getting work done on the head and you’re out a few shims, which you can likely sell or donate on here.

 

I will probably do that, since its all I can do at the moment anyway and would give me some disassembly/reassembly experience. The things that make me suspect needing to remove the head are the low compressions in 3 cylinders and suspected leakage between two. And other's experience showed burnt valves are a possibility which would require removing the head to identify. I'll start with the cam removal and shim measure / replacement and go from there. At least after that I can crank it up again and see if I can get my OBDII reader to communicate and tell me which one is misfiring (so far it wouldn't communicate but I didn't try it with engine running).

At the worst, I'm not looking to rebuild the entire valve train, unless I find the head is cracked. Just want to fix any valves that may need it.

 

Shim measurements:
I finally got them all measured, took the cams out to make it easy. Good thing I did too cuz I found a shard of metal stuck on the side of one of the valve buckets. Byproduct of my drilling. I ran a magnet all through there and inspected every bucket. All buckets have a but of wear as pictured, but it doesn’t look bad to me. Then again what do I know?

I need 9 new shims to bring them all back into spec. None of the old can be recycled, due to thicc-ness. I have the part numbers listed at the bottom of the sheet.

Now where to get them the fastest? My local Toyota parts counter is closed for the day. They’ll probably have to order them too. Toyota parts deal has decent prices, but it took them two weeks to get some other parts for me before they could ship them, very slow. Any tips? (Yes I remember when everything took 6-8 weeks, but this is the 21st century now).

I gave the bearing caps and other hardware a good wipe down from the grime. Timing sprocket bolt was tight, regular bar wouldn’t budge it. Had to use the long bar. Tensioner bolts looked rusty, but they weren’t stuck, came off easy. Brass punch got the half moon out.

 

any updates?

 

Yep, the shims arrived at the dealership yesterday. Took off work early to go pick em up and get em installed. But other things hindered me from finishing the job, like my dog’s vet appointment, etc. I should have it finished later this afternoon with pics of the progress.

 

New shims are installed. And all the valve clearances are back in spec. I scraped the edge of the head, replaced the valve cover gasket and tube grommets, and put it all back together with new valve cover bolts…well actually they’re just advance auto parts bolts of the same size as oem. I kinda like the silver and gold contrast though.

While scraping, I dropped a razor blade down into the timing chain area. I was worried for a minute, but then I realized I have good oil in there which should flush out the bits when the chain grinds them up……I’m just kidding I fished it out with a magnet.

Tomorrow, I’ll do another compression test and drive it around to see if the misfire still occurs.

I also picked up a scanguage to see if it can read my codes. My cheap Ancel code reader wont communicate with it. We’ll see if it works tomorrow.

 

The valve clearance adjustment definitely increased cylinder 1 compression. Dry tests put it on par with cyl 2 and 3. I’ll post full results here soon

 

Post valve adjustment compression test results:

Cylinder 1 saw significant improvement. The exhaust valves were .003-.005 inches out of spec and I adjusted them to be on the loose side of the acceptable range at .012 inches. This resulted in a dry compression increase of 36 psi. Cylinder 1 compression was about 142 psi dry, 151 psi wet, a difference of approximately 9 psi.

Cylinders 2 and 3 saw some improvement in compression with dry pressures at 134 and 136 psi respectively with only a 2-5 psi increase for the wet tests. Cylinder 2 improvement equated to a 10 psi increase from the pre-valve adjustment test. Cylinder 3 compression increased by only about 4-5 psi.

Cylinder 4 saw little change with both dry and wet tests at 155 psi. This equates to a variable difference of about 2-5 psi from the pre-valve adjustment tests.

For comparison, here are both the pre-valve adjustment and post valve adjustment compression gauge readings

Initial compression test:



Post-valve adjustment compression test:



Leak-down etc:
The good news is that all valve clearances and cylinder compressions are within factory spec. The wierd news is the cylinders are still a bit varied from one another. Cylinder 1 is closer to Cyl 4 and honestly doesn't look that bad to me. Cylinders 2 and 3 are now the lowest, but still within spec. I did another leak-down test and was left just a bit more confussed than I was the first time. They all seem to be leaking a bit from everywhere, but I don't know the volume of leakage, bc I'm a cheapskate who buys crappy chinese gauges from Amazon. I will probably need a valve job and piston ring job at some point in the future, which isn't surprising based on the age and mileage of this vehicle, especially since it's maintenance history is sketchy. I am going to plan for that, but if this solves the intermittent misfire for the time being, I'm going to focus now on the rusted frame repair and worry about engine overhauls afterward. After watching lots of YouTube, I will probably start by removing the head myself, doing my own valve inspection and lapping job, and see if the various factors are within spec or not. If not, have a machine shop reseat and replace the valves.

Finally:
I bought a scanguage and it did communicate with my ECU. However, it only had a P0135 code stored in there for the upstream O2 sensor. No codes were stored for a misfiring cylinder. Hopefully the misfire doesn't come back. Now, what to do about the P0135?

Shower thoughts:
The valves clearances tend to wear tight resulting in the need of a thinner shim. Instead of spending $10=$15 per shim, if you're a machinist, just mill the old shim as thin as you need it. Of course if you're a machinist you probably already thought of that. If your'e not, but you have a buddy who is, ask them to mill it down. I don't know if that would be cost effective. I just spent $98 on 9 shims. Worth the investment I guess.

 

Here’s the old upstream O2 sensor

 

Wasn’t that shim job enjoyable? I did mine via that goofy tool and keeper, (spent more time looking for it as it shot across the engine bay) and by pulling the cams. For all you newbies, removing the cams is the best way by far to do this. But don’t be drinking w/ your buddies or babysitting the kids at the same time. Pay attention.

 

Oh yeah, removing the cams was well worth it, especially when I had to remove the shims multiple times to double and triple check my measurements when I realized I measure wrong, measured again, realized I measured wrong again, measured again again, the realized I measured right the first time, funfun fun.

 

God I hope I don't have this problem

 

I'll have to have mine milled down sincy my specs came out so bad Toyota doesn't even make a shim small enough to fix my clearances lol. Deff need to redo the head, but this should buy me some time. Truck ironically runs fucking great, no codes, misfires, etc - I happened to pull the valve cover for a leaky gasket and decided to check clearances. Lucky I guess?IDK