3rz Top Dead Center and Timing marks

I have 1997 3rz Tacoma, Trying to check the valve clearances. I have the cams where the two dots on the exhaust cam is in line with one of the single dots on the intake cam; however there is a mark on the camshaft pulley/harmonic balancer on the outset lip; it is at 330 degrees rather than 0 degrees as I expected. What other indicators can I look for to ensure I am at top dead center before checking my valve clearances?

 

The notch on the harmonic balancer should line up with the TDC mark on the timing chain cover. It may not be pointing straight up. You may need to wipe away the dirt, oil, grease and crud to see the TDC and timing marks next to the harmonic balancer.

 

Wait. So you didn't remove the cams (yet)?

All you have to do to check clearance is make sure you're checking at the BASE of the cam lobe. You really don't have to worry about TDC and what the piston is doing. (I mean for speed's sake)

It can be TDC on compression OR exhaust stroke.

Now if you're trying to time up cams for install, you have to know.

 

You are 100% correct; the notch on the back side of the pulley is difficult to see because of the belt in the way... I was not paying attention to that notch; there is a notch on the front side which I took a photo of. I wonder what it is for?

now to measure valve clearances.

 

I only removed the valve cover so far. So you are saying that the cams can be at any position when checking valve clearances?

 

No, the lobe tip must be pointing away from the valve tip.


You are only going to get #1 to line up to marks, the rest will all be eye balled.
I'm just saying to eyeball #1 also.


edit: those 'marks' I believe are for installing the cams into the heads so as not to preload the valve springs as you torque it down. Just putting the balancer @ 0 gives you TDC. If the valves aren't closed, rotate 1 turn. Should be #1 TDC INTAKE.

 

With #1 at top dead center none of the lobe tips are pointing up...

 

The lobe just needs to be pointing up enough so that the circular part is above the valve. You can measure intake and exhaust on #1 and intake on #2 and exhaust on #3 in this position. Then turn the crank one full revolution and measure #4 IN/EX, #2 EX, and #3 IN.

And you can put 2 feeler gauges together to get more accuracy. Like a 0.20mm + 0.02mm = 0.22mm.

 

I put my thinking cap on and visualized how it all works to question your answers on which can be checked in this position. I 100% agree.
Where can I get a good set of feeler gauges; the set I have does not work well see picture

 

Got the first half done. I feel like the gauges work well enough...

 

That's why I don't worry about it. Just measure them as they roll into the right position. Base of the offset circle.

 

Well here are the final numbers; only the first intake valve is out of spec. As an FYI I am chasing down multiple cylinder misfires codes and a lean code.

I hate to delay progress because I will have to order the tool and a shim to get the one valve more clearance (thinner shim right?) I bought a smoke machine and had spotted some leaks below the throttle body using carb cleaner but pulled off of that trail when I showed poor compression in the #2 cylinder (see pics). I tested that first time with the engine warm. Then I retested it with the engine cold, with the fuel injection fuse out and with the throttle wide open and the compression numbers were fairly even

I’ve always suspected piston ring wear as a lot of pressure and oil comes out the oil cap when opened. Also notice my camshaft area is an oily mess.

I was sure I had a burnt valve as I had a cracked exhaust manifold for a quite a few miles; I did not know it ruins valve seats.

should I reshim the intake or get on with putting it back together and finding the intake air leak that I suspect?

FYI I’m just over 200k.

 

Yes, you need a thinner shim to open it up a tiny bit more. It's not real tight, it's an intake (not as hot, therefore not as critical) so I'm betting it's not causing a problem.

Double check all your numbers. You had 80 the first time? BUT.....the throttle HAS to be open so I'd trust those second test numbers more. Also, make sure to crank enough times it doesn't climb more with addl. spins.


Do a leak down (if) while waiting on a shim....you have to measure the shim in it and subtract what it'll take to get in spec. They are not a 'stock' size.

I've said this a dozen times on here. We need a travelling shim kit so people can do this in a weekend. Oh well. A Toyo. mech. will prob. swap 1 with you though.

Fix the leaks but I'm not sure if that's it. Is the MAF clean?

 

The MAF is clean and makes sense via the readings through my OBD2 interface.

 

Where would you recommend getting a tool to get the shim out? What is the procedure for a leak down test?

 

https://www.tacomaworld.com/threads/2-7-valve-adjustment.646356/#post-22424199

There are hundreds more. If you get a leakdown test kit from O'Really's it has instructions in the lid. It's a good kit.

This sounds like a spark issue though. Not familiar with '97 wires. Do they have boots from coil to plugs?

 

The oil is normal. If your PCV is working there should be no pressure. Your #'s aren't perfect but not worn out. 120 or 100 would be worrisome.

 

Checked the pvc and I can suck through it. I’ve had plugs go bad before and it only took one and you knew; would barely run.

 

What about plug boots? Those are really just short wires. They leak spark when old.