Valve adjustment formula

I'm currently trying to figure out the equation for new valve shim thickness. Math is not my strongest point. Currently getting infuriated by the hour trying to figure this out. Anyone out there can explain this as simple as possible.

 

https://m.youtube.com/watch?v=MOlmjtlO7TI

Have you watch this video? He does a good job on explaining it. Also he has a Google doc in the description area that you can download and print out, it's very helpful

 

I'm going g by the video step by step. Math ain't my strong point. I'll keep trying

 

Ok, so starting from the 33.30min mark of the video they start talking about how to measure it.

I'll try my best to explain it. I think you are getting confused at the N=T+A

So their:
"removed" shim measured .1185
"Measured" valve lash is .010
"Target" valve lash is .013

Removed(.1185) + measured (.010) - target (.013)= .1155 <---this should be your new shim thickness

Remeber: removed + measured - target

 

If you haven't yet, I suggest going to the local junk yard the grabbing a hand full of shims first, in the video they stated that even after the calculations the new lashes where still off and they had to do some more adjusting.

I was prepared for the job but luckily when checking my lashes they where all still within spec and I didn't have to do it.

 

Toyota made it easy for all technicians. Not because of trouble with math, but just to prevent from making any mistakes in calculation.

Two files attached : one for 3RZ the other for 5VZ (you dis not say which engine you have). Each file has two charts - one chart for intake, the other for exhaust valve. No calculations needed. You just find a row with your measured valve clearance and a column with measured current shim thickness. The crossing cell shows the shim number you need in there. There is a reference table of Shim number -> Shim thickness on the same page.

 

I'm horrible with math but luckily the shortcut above exists.

Seriously, don't stress on these, it's just mechanic work and you measure at the end also.

Maybe I just grew up using feeler gauges but that shows familiarity makes you fluent. I was failing math as I learned to use them.

 

Using the chart I keep finding blank columns lol. For example. 2.7 prerunner
Cylinder 3 exaust=2.6+.009-0.30=2.529
Is this correct?

Ex:2.7+.010-0.30=2.705

 

Tried matching with the chart but my 0's and decimal points are alittle diffrent

 

It looks like you have mm and in mixed in there.

So: 2.6mm = .1024in and .30mm = .012in

.1024 + .009 - .012 = .0994

So your gonna need a 2.52mm (.0992in) or
2.54 (.1000in) shim to put you within spec

Maybe another member can help verify the numbers.

 

You need to decide first what units you use: imperial or metric (inch or mm). Depends what tools you have - makes a calculation (formula provided above) a little tougher if your feeler gauge is imperial and micrometer metric (and vice versa). However the good thing that the chart is in both so you still can use it.

First use feeler gauge to check the valve clearance. If your filler gauge is imperial use the number range in parentheses, if metric use the first number range.



If measured clearance of exhaust valve falls into blank row (clearance is between 0.250mm and 0.350mm, or 0.0098inch - 0.0138inch) there is no need to replace a shim - the clearance is within the spec.

In your example the clearance is 0.009 inch so it is to small. Measured shim thickness is 2.60mm (I assumed you measured it with better accuracy than 0.1mm - you need a micrometer, not a caliper to achieve the accuracy below 0.01mm). So here is the result on the chart:




You need a shim number 1



I know the first time the chart looks overwhelming, but once you start using it, it is simply and straight forward, so even technician at Toyota dealer can figure it out.

 

Just adjusted mine recently and I created a spreadsheet to calculate the new shim needed. I can share it with you if you want or will give you the answer if you provide measurements.

 

How much of pain is it? I've been wanting to do mine and the valve cover gasket while I'm in there.

 

If a person had an assortment of thin ones before starting it's much less stressful. Very rare to ever need thicker. You can usually rearrange a few to get in spec.

It would have been nice for the site to have a few travelling kits made of spares.

 

It's tedious for sure. Here are some lessons learned.

You will need to modify the tool to push down the bucket, otherwise it doesn't create enough clearance for the shim to come out for some of them. I wrapped mine with a piece of tin to create more clearance.
Unless you're strapped for cash, it isn't worth it try to swap shims around without buying at least a few more. Swapping it (without having an extra shim around) means you'll need to have an empty bucket at some point and you'll need to be careful so the bucket won't get chipped.
Junk yards and even engine rebuilt shops don't have extra ones laying around to sell you. They said selling those for a few bucks isn't worth it for them. If you want used, you'll have to find a car and remove them yourself. I didn't think it was worth it for me so I went new.
Calibrate or check the caliper you'll use to measure the shim in advance to see how much they're off.
Don't call machine shops to see if they can mill it down for you as they'll just laugh.
Check in advance, I recall there was no torque spec for the valve cover bolts in the repair manual or the ones available could be wrong (i.e. too much)
If you're replacing the spark plug cover gaskets, replace them one by one so you know the correct orientation.

I adjusted the valves for a honda fit about a couple weeks before the tacoma and the adjusting nut style on the fit was just so much easier. Both were my first time and I wouldn't mind going back, check and adjust the fit every couple of years. Hope that helps.

 

Cheep Chinese digital caliper are great as long as you can accept 0.025mm accuracy. The resolution on these calipers is 0.01mm but this is just a resolution, not accuracy. So in other words I would not recommend them for shim thickness measurement. Get a micrometer. Even cheap digital micrometer from Harbor Freight or Amazon has accuracy around 0.0025mm - that is plenty enough for shims. Again, do not mistake the resolution (which is 0.001mm) with accuracy that is usually bigger number (usually 0.002mm).

 

Thanks. I had to do this for a 2zz which seems to be more of a pain on the ass than the 5vz. It didn't use shims but rather caps at the valve stem end.

 

Thanks for the info guys

 

Wow this is a game changer to get the correct shims, thanks,
Question, your example is using MEASURED CLEARANCE =INCHES? and INSTALLED SHIM THICKNESS = MM?
Just want to make sure I’m reading it correctly.
I’m showing some big differences in my compression test and I know it’s time to get these adjusted. I’ve put it off for too many miles.
This is the 1st time I’ve seen this chart and have not see it posted in other valve adjustments posts, thanks again