MudHippy

I almost can't believe someone smart enough to be able to adjust the valves correctly on a 3VZ-E could possibly be stupid enough to do it the wrong way. Causing more harm than good. Yet...I must believe it. Since I'm sitting here looking at the results of it having been done incorrectly.

Where to begin? The list of DO's I suppose.

1. DO grind down valve adjustment shims for more clearance. There's no reason to buy thinner shims. Any semi-competent machinist can make them thinner. Hell anybody with at least half a brain and a bench grinder can do it. No particular skill required(I taught myself how to do it, so can you). And nearly all adjustment will require thinner shims. So it's really the best, smartest, and/or cheapest, way to do the job...in most cases.

2. DO use a grinding wheel with a LESS THAN coarse grit. Medium to fine grit is best. Side wheel grinding is the only real option. A grinding wheel rated for side grinding is recommended. But not required. Go slower, using less pressure. And you should have no problems using a standard grinding wheel. Works just fine for me anyway.

3. DO grind the bottom of the shim ONLY!!! You are going to slightly "rough up" the side of the shim being ground. That's fine. So long as it's not extremely rough. And since that side of the shim is going towards the lifter/bucket while in use. The lifter/bucket has a huge flat area for the shim to "glide" on. Any wear potentially caused by the now less than perfectly smooth surface coming into contact with the lifter/bucket, if/when the shim is being spun within the lifter/bucket by the camshaft lobe, will be minimal to non-existent. In practice it's actually totally negligible/makes no difference whatsoever, if done within reason(so far as I've seen). They DO need to be as flat as possible on the bottom. But they DON'T need to be super smooth on the bottom. I know this from experience. Because it's worked perfectly for me(so far). In fact, a certain degree of roughness to the surface may even be beneficial(vs. a super smooth surface). By allowing more oil to be held under the shim for better lubrication. Thus reducing the possibility for wear. But that's hypothetical. And I've got no time to do the experiment to prove it.

4. DO use a lifter/bucket to hold the shim being ground. Or there's also a specialty tool to hold them in while grinding now(wasn't available years ago when I mastered my technique of using a lifter/bucket). It makes the job a thousand times easier.

5. DO rotate the shim/lifter/tool constantly while grinding. This will help keep the shim thickness even as it's gradually reduced.

6. DO stop and check shim thickness OFTEN while grinding. Checking around the edges and near the center. Trying to keep them as evenly thick as they were in those areas when you started. That way you'll be sure to not make them too thin, and/or be able to keep them from becoming unevenly thick edge to edge.

7. DO measure for the end resulting thickness from the center of the shim ONLY. That's where it's bound to be thickest initially. And is where the measurable valve clearance really matters. The shims will tend to wear slightly thinner near their edges. That's the correct wear pattern. And it DOES NOT need to be addressed or corrected. A slight dome on the top side of the shim, where the camshaft lobe makes contact, IS GOOD! Consider it the proper shape of a well broke in shim. Again...YOU DO NOT WANT TO MESS WITH THAT SIDE...LEAVE IT BE!!! You can grind them evenly thick while still being slightly thicker near the center. Slightly thinner near the edge DOES NOT MATTER! So long as it's even(same thickness all around the entire edge). It's not as hard to do as it sounds. Use your noggin. You'll be fine.

8. DO deburr the entire bottom edge of the shim after grinding/pre-installation. I prefer to use 180 grit sandpaper for this. As I feel anything more aggressive is unnecessary. At this stage in the process you could also use that same(or finer grit) sandpaper to lightly buff(or technically plateau) the freshly ground surface, if you're worried it might be too rough. But that's up to you. The shims are made of extremely hard material. So you're not likely going to remove any appreciable amount with 180 grit, or finer, sandpaper and light pressure. You should be able to create a slight bit more smoothness on the surface though(more or less...depending on the grit of the grinding wheel that was used). Just don't go too crazy with it is all I'm saying.

9. DO thoroughly clean, dry, then oil the shim(s) before installation. Sort of goes without saying. But I'm saying it anyways.

Now the short list of DON'Ts.

1. DON'T use a belt sander. It's the wrong tool for the job. Too coarse, too fast, too hard to control the amount of material removed. I can only imagine how sloppy that would turn out. Because I'm not dumb enough to even try it.

2. DON'T grind both sides, OR just the top side, of the shim(see also DO's #3 & #7). Like if you get the "smart" idea to flatten them out, removing the slight dome from their tops. THERE'S ABSOLUTELY NO REASON TO DO THAT. It has taken a certain amount of wear to the camshaft lobes to achieve that shape. IT'S A GOOD THING!!! IT'S FINE!!! If you try and "fix" it, you will be "fixing" NOTHING!!! You instead will be setting the camshaft lobes up to be excessively worn. As they will have to reshape/rework the now rougher than ideal tops of the shims back to their correct super smooth surface and slightly domed shape(when/where wear to both parts becomes minimized). Which will effectively reduce the amount of lift the camshafts can apply, since their lobes will have been worn even shorter in the process. SO STUPID!!!

3. DON'T PUT THE FRESHLY GROUND SIDE OF THE SHIM TOWARDS THE CAMSHAFT!!! Reread everything above if you don't understand why. Basically, DON'T ruin the camshafts by being a brainless idiot. They aren't cheap. Switch your brain on and do it right. You're smart enough to use the measuring tool(s) required(no small feat if using the proper tool...a vernier micrometer). So you're smart enough to do this job correctly. RIGHT!?


BTW, I believe I was the first person I'd heard of to do this "trick" many years ago. I thought I might have invented the idea(as improbable as that is). But, at the time and since, I've never went to the trouble to explain the finer details of it to those less knowledgeable. So having suggested it to others in the past, I may have inadvertently been at least partly responsible for the idiots who've since done so incorrectly. Not anymore. Now you know what's right and wrong...and why. And there's no more excuse to be stupid about it.



EDIT: Of course this all applies to ANY engine using shims for valve clearance adjustment. Duh.

EDIT 2: DON'T grind the tip of the valve stem(s) instead of grinding or replacing the shim(s). There's NEVER a reason to with these engines. Toyota has a specification for the valve stem length too. And there are limited tolerances for wear, and therefore limited allowances for removing material from them. If you were to remove more than .019" from the tip of even a new valve you would be left with a valve that was no longer the minimum length(not to mention from the tip of a used valve that might be slightly shorter). But like I said, there's no reason to ever need to. Since there is pratically no wear at the tip. And certainly none that would cause it to need resurfaced. The adjustment shim(s) takes care of ALL clearance adjustments. Don't mess your valve stems up for no good reason. That's just plain stupid dumb.

cazealan

Just wanted to say thanks for the info and confirmation that I could in fact grind down my shims. Some people were concerned with the integrity of the metal after, and some people said the shims are case hardened, so they couldn't be ground down. Since the shim on the inside face doesn't really have any wear totally makes sense as you described to be able to grind them down. I saw a YouTube video of a guy using an angle grinder, and that's what I used, seemed to work out well enough, especially for the shims I had to cut up to 0.5mm out of it. Those valves were bad! I would grind the outsides first, measure, then grind the center, measure, then repeat until the desired thickness. Using the flat side of the grinding wheel flat against the shims also seemed to give it a smooth, glazed surface as well like before. I was able to get the thickness within 0.01 on all sides, so not the best method out there, but it seems to be working. I used the valve bucket method like you and it worked great. Other forums I've read have guys who have run 30k miles after grinding down shims and have had no problems and the shims had no additional wear. 88 toyota 3vze now bullet proofed for the next 90k miles, even did the cross over delete to minimize extra heat and stretching of the new valves on that drivers side. We'll see how it goes