Flipping Shims??

[Yamaha V6]

Scott, is it perhaps possible that after the spring compression & the lobe passing perpendicular that the spring is pushing up on the bucket enough to "pop" it up to make contact with the lobe again, outside of the "10mm" circle you're talking about during slow rotation? At speed, with the spring compressing & decompressing rapidly, perhaps the bucket actually "jumps", making additional contact?

FWIW, I work in a machine shop during the day, and we deal with all kinds of oil, heat, dirt, etc., and everyone here says that if it were just oil wash over the numbers causing them to fade when they're upright, they'd fade below too.

Also, no one has shown a pic of a shim with the outer "race" style dirt gouges I've seen, or the "bucket got stuck in place" wear pattern. Again, I'll take some pics tonight.

 

[Mike Kopstain]

Scott take a look next time you do a valve shim adjustment. I don't know what you use to spin the motor, but if you use a bump starter, set it aside and have someone else spin the damper for you. Notice as the lobe begins to come down on the shim, it starts touching the shim well before that 10mm contact patch.

The examples I have shown above aren't flukes. Most of my flipped shims have the numbers gone, most of my non-flipped shims have the numbers there, and all of my shims have the larger ring around that 10mm contact area.

Forget my personal comments... Let's actually get this one figured out. I have a valve adjustment today on a SHO with 118k that used flipped shims at 60k. I certainly will be taking a closer look after all of this.

What's a "Bucket got stuck" wear pattern. Is it just one 10mm wide line down the shim?

Joe, no worries sir.

<small>[ May 23, 2003, 12:26 PM: Message edited by: Mikeys_Taurus ]</small>

 

[gosho89]

Well lets just all agree that the shim can be flipped and as long as you use the Sheet that Scott provides the numbers on the shims aren't necessary. Personally I have done over 20 valve adjustments including a 120k on a 92 SHO that Doug Lewis had done the 60k on. Doug had flipped all the shims but everyone of them was still legible. Reshimming was a bit tricky since both sides were worn, but nothing that a little math and calipers couldn't solve. Also have found shims install from the factory upside down but even after 100k they were still legible. No big deal.

<small>[ May 23, 2003, 01:38 PM: Message edited by: gosho89 ]</small>

 

[HopefulSHO]

Here is a picture of a shim I pulled from my engine @ 150k, not sure if it ever had a valve adj. done before. All other shims had the normal circular wear pattern except this one.

I took the best picture I could (my Kodak dosen't like close ups). If you want I can try for a better picture, but you can pretty much see what I'm talking about. It dosen't look like this shim rotated much. 95% of the wear is in one nice swath down the middle.

 

[DHMag]

not all shims are manufactured by the same company you guys. so that means not all shims will have the number in the same location. to each their own, ya know ?

 

[JoeHoe_SHO]

PROPHET:


PS:Joe get back to work and think someones trying to steal your donuts.

I always think someone is stealing my donuts! I think the machine I test for 12 hours a day gets an appetitte for apple fritters!

Back to the subject...is it safe/effective to just flip the shims instead of getting new ones? I think I would get new ones, thats just because I admire certain members' rides and I know what they've done to keep them as nice as they are...but in the event that I cannot afford the shims or something, can I just flip them?

BTW- I agree, I think Mikey and Scott should figure this one out, even if either thinks that there is nothing left to say, I'm sure many will benefit from data/input that will manifest itself from some of the most knowledgeable SHO guys on the forum...besides, makes great late night reading material!

 

[gosho89]

JoeHoe_SHO,
First I'll put it this way, I plan on running my current engine for another 100k miles and by installing new shims (while there still readly avaliable) it will allow me to flip them later to run the motor out to the end of engine life.

I don't know how many miles you have on your engine but the best thing you can do if you don't want to put new shims in is to flip what you got to keep from wearing the cam lopes. I've seen way to many motors that have been run over 130k without any maintance to the shims whether its replacing or flipping, on many the wear is very extreme on the shims and has already effected cam life.

<small>[ May 27, 2003, 06:39 PM: Message edited by: gosho89 ]</small>