Shim measurements

[cjames431]

I just finished measuring valve clearance and removing shims for measurement. 6 of the exhaust valves need reshimmed 0.001 and 2 need 0.002.
Do my shim measurements look correct. Some still had markings but most did not.
@Igofar

 

[dwalby]

I find it more useful to put the clearance value and shim size on the same page next to each other, makes it easier to visualize. No need to convert the shim size to inches, just remember every shim size is equal to 0.001" and do the adjustment on the page with the before/after shim sizes listed.

For example:





looking at that I can decide at a glance if I want to leave it at .007 or adjust it one step to 1.90 to put it in the center of the range. If I happen to have another 1.90 shim available as a spare or from another cylinder then for sure I'll adjust it, otherwise I may just leave it where it is because its still in spec. Seeing all the new sizes needed on the page helps visualize where you can swap shims around rather than buy new ones using circles and arrows to show what's being swapped where.

 

[cjames431]

I find it more useful to put the clearance value and shim size on the same page next to each other, makes it easier to visualize. No need to convert the shim size to inches, just remember every shim size is equal to 0.001" and do the adjustment on the page with the before/after shim sizes listed.

For example:





looking at that I can decide at a glance if I want to leave it at .007 or adjust it one step to 1.90 to put it in the center of the range. If I happen to have another 1.90 shim available as a spare or from another cylinder then for sure I'll adjust it, otherwise I may just leave it where it is because its still in spec. Seeing all the new sizes needed on the page helps visualize where you can swap shims around rather than buy new ones using circles and arrows to show what's being swapped where.

Thanks. I haven't messed with shims before so I wanted to know what I have on each valve and their standard equivalent. I will keep a record going forward so that next valve check I will know what shims I will need. I swapped where I could on the exhaust side but that only took care of 2 valves. I do want to reshim the intakes to midrange though. I recorded the swaps/changes on the lower section of the page. It's just not part of the picture as I still need to stop by the STealer tomorrow to swap with them for what I need.

 

[jfheath]

If you cannot get it spot on mid range, consider having a gap that is on the larger side of the tolerance range than smaller. The gap generally reduces with wear.
The actual shim sizes go up in steps of 0.025 mm and tend not to wear out.
a 182 shim will be 1.825mm
a 188 shim will be 1.875mm

 

[dwalby]

The actual shim sizes go up in steps of 0.025 mm and tend not to wear out.
a 182 shim will be 1.825mm
a 188 shim will be 1.875mm

just a trivia comment on the "in-between" shim sizing.

I always found it odd that the shim sizes ending in '8' were properly rounded up, but the ones ending in '2' were incorrectly rounded down.

 

[mjc506]

'cos 3 looks very much like 8 when you've got a used shim covered in oil

 

[John OoSTerhuis]

'cos 3 looks very much like 8 when you've got a used shim covered in oil

Aha. Never thought of that...

And once again I’ll remind folks that there’s no need for a shim calculator. Measure in thousandths of an inch (.001” = .0254mm), ID the current shim size and look at the shim list for the right size to move the clearance to what you want (one increment for each .001” desired). A sure fire method that won’t leave you questioning your math ability.

John

 

[John OoSTerhuis]

@Igofar

Thanks for your endorsement above, Larry. Appreciated. As we both suspect (or have actual knowledge…?), this is the way most shops will do a valve clearance adjustment (shim-under-bucket). There may be the rare occurrence where, for example, one shim size thinner for an exhaust valve may not quite register the change when trying to slip the one-thousandth larger feeler gauge in, post-R&R. But you did change it, so make a note for the next time you’re in there. Or…. If you’re anal retentive like me, juST pull the cam followers again and go one shim increment thinner. FWIW YMMV

John

 

[cjames431]

I stopped by the STealer to see if they would swap one for one and they no longer will. I made a second stop at a local non-STealer. Great conversation with the owner for an hour. He did not immediately agree to swap but after we had been chatting for a few minutes he takes me back to his shim kit and swapped me out. So, if your in the area check out GIXXER TECH, the one man ran shop that's not a STealer.