Thread: Valve lash correction chart..

Figured I'd share this.. I made a chart a while back to help keep track of valve lash when checking and/or replacing buckets (shims).





Basically, you can use this 1 of 2 ways.. If you're building a fresh motor and are starting off blind with your buckets/lash:

Step 1- Jot down the number on the bottom of whatever bucket you toss in, and put it in the spot that says "Current". Do this for all 16 buckets. Then, when you put the cams in and measure the lash, write down your clearance measure under "meas." Do this for all 16 buckets.

Step 2- For those that are out of spec (over/under .010" to .013"), write down in the "difference (+/-)" area how far off the clearance is + or - from the spec. From there, look at the bucket shim list in the 2nd graphic that I posted, and simply add or subract the clearance that you measured in the "difference" area. If the clearance is too loose, you will need to add to your current shim's thickness. If it's too tight, you will need to subract from the current shim's thickness. Either way, after you do your math, check on the bucket shim chart, match up the number to the closest bucket available, and this will be the bucket that you need. Round the number to the nearest figure that will correspond to the available bucket selection. I always aim for the middle of the spec, that way if I have to round up or down, I'm still within spec.

Step 3- Write down the new bucket that you are installing for the ones that you are replacing, in the area that says "New". Measure all of them again, and write down your clearance under "Final meas."


If you are starting off with a motor that's already together:

Step 1- Measure the lash, and jot it down in the "meas." section. If you have buckets that are out of spec, pull them, and jot down the number on the bottom in the "current" section.

Step 2- For those that are out of spec (over/under .010" to .013"), write down in the "difference (+/-)" area how far off the clearance is + or - from the spec. From there, look at the bucket shim list in the 2nd graphic that I posted, and simply add or subract the clearance that you measured in the "difference" area. If the clearance is too loose, you will need to add to your current shim's thickness. If it's too tight, you will need to subract from the current shim's thickness. Either way, after you do your math, check on the bucket shim chart, match up the number to the closest bucket available, and this will be the bucket that you need. Round the number to the nearest figure that will correspond to the available bucket selection. I always aim for the middle of the spec, that way if I have to round up or down, I'm still within spec.

Step 3- Write down the new bucket that you are installing for the ones that you are replacing, in the area that says "New". Measure all of them again, and write down your clearance under "Final meas."

Hope this helps..

Travis

Thanks for the sticky, Ash..

If one laps the valves obviously the lash will change. For conversation let's say a valve is under spec. by .02mm with a 7.10mm bucket. Can you take a previously run 7.08mm bucket from a different valve and use it? Or do the buckets need to be new?