Need a second opinion

[Moki of Rancho]

So I've been at this for months now, and I've finally gotten my valve clearances out of the negatives. Unfortunately, I overshot them by quite a bit it seems, and would like a second opinion before I go ahead and send out for yet another set of shims. (This is my fourth set, I just can't seem to get this damn thing right.) I got these values using Steve's spreadsheet:



Thanks.

[BassCliff]

Hi,

Don't over-think it. Make sure you are using the proper measuring standard (millimeters or inches) consistently. It's easier for me just to use millimeters everywhere, no conversion-to-inches approximations.

1) Measure it.

2) If the clearance is too small (less than .04mm) put in the next thinner size shim.
2a) If the clearance is too big (greater than 0.10mm) put in the next size thicker shim.

3) Spin the crank a few times and measure again. It should be somewhere between .03mm and .08mm.

4) Repeat as necessary.

It's OK to run them a little loose. Some of my clearances are out to 0.10mm.


Thank you for your indulgence,

BassCliff

[Steve]

Moki, sending a PM your way.


Are you kidding? You actually have 2.40 shims in all positions except #1 exhaust?

I have never seen that much consistency in an engine.

.

[BassCliff]

Hi,

It seems that you bought a bunch of 2.40 shims and put them all in your engine. The "Needed shim" row tells you what you should put in there. According to the spreadsheet calculations you need mostly 2.55 - 2.65 shims, and one 2.70. Not all valves will require the same size shim. Install the necessary shim to get the desired clearance for each valve.

Are you by chance confusing inches and millimeters when using Steve's spreadsheet?


Thank you for your indulgence,

BassCliff

[1948man]

Were your previous clearances really like .25mm or should that have been .025mm? If I'm looking at this right, if you have a clearance of .25 mm you need a shim 4 sizes (4 X .05=.20) larger to take up some of that slack and end up at .05mm. When you input your original values, maybe you dropped a decimal or used thousandths instead of mm.

[Moki of Rancho]

I originally used decimals in the inch clearance section of the spreadsheet and it gave me the wrong values. Based on that info, I put in a bunch of 2.40 shims, which was a miscalculation (one of many on my part!). The metric clearance readings are now correct, as are the standard/inch readings. The inch readings were between 0.08-0.13", which is a far cry from the recommended clearance of 0.03mm-0.08mm.

I've been using the exact method that Bass described above, except that I've been ordering the wrong shims based on various mistakes using the spreadsheet. On the bright side, I can now change all the shims in my 850 in less than 10 minutes!

A quick note: my feeler gauge has both metric and inch printed on the blades, so I'm not doing any inch-metric conversion there.

So now that I have what I think are new measurements/recommended shim sizes, should I go ahead and order a new set?

[Steve]

Moki called me.

Had a nice little chat, I'm reasonably sure we have things figured out.

.