Running into problems re-shimming my DE!

[slipnfall]

Hi there, I just got my head/cams back from the machine shop today and set out to re-shim it. This is a '91 KA24DE BTW. Basically AFAIK they just replaced the exh. guides, replaced all the seals, and re-ground the valve seats/valves. The machinist told me that my valve clearance will be tight when I get it back, presumably because the valve itself was re-ground. I asked the Nissan dealer, if I should have him return the valve stems to OEM length, and everyone I talked to said 'no', that I could make up for it with the adjusting shims. The top of my exhaust stems does show fresh metal, so he must have cut them down somewhat.

Anyways, maybe that's not what's wrong. My problem is that my calculated shim sizes are smaller than the smallest available. Listed below are my clearance measurements, original shim thickness(manual micrometer), and calculated thickness. Note that I have only done cylinder 1/3 on the exhaust, because I realized early on that they were way off.

I was meticulous(sp?) on the torqe/sequencing specs, and I verified that I had the right cam in the exhaust side. FWIW, the cam was so tight I could not turn it w/a wrench(the head was just sitting on a bench, so I didn't really go at it).

Valve1:Clearance:less than 0.005" (didn't have a smaller feeler gauge)Old Shim:0.0848"New Shim:0.0752"

Valve2:Clearance:less than 0.005 (didn't have a smaller feeler gauge)Old Shim:0.0838"New Shim:0.0742"

Valve5:Clearance:0.0065"Old Shim:0.0824"New Shim:0.0743"

Valve6:Clearance:0.0075"Old Shim:0.0829"New Shim:0.0758"

The FSM says the smallest available is 772mil. Is there something I could be doing wrong? Should I have him trim down the stem lenght? What is the reccomended stem lengh considering wear and shim sizes available(ie to allow for some wear/adjustability).

Hope this wasn't too much to digest at once... Thanks for reading: any input appreciated!

Cheers,-Slip
Modified by slipnfall at 7:55 AM 1/29/2005