After much delay I'm finally getting around to putting my sons '92 xj40 back together.
I measured valve lash for all 24 valves prior to Diss-assembling the motor. All intakes were .012-.014. Six of the exhaust were .015-.016. Valves were all good, no visible burning, pitting or metal transfer, so I just replaced valve seals while head was off.
I just remeasured clearances on the bench to bring all valve leash into specs, and I get readings .001-.002 greater. All cam bolts are tightened correctly, but of course no head bolts are being used yet since it is not on the block.
To all you techs out there (or fellow DIYers) which are more reliable measurements??
The pre-tear down measurements, or the bench measurements w/o head bolts?
I really prefer not to install on head and having to use spacer blocks to adjust if possible.
Advice please?

 

Personally, I would forget about the measurements before dis-assembly. I would remove the cams and check all the shim pucks for the valve stem dishing them out. If any of that is found, scrap all the hardened crud off the shim and turn it over, so the valve side is now perfectly flat. Put the cams back in and measure them all again, that is your starting measurement. Adjust any that need to be brought into spec range, and put her together.

Good luck!

 

Tanks for the tip. Have you found clearances change much between "bench" measurements and after installation on block? Head bolt torque is about twice that of cam bearing caps, but goes through caps on the '92 4.0. Hoping to set clearances on bench and not have to do again on block (will verify anyway).
Thanks again for the reply
Paul

 

I wouldn't worry about any "change" after the head is installed. When adjusting, just shoot for the center of the range. Then install and properly torque the head.
If you've read anything about reusing the head bolts, FORGET IT. Use new bolts and lube with engine oil when installing.

Good luck!