[Supras] Easy way to adjust valve lash

[berniek at technicaldevelop.com]

The TSRM way of removing shims is difficult at best.  Removing the cams is more difficult yet if the engine is assembled and in the car.  A much easier way exists if the clearance is excessive.

1.  Make sure the caps are properly fitted, as has been written about before.  Remove the two caps adjacent to the one to be checked, lay about 3 small squares of .003 common writing paper on top of the journals, and reinstall the two caps to push the cam into the saddles.  Reinstall the caps with the screws just snugged down, and measure the journal to cap clearance in the journal between the two with green plastigage. The front and second journals do not commonly wear unless the oil is sludge, so do not normally need to be removed.  The rear journal caps, especially in the exhaust side wear the most.   Carefully flat file or lap the cap to obtain a plastigage clearance of .0025" to .002".  For the last journal it is only necessary to "shim down" the # 6 cap with paper.  

2.  Recheck all of the shim to base circle clearances.  The exhaust should be .008" to .012", and the intake should be .006" to .010".  

For those that are excessive, the following procedure can be used:

1.  Use a screwdriver with a plastic handle and a blade width of about 3/8"  From the opposite side of the engine, drive the screwdriver between the cam base circle and the shim, compressing the valve spring using a light hammer.  Don't worry.  At least in my experience and opinion, the cam and shims are hard enough, combined with the low spring pressure to not be a problem (I have had no problems doing this, but I cannot guarantee it).

2.  Take a smaller screwdriver, perhaps with a 1/4" blade, stand it on edge between the rim of the bucket and the shank of the camshaft.  Tap lightly on the end with the hammer, so the side to side blade taper drives it in to compress the spring a little more.  You can now remove the larger screwdriver.

3.  Get stainless or brass shim stock assortments from McMaster-Carr or other sources.  McMaster has an assortment of stainless shim stock ranging in thickness from .001" to. 020" as stock number 9301K6 for $51.68.  

4.  Using a spare shim as a template, cut a circle out of the shim stock.  Make sure it is less in diameter than the shim (0.983 is the shim diameter, but about .050" less for the supplementary shim is OK).  

5.  Using the method described, you will not be able to remove the main shim from the bucket, but you can lift it enough to slide the supplementary shim between the bucket and existing shim.  

Hope this helps.  Do not skip the cap refitting step.  The cams lifting into worn caps is where most of the noise related to excessive valve clearance comes from.

        BernieK