Adjusting Valve Lash

[Steve S.]

This is my next project.   I've searched all through the web site and haven't found much on this other than the tech page from the engine manual and some notes Ron wrote in 1999.  Does anyone have any hints, tips, etc.   Thanks to all

[Ken Juul]

Doing the valves is actually pretty simple.  I find it easiest if you remove the correct feeler guage from the pack so you don't have the extra weight to deal with.  It's more work but for the first time either work front to back or back to front so you don't miss any valves.  You cannot see the camshaft so you will have to look at the valve. Turn the crank shaft clockwise looking at the front of the engine, until the valve you are adjusting is fully open. Turn the crankshaft one full turn more, the camshaft should now be in position to adjust the valve.  Loosen the jam nut, 10mm box end wrench if memory is correct.  Slide the feeler guage between the valve stem and the tappet and adjust using a screwdriver until the feeler guage has a slight drag when you move it.  Hold the screwdriver in that position and tighten the jam nut.  Re check that there is still the slight drag on the feeler guage.  Too tight or too loose start over.  How to check proper drag.  With the feeler guage in place there should be no movement of the tappet.  Remove the feeler guage, there should be slight rocking when you move the tappet, now holding the tappet against the pushrod/cam the feeler guage should slide back in easily.  If you have to force it, the clearance is too tight.  Move to the next valve on that cylinder, repeat the process.  After two or three valves you begin to get the feel for it and it gets easier.  When you get finished adjusting all the valves, if you want to check your work, replace the valve cover, nuts finger tight.  Pull the fuel T handle and crank the engine for 10 seconds or so.  Wait a few minutes to let the oil drain, remove the valve cover and spot check (or recheck all) a few tappets.  The valves should be adjusted when the engine is stone cold, if it starts for some reason during the cranking give it time to cool down before you recheck.  I get confused with my cars.  The feeler guage is either straight or has a slight bend in the blade.  The one in the boat tool box is bent so I think it is slightly easier with the bent style.  But then again the last time I used it was to adjust the prop shaft alignment so I might have swapped them out.

[prh77]

The crux of the biscuit, as Frank Zappa used to say, is knowing when the cam lobes are turned away from the tappets. In the Universal manual, they give you a nice procedure with marks on the flywheel, but you can't see them on a C 34, at least not on mine. I have worked up a system using closure of the intake valve and adding 180 degrees to get close to TDC compression stroke. Wondering if there is another formula to use.

[Ron Hill]

Payton : Yours is a good method.  Surprising that you can't see the marks on the flywheel! 
The most important tell tale is to make sure that BOTH tappets are loose.  That way you know that both valves are seated.   

[Steve S.]

Thanks all - really helpful.  I'll let you know how it goes.