The Stovebolt Site Forums The Shop Area Engine Shop valve cover

Does a chevy 40's valve cover stright 6 fit a gmc 40's motor.. just for the use of cutting the top off and be able to adjust the valves on a running motor without the oil going all over the block,, thanks kat unless someone has an old gmc one thats trash...

I think you will find that the GMC engines are longer so no interchange on the valve cover.

My question is, why adjust them with it running? It just ruins a good feeler gauge.

Amen.

gm even makes a wrench to do just that... it has the box end wrench and a flat blade built in... so one can to this alone.. feeler in one hand tool in the other,,, or I guess gm thinks its wrong to have a motor in operating temp.. or oil flow that coats the push rod ends and taps... a real world knock or no knock discovered right then... thats a bit tuff to tell with a motor not turning... done my valves four times and there is one that is taping so loud.... so I will find out which one.. it must have a grove that the feeler covers and cant tell... once I find the one,,, I will take it down a few thousands and if the really loud taping stops I'm good... I like it that they all tap a bit... but I got one thats off.. and the rods are all straight...

katrina,

What would be the GM part number for that tool? My guess is that it would have been a Kent-Moore tool, if it was a GM tool? I see no special tool mentioned in Chevrolet truck or GMC manuals. I have seen a non-GM Zim-Zip valve adjusting tool that sounds like the tool your describe. That tool could be used with any valve adjustment technique (and makes it easier).

I have seen Chevrolet Truck Shop manuals give specific warnings about how to make sure that the engine temperature is warm and stabilized. Before adjusting valves using either technique, the engine must run until temperature is properly stabilized. And, the Chevrolet Truck Shop Manuals state that after reaching a stable warm temperature, the valve cover may then be removed and the valve stems should then be lubricated.

I have not read a specific reference in a Chevrolet Truck Shop manual that the valves should be adjusted with the engine running or the engine not running.

I can easily determine where a knock is and where a loose valve is, by using a cheap stethoscope with the engine running. Then, that valve could be adjusted tighter with/or/without the engine running. Of course, I would have first made sure there are no grooves in the face of the rocker arms - this will also allow feeler gauges to last longer.

I have no old GMC manuals but I have a 47-54 manual. Usually, the GMC manuals have clearer descriptions of techniques - in the case of adjusting valve lash I cannot find as much information as stated in the Chevrolet manuals.

Mac tool guy sells the tool you are looking for.

I think the running engine procedure is for hydraulic lifters. Your GMC does not have them.

great advise guys thanks a million

before I got the rockers refurbished I used a feeler gage cut to the width of the groove in said rocker arms. You kind of have to dress up the little curly bit that happens when you cut them but it worked fine. I sent my rockers and shaft to larrowe and sons in sandy OR, they put bronze bushings in the shafts, and faced off the rockers, very nice job.