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Valve Adjustment on Any Engine


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I have this valve adjustment order that I learned way back when I worked at a Chevy dealership 13 years ago. I broke the process down and realised it will work for any engine. You will always have two cylinders at TDC at the same time. On a SBC and Datsun L6 (and many other engines) #1 and #6 are at TDC at the same time, one will be on the compression stroke and one will be on the exhaust stroke. So get the engine to TDC compression stroke on #1 and adjust both of those. Then follow the firing order adjusting exhaust valves. Skip #6. After #6 follow the rest of the firing order but adjust intake valves. Then just rotate the engine one revolution and adjust the rest.

 

Datsun L6 TDC #1 compession intake valves 1-2-4    exhaust valves 1-3-5

                         #6 compression intake valves 3-5-6    exhaust valves 2-4-6

 

Gen 1 SBC        #1) intake 1-2-5-7   exhaust 1-3-4-8

                          #6) intake 3-4-6-8   exhaust 2-5-6-7

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VW Flat Four...

 

But be VERY careful with the Datsun asymmetric grind. If you are not RIGHT on the heel of the cam when adjusting clearance you will likely be "loose" a thou or two, and as a result be down slightly on performance. If you "jiggle" the cam slightly from those two positions, you get a much better result.

Edited by Tony D
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VW Flat Four...

 

But be VERY careful with the Datsun asymmetric grind. If you are not RIGHT on the heel of the cam when adjusting clearance you will likely be "loose" a thou or two, and as a result be down slightly on performance. If you "jiggle" the cam slightly from those two positions, you get a much better result.

Do you think odd-fire engine would be any different? I'm thinking so but I've never worked on any.

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Paul who?

 

I'm lost on that reference.

 

The VW has "symmetric" lobes, same opening and closing ramps. So in one turn you could adjust all valves. With them it was no big rush as you did them "stone cold in the morning before the sun comes up, after you've had your coffee"...

But aftermarket cams since the 90's have started to use asymmetric grinds, and now on Hot VW's you have to take care... But again, it's done cold, so 1-4-3-2 is not that big a deal... Especially if your arms are long enough to reach the ratchet on the crank pulley nut...or you are big enough to leave it in 4th and just shuffle the bug/bus forward to adjust the next valve in line! That gets the neighbours thinking...

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