Adjusting Valve Clearances

[RagTopMan]

When inserting the feeler gauge blade, how snug a fit am I looking for? A little drag on the way in or clamped tight when re-tightening the nut? Something in between?

 

[KVH]

You want some drag on the steel plate. Loose will mean too loose. BUT, by far the better focus will be when you have each valve in just the right position, just beginning to open, just beginning to close. Hitting it at the top won't do it. Check out what the manual says on how to adjust.

And check this link:

https://www.macysgarage.com/myweb6/valve_adjustment.htm

 

[Geo Hahn]

...BUT, by far the better focus will be when you have each valve in just the right position, just beginning to open, just beginning to close. Hitting it at the top won't do it...

Well I see that is how Mr macy describes it but I have always just used the rule of nine and done 2 valves at a time -- seems to me that a closed valve is closed for a (relatively) long time and great precision is not required -- e.g. so long as #2 is pretty far open, #7 is fine for adjustment.

Yes, there is slight drag on that feeler but note that you can jam a 010 feeler into a much tighter lash - there is a spring involved. If in doubt try the next size larger & smaller than you are aiming for -- a go / no-go approach.

I always set the exhaust valve at 012 just to give a little margin of error. Perhaps a bit more noise but I don't think it hurts anything and might help avoid the problems a too-tight valve would create. I started doing this when I had stock heads and was seeing recessison but I still do it with the hardened seats.

I see that site also says to always use a new valve cover gasket -- I rarely do. Once the cork gasket has taken a good set and seals well I continue to use it again and again. I do affix it to the valve cover w/ RTV and set it on a sheet of glass to dry before first use.

 

[RagTopMan]

Thanks for the link KVH. I was using the Bentley book as a guide but this "cylinder by cylider" basis sounds simpler.

Back to the feeler gauge "drag". So if I just insert the blade with the gap wide open and then close down until the blade is sandwiched tight, this would be too snug? I've done this and when I remove the blade, which takes some effort, I really cannot easily insert it back into the gap.

All my clearances are too tight if I was wrong to tighten the feeler blade in the gap.

 

[TR3driver]

That's right, don't clamp the feeler tight. You should be able to remove and reinsert with moderate drag.

One way to double-check, while you're still getting the hang of it, is to recheck with .002 larger, then .002 smaller. .002 larger should be much harder (or impossible) to insert/remove; .002 smaller should be obviously too loose.

As Geo implies, .001" either way is not going to hurt anything.

Personally I prefer a different sequence : turn the engine until one cylinder has both valves partially open (which means it is nearly at TDC between intake and exhaust); then set both valves on the cylinder that is opposite in the firing sequence (which is nearly at TDC between compression and power).

But it's just personal preference, shouldn't matter as long as the valve you are setting is fully closed. The main thing to avoid is trying to set a valve that is about to open, because the lifter is riding up the edge of the lobe on the cam.

Oh, and don't forget that the "Rule of 9" becomes the "Rule of 13" on a 6-cylinder engine!

 

[martx-5]

I see that site also says to always use a new valve cover gasket -- I rarely do. Once the cork gasket has taken a good set and seals well I continue to use it again and again. I do affix it to the valve cover w/ RTV and set it on a sheet of glass to dry before first use.

The only difference in this procedure is that I use 3M weather stripping glue to fasten the gasket onto the valve cover, and then I smear a thin coat of thick grease on the underside of the cork gasket. It never sticks to the head, and can be used many times over. Just smear some more grease on it each time you take it off.

 

[Member 10617]

My question is to confirm what I have been told, so I am sure I understand.

Here are the instructions from Macy: For example, "When the #1 valve has opened fully and just starts to close, adjust the #8 valve (1+8=9)" That's the RULE OF NINE everyone speaks of. That's clear....

Here is what I want to make certain I understand: When the #1 valve has opened fully, this means it is DOWN (some say "compressed"). When the #1 valve just starts to close, this means it just begins to RISE. And as it just begins to rise, that is when you adjust the #8 valve.

In other words, "open" means valve is "down," and "closed" means valve is "up." Do I have it right?

Also, instead turning the engine unnecessarily by getting valves 1 to 8 to close in sequence, front to rear, the actual order of fully open valves will be, if for example one starts at #8 down (adjust 1), 6 down (adjust 3), 4 down (adjust 5), 7 down (adjust 2), 1 down (adjust 8), 3 down (adjust 6), 5 down (adjust 4), and 2 down (adjust 7).

I realize there are several other ways to sequence this, and this may not be the best.

 

[Geo Hahn]

I believe your understanding of the Macy method & terminology sounds right.

Of course the TR3 with the plugs out (I always take the opportunity to clean an inspect the plugs) is an easy engine to rotate, esp if you still have a crank hole in the radiator -- so the efficiency of any one method is not a real big deal.

 

[hondo402000]

you got it correct. if you go front to rear or rear to front its easier to keep track of what you have adjusted, it can be done in order of which valve opens next I would just make a chart so you can check off the ones adjusted so you dont miss any

Hondo

 

[hondo402000]

also for a 6 cylinder you go by the rule of 13

 

[Member 10617]

Thanks. And, yes indeed, plugs out make it a whole lot easier, especially if you don't have a crank (as is my case).

 

[GerryL]

Another approach for adjusting valves shown in video of John Twist adjusting the vakves in a MG.


https://www.youtube.com/watch?v=fezXUwVfH7U

 

[RagTopMan]

Thanks everyone. Using the .010 and .012 feeler blades in conjunction really did help me get the "feel" for what was a proper amount of drag. I definitely had them all too tight from my last attempt. Since yesterday's readjustment, the effects on the engine's performance have definitely been positive.

 

[GerryL]

You can actually use a go no go feeler gauge. The blades each have two thicknesses. You adjust the valve that the thinner portion can slide and the thicker edge will not. I adjusted my valves yesterday with a go no gauge and used the blade that had .010 and .012 sections.