Valve Adjustment

[sleepycruiser]

Plugs out. Cold engine. Spin engine with the alternator pulley nut. Set valves to cold specs. Replace plugs. Fire it up and let it warm up. Check again hot as a go-no-go scenario just to confirm everything's good. Re-adjust any outliers.

This might be the way I try to do it. Never done valves before.

 

[roadstr6]

a,b,c,d are telling you the order to check/set the valves with each rotation. It seems overly complicated, but it does save a little time as it has you to check exhaust and intake on first spin and then intake and exhaust on second spin. Theoretically, you only have to touch your feeler gauge three times because you're checking intake on the first rotation and immediately checking intake again on second rotation. I see a,b,c,d as merely a time-saver suggestion.

 

[roadstr6]

This might be the way I try to do it. Never done valves before.

Doing them cold is the easiest way. You have plenty of time, you don't need to be in a hurry and you don't have to be concerned with engine temp. Plugs out makes the engine super easy to spin, even by tugging on the belt or bumping the truck forward or backward in gear.

 

[sleepycruiser]

Doing them cold is the easiest way. You have plenty of time, you don't need to be in a hurry and you don't have to be concerned with engine temp. Plugs out makes the engine super easy to spin, even by tugging on the belt or bumping the truck forward or backward in gear.

Do you take all the plugs out?

 

[MatthewMcD]

a,b,c,d are telling you the order to check/set the valves with each rotation. It seems overly complicated, but it does save a little time as it has you to check exhaust and intake on first spin and then intake and exhaust on second spin. Theoretically, you only have to touch your feeler gauge three times because you're checking intake on the first rotation and immediately checking intake again on second rotation. I see a,b,c,d as merely a time-saver suggestion.

OK, I see that now. Still going to remove it because I only have 2 feeler gauges on the ring and just go top to bottom.

 

[MatthewMcD]

Do you take all the plugs out?

Not unless I am doing some other maintenance. I use the 4th gear bump method.

 

[roadstr6]

Do you take all the plugs out?

Yes. I do. It's not necessary, but I do it because it gives me a chance to look at the condition of the plugs, and it makes spinning the engine over that much easier with no compression.

 

[sleepycruiser]

Yes. I do. It's not necessary, but I do it because it gives me a chance to look at the condition of the plugs, and it makes spinning the engine over that much easier with no compression.

Makes sense. And does the valve cover gasket need to be replaced when taking the valve cover off or only if it is leaking?? Seems like a cheap enough part to just do it.

 

[roadstr6]

Makes sense. And does the valve cover gasket need to be replaced when taking the valve cover off or only if it is leaking?? Seems like a cheap enough part to just do it.

I only replace if it doesn't pass the visual check. They last a long time. I like to smear a thin layer of grease on the head where the seal makes contact. That way it comes off easy next time and the seal typically stays seated in the groove on the valve cover.

 

[RevISK]

Thanks, I am removing those

I think all columns have their place.

You don’t really need the chart once you realize they are in pairs and either in or out.

 

[Blue77FJ40]

See the link in my sig. It contains the best valve lash adjustment instructions direct from Jim C.

 

[charliemeyer007]

I like to set mine on the loose side of the range - better to hear the valves than burn them. +1 for look at your plugs. I lightly glue the gasket to the cover and I don't wrench on the hold down nuts either.

 

[Grayscale]

Okay, so you get to the point where you reset the lash on a few valves. It must be wear that is present somewhere between the valve seat and the non-lobed part of the camshaft. However, I learned of an engine builder who was actually measuring the amount of cam lobe as well. A plung-type dial indicator with a magnetic base can tell you how much the valve actually opens if it is measuring the travel on the valve spring retainer. It could be helpful in determining how much cam lobe wear is affecting valve opening. There is no point setting valve lash properly if cam lobe wear is preventing the valve from opening as much as it should, and there are specs for cam lobe wear - about .014-inch. (if you measured it at the top of a pushrod with the rocker arms removed).

 

[Mark Jennings]

What’s neat about these engines (I6 with side cover) you can pull the valve train, rockers, push rods and lifters, and actually get an ‘eye-ball’ on the cam. If you suspect a cam issue, you can see it. If you can see it, it’s not self healing, and requires further disassembly.

The attached picture is a F cam with over 100k, this engine ran strong….till it broke a piston. However, the cam was also beat and should have been replaced longe before the piston issue. Notice the ‘crinkle’ on the lobe ramp, indication of work hardening. I never did figure out if this was a lubrication issue (low ZDDP) or just normal wear for a high milage engine.

 

[RevISK]

What’s neat about these engines (I6 with side cover) you can pull the valve train, rockers, push rods and lifters, and actually get an ‘eye-ball’ on the cam. If you suspect a cam issue, you can see it. If you can see it, it’s not self healing, and requires further disassembly.

The attached picture is a F cam with over 100k, this engine ran strong….till it broke a piston. However, the cam was also beat and should have been replaced longe before the piston issue. Notice the ‘crinkle’ on the lobe ramp, indication of work hardening. I never did figure out if this was a lubrication issue (low ZDDP) or just normal wear for a high milage engine.

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Great tech here Mark, very informative.