EOIC vs. "The Chart"....

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beanhead

beanhead

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Nice evening to run the valves.
I do them dead cold, then a quick verify when they're hot and have always done it EOIC.. but I thought, "ya know what? Let's try the old MP chart and see how the two methods match up"...
They didn't. At least for me.
My cam is a 282/251@.050/.555/112 solid FT, not max-aggressiveness but no slowpoke either, and using the chart left me wide by .002"-.003" all the way around. In other words the chart method had me still on the ramps, just barely, and not fully on the BC...Damm that's about half of my 'wiggle room' lash number (I go .006" tighter than hot spec and end up on the money when it's hot--aluminum heads.)
Anyway. Be careful using the chart that so many swear by if you're looking to be accurate.
 
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LOLOL YES

EXHAUST OPEN (just opens) adjust intake
INTAKE has opened and is headed towards CLOSED, adjust exhaust

 
Screenshot_20200530-153257.png

You mean this?...
 
That's all I've ever used. The last 6 years...
I even got to little sticker on my inner fender wall...
 
I'm sure it all depends on the cam..I wouldn't think they'd give a different result had I not been bored and tried it both ways.
 
All I've ever done is bump the engine and get each individual valve closed all the way "plus a little more" and never had issue. Not once. One at a time right down the line. Hydraulic or solid makes no difference.
 
I would also say it highly depends on, if, your TDC is indeed truly TDC. If that is off, the whole process from there will be off. When doing engine mock ups, I have seen the balancer to timing cover marks off as much as five degrees.
 
408 swinger said:
I would also say it highly depends on, if, your TDC is indeed truly TDC. If that is off, the whole process from there will be off. When doing engine mock ups, I have seen the balancer to timing cover marks off as much as five degrees.
Click to expand...
Absolutely. I always verify TDC and punch mark the hub and ring if (it's not a one-piece damper.) Been bit on that before!
 
I really think it's the consistency and just doing it the same way every time. If you find that it's a little off you can compensate for that...
 
beanhead said:
Nice evening to run the valves.
I do them dead cold, then a quick verify when they're hot and have always done it EOIC.. but I thought, "ya know what? Let's try the old MP chart and see how the two methods match up"...
They didn't. At least for me.
My cam is a 282/251@.050/.555/112 solid FT, not max-aggressiveness but no slowpoke either, and using the chart left me wide by .002"-.003" all the way around. In other words the chart method had me still on the ramps, just barely, and not fully on the BC...Damm that's about half of my 'wiggle room' lash number (I go .006" tighter than hot spec and end up on the money when it's hot--aluminum heads.)
Anyway. Be careful using the chart that so many swear by if you're looking to be accurate.
Click to expand...


That’s weird because if you lash the valves with the intake off you can see using the chart the lifter is just about 180 degrees from the lobe on the base circle. So I’m not sure how you can be catching the ramp using the chart.

In fact, I have went through valve lash after customers have used other methods and I’ve caught them on the loose side.
 
A couple of things that can slightly affect it are, sideplay between rocker pairs, were the rockers in the same place side to side. If ductile rocker arms, how much wear on the tips? And a slightly bent pushrod will affect the lash as it rotates.
 
If you're going to turn the engine 90 degrees eight times anyway, why not just set both valves at TDC in the firing order? The valves are as closed as they'll ever be...
 
Mopar Sam said:
A couple of things that can slightly affect it are, sideplay between rocker pairs, were the rockers in the same place side to side. If ductile rocker arms, how much wear on the tips? And a slightly bent pushrod will affect the lash as it rotates.
Click to expand...
So maybe that's the difference. Turning by hand doesn't let things move and 'center up' the way they do when bumping the starter...which would be more like what's happening when the engine's actually running. We are only talking a couple thou, so I could see that...
 
DrCharles said:
If you're going to turn the engine 90 degrees eight times anyway, why not just set both valves at TDC in the firing order? The valves are as closed as they'll ever be...
Click to expand...


Because running a cam as big as you run doing it at TDC will make the lash loose because you are catching the ramps.

The chart method puts the lifter opposite the lobe.
 
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