I've used many different ways to start setting the valve lash including the Mopar decal, (original Chevy method) and setting them at TDC on the firing stroke as well as setting the intake valve when the exhaust valve started to open and set the exhaust valve when the intake closes and finally the latest way of setting the exhaust valve when the intake valve starts to close after max intake valve lift.
I've thought about this method more than once and decided yesterday to go back to setting the intake lash when the exhaust valve barely starts to open and now set the exhaust lash when the intake valve closes all the way and maybe a little more crank travel. My main reason for switching is with todays valve spring pressures I don't want any of that pressure pushing the lifter against the cam making it bend a little
What say you? Please give your reasons on your choice so maybe we can help all of us on here
Let the fun begin

I just use the open and closed method which seem to be more accurate on bigger cams.. but I got
so use to it I do it all the time even on my smaller SFT cams.. it might take a couple of minutes
longer but thats fine

The total duration including lash ramps on my cam is 340 intake and 356 ex. At .050 it is 284 296. With .867 intake lift and .800 ex lift i need a lot of spring. If i don't set the lash within 5 degrees of the tdc 90, 180, and 270 marks it will be off by .001 to .006 depending on how far off i am. I use the 90 degree method setting 2 int and 8 ex at tdc, then 1 int and 4 ex at 270 etc. Follow the firing order each 90 degrees and you will have very accurate settings for hi spring pressure valvetrain. You will be able to spot problems early since anything moving more than .001 to .002 is a warning sign IF you are on those 90 degree points. Lash settings on the cam i have only allow for a .002 loose to .002 tight change due to ramp design.

If you set each cylinder at TDC firing stroke, both valves are completely closed and nowhere near the ramps... What am I missing?
(Other than having to turn the engine 90 degrees eight times?)

EOIC is the easiest for me, and goof proof. You spin the motor a few more times, but you don't have to read a card or think, just go right down each bank.

I use EIOC. Cam is 287/294@.050". If you open the the exhaust to far or close the intake to far and can change the lash slightly. Maybe .001" But you have to miss it pretty far. If I find a valve off I'll bump it around and check a 2nd time. There is a log book of lash for my car. Every time its lashed if a valve is tight or loose that amount is recorded. Seldom is there more than 2 that are off by .001". Its lashed every 20-25 passes. Button on the firewall to bump it around. Takes about 15 minutes including a good visual, dragging a magnet trough the head and waxing the valve covers. I cant even imagine turning it every 90 degrees twice around with a bar at 15-1.
Doug

Do you ever tap the rocker to seat the valve better,Like when you do a leak down to make sure it is seated?

I want to be as close to 180 degrees from the lobe as I can so I use the method that Greg uses above. And I agree with him completely. For whatever reason, big spring loads and aggressive cams require more accuracy than the method of watching the valves open and close. Had a customer doing it so I made him run the valves 3 times and he never got the same lash twice. He just wasn’t accurate enough.


As for setting them off the firing order...I can’t remember why it’s not the proper way to do it, but there are reasons for it.

You can always do it off the FO and then go back through the valves using the 8 position method and see if the lash is the same. It probably won’t be. It would be interesting to see what you find.

Just a thought

Prostock is the pinnacle of drag race pushrod technology. Walk through the pits and watch a PS team run over the valves for lash, and spring tension. I've never once seen a team look for crank position. Good enough for them, good enough for me.

Technique and accuracy vary from one person to the other. And poor technique or accuracy is worse than which method you use.

Valve lash setting.
MP sticker vs Exhaust Opening, Intake Closing (EOIC).

If you look at the math, the MP sticker method and the E.O.I.C method are very close. And from a lobe profile stand point, the small difference doesn't matter. Be accurate; set the intake lash when the exhaust valve just starts to open. Not past that! IMPORTANT.
For example using the MP 0.620" solid cam, the tappet events are very close to this (depending on installed position). I am using the 0.050" tappet lift, because that is about when the eye ball will see it open/close after taking up the 0.028" lash.

Intake opens 34 BTC, closes 69 ABC
Exhaust opens 67 BBC, closes 35 ATC

The EOIC method would get you this:
Set Intake at 67 BBC, which is (180-67)= 113 ATC
Set Exhaust at 69 ABC, which is (180-69)=111 BTC

The MP sticker has the Intake set at 90 ATC
and the Exhaust set at 90 BTC. These are only about 20 degrees different. Have you looked at the base circle of a cam? Even a high lift cam typically has a base circle duration (zero lift) around 180 cam degrees (360 crank degrees). The cam is turning half the crank, so 10 deg on the cam opposite the max lift part is nothing.

To be exactly opposite max lift on the intake lobe (installed at 108 ATC centerline), the position is 108 ATC on the next crank revolution (cam is 1/2 speed).

Now the rocker, rocker shaft and pushrod deflection issue is real when you are trying to get that last 0.001" setting. So, you really want to set the intake before that 113 ATC point to avoid the exhaust putting pressure on the shaft. And the MP sticker method does it 23 degrees before the EOIC method. Likewise you want to set the exhaust after the 111 BTC, and the MP sticker method does that too, by 21 degrees.

You should also consider thermal growth. If you take too long setting each cylinder while hot, the other parts will cool and give you different lash measurements. So the EOIC method for finding the hot lash can be the fasest. For this I like to set the lash with the engine cold. Check it hot, and find what the best cold setting should be for all future lash adjustments.

I use both, it just depends... and you can turn that 20 degrees when doing the EOIC method too, but sometimes it requires turning backwards after you see it.

I wonder how much that "bend a little" affects power in the real world.

If EOIC is inaccurate as some suggest then why does the lash on mine repeat? Its been checked every 20-25 passes over the last 650 runs. Always logged in the lash book so any change shows, tight or loose. My bet is that many don't have a good feel with a feeler gauge either.
Doug

It depends on how good you are at doing it that way. Guys that do it way once in a while have consistency issues.

The cam cores they use i am sure are much less prone to flex like the junk i run. Plus those guys do it for a living and are qyite practuced i am sure.

Glad to see your post Cab, I have been doing the exact way you are doing now. Do the intake when exhaust just starts to open and when the intake closes plus a little more crank travel to make sure it is off the ramp. I noticed if I set the lash as soon as the intake closes. Then turn the crank a little more I've found .002 to .004 difference. And it is always consistent when I recheck.

Bingo!

"Honest" Bob Hickman, R.I.P.,(the So CA wedge God, guru, told me years ago to make all my lash adjustments so pushing the feeler gauge in with a finger would be tight enough that I thought the feeler gauge would cut my finger. I'm thinking we where both using the EO,IC method back then and that has worked good for me as far as consistency when I used that method
I do set the lash tight on new motors and then recheck them ASAP on the engine dyno after breaking in the cam or at least running the roller cam motors for 20 to 30 minutes to get the oil and engine hot. Check the lash on both sides one cylinder at a time and drain the oil and cut the oil filter open and inspect it, if every thing is good get after the dyno tuning
I've seen a pattern on component breaking in where after checking the lash several times, 2 to 4 times, it will settle in and stay there until something wears or breaks.
I now check the lash every 50 to 100 runs, depending on if running 1/8 mile or 1/4 mile . Good components last a along time

My feeler gauges are not inserted tight. Measure a feeler gauge with a mic. Is it tight? No. It's a relative as long as you do it the same everytime.
Doug

It is something you need to develop a feel for to get is exact on every valve. I've been an import tech for the last 40 years and i used to adjust valves enough every day that my feeler gauges would develop a wear pattern on them. With roller tips there should be little to zero drag on the feeler gauge when setting lash. Just try this one time, adjust the lash and have someone else who knows the drill re-check your adjustment and see what they think

Gus

Trade school tech (fwiw). for a .025" spec you want a .024" gauge to have no drag & a .026" feeler gauge to have a heavy drag