OK, I'm resetting the valve lash on the Iroc today. Freshly rebuilt heads, new cam etc. and after 9 months, the rockers were rattling a little bit. Sure enough they were all a little loose.

...anyhow, I just finished setting the lash using the tighten til ya feel resistance on the pushrod, then tighter 3/4 more turns. I did half on the compression/#1, half on the exhaust/#1 as specified in the manual.

here's what I noticed, and I'm not sure if this is correct. A few of the nuts don't seem to have threaded on to the stud very far. Most have about 1/8th to 1/4 of an inch of the stud showing, but 2 or 3 are just barely showing a 1/16. I checked and double checked, and as far as I can tell, I did everything correctly. All the studs were even before I started, so it's not like any of them are pulling out. Is this normal? Should I be concerned?

Thanks.

 

lol, this is going to sound stupid... but hey... KISS.

Did you possibly cross-thread the bolts? I tried pulling the studs on my 416 heads and managed to cross-thread the bolts very easily even with hand-tightening them as far as I could before I had to use a ratchet.

Just a possibility I supposed.

 

I've tried the method you used before for setting valves and just could not get it to work right, obviously I did something wrong, so I just roll motor over and do one set at a time (got it down to 15minutes for checking every valve now

You should have the same amount of threads sticking through the tops of all the lock nuts, if they are not all the same or VERY close to being the same, I would say you might have a problem...least that's been my experience anyways.

 

mine are like that too but i haven't started the motor at all since i bought it 2 years ago.

 

Don't know what manual you got that valve setting sequence from but if you set the exhaust valve for a cylinder when the intake valve is just seating and set the intake valve when the exhaust valve is just cracking open you can't go wrong. There is a 4 crank position adjusting sequence that works too but your method isn't it. Get a better manual.

 

Yep as the exhaust opens adjust the intake, as the intake closes adjust the exhaust, the only way to go.

 

Well, I didn't list a specific sequence. I don't remember it off the top of my head so I just said half and half. It wasn't a RANDOM choice

It worked last time.

...and to update, I started over and they're all fine now. Maybe I just forgot? Who knows.

 

What is it, I'm curious?

 

You bring the number 1 cylinder to TDC firing. Both valves will be closed at this point, for that cylinder, and you set the lash on both. Once done, rotate the engine 90°. Now, the next cylinder in the firing order will be at TDC firing, or the #8 hole. You set the lash on this cylinder. Proceed to rotate the engine and set the lash at 90° intervals, following the firing order around. Once done, you will have gone through 2 complete revolutions of the crankshaft.

 

Thats not it. I'll post it tommorrow.

 

Really? Then I guess I am curious as well.

 

why do people lay out this confusing way to set the valves..ill never understand it...
with the motor running its 10 times easier to do any valve in any order you want to...loosen it untill it clanks, tighten till it just stops go another 1/2 turn done...no crank rotation, no EVO or IVC on certain cylinders then rotate the crank 90 degrees and go back to #6 fire..comon who can remember that perfectly?...

who can FORGET how to do it with the motor running...

the first and only time i tried to set them BY THE BOOK with the motor off...and by doin this special sequence i ended up with a motor that didnt have any compression in any cylinder and naturally wouldnt even hiccup to start..

cranked the motor over by the starter and started goin down the drivers side bank backin off the poly locks...and sure enough the motor would compress everytime that valve acuated...

i will never adjust the valves with the motor off again...

 

I don't find it confusing at all. I just don't do it often enough to remember it off the top of my head.

The first time I did it by the book I had no problems. Yesterday who knows, maybe the phone rang, maybe the dog was barking, maybe a cute girl drove by. I went back and reset them all, and sure enough everything was fine.

Is your method with the engine running messy? I don't want oil everywhere. I'm not saying it doesn't work, but there's more than one way to skin a cat, and it doesn't mean another method is wrong just because you don't use it. I have two friends that are mechanics and one swears by the engine running method that you use, the other uses the method I use. I've heard them argue over it to no end, and I'm sure I'll hear it again at some point.

 

I do mine with the engine running. Just put something to catch the oil thatll dribble over the rear of each head under the engine and be quick about it.

 

F-Crazy like a lot of people you had trouble feeling when you had just adjusted the valve to "0 lash" and just start to compress the internal lifter plunger. What you did was to completely compress the lifter plunger till it bottomed out in the lifter body, any further tightening opens the valve. (no cylinder compression)
It's takes a bit of practice to get a feel for it especialy when the lifters are new and don't have any oil in them yet.
Try spinning the pushrod while tightening towards 0 lash.
As soon as the pushrod gets any resistance, (it may still spin) that point is 0 lash. (the internal plunger is now starting to compress.)
At that point add the lifter preload adjustment ( 1/4 to 1/2 turn).
Once you get the proper feel for it you won't have to go back and readjust the lifters , with he engine running on a fresh enigne fire up with a hydraulic cam.

There is a 2 crank position valve adjustment sequence but it's only good for very short duration cams (like a stock low perf hydraulic)

For any high performance cam use the 4 position method.

here it is:

Turn the crank shaft untill the #1 piston is at TDC on the top of the compression stroke ( fireing) both #1 lifters will be down.
adjust the Intake valves of cylinders 2 and 7
adjust the exhaust valves of cylinders 4 and 8

Rotate the crank 180 degrees (1/2 turn)
now adjust intake valves 1 and 8
adjust exhaust valves 3 and 6

Rotate the crank 180degrees again
adjust intake valves 3 and 4
adjust exhaust valves 5 and 7

rotate the crank 180degrees
adjust intake valves 5 and 6
adjust exhaust valves 1 and 2

Print it out and stick it in your tool box or write it on the tool box lid.

 

Try jiggling your pushrods

Its easier to feel when your getting close to zero lash.

 

Thats the EXACT method i tried to use...i spun/jiggled and moved the pushrods untill they stopped then went another 1/2 turn...and every cylinder was dead...these are also lifters with 70,000 on them that were soaking in a cup of oil for about a month..(i know they wont fill with oil, it was more for surface rust prevention)...i have a book on rebuiling and blueprinting SBC's and that method was in there with the valve sequence..and i know that when i started it was #1 with both valves closed..

about the "hardest" part of doing it with the motor running is the hot oil...after about 10 minutes the oil has gotton pretty warm...and like posted just fab up a piece of cardboard to keep the oil in the heads...i dont have the problem becasue LT1/4 motors only have 6-10 PSI of oil pressure to the lifters at idle..so it kinda dribbles out of the pushrods

 

Hey, I dig that method. I might just use that next time myself. Without trying to sound dumb, I was used to Ford non-adjustable rockers, just tourqe the rocker nuts to specs (not roller though) and your done, so when I started working on GM motors it confused me at first but what I think confuses most people is they must understand that the engine HAS to be at TDC on the compression stroke of the number one cyl, if not you can adjust the lifters a million times and your gonna come up with the same situation that the person that originated this thread did. But thanks for that 4 step method, I will myself print it and keep it in my garage.

Brian

 

Maybe its just in my head, but Ive always gotten a smoother, MORE POWERFUL motor. Setting the valves with the engine running.

I set them BY THE BOOK when the motor is first installed. Then after some break in miles, I adjust them with the motor running.

 

The only problem I see with setting the vlaves at TDC is how do you know exactly when TDC occurs with the engine in the car? I used to do the TDC method, but depending on how radical the cam is, if you're off just a little it can have an effect. If you just do the "as the exhaust opens adjust the intake, and as the intake closes adjust the exhaust" method you'll get it right every time, it's even more critical on a solid lifter engine to get it right. The "oil bath" method also works and your car will never ever rust, but you can't really do it this way on a solid cam. If you attempt the "oil bath" method, find some old valve covers and cut holes in them that line up with the rocker nuts, that way oil doesn't run everywhere.

 

i tried that method and unless I was doing something wrong when both valves on#1 were closed the exhaust on #4 was opening and I couldn't adjust it

 

what he said... he's the one who taught me how to do it for my FIRST time ever, and my engine fired right up first time. it's a very simple method, pretty much fool proof. for me, anyways.