Quick valve adjustment question...

[Guest butlersZ]

Is there a way to set the valve lash cold on hydraulic lifters on SBC? A friend says with the valve closed, to lock down the nut until the rocker arm doesn't move then back off a half a turn and your done. Is this accurate? He's a redneck and I don't want my new cam to go flat on startup. Oh and the rockers are stock as well as the springs and such.

[strotter]

It's the other way around - with the valve closed (and make darned sure it's closed) you run the nut down until it doesn't rattle (take up the slack) and then *tighten* it 1/4th to 1/2 turn. Very strongly recommend you get a good manual.

[80LS1T]

Yeah bent valves suck!

 

and ditto!

with the valve closed (and make darned sure it's closed)

 

Guy

[waynekarnes]

from the champion website .... hope this adds to the confusion LOL ...

 

Valve Adjustment The Quick Way:

 

Ok, now to the good stuff! First, view this little chart for Small and Big Block Chevy Engines that I made and see if you can understand it ... for other engines, use your firing order that matches your engine to do the same. You set up this procedure based upon "opposite" cylinders of your firing order. (see below)

 

Intake Valve Adjustment: ENGINE OFF!

 

with #1 cylinder Intake Valve at full valve lift .... Adjust #6 Intake Valve

with #8 cylinder Intake Valve at full valve lift .... Adjust #5 Intake Valve

with #4 cylinder Intake Valve at full valve lift .... Adjust #7 Intake Valve

with #3 cylinder Intake Valve at full valve lift .... Adjust #2 Intake Valve

with #6 cylinder Intake Valve at full valve lift .... Adjust #1 Intake Valve

with #5 cylinder Intake Valve at full valve lift .... Adjust #8 Intake Valve

with #7 cylinder Intake Valve at full valve lift .... Adjust #4 Intake Valve

with #2 cylinder Intake Valve at full valve lift .... Adjust #3 Intake Valve

 

Exhaust Valve Adjustment: ENGINE OFF!

 

If you have noticed, this is the same procedure as the intake valves listed above, just that you are now adjusting the exhaust valves the same way.

 

with #1 cylinder Exhaust Valve at full valve lift .... Adjust #6 Exhaust Valve

with #8 cylinder Exhaust Valve at full valve lift .... Adjust #5 Exhaust Valve

with #4 cylinder Exhaust Valve at full valve lift .... Adjust #7 Exhaust Valve

with #3 cylinder Exhaust Valve at full valve lift .... Adjust #2 Exhaust Valve

with #6 cylinder Exhaust Valve at full valve lift .... Adjust #1 Exhaust Valve

with #5 cylinder Exhaust Valve at full valve lift .... Adjust #8 Exhaust Valve

with #7 cylinder Exhaust Valve at full valve lift .... Adjust #4 Exhaust Valve

with #2 cylinder Exhaust Valve at full valve lift .... Adjust #3 Exhaust Valve

 

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Need an explanation?

 

Well, what you have here is "opposite" valves on the engine cycle. The small and big block Chevy engines use a firing order of 1-8-4-3-6-5-7-2. What you do is separate the order into the two sides of the firing order. These are "exact" opposites that put the opposing valve at the correct location for adjustment, meaning the back side (base circle, or heal) of the cam lobe (see image at left). This procedure works on most V8 and V6 engines. (base circle, or heal) of the cam lobe (see image at left). This procedure works on most V8 and V6 engines. (base circle, or heal) of the cam lobe (see image at left). This procedure works on most V8 and V6 engines. (base circle, or heal) of the cam lobe (see image at left). This procedure works on most V8 and V6 engines.

 

1 - 6

 

8 - 5

 

4 - 7

 

3 - 2

 

If the lifter is anywhere other than on the heal of the cam where there is NO ramp contact you will have incorrect lash. The chart above makes sure you are on the backside of the cam lobe. When the cylinder is at TDC, this is not often the correct location to get the proper lash setting.

 

 

 

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What about the actual adjustment procedure you ask?

 

Hydraulic Cams:

 

Ok, let's get to the actual wrench turning ... how many of you read or were taught that with a hydraulic lifter cam you adjust it down to where there is pushrod resistance (zero lash) and then turn it down 1/2 to 3/4 turn? Well, if you did this, you more than likely have the valves not closing all the way!

 

The hydraulic lifter requires roughly a .030" pintle depth setting. This means that you adjust valves by the depth that the pintle in the lifter drops. Too tight and the valves do not close, too loose and they rattle and do not open properly and damage the lifter. How do you get .030"? Well, on new engines I will actually use a dial indicator and measure the depth of travel. On an engine in the car this is a bit different, and harder to do..

 

Now, I have two ways that I use to adjust hydraulic lifters. One uses the "clean" method with the engine off and the other is the messy way with the engine running.

 

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Engine "OFF" Hydraulic Lifter Adjustment:

 

Warm the engine by running it until it gets to operating temperature (15-minutes or so). Have all your tools ready and then quickly remove the valve cover(s) and start the adjustment procedure by using the chart above. With the #1 Intake valve at FULL LIFT (this means that you spin the engine until the Intake valve on the #1 cylinder is fully open ... you can tell this by the rocker arm pushing the down until it goes no further) you can now adjust the "opposite in firing order" cylinder (see the above chart). In the small and big block Chevy engines this is the #6 cylinder. Loosen the rocker (if using roller rockers there is a Jam Nut that you must loosen with an Allen Wrench). Now, with two fingers spinning the pushrod between them to feel for resistance you easily snug the adjustment nut. When you feel resistance STOP, now you will adjust the nut down "Only" 1/8-1/2 turn. If you operate your engine a consistent high RPM, use the lighter setting (1/8 turn).

 

What is 1/4 turn? (see image at right)

Well, imagine the hands on a clock. You have the obvious 12:00, 3:00, 6:00, and 9:00 settings as well as the numbers in-between those. If you start with your wrench at the 12:00 position and turn it clockwise to the 6:00 position you have just made 1/2 turn. Going from 12:00 to the 3:00 position would be 1/4 turn.

 

 

 

What is 1/4 Turn?

click image to enlarge

 

Now, you will do this for all the intake valves and then do the exhaust valves the same way.

 

PRECAUTION: If you have an older high mileage engine that the lifters bleed off pressure (drain the oil out of). You can improperly adjust your valves. You need oil in the lifters to be able to get an accurate setting. If you repeatedly adjust the valves this way and they are still not correct, you probably have lifters bleeding off during adjustment. You have two options: Replace the Lifters -= or =- adjust the valves the "HOT" method as below.

 

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Engine RUNNING Hydraulic Lifter Adjustment:

 

Ok, so you really like messes? This has to be one of the most miserable maintenance procedures if you do not properly plan ahead.

 

Some helpful hints:

 

*

 

Adjust only one side of the engine at a time.

*

 

Use oil restrictors on the rocker arms, or better yet a butchered up valve cover that has an access cut into the top of it to facilitate adjustment access.

*

 

Stay calm ... you WILL get burnt, you WILL make a mess and you WILL not look forward to doing this again, especially if you screw up the first time.

*

 

Using a mechanic's stethoscope can substantially make this procedure easier

 

Adjusting hydraulic lifters with the engine running is not one of my favorite activities (as you can tell). With the above considerations taken care of, start the engine and loosen one of the rockers. You should hear it just start to "clatter". Slowing tighten it down until the "clatter" just stops and then turn it 1/4 - 1/2 turn additional to set the pintle depth. Continue on all the valves. If you hear excessive noises or the vehicle runs crappy you will be doing the procedure again. As stated above, if you have access to a mechanic's stethoscope, you can set the end at the top of the rocker stud to listen to the noise a loose adjustment makes, which will make finding "zero" lash easier.

 

NOTE: If you make a mess, PLEASE check your oil level once you are done.

 

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Solid Lifter Adjustment:

 

First warm the engine to operating temperature (about 15-minutes) and then quickly remove the valve covers. Follow the chart above. With the #1 Intake valve at FULL LIFT (this means that you spin the engine until the Intake valve on the #1 cylinder is fully open ... you can tell this by the rocker arm pushing the down until it goes no further) you can now adjust the "opposite in firing order" cylinder. In the small and big block Chevy engines this is the #6 cylinder. Loosen the rocker (if using roller rockers there is a Jam Nut that you must loosen with an Allen Wrench).

 

Now, based upon your cam card (cam specs) you should know what the valve lash setting should be. Let's say that your valve lash setting is .022". Get out the .022" feeler gauge and place it between the top of the valve stem and the rocker arm tip. Snug down the rocker "just" until you begin to fell resistance. The valve lash setting should not be tight ... the feeling should be about the same as putting a knife through a stick of cold butter. Not too hard, not too soft. Now, hopefully you are using "positive-lock" rocker arm retention instead of just pinched rocker nuts or Nylox. If using rocker nuts your job is done, go to the next valve. If using positive-locks, hold the body of the lock in place with a box end or open end wrench (there are special tools for this available) and then tighten the Allen screw.

 

NOTE: In most cases the Allen screw will make a slight "click" when it is tight. Now, go adjust the remaining valves.

 

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Closing Remarks:

 

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You can change the power band a bit when using a solid lifter motor by varying valve lash settings. A looser lash setting increases the low-end power of the engine where a tighter lash increases top-end power. Also, be careful because the valve lash is the "Cooling Time" that the valve needs on each cycle. If you have no lash you take a chance of burning the valves.

*

 

Using roller rockers dramatically increases valve guide life, increases horsepower and also maintains better valve lash settings. Use them when you can!

*

 

Too loose a valve lash setting can damage valve stem tips as well as roller rocker tips, and can crack OEM stamped steel rocker arms.

*

 

Engine materials, engine operating RPM and valvetrain deflection contribute to varying valve lash settings. The higher the RPM, the cheaper the parts you use and the different types of materials contribute to sooner need for valve lash adjustments. (By the way, while you are in there ... test your valve spring pressures).

*

 

There is FREE horsepower when using Roller Cams ... if you can afford it, do it. Plus, when using roller cams, you can change cams without the need to change lifters which is mandatory with Hydraulic or Solid "tappet" cams.

 

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[waynekarnes]

maybe this is easier to figure out, less technical ... from another website ...

 

Start over adjusting ALL your valves using the Exhaust opening/Intake closing method adjusting/setting lash on 1 cylinder at a time.

 

To make things easier start with the #1 cylinder (driver's side at the front) and before cranking be sure to ground the coil wire.

 

Observe the #1 exhaust valve rocker (which is directly over the header tube for that cylinder).

 

When it just begins to open the valve (rocker nose rotating down) stop and you are now in position to adjust the intake valve on that cylinder.

 

Loosen the poly lock and back off the set screw.

 

Now slowly turn down the poly lock with your fingers until it just seats on the rocker's fulcrum. Now back it off a 1/2 turn and rotate the pushrod between your fingers. You'll find that it spins rather easy.

 

Now continue to rotate the pushrod this time while slowly tightening the poly lock again with you finger. As it seats on the fulcrum you'll feel the pushrod now having a slight resistance aka ZERO LASH!!

 

At this point the intake valve on the #1 cylinder is at zero lash and you now move on to adjusting the exhaust valve. Do NOT tighten the set screw at this time IF you are going to add preload!

 

Next you observe the #1 intake valve (directly over the spark plug for that cylinder.

 

When it fully opens (nose of the rocker rotated completely down AND rotates back up to the point the valve is almost closed (back on it's seat), stop and you are now in position to adjust the #1 exhaust valve.

 

Same procedure as above.

 

Loosen the poly lock, back off the set screw and turn the poly lock down with your fingers until it just seats on the rocker's fulcrum.

 

Do NOT proceed beyond the #1 cylinder until you are confident you've set zero lash correctly.

 

Develop a feel for it.

 

Once you're certain move on to #3 cylinder, then #5 and so on.

 

Upon completing the adjustment of all valves/lifters, you can now set preload (hydraulic cams only) regardless of where the lifter is positioned on the cam's lobe.

 

Your choice 1/8 to 1/2 turn IF you feel you must.

 

Just place a box wrench on the poly lock and position it as it relates to the hands of a clock.

 

Best to use 12-3-6 or 9 o'clock positions.

 

If you want 1/4 turn of preload then with the wrench at 12 o'clock turn clockwise (tighten) to the 3 o'clock position and you're done. NOW tighten the set screw while holding the poly lock in position without moving it.

 

Continue the same for the remaining valves/lifters.

 

No need to prelube/prime before adjusting the valves if done correctly!

 

Same procedure is used for solid cams as well. However instead of setting zero lash, when in position to adjust you'll set the lash required (per cam card) using a feeler gauge.

 

To verify the lash is correct use the go-no-go method.

 

What that means is that if your cam calls for say .022 lash then a .021 will go and a .023 gauge will NO go.

 

Now wasn't that easy?

[waynekarnes]

opps, skip the set screw part of that message ... the method is correct ... just no set screw ... instead you just tighten the roker arm nut.

 

i think i borrowed this from one of my favorite VW websites.

 

if you over tighten the rocker arm nut, the valves will not close and the engine will run like crap or not start at all. ( the voice of experience speaking LOL ).

 

good luck, wayne

[Guest butlersZ]

Ok, well all that was a little confusing but I think I got it. Would it possible to adjust the valves by cranking the engine to TDC one cylinder at a time on the compression stroke and adjust both valves at the same time, then proceed to the next cylinder? At TDC on the compression stroke would either of the valves even be slightly open?

[waynekarnes]

that's how i did mine, adjusted half the intakes, half the exhausts with engine on the timing mark, turned the engine over so number 6 cylinder was on the mark ( i think, 180 degrees from where i was ). adjusted the rest of the valves.

 

only i tightned down an 1/8 th of a turn. half a turn was too much, 1/4 turn also too much ... at half turn, valves were open and engine wouldn't start. 1/4 turn started, but ran like crap.

 

i did this when i put the heads back on after a valve job. i didn't replace the cam, might be going flat or may be a high lift cam. i don't know ... previous owner bought a rebuilt engine from a wrecked car. he has no idea what is in it. i don't know which would cause the valves to stay open with a quarter turn. my guess would be a high lift cam. i also replaced the lifters and push rods when i did the valve job. one lifter was scarred. i don't think this would be the issue, they are both stock chevy parts.

 

i am thinking of changing to high ratio rockers, but then, i might end up with valves that won't close again ... wouldn't that be a kick in the head ???

[waynekarnes]

how's this ?? easier ??? this is the way i did mine ... ignore my most last post instructions, i was mistaken about the 180 degree turn, it is 360 degrees.

 

do it this way and you will save a bunch of time ... works really well.

 

 

Small Block Chevy Valve Adjustment Order

 

0 deg TDC, both number one valves shut.

 

both intake and exhaust on the number one cylinder are closed.

 

Adjust the #1 exhaust valve

 

Adjust the #1 intake valve

 

Adjust the #3 exhaust valve

 

Adjust the #5 intake valve

 

Adjust the #7 intake valve

Adjust the #2 intake valve

Adjust the #4 exhaust valve

Adjust the #8 exhaust valve

Now rotate the engine 360 degrees. The mark on the balancer should be back at the TDC mark. Keep in mind that this is not the TDC where #1 would be firing! It's where #6 would fire.

 

both the intake and exhaust of number 6 cylinder are closed.

 

Adjust the #3 intake valve

Adjust the #5 exhaust valve

Adjust the #7 exhaust valve

Adjust the #2 exhaust valve

Adjust the #4 intake valve

Adjust the #6 exhaust valve

Adjust the #6 intake valve

Adjust the #8 intake valve

 

again, hold the push rod between finger and thumb, twist the push rod, tighten the rocker arm nut, when you start to feel resistance, when the push rod gets hard to easily turn with your finger and thumb, that's when you give the rocker nut a 1/4 turn and STOP ! that valve is now adjusted, move to the next one and repeat, until you have done all 16 of em.

 

hope this makes it a little easier for you ...