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#1 |
Alright Alright Alright
Join Date: Mar 2004
Location: Midland, Texas
Posts: 1,672
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valve adjustment confusion
i am currently installing a cam into a 350 and reverted back to an old question i posted a while back when i was doing the same thing. heres the post
http://www.67-72chevytrucks.com/vboa...ain+adjustment if you look at posts 7 (corn) and 8 (rage n rat), they both show the valvetrain sequence, but they are completely diffrent from eachother. one of them is incorrect. the problem now is that i adjusted them according to the # 8 post and my engine has valvetrain noise and the headers glow red hot. did i get screwed on this? im looking for expert advice on this one.
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1972 Cheyenne Chevrolet red and white 357ci, Vortec heads, GM Performance high rise intake, Comp 268H .454/.454 218/218 110 LSA Quadrajet carb, Flowtech headers, 2.25 40 series HEI, Curve kit, TH 350, 3.07 gears 275/60/15s on 15x8 rallies |
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#2 |
Registered User
Join Date: Feb 2007
Location: Winston Salem, NC
Posts: 310
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Re: valve adjustment confusion
I adjust mine according to post #7.
be sure you are at TDC #1 when you start
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#3 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
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Re: valve adjustment confusion
rage-n-rat is word for word number by number out of the factory service manual (a bargin at about $25 from all vendors)
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71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY |
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#4 |
Just hang'n around
Join Date: Nov 2005
Location: Camano Island WA
Posts: 248
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Re: valve adjustment confusion
It's really not that hard. I did mine while it was idling. First you need to get some spray deflectors from NAPA to control oil spray from your lifters. Next, you loosen them carefully until they begin to rattle. Then, you tighten them slowly intil they stop being noisy. Then tighten them no more than one full turn. I do one side and put the valve cover on and then do the other side. There is no order, just one by one. Sometimes when you get a new engine, the first start is with the valves loose.
You more experienced guys might have special tools for this, but I've always done it and seen it done with the engine running. I have over 200k on my engine with no problems.
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Driving a '68 Chevy C20 and a '93 Astro Van. Lots and lots of mileage that I deduct each year. |
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#5 | |
Senior Member
Join Date: Apr 2005
Location: Joppa, Maryland
Posts: 4,408
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Re: valve adjustment confusion
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1997 GMC Sierra Ext 1965 Mustang |
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#6 | |
Registered User
Join Date: Nov 2007
Location: peaster, texas
Posts: 71
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Re: valve adjustment confusion
Quote:
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#7 |
Alright Alright Alright
Join Date: Mar 2004
Location: Midland, Texas
Posts: 1,672
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Re: valve adjustment confusion
well im getting different answers on this from people who are certain, which has been my demise from the beginning. im not trying to discredit anyone, but i have to be certain.
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1972 Cheyenne Chevrolet red and white 357ci, Vortec heads, GM Performance high rise intake, Comp 268H .454/.454 218/218 110 LSA Quadrajet carb, Flowtech headers, 2.25 40 series HEI, Curve kit, TH 350, 3.07 gears 275/60/15s on 15x8 rallies |
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#8 |
Senior Member
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
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Re: valve adjustment confusion
one sure way buy service manual read service manual
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71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY |
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#9 |
Registered User
Join Date: Oct 2006
Location: Arizona
Posts: 835
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Re: valve adjustment confusion
Well, I did mine by adjusting the opposite valve when the other started opening. Worked just fine.
If your headers got hot, it's probably timing more than valve adjustment. I'm guessing it's way advanced.
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67 Short Step, 355, 700R 4.11 posi rear, 4/6 drop Discs on all 4 corners. Build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=219094 |
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#10 |
Just hang'n around
Join Date: Nov 2005
Location: Camano Island WA
Posts: 248
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Re: valve adjustment confusion
On post #7 he talks about wet adjustment. That is the method I described. When you do it "wet", you really get a feel for the proper tune. You can actually hear a feel the engine gradually begin to run properly. While SBC are forgiving, don't gun the engine while doing this adjustment. The wet method only takes about 15 minutes and you're ready to roll.
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Driving a '68 Chevy C20 and a '93 Astro Van. Lots and lots of mileage that I deduct each year. |
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#11 |
Account Suspended
Join Date: Sep 2005
Location: Monroe, WA
Posts: 3,815
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Re: valve adjustment confusion
Post #7 is what I use - the companion cylinder method. It's worked for me a few hundred times
![]() Our old pal Mark has the intake/exhaust reversed - right cylinder numbers, wrong valves. There's no reason to adjust the valves with the engine running IMHO. Last edited by Billla; 04-16-2008 at 03:41 AM. |
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#12 | |
Just hang'n around
Join Date: Nov 2005
Location: Camano Island WA
Posts: 248
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Re: valve adjustment confusion
Quote:
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Driving a '68 Chevy C20 and a '93 Astro Van. Lots and lots of mileage that I deduct each year. |
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#13 |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: valve adjustment confusion
I agree 1000% when talking about a new or rebuilt engine (meaning at least new cam and lifters).
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#14 |
Chasin' the Dream
Join Date: Mar 2008
Location: Lost in the 70's
Posts: 200
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Re: valve adjustment confusion
Wet method here, you simply can't mess it up. (Unless you don't have the rocker clips, or an old valve cover with the top chopped off!)
Sixteen valves adjusted and down the road in about 15 - 20 minutes. Its how my Dad taught me in the '70s. (",) |
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#15 |
Senior Member
![]() Join Date: Jul 2004
Location: Estherville, Iowa
Posts: 3,371
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Re: valve adjustment confusion
I like the cold not running method - but i do it running wih the old cut valve cover if there is a possible problem-
From Chilton manual the greasy page I always use- No 1 firing position - balancer at 0 deg exhaust 1 3 4 8 intake 1 2 5 7 No 6 firing position - just set the rest that are loose but for the record - exhaust 2 5 6 7 intake 3 4 6 8
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1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0 |
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#16 |
fugedaboutit
![]() Join Date: Mar 2005
Location: Gresham, OR
Posts: 832
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Re: valve adjustment confusion
I went down this road when i got my motor going and the answers I got from mechanics is- use the dry method to get it going and close, and the wet method for a final adjustment. There reason was the hydraulic lifters need to be pumped up (full of oil) to get the accurate reading. Running, they are pumped up.. makes sence to me. I tried the deflectors from napa and another brand as well--big freakin mess!! oil on the headers = major smoke screen! PITA it will still drip. I cut up a set of valve covers as mentioned and did one side at a time. I can take a pic of the valve cover if you need so you get an idea. This was on my first motor build and was freakin out over every little sound and wanted it perfect.. I know your frustrations! Anyway just my .02
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Currently truckless ![]() Last edited by redhead69; 04-16-2008 at 05:53 AM. |
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#17 |
laying low
![]() Join Date: Mar 2001
Location: Searcy, Ark. USA
Posts: 13,276
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Re: valve adjustment confusion
Red brings up another important item. If you are replacing the cam and lifters the lifters will need to be pumped up to get your proper valve adjustment. Running engine pumps them up. With the running adjusting method you near bouts can't get it wrong. Zero the lash and turn slowly up to one turn more. That's it, it's done, put the valve covers on it and wipe it down cause it's ready to roll out the door!
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Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross |
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#18 | |
Just hang'n around
Join Date: Nov 2005
Location: Camano Island WA
Posts: 248
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Re: valve adjustment confusion
Quote:
This method is safely prelubes the engine w/o the need to fire it up. This method can be done with the engine in the truck or on the stand, you pick.
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Driving a '68 Chevy C20 and a '93 Astro Van. Lots and lots of mileage that I deduct each year. |
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#19 | |
Registered User
Join Date: Dec 2006
Location: Idaho
Posts: 210
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Re: valve adjustment confusion
Quote:
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#20 |
Account Suspended
Join Date: Sep 2005
Location: Monroe, WA
Posts: 3,815
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Re: valve adjustment confusion
The valves should be adjusted warm just because the clearances change, but there is no "pump up" of the lifters. If you take a hydraulic lifter apart you'll see how that just isn't possible. With a spring pushing the cup up to the limit of it's travel, what exactly is going to "pump up"?
Look at what the race shops do - how many of those do you see adjusted running? Zero. It's always a charged discussion ![]() |
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#21 | |
Registered User
![]() Join Date: Apr 2008
Location: auburn,al.
Posts: 32
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Re: valve adjustment confusion
Quote:
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#22 |
fugedaboutit
![]() Join Date: Mar 2005
Location: Gresham, OR
Posts: 832
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Re: valve adjustment confusion
Billa you helped me with my motor (thanks by the way!!) and am throwing a few things out to try to learn more so heres a passage out of a book I got
"The operation of the hydraulic lifter is simple. When the lifter is sitting on the base circle of the cam lobe (valve is closed), it fills with oil from the lube system under the plunger. When the cam lobe moves under the lifter (valve begins to open), the oil becomes trapped in the chamber under the plunger. This takes up the clearance in the system, eliminating noise. When the lobe moves out from under the lifter the chamber is opened again to oil pump pressure, and new oil is pumped into the lifter. At the same time, the spring load under the plunger forces it up against the pushrod (or valve). So its full of oil right, and not sealed but open to new cycling oil so they bleed off and pump up ?? or am I lost in this one
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#23 | |
Account Suspended
Join Date: Sep 2005
Location: Monroe, WA
Posts: 3,815
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Re: valve adjustment confusion
Quote:
We're all learning all the time. ![]() The spring presses the cup up against the very top of the travel - at rest, with no oil flow, that cup is going to be as high as it can possibly go. When it's warm, the whole lifter will be a bit taller due to thermal expansion, but regardless of how much oil is in it that cup CAN'T go any higher - fair? The oil just provides assistance to the spring at higher RPM; a spring that would work at 5000 RPM would be too much at idle...this is the beauty of the hydraulic lifter - adjustable tension. The description is right on, but it describes operation at speed, not when the engine is off. When we do a static adjustment (of a warm engine), we're setting preload against the pressure of that spring - that 1/2 turn (or whatever the cam manufacturer recommends) pushes the cup down against the spring. Ultimately, that's what we're after in this whole process - the RIGHT amount of preload. Too little, we have clearance and so clatter...and we're beating on the lifter, cam, pushrod and valve stem tip. Too much, and and the system "goes solid" - there's zero clearance and something has to give - usually the lifter and cam lobe, but sometimes the pushrod, rocker or even valve stem. When we do a "dynamic" adjustment (engine running), we're pushing against a lifter filled with oil in addition to the spring. The lifter isn't "pumped up" - because the cup can't move any higher in the lifter body - but we're setting preload against the spring AND oil pressure. IMHO, this situation makes it easier to add too much preload and it's also error prone...because rather than having a relatively precise means of determining zero lash (pushrod "drag"), we're doing it "by ear" - we're listening for "clatter" and then adding preload. Also, as a newbie - if you screw up and add too much preload (you'll hear the engine bog or stall) - it's too late - you've likely already caused damage at the lifter/cam interface that will show up later as a wiped cam lobe. I see it all the time. There's a fair amount of "give" in a stock or aftermarket lifter, but as we start getting into aftermarket, higher lift cams my experience is that the adjustment becomes more critical - and the flaws in "dynamic" adjustment become more apparent. Finally, you're working under the hood with oil flying and dripping, smoke from oil on the exhaust manifolds and very aware that getting a finger in the wrong place is going to be painful. No thanks. For all the debate, the fundamentals are simple; we need to locate zero lash, and we need to set the appropriate preload. To do this, the valve needs to be on the base circle of the cam, it needs to be warm, and we need to fairly precisely find zero lash...which for all the jokes is done very easily by a newbie by just spinning the pushrod while slowly tightening the rocker nut...and the FIRST TIME DRAG IS FELT we have zero lash. Once you can determine that reliably...everything else is easy. IMHO, the "old way" may work, but if it was "better" I can assure you that you'd see the crate engine companies, racing teams and engine dyno guys using it - and they don't. Last edited by Billla; 04-16-2008 at 08:01 PM. |
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#24 |
Senior Member
![]() Join Date: Jul 2004
Location: Estherville, Iowa
Posts: 3,371
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Re: valve adjustment confusion
The main advantage as I see in doing the valve lash running, is if you have older lifters that may have some varnish or buildup of some kind on the lifter. Sometimes we are working with engines that still run but are 40 years old. You really can't count on the spring in the lifter to push the cup to the top on an older engine that could have some varnish. The additional oil pressure during running can help to position the cup at the top of the travel. Sometimes you have to run it a little loose and let it tick/hammer a while to free up the lifter.
When adjusting warm and running, when you back off the nut, you can tell roughly how much preload was there.
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1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0 |
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#25 |
Truck and auto performance nut
Join Date: Feb 2007
Location: McKinney,Texas
Posts: 3,848
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Re: valve adjustment confusion
I'm afraid I may be dealing with the results of the valve lash adjustment being set while running. I'm afraid one valve was tightened too much and did some damage but am not sure. I'm planning on doing a static adj. today and see what the results are.
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Kurt - '68 GMC short step - NIB '09 LY6 6.0L crate motor w/mods, NIB '12 crate 4L85e w/billet 3k stall Circle D, 3.73 posi 12 bolt, DynaTech f-swap headers, 3/4 drop, handling mods, etc. - my toy '72 Chevy LWB C-10 Highlander - 350/350 ps/pb/tilt/ac - not original but close '06 Chevy TrailBlazerSS - LS2/4L70e - little black hot rod SUV - my DD '18 Kia Sorento - wife's econo-driver '95 Chevy S10 - reg cab shortbed, LS, 4.3, auto... my '68's powertrain and chassis build -links broken A surprise phase - carb to efi -links broken |
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