The 1947 - Present Chevrolet & GMC Truck Message Board Network

The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks.com/vboard/index.php)
-   The 1967 - 1972 Chevrolet & GMC Pickups Message Board (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=3)
-   -   valve adjustment (https://67-72chevytrucks.com/vboard/showthread.php?t=326287)

fdbdw 01-30-2009 12:49 PM

valve adjustment
 
350 sb valve adjustment, everyone has a dfferent opinion Ive been told 1/4, 1/2 turn 3/4 and full turn after zero lash any one know for sure or is there away to tell whats best for yours,

BluTrukker 01-30-2009 01:13 PM

Re: valve adjustment
 
My manual says 3/4, but I have found that is too much in some situations. I go with 1/2 and snug up if they make noise when its running

68gmsee 01-30-2009 01:42 PM

Re: valve adjustment
 
Quote:

Originally Posted by fdbdw (Post 3116242)
350 sb valve adjustment, everyone has a dfferent opinion Ive been told 1/4, 1/2 turn 3/4 and full turn after zero lash any one know for sure or is there away to tell whats best for yours,

The reason you have so many opinions is that no two engines are going to have the same type of wear or identical parts. Some require tighter adjustment than others.

You have a standard that the books call out for most vehicles. I adjust mine like BluTrukker mentioned when I install new lifters: remove all lash and turn an additional 1/2 turn. It may vary plus or minus a little.

tim21391 01-30-2009 02:13 PM

Re: valve adjustment
 
mine is set at 0 plus a half.. but mine is a 402..thought id throw that out there

Wreckless_71 01-30-2009 02:32 PM

Re: valve adjustment
 
I believe if you're building a new engine with tight parts it's gonna be zero lash+1/2 turn. On my old warn out 350 in the 2wd I ended up with zero+3/4 turn. Like these guys said before me it all depends on the engine and who you talk to....

joemacho 01-30-2009 02:47 PM

Re: valve adjustment
 
yeah i was told also 3/4 turn is good enough on a 350.

drewdude92 01-30-2009 02:49 PM

Re: valve adjustment
 
alright noobie here whats 0 lash?

BluTrukker 01-30-2009 02:55 PM

Re: valve adjustment
 
Zero clearance between pushrod and rocker. I spin the pushrod between my fingers as I tighten the rocker down. When you feel some drag and it doesn't spin quite so freely, then you tighten 1/2 turn from there. I'm sure there is a tool for it, but everyone I know goes by feel.

see ten 01-30-2009 03:01 PM

Re: valve adjustment
 
I've got manuals that call for a half a turn and I've got em that call for a full turn...So I split the difference at 3/4 of a turn. It's been working out for us so far.

sflanagan 01-30-2009 03:28 PM

Re: valve adjustment
 
That usually works however for performance applications the valves call for less of a turn due to the high rpm's you run, let's say 1/4 inch turn for constantly high rpm running engines. If your engine is running a stock combo or mild upgrade 1/2 to 3/4 turn will do you just fine....Sounds like you got it though, just food for thought...

cparman 01-30-2009 07:03 PM

Re: valve adjustment
 
I have used this many times, and it is a no mess way to adjust the valves on your small block Chevy. Read the procedure, and what you are looking for is to be able to turn the push rod with a little resistance.


STATIC ADJUSTMENT

1. says to run the engine. On a new engine I always soak the lifters in oil over night. Then do this
2. With engine in position to fire No. 1 cylinder, adjust the following valves: V6-229 and 262, Exhaust Nos. 1, 5 and 6; Intake Nos. 1, 2 and 3. 6-250 and 292, Exhaust Nos. 1, 3 and 5; Intake Nos. 1, 2 and 4. V8 engines, Exhaust Nos. 1, 3, 4 and 8; Intake Nos. 1, 2, 5 and 7. To properly adjust valves, tighten adjusting nut until all lash is eliminated, then tighten nut the specified additional number of turns. On V8-454 / 7.4L engine, tighten nut 3/4 additional turn from zero lash. On all others, tighten nut one full turn from zero lash.
3. Turn crankshaft one complete revolution, which will bring engine in position to fire cylinders 4(V6) or 6(Inline 6 and V8). With engine in this position, adjust the following valves: V6-229 and 262, Exhaust Nos. 2, 3 and 4; Intake Nos. 4, 5 and 6. 6-250 and 292, Exhaust Nos. 2, 4 and 6; Intake Nos. 3, 5 and 6. V8 engines, Exhaust Nos. 2, 5, 6 and 7; Intake Nos. 3, 4, 6 and 8. When zero lash is obtained, tighten adjusting nuts as specified in step 2.

tim21391 01-30-2009 08:24 PM

Re: valve adjustment
 
on my dads mustang all i did was tighten it down snug and it ran perfect..its a 67 mustang with a worn out 79 cougar motor

crm318 01-30-2009 08:46 PM

Re: valve adjustment
 
I think that ford has non-adjustable valvetrain.

dhaymaker 01-30-2009 08:57 PM

Re: valve adjustment
 
There are a number of theories on this and, as many responses have indicated, even the books don't all agree. But one issue, as sflanagan indicated, what your engine is designed to do has a lot to do with the lash. If the engine is designed with higher rpm/horsepower in mind, you want the lash a little "looser". If the engine is designed for lower rpm/torque applications, you want the lash a little "tighter". As mentioned in various responses, a big factor is new parts versus old, etc. Personally, unless it's a well-worn engine, I'm a 1/2 lash kinda guy!

100%Chevy 01-30-2009 09:28 PM

Re: valve adjustment
 
I use the book "How To Rebuild Your Small Block Chevy"
Probably the most used book on the market.Although a little dated now,it's still the single best source of information on small block Chevies.
It calls for 3/4 turn after slight resistance.This is a starting point for me.After starting and warming the engine,I will loosen each(keeping up with the amount I turn the nut)until I hear noise,then re-tighten it till the noise stops.Sometimes it's more,some less.I do this several times on all of them.
On new engines,you may have to do it again later.On worn engines,some lifters may be too weak to ever be quiet!New parts time!
Mike.:chevy:


All times are GMT -4. The time now is 12:55 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com