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#1
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Valve Lash adjustment
Hi folks! Looking for some help on valve lash adjustment. I have searched and read many posts on this and have only confused myself more lol. I am rebuilding a 350 out of a 79 chevy 1/2 ton and have found myself at this stage in the game. To help you guys out i replaced the engine with New lifters and a energizer cam from crane. Now i have tried adjusting 2 ways, 1st way (per chiltons) at tdc 1 adjusting the exhaust and intake valves described then rotating engine to tdc 6 and finishing it up by adjusting the remaining. Lash adjustment was found by adjusting nut until there was no up and down movement then i turned 1 complete turn. 2nd way was per a friend of min Start and tdc 1 and rotate push rod and tighten nut until resistance was found then rotate 3/4 turn rinse and repeat in firing order.
Know heres where it gets interesting, After i have done this and rotated teh motor back to 1 i feel where some of the arms are extremely loose to teh point where they will almost and some will come completely of the rod. Its usually only one of the two per cylinder intake or exhaust. Any help will be apreciated. Thanks in advance. Sincerly, Scared.. P.s i did prime the oil pump if that is some info that someone needs..... ![]() |
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#2
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re: Valve Lash adjustment
Well what I do is to set them all a little loose. Just a little. Then with the engine running tighten until they stop clattering. Then an aditional 1/4-1/2 turn. Cause on a new cam if your set to tight it will flatten the cam.
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#3
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re: Valve Lash adjustment
All I do is get each cylinder on TDC one at a time and tighten the rockers until there`s no play, then fire it up and adjust them with it running, even so it`s somewhat sloppier this way, I`ve never liked the other methods of adjusting rockers.
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#4
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Valve lash
Going by the chilton's way should get you pretty close. I usually soak my lifters for several days to make sure they are bled of air so when I do the adjustments I do not have to worry about them bleeding back down and trying to adjust rockers arms to take that slack back out as I rotate the engine. I've noticed over the years when they are just about perfect that there is about 4 threads showing on the rocker stud, even the ones from the factory when you pull a valve cover off. If you have them close I would crank the engine up and let it pump up the lifters to make sure of your adjustments, just like Double Vision stated.
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#5
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valve adjustment
#1 sounded good to me, after the run through on # 1 cyl, then on # 6, if you did it correctly, ( I turn the push rods as I adjust the nuts until I feel some resistance then stop. I recheck on #1 settings afore I move on to #6. Oncer I set and rechecked them, I crank the engine, (sorry, I have some clips I got somewhere years ago, that clip on the rocker arms to keep oil from going everywhere while I adjust the valve) with the engine running I start at # 1 cyl. and tighten them 1 valve at a time until they stop clicking, then move to the next, and so on until I've gone through all the valves. sometimes i'll have to back track, cause one will start ticken again. just tighten enough to stop the tick. After going through them all, and getting them quite, I start at one again. I loosen one until it start click en, then slowly tighten it until it stops, the tighten it 1/4 of a turn at a time, letting the engine smooth out as the lifter bleeds down, until I gone 1 complete turn. I have have people tell me they only go 1/2 a turn. I think that if you don't go the complete turn, you want get the total cam action. Now you didn't say, but I hope this is for a hyd lifter and not a solid lifter. The loosest after your adjustment sounded like you had missed some. Hope this helps, sorry its so long.
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#6
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re: Valve Lash adjustment
I do just as Restore60 said.Soak the new lifters,then prime the oiling system until you get flow from each pushrod.I set inital lash per the book,then start engine and twist each pushrod with fingers while slowly tightening.At the point where there is slight drag on the pushrod I turn it down 1 full turn.I have a set of valve covers that have the intake side removed with the top bent outbound of the intake to catch any slinging oil also,oil on the headers or exhaust manifolds while running make for a smokey good time.
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#8
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primin lifters
We always submerged them ( up right) in the oil we were going to use, then using a push rod, push down on the top center. I have and old dist. that i install and hook a slow speed 1/2 in. drill to and run until i get oil out each rocker, then i know the system is primed. don't forget to pull the oil pressure outlet, an oil pressure gage is nice, lets you know how much pressure its building, of which i could care let as long as there is oil coming through.
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#9
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re: Valve Lash adjustment
Hold the phone!! Everyone cover their toes cause I am about to start stomping...... We have covered this many times. Chiltons is a piss poor way to set lash as is the method with the engine running. The only proper way to set lash is one cylinder at a time when the engine is on the stand before it is fired. You set the exhaust valve when the intake valve opens and has about half closed and the intake valve as the exhaust starts to open. What this does is insure that the valve is on the back side of the lobe opposite the ramp. Using chiltons method you have some valves that are actually starting to open. This is especially true for engines with agressive cam profiles. Using the running method you either beat the piss out of the BRAND NEW cam while it is breaking or you let it idle while you set the valves....either is bad.
If you set the valves properly one cylinder at a time you can go 1/4-1/4 turn past zero lash and you are set from now on. I never take the valve covers off of an engine once I have cranked it unless something is wrong and have never had an issue with not having the valves set properly. Chris |
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#10
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re: Valve Lash adjustment
Whew Turbo....it is a good thing I wear steel toes.I do not argue the way you set lash at all.I set mine the way I stated,never have had a problem.I like setting mine once the engine is hot.That is just my method.I did not swear by it.Damn,you almost got my ankles!!Haha
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#11
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re: Valve Lash adjustment
Hehe....I just could not believe anyone had not mentioned the proper way to set valves yet. I feel it is very important for anyone building engines to know the proper way to set valves. I know that alot of guys use the ole "oil everywhere" method or chiltons method, but I can guarantee you that if you ask any engine builder they will recommend the method I described. If you want to go back and reset them when hot, that is okay as well. Typically this is only needed when we start talking about setting lash on a solid cam engine. In that case, the valves have to be set when warm and absolutely MUST be set one cylinder at a time.
Chris |
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#12
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re: Valve Lash adjustment
I`ve broke in many cams doing it the way I suggested, and I`ve set rockers one in the same, not one problem yet, I still have several cams on the shelf that were broken in like this, they show normal wear patterns and have seen service in several engines, So what one would call proper I would call opinion, as for me it`s whatever works and doesn`t do any harm works for me.
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#13
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re: Valve Lash adjustment
DV, the TDC method you described is probably the closest and will work I am sure since the lobes should be close the the back side of the lobes. What you described is very close to what I described. But, I think we can agree that the chiltons method is not a good practice while it is probably the most used. It flat will not work with solid cams.
With mild hydraulics, it is really not much of a big deal. With solids, it is very important to set the valves one at a time. And, I still believe that setting the valves on an engine that is new while it idles is really bad. Chris |
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#14
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re: Valve Lash adjustment
If for some reason the geometry was off (even though checked) and a valve was kissing a piston, would you still be able to turn the engine by hand? I am feeling some good resistance (from teh crank pulley turnin by hand) however I can still continue to turn it . . its just pretty hard.
Im probably being paranoid lol.
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1997 BMW M3 - 3.2litre Inline 6 cylinder |
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#15
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re: Valve Lash adjustment
Why would you go from adjusting #1 to #6??
The next cylinder to reach TDC is #8. It is only a 1/4 crank turn to get there while on the stand. Another 1/4 crank turn and you're at TDC #4, etc, etc, etc. |