Aside from the usual crap that I have been reading here. I just wondered if anyone could tell me the procedure for adjusting 350 chevy valve lash while the motor is running. Number of turns etc. Using hydrolic lifters. Thanks
Back off the nut until the rocker is loose, tighten to just take the play out, and then 1/4 turn more. Mutt
Yeah, my mind hasn't had enough coffee yet. Should have said turn 1/4 turn, wait 5 seconds, then repeat until you have 1 full turn. Thanks for the heads up. Today has all the earmarks of being a crappy day Mutt
i wouldnt set them with the engine running, but if you do, take up the slack, when they stop clicking, a 1/4 to 1/2 turn is plenty! do not crank it down a full turn while it is running. do a search on here, this was discussed a while back, and the description of how to do it while engine is off was posted, even then 1/4 turn is plenty, 1/2 turn if you are really gonna wing the engine i think Rocky had a good post on it, maybe he can cut and paste it here? i can not find the one i wrote.
Racefab is right...I go between 1/4 and 1/2 turn on running motors myself. You can get it DAMN close by cranking the motor till it has oil pressure, then rotating the balancer with a breaker bar to get it where both valves are CLOSED on a cylinder. Tighten the nut until you can still spin the pushrods with your thumb and index finger, but there should be some 'drag' on it. If you start at TDC and rotate the crank in several incriments doing this, you'll have all the rockers adjusted really close to perfect! (I do the 'running' method just to double check my work sometimes, but it's usually within 1/8 of a turn!)
on the big Chevs, basicly the same setup, I set them cold, not running at an eighth turn past zero. I roll the motor over to TDC compression stroke on the number one cylinder and adjust both intake and exhaust. then with a breaker bar on the dampner bolt I roll the motor over exactly one quarter turn watching the marks on the timing tape I put on the ballancer and adjust both valves in the next cylinder in the firing order. I continue like that till all are adjusted. don't know if it's the best way, but it works for me. Paul
I gave him the Motor's spec. They recommend as I stated, with the five second wait between 1/4 turns for the lifter to set before continuing, to get to one full turn. I agree that it's best to set them with the motor not running. Mutt
One full turn from zero lash is just too much preload on hydraulics IMO. Thats the dealership adjustment for civilian cars that will see no maintainance for 50,000 miles. At one full turn the preload on the plunger is such that at full rev you take a chance on the lifter pumping up and holding the valve off the seat limiting the RPM potential. A small point I know, but if you've ever drag raced with hydraulic lifters every little bit counts. I go 1/4 of a turn past zero lash and relash my street engine about once a year. Frank
Saved from a while back.... The Subject: Re: valve adjusting-SBC Desoto wrote: 1. Warm-up the engine and remove a valve cover. 2. Restart the engine and let it idle (as slow as possible to prevent massive amounts of oil splashing around) 3. Loosen an adjuster nut until the lifter clacks. Go a bit more so that the lifter can fill itself with oil. SLOWLY turn the nut back down until the clack diminishes then stops. 4. Go 1/4 more turn and move on to then next valve. 5. Do this for all 8 valves then go back and turn them ALL down 1/4 more turn each. 6. Do this one more time so that you have a full 3/4 turn of pre-load on the lifters. Sometimes, 5/8 is better than 3/4 so only go an eighth of a turn on the last go-around. Repeat the procedure on the other side. 7.Stock lifter settings are usually 1 full turn. The looser you leave them, the better top end you'll get and it'll help the exhaust valves stay a bit cooler as well. 8. The reason you only go a quarter turn at a time is to give the lifter a chance to stabilize. Otherwise you'll stall the engine if you try and crank the full 5/8 or 3/4 turn in all at once.
Thanks Bustingear and Dr. J for the excellent question and step by step. I just got done installing a new head gasket after mine cut loose and had the exact question. I tried to the the valve adjust just right but had some question. I read this post and had the confidence to go and re-adjust while running. That made all the difference. The motor runs great. I love you guys, man; and I love the HAMB.
The way I set them on hyd or soled is warm it up then shut it off. take off one cover at a time. Bump it over till the INTAKE valve goes SHUT on a cyl. then bumb it another 1/4 to 1/2 revalution. Set both valves on that cyl. Now go to your next cyl and repeat till one side is done. Put cover back on and warm it up then do the other side. I set hyd.1/2 turn past 0 lash soleds whatever your cam calls for. This allso works turning it over by hand and does work with all cam grinds. On hyd. you find 0 lash by turning push rod with your finger as you slowly tighten rocker till you just start to fill drag on push rod.Thats 0 lash Make shure you are not pushing down on the rocker with you socket when you are getting 0 lash
[ QUOTE ] Thanks Bustingear and Dr. J for the excellent question and step by step. I just got done installing a new head gasket after mine cut loose and had the exact question. I tried to the the valve adjust just right but had some question. I read this post and had the confidence to go and re-adjust while running. That made all the difference. The motor runs great. I love you guys, man; and I love the HAMB. [/ QUOTE ] You're welcome but I can't take credit for that particular writeup. as stated, Skip Readio/aka/Desoto wrote it and because I know it works and he doen't post here often, I posted it, because it's good info. I just saved it, I'm just the messenger.
Big timesaver on Chevy V-8. With engine in position for #1 to fire set exhaust 1-3-4-8, intake 1-2-5-7. With # 6 in position to fire adjust exhaust 2-5-6-7, intake 3-4-6-8. Saves a buch of time, catches them all. I always set lifters at 1/4 turn past zero lash & leave them at that.
The problem with trying to set hydraulic lifter preload without the engine runniong is that you have no reference point unless the lifter is up against the snap ring to start with and you can feel the plunger starting to move down. Most of the time, however, you'll be well down the bore of the lifter when you think you're just starting to preload the piston. THAT's why it's best to set hydraulic lifters withe the engine running. When the egine is running, the oil pump is replenishing the spent oil. When you loosen the rocker off so much that the lifte clacks, you know you've gone beyond the zero-lash point. You can gradually bring it down to the zero-lash point (it stops clacking) and go from there to set whatever preload you want. BTW, thanks for saving my post.
I am trying to learn about lifters as it's one more thing I have never tackled. Is "lash" when the lifter is clicking and needs adjustment?
Gonna bring this one back up. Did a G search for my Q and was led back to teh HAMB I just installed a new cam. New hydraulic lifters as well. My question is, how do you do this with new lifters before you start the motor? help
Ive worked with some of the engineers from Detroit, who ever said the 1 full turn adjustment is dealer spec is correct. That's based on a nice STOCK spec. engine with no machining or mods., and all stock components. Take a 30plus year old used engine with unknown history, maybe some swap meet domed pistons, an lumpy cam, old cast iron heads milled .030", block decked .015", who knows what head gaskets, and you tighten down 1 full turn past zero lash- your asking for trouble. There will be no room for error if you miss a shift or over rev the engine. 1/4 to 1/2 turn past zero lash is 100% safe and correct. There is only about .125" , an 1/8" or less of plunger travel inside a hydraulic lifter, sometimes much less. Milled heads, decked block, and some thin .015" head gaskets, and you have already used up 1/2 of the travel in the lifter- with ZERO LASH. BDM
Lash, is the amount of clearance between two components, in this case in the valve train. The tip of the valve stem to the rocker arm tip or roller, pushrod upper end to rocker arm, and even the top of the cam lope to the base of the lifter. When there is no gap or clearance between any of those points, you have zero lash. { Please dont be critical and ask about the amount of oil film }. Some hydraulic lifters have very light internal springs in the lifter body supporting the plunger. One has to be very careful when establishing zero lash, that you have NOT used up any of the clearance or travel downward of the plunger. When cold static zero lashing of the valves sometimes people feel for the pushrod to no longer turn and believe this to be zero lash. This is CORRECT, but, only someone very experienced should do the setting in this manner. A better method is to feel when the pushrod no longer has any up and down lateral movement, while tightening your adjuster. This will ensure you are not compressing the plunger into the lifter body. That is zero lash, and then 1/2 turn tighter, and you have correctly set a adjustable hydraulic lifter. When performing this while the engine is running, yes, the clicking is when you begin to have clearance between the components. BDM
When adjusting a Hyd Cam, Always remove the tool as to hear the Tapet clater, after the slitest turn of the nut. As the socket will silence the taping of the Tapet. 1/2 turn to 3/4 turn is fine after clater stops. Sneek up on the adjustment, as you can go wright past the point of no last. This is the point that, the valve train, cam / lifter / pushrod / rockerarm / valve stem, all make constant contact under power. Use a a small 3/8 breaker bar, as this makes tighting and loosing easier. Don't be afraid to loosen the nut one turn after you acheive the adjustment needed. You will hear the the clater again,(removing the tool) retighten the one turn, this will allow the beginner to have the confindence in work. In you hear ths idle slow down, wait a few and the it will return and smooth out. If you have an old set of valve covers, hole saw a 1 inch hole above all of the rocker studs. Insert your socket thru for adjustment. Glue a set of cork gaskets on for sealing. The hyd lifter has a pocket of oil retained in it all the time, this is what keeps the valve train in constent contact , and keeping it quiet. act's like a very small impact dampner, takes the pounding of of the valve train.
You can call Lash whatever you want, I call the clearance between the rocker tip and the valve stem lash. But usually I run solids so I call it valve clearance. We use to call adjusting the valves...running the lash. Lots of different lingo. When I build a new engine, I set them with the intake manifold off. I can see the lifter plunger and set the lifter preload easily. Plus I fill the engine with oil in the lifter valley. Easy. Put the intake on and good to go. Run it for a few miles and readjust the valves, drive the crap out of it.
I have never EVER set hydraulic lifter lash when the engine is running. I set 'em cold at 1/2 turn and have never had a problem. That's what works for me. I did try (a long LONG time ago) to set them with the engine running (and did not succeed) .... never again, pain in the ass, messy and basically no point to it. After setting them cold, I apply silicone to both sides of the cover gasket because I know for a fact that I will not have to remove the covers again unless I am going to remove my intake manifold. This is simply my opinion and my experience. Your results may vary.
I dredged up a thread that had been dead 3 years. I read all that and found this thread the best place to ask my question. How to adjust when its all new. Before startup. WIthout running it.
check the links below......... http://www.cranecams.com/faqview.php?s_id=41 http://www.youtube.com/watch?v=89o5rLpbCgI
I did them the same way I do all flat tap engines . I tighten the rockers down till they touch the lifter and do all of them . Now pull the distributor and prime the engine oil system until it holds good oil pressure for a few minutes . Now set all the rockers till you take the slack out but don't tighten anymore . When all is done , prime the oil pump again to make sure there is good oil pressure through out the engine . Drop the distributor back in . Start engine and do the final adjustment . Tighten 1/4 turn once the "tap sound" is out . You can tighten the final 1/4 turn when engine isn't running but with a new cam and lifters I really don't want to put the full pressure from the stronger valve springs on the lifters that fast . I have done it this way for many years and I have never had a problem . Now after the cam & lifters are broke in properly , time to check all the adjustments again with the engine running ! After about 1000 to 2000 miles , I always recheck the lifter adjustments again . After that I change the oil and drive it until I change the oil again , As long as I don't hear any problems I just keep driving . It doesn't hurt to check the adjustments again after about 25,000 miles . That's just the way I do them and I get great performance and mileage from my engines that way ! Retro Jim
gasser300, if you have any questions or issues while adjusting your valves, PM me and I'll give you my home number, I'll be working on my T tommorrow too. BDM
Did any of you guys know that you get better engine vacuum with the rockers adjusted 1/4 of a turn from "0" instead of a 1/2 turn or more??? It's something to think about..... The better the vacuum readings, the happier the motor will be. I also set the lash cold without the intake bolted on on a fresh engine build...
Gasser300, here is how I adjust a SBC with hydraulic lifters.....taken directly from a book. Rotate the engine clockwise as viewed from the front until it is on top dead center with the number-one cylinder firing. This is easy to check because the lifters on number 6 will be rocking, that is the intake valve will just be opening and the exhaust valve will just closing. With the crank position at TDC you are ready to adjust the two valves of number one cylinder. To do this, use a box wrench to turn the adjusting nut on its stud until you take up excessive clearance so the pushrod will just rotate between your fingers. In other words you have just taken all the slack out of the system. But you haven't adjusted it so far that you have taken any of the spring-loading action out of the hydraulic lifters. At this point turn the adjusting nut one-half turn farther. This puts the pushrod tip about 75 thousandths into the spring-loaded action of the hydaulic lifter - about half of the lifter travel. Do this on both valves for number 1 cylinder. Now turn the engine over one-quarter turn clockwise as viewed from the front so the lifters on are rocking on number 5 cylinder. When the lifters are rocking on cylinder 5 you adjust both valves on cylinder 8. Here is the chart. Adjust cylinder 1 when cylinder 6 is rocking Adjust cylinder 8 when cylinder 5 is rocking Adjust cylinder 4 when cylinder 7 is rocking Adjust cylinder 3 when cylinder 2 is rocking Adjust cylinder 6 when cylinder 1 is rocking Adjust cylinder 5 when cylinder 8 is rocking Adjust cylinder 7 when cylinder 4 is rocking Adjust cylinder 2 when cylinder 3 is rocking To simplify this, basically all they are saying is turn the engine over by hand until a set of lifters is "rocking" (by lifters "rocking" they mean an exhaust that is just closing and an intake that is just opening on the same cylinder, do not get mixed up and watch lifters for movement from two different cylinders), then use the chart to determine which cylinder to adjust based on which ones are rocking (and remember to adjust both intake and exhaust on that cylinder). Slowly tighten the rocker stud nut until you just feel drag on the pushrod that you are spinning in your finger ... now go 1/2 turn more. Once you've done it once it is easy. Hope this helps. Again, this is for a SBC with hydraulic lifters. I got this info from a book (How to Rebuild Your SBC) and it has not failed me yet. Again, this is the procedure for adjusting a cold engine that is not running.
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