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350 Rebuild, valve noises 1 Attachment(s) Looking for some advise...rebuilding 350 Specs: Dart Pro1 new heads 64cc Chamber, 200cc Intake Runner lunati cam - Hydraulic Flat Tappet, Advertised Duration 276/286, Lift .454/.454 1.6 rods comps comp hydraulic roller alum rockers 1.6 Attaching audio shot right above valve covers to explain consistent noise, replaced matched lunati lifters to ensure no fault(no change) Reset valves multiple times setting at zero lash+1/2 turn, rotating 180, setting 8/8... Any further questions please ask...looking for ideas...spins nicely and starts effortless. Thanks in advance for any insight! Mike |
Re: 350 Rebuild, valve noises That is an interesting sound. You can't set the valves in just 2 positions of the crankshaft - 180 degrees apart. You are not even close enough right now to loosen one rocker and listen for the tick because you have multiple ticks. You will have to use the EOIC method - Exhaust Opening, Intake Closing to get back on track. https://www.google.com/url?sa=t&rct=...qj0ywOFfkXuQMp Since you have a hydraulic flat tappet camshaft, you WILL need to do the proper 20 minute break-in process. |
Re: 350 Rebuild, valve noises Yeah that "Chilton's" method of setting the rockers only works for the WEEEEEEEEEENIEST of weeeenie stock cams. Totally worthless for anything aftermarket. The EOIC method is probably the eeeeziest for most people. Works great, definitely a good option. The most accurate is to set each valve at the point where the same valve of the cyl 4 cyls away in the firing order is at peak lift. So for example, you'd set the #1 intake when the #6 intake is at peak lift. (firing order is 18436572; #1 & #6 are 4 cyls apart) Eeeeeeziest way to do that is, pick a valve any valve, and turn the motor by hand until it reaches peak lift; then set the one as described above. Once you find the 1st one, the other 7 valves of that kind are all at exactly 90° intervals of the crank, in the firing order: you can find one, turn the crank EXACTLY ¼ turn (90°) and set the next in the order, turn it ¼ turn again, and so on. It will take 2 full revolutions of the crank to get to all 8. Then find a valve of the other kind, set its companion, then repeat the 90° exercise for 2 more crank revs. Either way, either the EOIC method or the 180° method, that will put you at the "heel" of the cam lobe. Once there, loosen the rocker until you can jiggle the push rod UP AND DOWN, and tighten the rocker until you JUST BARELY can't move the push rod UP AND DOWN any more. DO NOT use the "spin the push rod between your fingers" method!!! Repeat, DO NOT "spin the push rod"!!!! You will come up with inconsistent, aka WRONG results, EVERY TIME. The point at which the push rod stops being able to be moved UP AND DOWN is "zero lash". From there, add your desired preload; I'd recommend ½ turn after zero lash is reached. Then once you have them set as close as you can with the motor not running, start it up and let it get hot, without letting the RPMs go below 1500 or so; then use the truly most accurate method, at idle. Which is, back each rocker off, one at a time, until it starts to clack, then tighten until it JUST BARELY quits clacking. Go through all 16 as quickly as you can that way, should take no longer than a minute to do them all. DO NOT try to add preload at this stage, just do the clack/no-clack thing to all 16 as fast as you can. THEN shut the motor off and add preload to all of them, put the VCs back on by gluing them down, COMPLETELY reassemble the engine (all hoses, wires, etc.), make sure all fluid levels are correct, close the hood, get in, and drive it for about 20 minutes to a half hour. During this drive, DO NOT do any full-throttle pulls to top RPMs, DO NOT let the motor idle for more than a few seconds at a time, and DO NOT let it run at the same RPMs continuously for more than a few seconds at a time. DO NOT let the RPMs go below 1800 or so for any more than a few seconds. I prefer to get on the freeway, use about half to 2/3 throttle in 2nd or 3rd gear to let the engine run from maybe 2500 to 4500 RPM or so, then leave it in that gear and take your foot off the gas and let the motor brake the car back down to 2500 RPM. Do that 4 or 5 times, then let it drive somewhat normally for a minute or so, then repeat. Do at least 5 repetitions of that, preferably more. |
Re: 350 Rebuild, valve noises
Originally Posted by phibberz80
(Post 6331035)
comp hydraulic roller alum rockers 1.6Mike I had a set of their ultra gold and they were the nosiest rockers I've ever herd! Replaced with the magnum chromoly ones and been happy with them. |
Re: 350 Rebuild, valve noises To add to what Sofa described, here is a chart to follow. https://www.centuryperformance.com/v...procedure.html |
Re: 350 Rebuild, valve noises :thumbsup: Good chart. I've never seen that method in print before, but that's pretty good. The EOIC method is well covered by the cam mfrs and others, and is a valid choice as well, especially for hydraulic valve trains. I would add, as far as tightening the rockers: There's NO WAY to tighten the Allen in a polylock tight enough to permanently guarantee that it won't break loose. In fact, that might be what happened in this case. It will work well enough as you find zero lash and stop the clack, but you don't want to leave them that way; one nice high-RPM blast will buzz them right off of there. Instead, use a box-end wrench on the polylock and a key or whatever on the lock screw; and just before you reach your preload point after you shut the engine off, tighten the Allen with your key or whatever, and then for the last little bit of tightening on the nut (maybe 1/32 of a turn), tighten the NUT AND THE ALLEN TOGETHER. Don't get too carried away with this though, it makes the set screw REALLY tight, like 10 times as tight as you can tighten it with a key, and can even put enough force on the polylock to split the set screw thread part of it right off. (ask me how I know this...) |
Re: 350 Rebuild, valve noises
Originally Posted by sofakingdom
(Post 6331310)
:thumbsup: Good chart. I've never seen that method in print before, but that's pretty good. The EOIC method is well covered by the cam mfrs and others, and is a valid choice as well, especially for hydraulic valve trains. I would add, as far as tightening the rockers: There's NO WAY to tighten the Allen in a polylock tight enough to permanently guarantee that it won't break loose. In fact, that might be what happened in this case. It will work well enough as you find zero lash and stop the clack, but you don't want to leave them that way; one nice high-RPM blast will buzz them right off of there. Instead, use a box-end wrench on the polylock and a key or whatever on the lock screw; and just before you reach your preload point after you shut the engine off, tighten the Allen with your key or whatever, and then for the last little bit of tightening on the nut (maybe 1/32 of a turn), tighten the NUT AND THE ALLEN TOGETHER. Don't get too carried away with this though, it makes the set screw REALLY tight, like 10 times as tight as you can tighten it with a key, and can even put enough force on the polylock to split the set screw thread part of it right off. (ask me how I know this...) Stud girdles also help keep locks from backing off, provided you get the correct one for your heads. I like Jomar's |
Re: 350 Rebuild, valve noises
Originally Posted by sofakingdom
(Post 6331310)
:thumbsup: Good chart. I've never seen that method in print before, but that's pretty good. The EOIC method is well covered by the cam mfrs and others, and is a valid choice as well, especially for hydraulic valve trains. I would add, as far as tightening the rockers: There's NO WAY to tighten the Allen in a polylock tight enough to permanently guarantee that it won't break loose. In fact, that might be what happened in this case. It will work well enough as you find zero lash and stop the clack, but you don't want to leave them that way; one nice high-RPM blast will buzz them right off of there. Instead, use a box-end wrench on the polylock and a key or whatever on the lock screw; and just before you reach your preload point after you shut the engine off, tighten the Allen with your key or whatever, and then for the last little bit of tightening on the nut (maybe 1/32 of a turn), tighten the NUT AND THE ALLEN TOGETHER. Don't get too carried away with this though, it makes the set screw REALLY tight, like 10 times as tight as you can tighten it with a key, and can even put enough force on the polylock to split the set screw thread part of it right off. (ask me how I know this...) I have a 302 SBC that spins 8000 rpm and I cannot use t-bar valve cover hold downs. They vibrate right out. But that would be minor compared to poly locks loosening at high rpm. :eek: |
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