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How much can I pre-load my hydraulic flat lifters? |
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rang-a-stang 
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Joined: Sep/25/2018 Location: Camarillo, CA Status: Offline Points: 272 |
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 Topic: How much can I pre-load my hydraulic flat lifters?Posted: Jun/18/2019 at 5:48pm |
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I have a few hours of run time on my 401. It's running a Comp Cams 268H cam (mild street cam), Comp Cams hydraulic flat tappets, Comp Cams push rods, and Harland Sharp 1.6's. I have iron heads with Comp Cams springs, retainers, and stainless valves. I have adjusted the rockers twice to 1/2 turn but I am still getting some valve train noise when at operating temp only. (oil pressure is at 10psi at 600RPM hot, idle)
Comp Cams recommends 1/4-3/4 turns of preload for a street engine with this equipment so the 1/2 turn seems logical. Would any of you recommend against me pushing it a bit to 2/3's or 3/4s turn? Should I assume I have other problems?
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billd
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Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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Posted: Jun/18/2019 at 5:57pm |
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If you have preload then you don't have lash so setting them tighter shouldn't make things more quiet - because you don't have the clatter of lash anyway.
It is said that some synthetic oils can make valve trains a bit more noisy - not that is protects less, it's a noise transmission thing. A non-stock cam can often make a bit more sound anyway - my 4.0 with Comp cam and Harland Sharp rockers sounds like a truck engine - the ramps are more radical, I assume it's because they assume you don't care about a whisper quiet engine? Is it so noisy you think you have a problem? Could it be you are hearing normal noise with that setup? |
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rang-a-stang
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Joined: Sep/25/2018 Location: Camarillo, CA Status: Offline Points: 272 |
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Posted: Jun/18/2019 at 6:13pm |
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Having internet issues. I just posted this then my internet died so I apologize if this is a duplicate.
Copy. I am running Castrol GTX 10W40 with about 45 minutes of run time on it. It might be normal? Honestly, this is my first full engine build and first set of roller rockers. I didn't hear my valve train before the rebuild (stock everything) and don't hear it when it's cold now so I assumed I shouldn't hear it when it's at normal temp? I can't hear it when I am driving my Jeep, but when I get out, I can hear it outside my Jeep with the hood down. Pop the hood and I can hear it. It's not obnoxious but I can hear it. I wouldn't say it sounds like a truck but it's distinct.
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Boris Badanov
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Posted: Jun/18/2019 at 8:34pm |
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Are you sure you are not just hearing a exhaust leak?
Header flange leaks can and do sound like valve clatter. |
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Gremlin Dreams
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jcisworthy
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Posted: Jun/19/2019 at 2:41am |
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I have heard a lot of complaints from other shops about noisy Comp Cams lifters.
They will not use Comp hydraulic roller lifters anymore. Not sure if the flat and roller lifters have use the same internals but it may be the lifters.
I always use Johnson Hylift lifters with no problems. |
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Specializing in dyno services, engine building, and cylinder head porting
rbjracing.com Phone Number 518-915-3203 |
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BassBoat
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Posted: Jun/19/2019 at 7:08am |
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Full disclosure, I am the guy that always run zero lash. I have done so for 50 years, but am now considered a pariah because I risk hammering out the clips and clearly don't understand that there is no such thing as lifter pump up.
Leave it alone. If I am worried about noise I run 1/8 turn just so it doesn't clatter when cold but 1/2 turn is plenty of preload.
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PacerLarry
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Joined: Aug/02/2010 Location: New Lenox, IL Status: Offline Points: 103 |
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Posted: Jun/19/2019 at 11:44am |
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For what it's worth, I have a 360, same cam, same rockers, and I'm assuming the same springs, lifters, and retainers (everything recommended by Comp as a package). I heard the same thing you are experiencing. It wasn't very load, just a little rattlin and tappin at idle if you had your head under the hood. Always used 10-40 oil. I ran both 1/2 and 3/4 turn and it made no difference. I raced the engine for 3 years without issue, and when the motor was taken apart I saw no signs of wear, damage, or concern.
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rang-a-stang
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Joined: Sep/25/2018 Location: Camarillo, CA Status: Offline Points: 272 |
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Posted: Jun/19/2019 at 12:08pm |
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Yeah, it's definitely in the valve train. I used to have a TON of header leaks so I bought Remflex gaskets and have torqued them 3 times (though the second 2 times, they didn't really need it). Doesn't really sound like exhuast leak, it more sharp sounding (if that makes sense).
OK, copy that. Good to know. If I ever pull my intake again, maybe I'll swap them out for some Johnson Hylift. New lifters old cam=ok, new cam old lifter=no muy bien, right?
Hahaha! Copy that! Sounds like the consensus is "Don't mess with it". Old addage: if it's stupid but it works, it isn't stupid. sounds like zero lash isn't stupid in your engines!
EXACTLY what I am hearing. We probably bought the same part number. Also had a timing set in it, too. Your post is what I was hoping (but not expecting) to get. I appreciate you all chiming in. I will let it ride!
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79 Cherokee, 401
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DragRacingSpirit
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Posted: Jun/20/2019 at 3:15pm |
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Are you using the stock rocker arm studs ? The rocker arms will bottom out on the stock stud and not allow the correct pre-load. If that is the case either replace the stock studs or chuck them up in a lathe and cut them back. For me flat tappet hydraulic cams get a 1/4 turn of preload.
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Best 1/4 mile 8.99, 1/8 mile 5.71, 60 foot 1.27, no power adders
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rang-a-stang
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Joined: Sep/25/2018 Location: Camarillo, CA Status: Offline Points: 272 |
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Posted: Jun/20/2019 at 4:16pm |
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Good thought, but no. I am running ARP 7/16" studs. ARP Part number is 100-7101. Maybe I try and back off to a 1/4 turn?
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79 Cherokee, 401
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billd wrote: