Question on hydraulic preload
#2383359
10/07/17 12:19 PM
10/07/17 12:19 PM
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Joined: Aug 2009
Posts: 1,317
Ohio
jlatessa
OP
pro stock
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OP
pro stock
Joined: Aug 2009
Posts: 1,317
Ohio
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Putting our 440 back together after a spun rod bearing, (pig rich idle causing pre-ignition!)
Crank now .010 under rods, new bearings on lower end, new head gaskets.
Started engine to look for leaks and adjust idle and heard a rocker tick.
Pulled covers and found # 6 intake rocker (Hughes roller, hydraulic .484 cam) with too much clearance. Adjusters tight and the same amt. of threads showing as the others??
This was the cylinder that spun the bearing so I pulled the rocker shaft to see if the rocker had unusual wear showing, also pulled the lifter out to look for face wear, every thing looked normal, lifter face looked great with good convex still apparent, cam lobe too.
so I proceeded to reset that rocker's preload and now I have questions
about lifter pump-up when setting.
Does it matter if lifter is still "solid" when setting preload?
Will one full turn of adjuster still be correct as Hughes recommends?
New head gaskets, so maybe some variance there, but why #6 only??
Thanks, Joe
Last edited by jlatessa; 10/07/17 12:27 PM.
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Re: Question on hydraulic preload
[Re: jlatessa]
#2383367
10/07/17 12:37 PM
10/07/17 12:37 PM
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Joined: Jan 2003
Posts: 4,269
Morrow, OH
markz528
master
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master
Joined: Jan 2003
Posts: 4,269
Morrow, OH
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Are you sure the cam lobe is good? I would personally be putting an indicator on it and determining if the lobe is worn.
The way I set the preload is rotating the pushrod till the slightest drag is felt and then go the prescribed turn. I usually do it 2 or 3 times to ensure I get the same result - I look at the position of the allen wrench to determine if the results match. So I don't think it matters if the lifter is pumped up but I have heard others say it does.
67 Coronet 500 9.610 @ 139.20 mph
67 Coronet 500 (street car) 14.82 @ 94 mph
69 GTX (clone) - build in progress......
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Re: Question on hydraulic preload
[Re: jlatessa]
#2383414
10/07/17 01:50 PM
10/07/17 01:50 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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I would open it up again & measure everything to find out where the extra clearance is coming from as said starting with the cam. we gotta answer that first. I think you would need to dissassemble/drain the lifter to free it up to be able to check the preload
live every 24 hour block of time like it's your last day on earth
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Re: Question on hydraulic preload
[Re: RapidRobert]
#2383420
10/07/17 02:04 PM
10/07/17 02:04 PM
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Joined: Aug 2003
Posts: 43,097
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,097
Bend,OR USA
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I would open it up again & measure everything to find out where the extra clearance is coming from as said starting with the cam. we gotta answer that first. I think you would need to dissassemble/drain the lifter to free it up to be able to check the preload  Especially the lifter and cam lobe  As far as how much preload I back the adjusters off enough to be able to rock the rocker arm up and down a little and then use one hand to pull on the pushrod up and odwn and slowly adjust the adjuster until there is just barely no up and down movement and spin the pushrod like already mention until it has a tiny bit of resistance and then add from 1/8 to 1/4 turn preload on iron heads, 1/4 to 1/3 turn preload total on aluminum heads cold 
Last edited by Cab_Burge; 10/07/17 02:04 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Question on hydraulic preload
[Re: jlatessa]
#2383832
10/08/17 12:41 PM
10/08/17 12:41 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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Putting our 440 back together after a spun rod bearing, (pig rich idle causing pre-ignition!)
Crank now .010 under rods, new bearings on lower end, new head gaskets.
Started engine to look for leaks and adjust idle and heard a rocker tick.
Pulled covers and found # 6 intake rocker (Hughes roller, hydraulic .484 cam) with too much clearance. Adjusters tight and the same amt. of threads showing as the others??
This was the cylinder that spun the bearing so I pulled the rocker shaft to see if the rocker had unusual wear showing, also pulled the lifter out to look for face wear, every thing looked normal, lifter face looked great with good convex still apparent, cam lobe too.
so I proceeded to reset that rocker's preload and now I have questions
about lifter pump-up when setting.
Does it matter if lifter is still "solid" when setting preload?
Will one full turn of adjuster still be correct as Hughes recommends?
New head gaskets, so maybe some variance there, but why #6 only??
Thanks, Joe If the lifter face looks good, you don't have a cam problem. Same with the rocker. How's the push rod ends? No, they don't have to be pumped up to adjust them. As said, roll the push rod by hand as you tighten the rocker adjuster screw. You will be able to tell when there is no more clearance. Add your 1 turn ( or what ever you choose ) and your done. Yes, they can bleed down occasionally and can take some run time for them to fill back up and quiet down - even after some period of use.- and especially if the car sits for an extended period of time. My guess - The lifter was partially on the lobe ramp when you went to adjust that one innitially.
Last edited by Crizila; 10/08/17 12:42 PM.
Fastest 300
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Re: Question on hydraulic preload
[Re: jlatessa]
#2384046
10/08/17 06:58 PM
10/08/17 06:58 PM
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crabman173
Unregistered
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crabman173
Unregistered
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Different lifter brands require or call for different amounts of preload--most all of the Morel hyd rollers call for 1/4 turn--also some of the more expensive units advertised as being capable of higher RPM ( morel makes some of these) call for specific weights of oil
The old "throw 3/4 on them and never take the covers off" is OLD stuff for std hyd flat tappet lifters and will not work on modern hyd rollers so
Make Sure what mfg they are and call the tech there to make 100% sure what you need
A full turn on many Morels is a big no no and cost you performance and will not allow lifter to function as designed
quiet operation is not all it is cracked up to be
The hyd rollers are so darn heavy--they limit RPM in many cases
Solids for me after decades of hoping the hyd rollers would appear--now that they have and I have run them I am back to flat hyd's or my very favorites for performance applications--a solid
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Re: Question on hydraulic preload
[Re: jlatessa]
#2384323
10/09/17 10:35 AM
10/09/17 10:35 AM
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crabman173
Unregistered
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crabman173
Unregistered
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OK
Then many go a full turn but the more you preload the less RPM usually --3/4 is a Plenty and half is what we do in our shop
pretty much anything will run
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