Crane Gold adjustable rocker preload help please?
#63200
05/25/08 01:51 PM
05/25/08 01:51 PM
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Joined: Apr 2008
Posts: 1,195
Snowing in the north!
Dart 340
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moparts member
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Posts: 1,195
Snowing in the north!
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Quick question on preload for Crane rockers. My cam (edelbrock) says to adjust rocker arms as follows: When no 1 cylinder exhaust valve starts to move up, adjust intake rocker arm to zero clearance between rocker and valve tip. Turn adjusting screw down 1/4 turn more for final adjustment. They are hydraulic rockers. This seems a little vague and error prone dont you think? So is there a better way, and should the pushrods be snug to tight at TDC or should they both be loose? Someone with real experience please? 
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Re: Crane Gold adjustable rocker preload help please?
[Re: Dart 340]
#63201
05/25/08 02:25 PM
05/25/08 02:25 PM
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Joined: Jan 2003
Posts: 9,826
las vegas
70AARcuda
master
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master
Joined: Jan 2003
Posts: 9,826
las vegas
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hydraulic lifters use preload...
you turn your adjuster until all the slack is gone in the adjuster, then preload the lifter..as noted 1/4 turn.
you can use edelbrock method of determining went to adjust a valve or you can use the valve lash sequence that mopar has which ever you like...
Tony
70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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Re: Crane Gold adjustable rocker preload help please?
[Re: mark7171]
#63205
05/25/08 07:36 PM
05/25/08 07:36 PM
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Joined: Apr 2008
Posts: 1,195
Snowing in the north!
Dart 340
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Quote:
you primed the engine's oil pump, right ?
do it while someone turns the crankshaft slowly. the lifters will be filled.
I was the one turning it slowly.........
I used a dial indicator to find exact TDC and could
lightly spin the pushrods. They were the same of all
cylinders. I drive it last night and turned the crank by hand today as I was finding tdc for all cylinders. Would that be close enough?
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Re: Crane Gold adjustable rocker preload help please?
[Re: Dart 340]
#63206
05/25/08 09:50 PM
05/25/08 09:50 PM
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Joined: May 2008
Posts: 5,399
Aurora, Colorado
451Mopar
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master
Joined: May 2008
Posts: 5,399
Aurora, Colorado
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Quote:
Quick question on preload for Crane rockers. My cam
(edelbrock) says to adjust rocker arms as follows:
When no 1 cylinder exhaust valve starts to move up,
adjust intake rocker arm to zero clearance between rocker and valve tip. Turn adjusting screw down 1/4 turn more for final adjustment.
They are hydraulic rockers. This seems a little vague and error prone dont you think? So is there a better way, and should the pushrods be snug to tight at TDC or should they both be loose?
Someone with real experience please?
Note, Applies only to individual cylinders:
When Exhaust starts to open, intake lifter is on cam base (completly off the lobe), so you can adjust the intake valve lash.
When Intake closes, adjust exhaust lash (same reason.)
If you can verify TDC of Compression stroke (not overlap), you can adjust both intake and exhaust valves.
The Adjuster screws are 24TPI so one turn = 0.04167"
If you remove the freeplay, you should be at zero pre-load and the inner piston of the lifter should be all the way up to retaining clip.
Adding an additional 1/4 turn should depress the lifter piston 0.01042". This is the spec often used to get maximum performance, but most cam/lifter suppliers spec 0.020" to 0.060" of lifter pre-load. I would use 1/2 turn pre-load or more unless you plan to re-check the valve adjustment ofter engine break-in. Also when running with small amounts of pre-load it is recommended to use the "C"-clip type lifter retainers, not the wire type retainers.
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Re: Crane Gold adjustable rocker preload help please?
[Re: Dart 340]
#63208
05/26/08 01:05 AM
05/26/08 01:05 AM
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Joined: Jan 2003
Posts: 9,826
las vegas
70AARcuda
master
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master
Joined: Jan 2003
Posts: 9,826
las vegas
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too much preload and the valves will not shut.
Tony
70 AARCuda Vitamin C
71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield)
71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas)
71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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Re: Crane Gold adjustable rocker preload help please?
[Re: mark7171]
#63211
05/26/08 10:47 AM
05/26/08 10:47 AM
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Joined: Apr 2008
Posts: 1,195
Snowing in the north!
Dart 340
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Snowing in the north!
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Quote:
nahh at, +90 +90 on a hydraulic lifter adjustment, is fine. check them after a heat cycle anyways. the oil psi is #60lbs -/+, the pushrod will sink and the valve will close, because the spring pressure will overcome it.
the oil pressure keeps them even. adjustments keep them even.
on a cold HP hyd. cammed engine with lifters that have bled down, on start up it will "lifter clack" until psi builds in the lifter. that is normal after 1/2 " of high performance valve lift.
So the question is does it sound like my preload is set ok then?
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Re: Crane Gold adjustable rocker preload help please?
[Re: mark7171]
#63212
05/26/08 10:51 AM
05/26/08 10:51 AM
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Joined: Apr 2008
Posts: 1,195
Snowing in the north!
Dart 340
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moparts member
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OP
moparts member
Joined: Apr 2008
Posts: 1,195
Snowing in the north!
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Quote:
nahh at, +90 +90 on a hydraulic lifter adjustment, is fine. check them after a heat cycle anyways. the oil psi is #60lbs -/+, the pushrod will sink and the valve will close, because the spring pressure will overcome it.
the oil pressure keeps them even. adjustments keep them even.
on a cold HP hyd. cammed engine with lifters that have bled down, on start up it will "lifter clack" until psi builds in the lifter. that is normal after 1/2 " of high performance valve lift.
mark, this is the nasty edelbrock cam you were helping with in my hesitation an low rpm post. Lots of overlap on this one. Still pulls 120 cranking pressure if that helps
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Re: Crane Gold adjustable rocker preload help please?
[Re: Dart 340]
#63213
05/26/08 12:03 PM
05/26/08 12:03 PM
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Joined: Apr 2007
Posts: 1,261
ILL
mark7171
pro stock
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pro stock
Joined: Apr 2007
Posts: 1,261
ILL
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are you affraid you'll coil bind with the performer cam, and bottom out the lifter ? im not. if you had a light twisting effort on the pushrod at addjustment. then went +90, and again +90 more for preload, it will NOT BOTTOM OUT (opening the valve), or FALL OUT at high rpm.
the cam is mild enough should have no geometery problems..
Last edited by mark7171; 05/26/08 12:06 PM.
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Re: Crane Gold adjustable rocker preload help please?
[Re: MoparforLife]
#63216
05/26/08 10:51 PM
05/26/08 10:51 PM
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Anonymous
Unregistered
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Anonymous
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If you've run the engine and after sitting all night you can "SPIN" the pushrods at TDC on each valve, you have no preload. Here's how to develop the feel you need to do this right. Bring #1 intake up to TDC and back off the adjustment until you can shake the pushrod up and down. Then, while still moving the pushrod, slowly turn the adjuster until the pushrod "JUST" won't move up and down,then turn the pushrod. This point is zero lash. While you continue to try and turn the pushrod turn the adjuster whatever additional the cam grinder says is appropriate. After doing this a few times you will develop the feel and the proper technique.
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Re: Crane Gold adjustable rocker preload help please?
#63217
05/27/08 09:33 AM
05/27/08 09:33 AM
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Joined: Apr 2008
Posts: 1,195
Snowing in the north!
Dart 340
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moparts member
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OP
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Joined: Apr 2008
Posts: 1,195
Snowing in the north!
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Quote:
If you've run the engine and after sitting all night you can "SPIN" the pushrods at TDC on each valve, you have no preload. Here's how to develop the feel you need to do this right. Bring #1 intake up to TDC and back off the adjustment until you can shake the pushrod up and down. Then, while still moving the pushrod, slowly turn the adjuster until the pushrod "JUST" won't move up and down,then turn the pushrod. This point is zero lash. While you continue to try and turn the pushrod turn the adjuster whatever additional the cam grinder says is appropriate. After doing this a few times you will develop the feel and the proper technique.
Is this with engine cold or hot? Expansion, lifter pump up etc changes from cold to hot engine.
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