rocker arm adjustement question
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Laughing Gas
Joined: Jan 2006
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From: New-brunswick,Canada
rocker arm adjustement question
I'm installing roller rocker and i'm not sure when to stop tighning the adjustment screw. I read in the book how to rebuild ford engine v8 and they said the lifter plunger have to be collapse to the midpoint of it's travel. So i thight by hand the adjustment screw until the rocker and the push-rod stop to wiggle then give 3/4 of a turn. That 3/4 of a turn didn't push the lifter plunger to it's midpoint. That's where i'm lost. The cam was on the base circle, the valve is fully closed. Can someone help me with this one ? Did i need to put the filler gage between the valve and rocker and if so by how much ? i'm using hydraulic lifter and the conversion kit for roller rocker.
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Are your heads converted to adjustable rockers now? I would count how many turns it takes to fully collapse the lifter and then back off half the amount to get to the mid point. If the lifters are wet it will take some time for them to bleed down otherwise you will just open the valve if you tighten to quick. Do you have the specs such as how far the lifters collapse and how many thread per inch with the new rockers?
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Laughing Gas
Joined: Jan 2006
Posts: 883
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From: New-brunswick,Canada
No, my heads are not machined to have stud but i bought a converssion kit from crane cams that allow me to run adjustable roller rockers. The kit is a stud that bolt in my stock bolt who hold the stock stamped-steel rocker arms then come bigger to receive the roller rocker. The lifter are dry(new) with cam break lube on the bottom. I dont have any spec on how far the lifter collapse. The only thing is 3/4 turn after the loose is taking up. The converssion kit number is 35655-16 and 52655-16. It come with screw in stud, guide plate that screw in the head. I used hardened, for the guide plate, stock pushrods lenght but the kit said i don't need the hard one. As i read the page they give me, i saw: For more information see www.cranecams.com. Gonna take a look. thanks for reply.
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I couldn't get your link to work but assume you were trying to show me these:Crane rocker conversion kit - Clevelands Forever!
I want to get some of them myself but now that Crane closed its doors I'm not sure where or if any other company bought them out. I know S&S Cycle bought the motorcycle ignitions.
The instructions say lifter preload should be .020-.060. If the new 7/16 studs are fine thread(20 tpi) it would take 3/4 turns to collapse the lifter .040. Maybe you did do it right in the end.
http://cranecams.com/pdf/301g.pdf
I want to get some of them myself but now that Crane closed its doors I'm not sure where or if any other company bought them out. I know S&S Cycle bought the motorcycle ignitions.
The instructions say lifter preload should be .020-.060. If the new 7/16 studs are fine thread(20 tpi) it would take 3/4 turns to collapse the lifter .040. Maybe you did do it right in the end.
http://cranecams.com/pdf/301g.pdf
Posting Guru
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From: chicago burbs
what cam are you using?
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The instructions say if there isn't at least .030 between the underside of the rocker arm and the guideplate slightly longer pushrods will be needed.
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Lead Driver
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To find push rod length, put a light checking spring on the valve, get or make a adjustable push rod, set it around the stock length, put a marking compound on the valves tip. Turn the crank till the rocker cycles once making sure you don't compress the lifters plunger while turning the crank. Check the pattern. You want the pattern centered on the tip. Adjust the push rods length till you get the pattern set right. Then measure the adjustable push rod and add the preload into the measurement, that will be your length. I always add .020 for preload and use a dial indicator to adjust the rockers to the .020 preload that I figured in.
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Mark, do you know what the total plunger travel is with the oem lifters? Sounds like .020 is leaving it a little more towards the top rather than midpoint which I'm not saying is wrong. I would guess with adjustable rockers you could set preload with the tpi and calculating how many turns it takes to get to .020. It would save the trouble of borrowing a dial indicator for those who don't have one yet.
Lead Driver
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Mark, do you know what the total plunger travel is with the oem lifters? Sounds like .020 is leaving it a little more towards the top rather than midpoint which I'm not saying is wrong. I would guess with adjustable rockers you could set preload with the tpi and calculating how many turns it takes to get to .020. It would save the trouble of borrowing a dial indicator for those who don't have one yet.
Yes, you can do tpi, I just don't do it like that, a dial indicator is right on the money.
Junior User
Joined: Feb 2010
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From: Oklahoma
He is right about checking the lenght. I trashed a set of heads, valve guides. By not checking the lenght of the push rods. The roller rockers rolled off the valve stems at all the way open, pushing the valve sideways into the guides.
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Laughing Gas
Joined: Jan 2006
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From: New-brunswick,Canada
Then when i check the push rod lenght the rocker is not adjust ? What i understand is i have to turn the crank by hand with the rocker in place but not tight to not collapse the lifter.. right ? When the lifter come up it's collapse the lifter, then to not callaps it, i slack the rocker.
With the roller rocker adjust on the intake valve on cyl one, it's on the center of the valve tip when the valve is fully closed but when the valve is open the roller is not in the center, it's more at the end of the tip of the valve(exaust side of the engine) I think i need shorter pushrod...
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From: chicago burbs
mark a's method requires a very light spring installed in place of the valvespring, so light a spring that the lifter does not collapse, just barely enough spring to hold the valve closed
are you using the light spring?
are you using the light spring?
Lead Driver
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When you check, the rocker should be adjusted to zero, no play. You have to find a light spring of some kind to put on the valve. If the lifter plunger collapses any it makes it impossible to find the length. When it's set right, the rocker's tip pattern will start in above the valve tips center line and will stop below the valve tips center line.