In over my head (rocker geometry)

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younggun2.0

younggun2.0

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i am in the final assembly stages of my engine. it is a 383 with eddy heads. comp cams magnum roller rockers. cam is comp cams. 525 lift. i have already verified top dead center on the #1 cylinder and check for valve to piston clearance (.085). i am checking my rocker arm geometry and this is where my problem is. i cant get my head around it. I assembled one intake and one exhaust rocker and marked the tip of the valve stem with a marker. then i rotated the engine a few times by hand. the marks are dead center of the valve tip. the adjusters on the rocker arms show 3 threads showing. does this look right? or do i need longer push rods? if i do a longer push rod will if change my geometry? here are some pictures.

SSPX0236.jpg


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SSPX0239.jpg
 
........I prefer 1 or 2 but have run them at 3 in mild builds to 5500 rpm.......longer rods will change the pattern some............kim........
 
oldkimmer said:
........I prefer 1 or 2 but have run them at 3 in mild builds to 5500 rpm.......longer rods will change the pattern some............kim........
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my current push rods are 8.555 long. they sell them in 8.600. that i think would bring them in a full thread. i was planning to spin this engine to 6000-6500.
 
Check the rocker arm manufacturers specs, Crane used to say 3/4 of a turn below the rocker was optimum. Longer pushrods won't change the pattern on the valve stem since these engines are a rocker shaft type setup, but the patttern on your valve stem tip looks fine, so you have no worries there.
 
got my new push rods. they now have 1 1/2 thread showing out the bottom of the rocker. that is at zero lash also. should be just about 1 thread once i dial in the valve lash. much happier with the new set up.

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Looks nice,guy.Taking the time to do it right once,beats throwing parts without knowledge shows some chops.
 
Abodybomber said:
Looks nice,guy.Taking the time to do it right once,beats throwing parts without knowledge shows some chops.
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Don't give me too much credit. lol It just looked wrong to me when i mocked it up. then i turned to my all knowing pals here and they steered me in the right direction. it does suck though. .045" cost me $120.
 
Spending the money now to get things right will save you even more later on,by virtue of the valve train living longer.You'll be glad you did.
 
younggun2.0 said:
Don't give me too much credit. lol It just looked wrong to me when i mocked it up. then i turned to my all knowing pals here and they steered me in the right direction. it does suck though. .045" cost me $120.
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$120 is stil cheaper than gaskets, fluids, and parts if the rocker or pushrod fails. Good work in checking, and then correcting the small things. It will run better, and for longer, as a result.
 
thank you for the kind words guys. the car has been apart for 10yrs now and im finally getting down to the little details before the car is all back together. there are so many little things that i never even gave a thought to that are needing attention.
 
10 yrs huh? I sure can relate to that! I've had mine for better than 18,and it has been completely disassembled for a few years now. Mostly due to my health,but that is now coming around,so hoping to get soome stuff dun this winter. We shall see. I am currently challenged by my GM pickup not running,lol.. Tough to remove a gas tank when your truck is parked nose down on a 30 degree slope...

Anyways Im glad to see your not discouraged by the mental barrier a huge amount of off time can do!
 
i have been really suprised at how long it has taken. i have lost a house, been layed off from 2 jobs and have had several girlfriends come and go. hell the car sat in a storage unit for nearly 2 yrs but i still go thru phases where i get alot done. I got a really good job now and making pretty good money and a good woman that understands my passion for the hobby so it has made alot of progress lately. this forum board is also a huge motivator.
 
Don't Mean to but in but I want that exact rocker setup for my puller. What lifters are you using? The reason I ask is because I want to use a ball/ball pushrod and I was told to run AMC oil through lifters
 
Jonnylightening said:
Don't Mean to but in but I want that exact rocker setup for my puller. What lifters are you using? The reason I ask is because I want to use a ball/ball pushrod and I was told to run AMC oil through lifters
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it is a solid lifter mech. cam. i am running the solid lifters that came with my comp cam. if your asking about the push rods. they are comp cams 8.60" long 5/16" diameter and .080 wall thickness.

COMP Cams 7977-16 Hi-Tech 5/16" Diameter 8.600" Length Pushrod, (Set of 16)
 
younggun2.0 said:
it is a solid lifter mech. cam. i am running the solid lifters that came with my comp cam. if your asking about the push rods. they are comp cams 8.60" long 5/16" diameter and .080 wall thickness.

COMP Cams 7977-16 Hi-Tech 5/16" Diameter 8.600" Length Pushrod, (Set of 16)
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Jus curious, but how you get oil between pushrods and adj. cup?
 
younggun2.0 said:
there is a really small hole in the rocker body that will squirt oil toward the cup tip.
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what lift cam are you running? Ever have any issues with your setup? The reason I am asking is because I want to buy a set of the comp cams rockers as well for my pulling engine. My current setup (Crane Gold) kept breaking on me and shooting the lifter outta the bore, so I wanted to go with a cup style adjuster vs the ball adjuster.
 
no a single problem. they have been great. ha ha ha they have never been run. this is my first big block build and i havent got it up and running yet. the cam is .525 lift 294 duration. my dad runs these rockers on his 10 sec. demon. have had them for 5 yrs without a problem. for a couple hundred bucks more you could go with harlands. that is what i wish i would have done. i paid 525 for this set up then another 100 for billet alum hold downs from mopar.
 
Another advantage of the ball/ball pushrod over the ball/cup is when you reduce the the threads sticking past the rocker, the cup pushrods have a tendency to rub the rocker at max lift. I may go this route
 
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