Rocker Arm Retainer Clearance

[lun40119]

I used +.100 valves to achieve 1.850 installed height. I have Rocker arm, retainer clearance issues now. I have +.100 pushrods, and the clearance is to the top of the retainer. Is this a normal? Is ok to remove around .030 from the rocker to get the clearance. The pushrod length is ok. The swipe is around .100 in the center 1/3 of the valve. The application is a Dart Pro 1 on a GM SBC block. Thanks in advance.

[Awesome Bill]

Add .030 to .050 to the push rod, do not cut the rocker. .100 is way to wide, should be under .050. Keep adding pushrod until the mark becomes narrower. It will not matter if it is a little off center to the bottom side. Rocker arms hitting the retainer are a sure sign of 2 things, either cheap rockers, or push rod to short.

[lun40119]

They are crane gold 1.6 rockers, and the scrub follows what crower outlines on there website. They say it isn't supposed to center on the exhaust side. In fact, the opposite it should achieve max load, half gross, at the center of the valve. Which it does.

[Awesome Bill]

I really don't care what any article says, if it don't work you don't cut a rocker arm up. The best procedure is to go for the narrowest line. I have seen them under .020 and not be dead center with no guide wear at all after years of running. You can always tell when it gets good for the valve when you keep adding or subtracting .025 lenght to get the narrowest pattern. We have every lenght push rod in .025 from 6 inch to 12". We use the narrowest pattern in engine running conditions. Meaning head gaskets, valve adjustment etc. Push rods are our last engine part installed. Base circles, valve angles, lifters, all make a difference here. I know yours is a simple sbc so that is why it should not have this problem. The only other explaination is your machine shop or engine builder installed +.050 locks to get installed height and this raises the retainer up to far and will allow the rocker to contact it. All you need is .010 air gap for the rocker so a push rod a little longer will not hurt. Your splitting hairs here were you could use a ruler. Hope this helps.

[lun40119]

I tried a set of ss rockers from comp, and those were even worse. So I went to a 8.100 pushrod and it is perfect. The wipe is around .045. That is about at good as I can get it. I have plenty of clearance to the retainer. Sorry for the premature response, and thanks for the help.

take care

[Awesome Bill]

you could most likely get it closer with a 8.150 or even 8.125" it cost but I have purchased a few push rods to change out to actually see the patter with just .025" length changes. It works. Then I just purchase the proper length that makes the narrowest pattern. .045 is a little wide but beats cutting the rocker. Most people assume the stock stuff will work but that is just not the case. Nothing fits and you have to find out what does. Good job.

[jeepmanpow]

whats up,dont want to sound dumb here guys,but im getting ready to do my pushrod length,so how do you measure the swipe on the valve.thanks

[lun40119]

What I did was take a sharpie and color the tip of the valve and then assemble that valve train with an adjustable pushrod. Rotated the engine 2-3 times. The rocker tip will take the marker off where it is running. I lengthened the pushrod until i got a narrow pattern in the center of the valve tip. Mine is just a touch to the exhaust side but not much. I ended up with 8.100 pushrods, with comp stainless rockers. There are excellent instructions on the Lunati website in there catalog. hope that helps.

[Awesome Bill]

gear marking lube works very well, as the sharpie.