HOW TO FIND PROPER ROCKER ARM GEOMETRY!!!!

welcome to Sara Racing garage today we're going to discuss is how to find the proper rocker arm geometry and with the proper push rod length so we got here it is a rocker arm this is a few things that I like to do some people do it differently but I like to determine when I'm looking at the rocker arm the center pivot point between the trinium this is called the training and the roller tip so what I like to do is I like to put a marker line this will help us down the road and roughly about the center of the trillion and center of the pivot point of the roller okay so how we're going to determine the proper push rod length and the proper geometry is we've got a push rod that's adjustable okay so we can find actor when it's all done we can find actuals we can take this out and find the right length that we need to order okay so we go back to the engineer this is the stud where the rocker arm mounts to so 7/16 stud and we know that the pitch on here is basically like 20 threads per per inch which equals both every turn equals about 50 Cal per turn so that's very important to know it which stud you have you can have 3/8 which will will be a different pitch and different every turn different thread per inch so every time you turn one thread it's a different sights so this one here in particular is a 7/16 that we're using which is on the engine over there as well and we know every time you turn with your one full circle it's 50,000 in in an inch which is 50,000 in $50 inch $50 thread every time you turn one one one revolution okay so anyways well we determined that and that's going to be very important guys to find the proper geometry of the rocket this method was taught to me about five six years ago from a very intelligent and one of the best engine builders and no growth it's worked out so far really good for us so anyway so and this is what we're doing okay so we're going put the rocker arm arm arm on and we just put a couple threads on the top okay and where you're going to look here on this line here and what we're going to find here is we're trying to determine a ninety degree from here to the valve okay which is basically about ninety degrees right now what you want to do to find proper a rocker arm geometry is have a ninety degree at half lift which would be on this camp which is five hundred seventy lips would be two hundred eighty five south okay and and then this should be exactly most likely like exactly like the way it is now which is ninety degree to the top of the retainer so if you look at that that's ninety degrees okay so what we're going to do now is we're going to turn the motor we're going to we're going to count the threads on the top or make a mark on the threads and wrap up marker and we're going to make a mark on the threads so right now all the way to the top is ninety degrees okay but we need to just need to find we need to get ninety degrees at half lift so how are we going to determine that you're going to we know that every time we turned the nut one full revolution okay will be 52 so at 285 lift we're going to turn it five times okay now which will be 250 and then just a little more for the 30 for the 35 for the 35 more okay so if you look at the line here to there we're going to turn it five times we're going to go one two three four five and then now that would be $250 so halfway would be 275 okay and we're just going to go a little more so all right both there that should be 285 right there okay so if you look at now what we need to do we need to turn the motor over okay and that's we need to adjust the rocker arm okay so that it it's a tough way left of five five turns five and three quarter turns basically on the top that that's roughly about 285 now from from using the pitch of the stud and basically 50 fell each each turn so and that was that we had said it already originally at a 90 degree angle so now what we're going to do is we're going to adjust a push rod okay underneath it that it's snug okay so it's not there and what we're going to do is now we're going to check to see if it's a 90 degrees at half turn half lift okay so we snug the push rod to the bottom okay and now we're going to go dial indicator here and we're going to go to half lift so which would be 285 now that's one two and that's about 285 we're in about there okay and there we go so now we're going to look back and look at the valves okay which is the valve stem okay to this line and if you look at it it's exactly 90 degrees and that's what you want that's proper drops a proper rocker arm geometry halfway through the list of the camp you want a 90 degree to from the roller to the trending here you want 90 degrees line the rock bottom two people at many degrees and that's where it is right now so now that we've established that what we're going to do is take out the rocker arm take out the nut on the top let me send it back off okay take it off and we're going to try another method just to make sure this is good and what we're going to do first actually is we're going to measure the pushrod so we measured the pushrod and it set this push right here is seven point two roughly seven point two long okay and we have them here now I'm going to just double check our work put the push right in okay we're going to hit the marker and we're going to keep the tip on the valve here I'm going to paint it all blue okay and what that's going to show us also it's called aware that roller the tip of the roller is going to be working on and what you want it to work on is not too close to the edges mostly in the middle and you only want to basically a fifty thousand area you know that's all basically what you want you want you don't want any more than that so we got the seven two hundred push rods in there and we're going to spit that in and when you're going to do is you're going to put it at zero lash for now just to see where it's running okay and then you have to set your lash later on what your cam specs are to run hydraulic roller II just there's different procedures of doing it we're not going to get into that we're just going to get into the proper geometry of the rocker arm right now and see if we've done pull is right okay so that's pretty snug on there and we're going to do is we're going to turn the water a full revolution okay so the valves going all the way down and and we're going to check it one more time again so we're going to go 1 2 285 that should be 90 degrees to the valve with those push rods and that's what it's 90 degrees to the valve and you can see the line goes straight across and straight down so it's 90 degrees we're going to continue going all the way down okay okay and and now what we're going to see is what market did to the tip of the valve okay so if you focus on so if you notice the line well the rocker travel through the whole duration go through the whole duration was right in the middle that's that's basically where you want it it's right there you want it right in the middle of the valve and it's approximately 50,000 and it's about 50 this one's about 59 58 now which is perfect geometry okay if you look at the caliper or about 55 and if you look there that's about the line where it is and it's about 55 now that's perfect rocker on geometry and it's very important when you rub in the engine at higher rpms that you're using very deep push rods and getting the rocker arm set up properly with the right adjusted right height of a push rod that's basically how I adjust it there's other people doing it differently but this is worked out for us in the past and that's our method so this method is what I used and I've been using it now for a long time and it was taught to me by a master engine builder a long long time ago and and it's worked out really well I've used it in the booster application nitrous application normally ask for an application there's other methods this is one I use and it's always found the right push rods and you never really had any issues so and what we're doing here is trying to share some of this knowledge to the public I'm trying to do a good deed and I hope you liked the video and click like and subscribe and more videos to come [Music]

Channel: serracon

Views: 145,291

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Id: Sr4JbpO6034

Length: 13min 7sec (787 seconds)

Published: Tue Jun 20 2017