SBC push rod checker?

[Greg Reimer 7376]

Well, here I am at 6:07 AM on a Monday reading this. Here's two more cents. Since most of these stocker cams are ground with more precision and consistancy as to lobe lift and profile, which can be verified by checking all 16 lobes with the cam in the block, then the places correction is necessary would be in the rest of the valvetrain. If all 16 lifters check,then the pushrods, rocker arms, and the valve stem lengths have to be considered. The post regarding minimizing the sweep of the tip of the rocker arm across the tip of the stem revealed the secret to minimizing valve train friction, that sounds like the optimum goal. Variations in rocker arm ratio and valve seat depth and variations in stem length are the only variables left to play with. The actual ratio of rocker arms vs. effective ratio is one more thing to concern yourself with. Seems like these two threads have revealed more areas of thought to be considered than anything else I've seen in a long time.Yes, push rod length is more critical than most persons have probably thought.

[Pat6868]

I was told by an engine builder that if you have your geometry right ,this will give you maximum lift. Would anyone have any info on how much lift is lost through hydraulic lifters due to spring pressures at race rpms. Thanks, Pat.

[Reed Granrt]

Originally Posted by Greg Reimer 7376

Well, here I am at 6:07 AM on a Monday reading this. Here's two more cents. Since most of these stocker cams are ground with more precision and consistancy as to lobe lift and profile, which can be verified by checking all 16 lobes with the cam in the block, then the places correction is necessary would be in the rest of the valvetrain. If all 16 lifters check,then the pushrods, rocker arms, and the valve stem lengths have to be considered. The post regarding minimizing the sweep of the tip of the rocker arm across the tip of the stem revealed the secret to minimizing valve train friction, that sounds like the optimum goal. Variations in rocker arm ratio and valve seat depth and variations in stem length are the only variables left to play with. The actual ratio of rocker arms vs. effective ratio is one more thing to concern yourself with. Seems like these two threads have revealed more areas of thought to be considered than anything else I've seen in a long time.Yes, push rod length is more critical than most persons have probably thought.

Greg
Several years ago, I made myself a rocker ratio checker. It is simple. Take a flat piece of metal and install a stud. Really needs to be what ever stud diameter your rocker system. Since I was using a small block chevy, I used a 5/16 steel ball out of a roller bearing. I then placed this on top of a gage block. It seemed easy to put 1 inch lift on small side of rocker ratio was easiest to use. I then put a dial indicator on the large ratio side. You can then measure the correct ratio of the larger side. I then went thru every stamped rocker arm I could find. I then put 8 together for the intake and 8 more for exhaust. All as close to each other as I could get. While doing this, for my stock rockers, I decided to check some roller rockers that I had (used-couldnt afford new ones). Man was I ever surprised at what I found. You have to remember this was several years ago and I found out later that some companies was still repeating the wrong way to build a rocker arm. I had no idea what was wrong but I knew it was wrong or the rockers did not make 1.5 (SBC). I was at one of the first PRI shows in Nashville, Tenn and I went to a presentation by Smokey Yunick. I waited until after his presentation and asked him. His comment was " Damn son, dont you know that cause it is new does not mean it is right" He then splained the world too me in a language that embarrassed me then. I came back and got a set of rockers (used)like he told me to get and they checked all the way thru a rotation. Apparently, people like he and Bill Jenkins new this but I had no clue.
reed

[Reed Granrt]

Originally Posted by Bub Whitaker

Grant says
" I'm now questioning whether the objective might not be to achieve the narrowest contact pattern on the stem tip, thus minimum side thrust and drag, then consider grinding even more lobe lift into the cam? "
Bingo, you got it...

I had already signed off and went to balancing a crankshaft but I would like to take a second to expound on this. I will never tell you this is correct but I BELIEVE it to be so. If you measure and set the correct rocker ratio, you will always have the smallest swipe pattern across the valve. Yes you can set rocker ratio by measuring the swipe pattern but that length is the result of correct ratio so why not set the correct ratio to start with, but proper ratio can be measured and attained by several methods. Choose your poison
reed

[Bub Whitaker]

Originally Posted by Robert Simpson

Bud you have a PM. Thanks.

It's Bub... BUB

[Robert Simpson]

Originally Posted by Bub Whitaker

It's Bub... BUB

Sorry about that Bub...

[Dwight Southerland]

I'm surprised that no one has meentioned grinding the rocker arm tip. . .
If roller rockers are accepted next year, this discussion expands arithmetically.

[eddie c]

Long ago stocker racer here, I still like the idea of putting my mechanical
knowledge or lack there of to the test. Years back my co engine builder
and I were trying to work thru some of these exact same problems.
We had a couple of coffee cans of CHEVY SB rocker arms and were
testing them on a base engine. Then we started to grind them and we were told by some smarter, older guys that it wasnt a good idea to grind rocker arms because the rocker tips were only hardened a few thousands into the metal and once you got past that point you would chew through them very quickly,So unfortunately we stopped working in that area,. Anyway this subject lends itself to a real cause and effect
senario. I dont think I have to worry about setting a record and being in a tear down barn anytime soon,but I think one of the main subjects of this thread is, how do the tech guys check cam lift and is there consistency from division to division. If I was currently racing that is something that I
would like to get established so when I built my motor during the off season ,I could build it and check my cam lift just like the tech inspectors were going to do in the new season. ed

[Reed Granrt]

Originally Posted by Dwight Southerland

I'm surprised that no one has meentioned grinding the rocker arm tip. . .
If roller rockers are accepted next year, this discussion expands arithmetically.

Dwight
Grinding a rocker tip has been done several times by such people as Smokey. And yes I have been following the thread on roller rockers. I know this may be the easiest and cheapest way out for many racers BUT I have a big big problem with this. I get upset when I hear people talk about the amount of technology and development that has been put into Pro Stock, Top Fuel and all our pro classes. But do you know what I feel is the most technological advanced class in racing today. NASCAR was included in that short list but no longer. Stock Eliminator is the most advanced. Think about how many people and for how many years have racers and engine builders been tweaking on stock parts to make things more frictionless , more advanced than they were ever intended to be. Sure the cost went with that but this is what has made the class what it is today. Look at how much science has just been discussed on rocker arms here on this forum and now we want to take that advancement all away and turn it over to vendors and let them just build us a set of roller rockers. Look at how many parts we have scienced out and now turned over to vendors to capitalized on. Let NHRA and NASCAR leave us alone and we will find a way to make it better. It is no longer race on Sunday and sale on Monday. Every month stock eliminator gets closer to being a Super Stock. Leave the parts alone and stop the cheating. Let us as racers tweak and build the best we can. Let us accel in developing our rides and our power plants and receive the fruits of our labor and OUR ingenuity not some damn vendor that wants to do nothing but make money off us. If we break it enough, we WILL make it better. Let US play in our sport and be the best not some vendor for hire. If we can make our one part better and we are faster, great that is what makes our labor of sweat and tears worth that extra .1 on Sunday and then I go home and try to beat your .1 for the next Sunday. Let us use OUR brains not them.
Damn got on a rampage already this early. Woman come git me off here whilst I am aspoutin
reed

[eddie c]

Reed, I am very new to this site,but I really have enjoyed listening to
what everyone has to say regarding their class" stock eliminator".
I also read what you had to say about the large amounts of knowledge
thats posessed within the stock class . If we were to state that
we had more or equal knowledge of engine design and theory to the folks at the NASCAR shops of Hendrix and Rousch we might get a few
funny looks,with that said, I strongly believe the people in Stock Eliminator do more with less than any other class hands down. ed