[Awesome Bill]

Originally Posted by want-a-be

Push rod length does not change rocker ratio or the valve lift.

Don

Don, think about this, if your running to short of a pushrod and your geometry is off and your rocker tip is riding the short side of the radius and never reaches the 9:00 mark but does not get the extension over to 8:00, you will kill a ton of lift. Say piston to valve is around .060" I come along and say wow, your push rods are .200" short and install them. Once over center, the valve lift is picked up by the shorter side of the now max lift radius. This sometimes will pick up .100" with proper geometry, just depends how far it was on the short side of the radius.

Proper geometry is the basic fundamental procedure that must be set with the valve train at the time you set it up. Change anything and it changes. Rocker arms are not even close and I have seen .100" difference in just brands. If we make any change with rockers, we recheck the pattern.

The final assembly with all parts being used is check on both heads. Sometimes we add or take away lash caps for changing rocker arms up also. This gives us about .050" and also gives us a cushion for rocker tip failure. Had a ton of that with the T&D stuff and had to move over to Jesel. I think they are getting a handle on it. If the rocker makes it threw break in, their perfect, but we would get 3-10 tip failures for a while there and did not get any help when it warrantied pulling the heads back off to tip the valves. We set up with lash caps when using T&D until we see no more failures

Yes I use good assembly lube and moved to Renegade 5-20 oil with 3000 ppm of zinc and we still had the problem. Not 1 failure with Jesel, that was the tattle tale of knowing what was going on. I was not the only engine builder that went threw this.

Either way, push rod length will change duration and lift more than most people even realize.

[Awesome Bill]

Originally Posted by lun40119

.020 Bill, cmon Bill, that will be hard to get with a stud deal. Ive got more than that with the T&D's.

The proper valve train geometry will yield even tighter patterns when near perfect conditions are used. A lot of wider patterns happen also from the push and pull on standard stud rockers. Any type of drag or push and pull will change the pattern. A stud girdle was not to stop side to side flexing, that is stopped with just the push and pull of the cam with the basic valve angles to keep it going the way it is supposed to, it is used to stop the rocker studs from moving back and forth from friction, bad rockers, rocker wheels that bind and any other thing that can bite you in the __ss when your engine decides to just quit because it says so.

I never understand why shaft rockers are not used. When you take into consideration the cost of an engine and the valve train being the weakest link, even the cheaper shaft rockers are a bargin. I think you can buy them for under $300. That is just as cheap as the Chinese rockers. Most likely are Chinese shaft rockers.

This is why when we talk about people with problems and their engines are down on power and everyone wants to know what the head flows. Let me tell you a little about head flow, it is not the gauge for anything! Volume, valve size, intake manifold and carb is the key with proper application.

I don't get paid for this and do it because I hate to see hard earned money or even easy earned money get wasted. If you give a customer the best set of flowing heads anyone can produce and he or she does not understand everything else that goes with it, then its all for nothing and he or she will be __ssed off and talk __it about it. And then someone else reads it and another and another __it storm is out there because he or she does not understand nor are they professional enough to ask.

So lets just port their heads more and change the cam, that always fixes everything. If most people just got 400 real HP from their engines with a proper combination from front to back in a 3500 lb car, everyone would be running 11.50 @ 133+mph