Has anyone ever heard of welding on top of the valve stems to open them up more
Has anyone ever done it?
If I do weld on top of the valves would it be more beneficial to weld on just the exhaust valve or on both of them
the only thing welding on top of your valves will do is make the valve longer and illegal in BSP rules. No benifit what so ever, unless you just like to weld on tiny round things,
Changing the length of the valve changes the angle of the rocker. Changing the angle of attack can cause the rockers to act like they have more or less ratio. Thus lift is affected. However making the valve longer is not really the way to go. Shortening it will give more lift. It does this by raising the pushrod end of the rocker and lowering the valve side. By starting at a greater highth the the push rod is closer to the stud and gets even closer as it lifts the rocker. That's what ratio rockers do is move the pushrod closer to the center point for more lift. So by shortening the valve your stock rocker will gain ratio and lift the valve more. Thats assuming that all other parts are stock.
If you don't believe it. Measure your lift at the retainer, then shave .005 off the valve and measure again. You will see a differance. It's not huge like 1.2 rockers, but it does add a small amount of lift. Thus you could bring a cam at say .228 lift up to .237.
Making the valve longer lowers the push rod side of the rocker and the valve will open faster initially but ramp speed will slow down faster and you will lose max lift. This is because the push rod moves away from the center point as it rises. This reduces the ratio of the rocker.
And somehow the Cloner's thought they could just take the motor out of the box, remove the Gov., etc, and race it. Has anyone learned anything yet?
Valve length, piston ring package, ceramic crank bearings ( don't laugh, it's out there, but could be a reality ), etc, some people will spend the $ to win. If one guy at the track is "creative", wins all the time, he is claimed each time, the whole track will have his motors. LOL
If that is true,then It Looks like a valve length tech rule will be coming soon to a track near you.
As long as the lift is right at the valve retainer. Don't worry about it. It's a simple prcess that anyone can do, sort of like lapping valves. No one is going to have to pay a builder to do it. Besides if you lap the valves you are also slightly changing the rocker geometry by lowering them in the head. This takes away lift and makes you slower. So trimming them just puts you back where you were to start with.
Like I said, the power differance is so small it's not even noticeable. So it's not worth worrying about it. After all what are we talking about, gaining maybe .005 lift. You go ahead and worry about it, I'll work on my tires.
Welding on the tip of the valve will not gain you lift, just make your rocker geometry out of wack. valve lift is all in the cam and the ratio of your rocker and how much lash you run.....
That would be correct. But when checking the cam you should also check the center lines (106 - 112 note that both lobes should be within 1 degree of each other) Also check the base circle (.860 +/-.005) and lobe length (1.094 +/-.005) Do this and you will catch 90% of the non stock cams, the other 10% will be caught by the new duration check.
Special note on the centerline. Both lobes should have the same center line. Most techs only check the intake. There are cam twisters out there that are made to twist one lobe and leave the other unchanged. Yes these cams can be purchased also. This is an area of concern and needs to be addressed. However a tech has a lot of options and parts are to be stock. Twisting cams is one area that is not allowed.
Hey Renegade...you've peaked my interest. You're to blame for me buying a clone anyway. I ran into one of your Super Box motors on Fleabay. I'm starting to like your knowledge. I ended up buying one from Dover...15.4hp @ 6400, for $812, shipped. What can you do for me? PM me, if you want. I'm always lookin'. Thanks. Scott.
I think I build a pretty good Super Box. I just don't want to say I can do it better than anyone else. Because until you have dynoed their engine you just don't know. My SB's have a real good record and the only complaint I have had is the kart won't quit spinning the tires.
Can I do more? Maybe, but I don't know what they are willing to do. I can honestly say i will build the best engine I can, and I stand behind my work. I don't do rush jobs, or take shrotcuts. If it's not good enough for my kart, it dang sure isn't good enough for a customer.
i have a question would pushrod lenght effect the rocker arm angle of attack? (.100 short vs std) and would running std exhaust rocker and a 1.3 intake make more power than a std vs std or 1.3 vs 1.3?
