Box Stock

Predators, Clones and all things in between.....

sneaks12303 said:
My bad....The 60730 has the plastic gear...The hemi has the more traditional clone cam...Thanks Barry...
Click to expand...

I was second guessing myself though. LOL. I have only had two predators with the plastic cam gear actually, they were the older ones that had the thick ring pack as well. And by the way, they didn't show any different power than any other old style predator either. Is that what you have seen Gary?
 
thanks guys!! i'm looking at using the hemi head bottom end for the cam journal and then "working" with the big valve head and tweaking it just a bit! ok, tweaking it a lot!! lol! one thing that concerns me tho is the valve stem size...i want to go with the stronger stainless valves, but i'm not sure about reaming the guides to accept the 5.5 valve stems....stupid question time...are the stainless 5.5 longer or the same as the 5.0 valves and do i need to do anything with the seats? i'm already working on the black plastic spacer that fits between the carb and the head....it's like a restrictor plate from hades.....doesn't do any good to have a sa carb and then slap this plate (in stock configuration) on it.......
 
Why not use the Hemi head Mikey? Those angled valves pick up lots of flow and already have 5.5mm stems.

.5mm is a lot to ream out, if you have a # set of drill bits I'd drill it out closer and then ream the last couple thou.
 
i can rebuild any engine put before me....i just don't have the equipment, or more importantly, the knowledge to get into modifying everything that needs to be done to convert the hemi head into racing form. one friend is "experimenting" with one now. it's a stock head on a stock bottom end, but he's installed a CL2 cam...and the dang valves have already dinged the piston. yes, he should have compensated for the higher lift by installing the correct length of push rod, but still....not enough research that i've read has gone into converting the hemi head for racing...the tolerances are too close and i risk loosing a sizable investment if i'm so much a dog's hair out....
 
I think the issue is people are shaving the hemi head a lot to get the cc's down and it needs to be welded up some like I did instead, so the valves stay further away from the piston. I also cut my seats so the valves sit in the head a bit deeper as well. Even cut some shallow valve reliefs into the flat top if you have to. Because the only rev limiter you guys have on dirt is valve float, it's very risky to build an interference engine.
 
youngengines said:
I was second guessing myself though. LOL. I have only had two predators with the plastic cam gear actually, they were the older ones that had the thick ring pack as well. And by the way, they didn't show any different power than any other old style predator either. Is that what you have seen Gary?
Click to expand...

Surprisingly similar until you "unleash the beast" within, with a mod. or 2. Or a Mod2...lol
 
.5mm=0.0196850393700788 = Thousandths Your GOING to Drill It?????????????????? How Did They "Ding the piston w/a CL/2??? Gotta have 1.3's or a seriously!!!!!! cut head; or cam off a tooth
MIKEY MIKEY just ask??????????????? You Could "Stage" a picture & let us see the cam gear. & By the way they are the same length(valves)
 
Astrowrench, yes I was a machinist for several years and .020" is really pushing a reamer that size. For accuracy and tool life we preferred to drill around .005-.010" undersize first and then ream. If you've got stepped reamers though no problem. Maybe it's overkill but I'm picky with my machine work.
I'm doing a build on a hemi with a welded chamber head(old forum ate my pics when it crashed sorry), billet rod and mod2 cam for an asphalt sprint track gas build. I expect it to be a good 2HP over my BP build.
 
i'll see if I can't get pics to show...I think he said that he's already cut some valve reliefs...but I can't be sure. the way I figure it, if I don't ask, then the answer will never present itself. harkening back to the old adage that the only stupid question is the one you don't ask, I figured that I'd ask the stupid questions...and I've got a ton of them!!
 
Without welding, you have to cut the Hemi head down ALOT to get the compression up. I did a lot of welding on mine and with a thin gasket it's still only 10.4:1 compression....about perfect for premium gas for my application, but not enough for the alky guys. So I could see how the valves can easily get into the piston.
 
astro....then it becomes a matter of the cam and the lift that you want to run. the higher the lifter, the deeper the valve will open into the combustion chamber right? so then you are faced with the same problem....piston/valve interference. this is the area that I'm not really and not ready to accept and risk ramming the head of the valve into a brand new wiseco piston. this is why I said that not enough research has gone into the development of the hemi head for racing applications. it's not a question of why don't you, it's a question of what will it cost if you don't do it exact and right the first time.
 
easy dude! switch to decaf!! it's only the way that I feel! no one is saying that you don't have the knowledge or the ability to make them work! I don't have that same knowledge or the right stuff to do it myself! I'd love to get one of the heads working for me and working the right way because I think that the head has great potential, but until I can see the results and know that I'm not going to tear my stuff up, then I have to be cautious! I don't have an unlimited wallet so I have to be careful on what I do have! do I stretch the limits on the motor? yes....within what I feel is safe. safe is not welding, cutting, grinding, polishing and spending all night, every night doing it. I take what I know, what I have and what resources I have available and make do. if that means not winning, am I worried? no my son gained his first feature win this past season on a motor that I built. that was a first and hopefully not a last.....and I had the time of my life!! even tho he lapped me twice while I was having carb problems.......
 
You must log in or register to reply here.
Back
Top