Hello guys, i was a little unsure of how you guys would take to my rambling. Thank you though for taking the time to read that. Cylinder head function really is they key to any engine. Well, i'll try to sum up on you guys questions. 222 asked "Who are You?" I'm not sure what you want to know, but i'm basically a guy in Fl. that loves building engines and the "Research&Development" of any cylinderhead. My name is Bill. Just ask me something, and i'll answer ya'. No problem. Ok, Dragon asked to expand on "Have your cake and eat it Too". This is easy, for the most part, the "Porting" available to most people is not always what it's supposed to be. Alot of people have had the experience of a "Ported&Polished" head put on an engine, and it did not perform like they expected. Sometimes it may gain somewhere in the upper RPM range, but at the expense of bottom end torque. This can be caused by a ton of reasons, but if the only change was the head, this is usually from improperly shaped ports causing a loss in "Low-Lift Flow". Sometimes a really big one! The intake port is extremely sensative to certain areas being shaped incorrectly.
Much of the time, this tends to be the unfortunate result. The problem usually is in the relationship between the "Short-Side Radius" and the "Bowl-Area" and the "Valve-Job". Yes, the valvejob. I've picked up 10cfm between .100-.200 lift just by altering the valvejob. So, basically what i'm saying is, after a while, people begin to spread the "word" about this whole experience. Next thing you know, most people will tell you that headporting gets you more HP, but usually at some exspense.
This is true, if the guy doing the work doesn't know what he is doing. I'm gonna give you guys the basic path i follow when reshaping Intake ports. Always Flow the head first!!!!! DO NOT !!! Depend on magazines or hear-say for this information. You'd be stunned at what some companies will say their heads flow! Some are way off! Get your baseline, then determine the Valve to Bowl % you want to use, then take the bowl-circumfrence to roughly 80% of that size, then "rough in" a valvejob that suits the valve/bowl% you have chosen, then raise the roof to 90% of the desired height (judgement), then get the straight-wall, or Common-wall as straight as possable, sometimes it takes headbolt sleeves, or port-intruders to do this, but it is worth the extra effort, then blend/straighten out the uncommon-wall to 80%, then open/blend/channel around the"Guide-Boss" area to roughly 90% completion, and then rough-in the "Short-Side Radius" to around 75% completion, it is critical to not over-work the "Short-Side Radius" to soon. This will be the last area for major material removal, only after the rest of the port is at least 95%! Next, finish off the valvejob with stones. This is when the flow testing begins again. Based on what is found on the bench, which can be alot, minor adjustments are made through-out the port until the peak flow is maximized, (this peak flow# depends on head being used), not all heads are equal, so this does not mean keep on hoggin' till the thing flows 320cfm! This is where experience really takes over, you have to know when to say when. Just try to keep the peak at as low of a lift point as possable. You'll only be able to get it so low. On V8 stuff, .600 lift is a very good peak point, but not easy to reach.
Once this part is completed, then the finishing-work of the "Short-Side Radius" is next. There are many techniques used to finish a "Short-Side Radius". Mine usually ends with the final shaping done by hand with various grit sanding strips. Yes, by hand, meaning my little fingers. This "finishing" of the "Short-Side Radius" is done until the low-lift flow numbers (.100-.400) maximize right up to the point of trimming off some of the peak flow, and i mean trim, not hack some of the peak flow. Maybe 2-3cfm at the most. This may sound scary, to actually shape until the peak sees a slight loss, but it boosts the low-lift flow to it's potential. People, this is where it's at! I can not stress this enough!
This form of port-shaping is what has allowed me to build(example) a 3,790lb Camaro with a naturally/aspirated 400ci sbc, (with 23dgree heads) on pump-gas, NO NOS, no Trans-Brake, and dot tires run consistantly in the 10.70-10.80 range. For a pump-gas smallblock car, full body, this thing flies! The motor is now just turning 6yrs old too, we build em' to last . This car belongs to my best friend, so i know it intimately. Now, back to the subject, all this talk of low-lift flow and cylinder fill, has been discussed with Randall several times on the phone. He understands this, believe me. Guys in this "Porting" business know this second hand. It truly is the key to properly shaping intake ports. But then there is the exhaust ports, which i am not gonna dive into at this time, as my fingers are sore. (lol)
So, if you follow these instructions, you will have cylinder head/s that will make tremendous power everywhere. Not just up top. Remember, when you perform a dyno pull, it reads torque first. Not HP. HP is a mathmatical derivative of Torque. Anyone see the "EngineMastersChallenge"???? They reward the builders big time for "Average Torque" production, not peak HP. They are trying to tell the readers something.
So, it is possable to have your cake & eat it too. Very possable. Oh, Big Daddy, no problem. I kinda live for the stuff, and that pic of Elvis, the pure-speed ears joke, dude, i almost pissed. Man that was funny. And Viper, what trend were you talking about, i wasn't sure what you meant. Till' next time.

 

222

If you are going to be seeing those kinds of numbers on a stock bore, why buy a big bore? I haven't seen any dyno sheets for 730's showing more than 76 hp. Should we expect new numbers for the 730 that rival the horsepower the 800 strokers you were making a year ago just because of porting and cam improvements?

Wouldn't whatever power you can make with a stock bore by improving the head mean that much more with either a bore kit or a stroker?


Rob

 

The new head on my 855 will be most empressive!!!!! CANT WAIT!!!! I have seen what it did for the 800 allready[img]i/expressions/face-icon-small-happy.gif[/img]

 

HOLY SMOKES ALLRED I wish you hung around here more often!!


Now that kind of stuff is what I love. Great info and makes sence..


Id like to send you my race head thats already been done for you to inspect I will make it worth your while... If that would be ok With you. If not no prob. Ive seen and rode first hand different bikes with different port jobs. Ive had a bunch of different mechs with different teckniques, Ive seen little to no gains , and also MAJOR gains... Thanks for all the info, It actually took my headache away[img]i/expressions/face-icon-small-smile.gif[/img] Seriously.

 

Absolutly, feel free to ramble on anytime you like. This has been great stuff. I did not understand much of that last one, I need to do some more research to make it make since. Like I said before, I am just a student of the game [img]i/expressions/face-icon-small-smile.gif[/img]

 

Allred, thanks for that. Very informative. Randall, I hope you were talking about me sitting across from you. Thanks for replying.

The trend I was talking about was everyone moving in the HPR direction. Most that have posted have said something in the direction of HPR. Thats all.

 

You know if you listen real close....... I swear you can hear die grinders running in the back ground. =]

 

Now I really know that I KNOW absolutley nothing about my head other than I assume its was built for the last few HPs. It seems to do the job. I dont know why it would need different cams but if I could afford it I would let the continuous improvement evolve.

 

I'm sure that my 730 will dyno more than 76 in the near future. By the time you run the ugly stick, head and cams, the right tires and gearing, the number will be easily obtainable. That said, the peak is not what concerns me... it's the power made early and long. In my particular case, I need power early and long to get my BIG BUTT up the hill. I also do more than dunes, as I'm always in the desert and riding rocks! My HPR3 cams displayed such good/long power this last weekend that I was laughing coming down the hill after handing out MOPPING after MOPPING. Even the heavily modded YFZs that had me by 4 - 5 lengths were cought and passed at the top. I give up SO much at the start without a swing arm and good rubber that I have to make it up through the whoops and at the top.

If the right head work is done, and you match your components with that head work, your gains will be exactly where you want them. I've said this many times... Use a builder that you trust, and use their products. They know their products and are prepared to point you in the right direction accordingly.

Keep it coming Allred.... I'm still listening! And as long as this keeps coming, I'm sure I'll be doing a lot more of it.