Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
This is full of awesome Mike. Very impressive.
Billet head - design / build thread !!
- Thread starter BlownV6
- Start date
Here are pics of the prototype head. It has 2.225" intake valve and a 1.600" exhaust. Right off the CNC machine it flowed 402 cfm at .850 lift on a 4.030 bore, hope to maybe get that to maybe 410 cfm but not sure if it will make it. Mike
good on ya! awesome project! i hope to design billet heads with an engine builder very soon.
what are your performance targets? what hp at what rpm? what stroke do you run? (engine displacement).
the latest 2v valve sizing would make your valves 2.15" x 1.575". a 2.15" valve will support 600+ hp at 8700 rpm naturally aspirated (4.2L). do you know what port area and runner length you need to tune to your rpm? it's smaller than your port is currently. what about exhaust port size and header dimensions?
if you're working from a clean sheet of paper, and you're fabbing your own intake, why not raise the ports more? will you be drilling coolant passages?
unboostedV6
Member
- Joined
- May 25, 2001
Bump for the 1st S2 update in 20 years! I must say I would have considered raising the valve cover rails and ports, and/or rolling the valves back to 12-14 degrees to help the short side. In Mike's case, however, it'd probably be insignificant, given the 14-71 and alky flow. Holding the heads down flat is his biggest problem. Nice job getting 410cfm...almost sb2.2 range!
Greg
Greg
GARY HARVEY
Member
- Joined
- Aug 17, 2001
i missed something...
How were you torching your heads?
How were you torching your heads?
I want to a 3.999 or quicker in the 1/8 mile. Opinions vary on exactly how much Hp that will require being that the 1471 blower requires about 400 Hp to turn at this boost and rpm level. 1500HP at the flywheel will get it done. My port will be larger than most think it needs to be , my thinking is at 65+ # of boost I creat my own velocity and need to supply volume to the throat area above the valve much more than I need velocity. Thats my opinion and its my project so thats the path Im taking.
I already had 6 billet aluminum chuncks at this demension so it what Im using.
Also wanted to keep it looking somewhat like a buick v6 head , so a 12" thick head would simply look to weird and I still need to get a blower belt on it.
I dont use water so no cooling passages will be installed.
I will be at 4.030" bore by 3.500" stroke with my next motor that these will be going on and plan to turn 8500rpm. Mike
We did raise the valve cover rails , and everything eles came with it to accomodate more lift at the valves. Valves centerline was moved toward the intake and are at 10 degrees. Hey it not GM engineering , but we will see what a little hillbilly engineering can do!!! Mike
How were you torching your heads?
This is what 65# of boost and 33 degrees of timing will do to stage 2 heads!!!
There simply is not enough material cast into the head at the exhaust valve to withstand the heat , cylinder pressure etc required at this power level with no coolant to maintain a flat seal at the head gasket. Mike
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GARY HARVEY
Member
- Joined
- Aug 17, 2001
Gad...
Yep, I'd say you exceeded you cylinder head design limits (just a touch)!
.............................................................................................
First let me say, I am NOT trying to piss you off.. OK.
A 1.5" or so exhaust valve will only flow so much.
You would have [better] success with a MUCH smaller supercharger.
Try a 6/71 and see if things don't work a little more in your favor
(and I'm guessing it's too big to).
Make friends with a T/A player and see if they don't confirm this.
Yep, I'd say you exceeded you cylinder head design limits (just a touch)!
.............................................................................................
First let me say, I am NOT trying to piss you off.. OK.
A 1.5" or so exhaust valve will only flow so much.
You would have [better] success with a MUCH smaller supercharger.
Try a 6/71 and see if things don't work a little more in your favor
(and I'm guessing it's too big to).
Make friends with a T/A player and see if they don't confirm this.
I want to a 3.999 or quicker in the 1/8 mile. Opinions vary on exactly how much Hp that will require being that the 1471 blower requires about 400 Hp to turn at this boost and rpm level. 1500HP at the flywheel will get it done. My port will be larger than most think it needs to be , my thinking is at 65+ # of boost I creat my own velocity and need to supply volume to the throat area above the valve much more than I need velocity. Thats my opinion and its my project so thats the path Im taking.
I already had 6 billet aluminum chuncks at this demension so it what Im using.
Also wanted to keep it looking somewhat like a buick v6 head , so a 12" thick head would simply look to weird and I still need to get a blower belt on it.
I dont use water so no cooling passages will be installed.
I will be at 4.030" bore by 3.500" stroke with my next motor that these will be going on and plan to turn 8500rpm. Mike
just to preface what i'm about to say, naturally aspirated motors rely on atmospheric pressure to force air in, and too large a valve will kill velocity, lower volumetric efficiency, and the motor won't pull as hard. many of the rules still apply to supercharged motors.
at 8500 rpm you want a 2.18" valve. your 2.225" valve wants to peak at 8900 rpm. i saw an LS7 port today that flowed 400 cfm at 0.650", with stock valve and standard port mouth (3.04 in^2). i still believe a smaller valve and port, flowing 400+ cfm, will get you down the track quicker (3.999 is quick!). you've done an excellent job on the ports. did you port it yourself? what does your port flow at lower lifts?
i'm curious what diameter header you'll use...i'm calculating 2.5" x 24" long
i wouldn't be surprised if you only ran 50 psi - maybe 60 - which would lower blower rpm, less drag, less heat, more power. i know you'll get there!
can you run a turbo? it makes me
that you have to make 1900 hp to get 1500 hp.I have been busy with toooo many other things to mess with this much, but I did get my rockers and some mock up pushrods and ordered material for the rocker stands. Since it started raining finally I have been able to get some time in the garage and Tuesday I had a cyst removed from my wrist and have a cast on. So I have done some things to keep the cast clean and have been sort of one handing my bridgeport to get this material into shape. In my hast to get material ordered I settled for 1.5" bar stock (BIG MISTAKE) as I need to machine it down to 1.300 x 1.365" x 1.700" long. This was quite time consuming to say the least!! I hope to finish all 26 stands tomorrow and will post more pics. Thats all for tonight!! Mike
Well I tried to figure out how to upload pics from my camera floopy disc to this post but I can no longer do it!!
The old system was very simple to use. This new system is out of my pay scale so I guess this thread will be ending very soon!!! Sorry Mike
Well I tried to figure out how to upload pics from my camera floopy disc to this post but I can no longer do it!!
The old system was very simple to use. This new system is out of my pay scale so I guess this thread will be ending very soon!!! Sorry Mike
A little update!! Rocker shaft studs I choose to use are 3/8 to 7/6 coarse. The program just drilled and tapped the 7/16 holes , but as you can see there is actually a shoulder at the top of the 7/16 thread which will not allow it to be screwed down into the head so I had to make a relief to get it where I wanted them. We will change the program to do this automatically.
Third pic shows about 75% of the shavings I created carving out these rocker stands. This turned to be way more work than I originally pictured.
Forth pic is parts ready to test fit!!
Last pic shows a slight miscalculation on my part in that I forgot to leave room for the thrust washers!! Back to machining to fix this problem and to make clearance for the original style stage 2 valve covers
Mike
Third pic shows about 75% of the shavings I created carving out these rocker stands. This turned to be way more work than I originally pictured.
Forth pic is parts ready to test fit!!
Last pic shows a slight miscalculation on my part in that I forgot to leave room for the thrust washers!! Back to machining to fix this problem and to make clearance for the original style stage 2 valve covers
Mike
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Yes I plan to build 3 sets cause thats how much billet material I alread bought for this project. I bought enough stell to build stands for all 3 sets while I was making them , plus ended up with 2 spares. Mike
unboostedV6
Member
- Joined
- May 25, 2001
I dig the captured rockershaft concept! What fit are you using between the stand and shaft to maintain a good clamp with the four studs?
I used a 3/8 & 1/2" drill bit then went to a 3/4 end mill then a 13/16 end mill which left me with a bore of like .817 to .818" which is about .005 clearance. the shaft goes completely rigid with just finger tightening of the stud nuts. So that going to be great in my book!!
Mike
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