I think to make billet heads to my 8BA flathead. I have drawn models of them in Solidworks I wounder what will be the best consutions chamber? Spark plug lokaltions?? how many cc. on the head woulld be good? for n/a engine 3 5/16" x 4 1/8" and for a blown one hers som some pics of them i have drawn Right side bottom Right side top veiw Right side water cannels Left side top veiw Bottom veiw of the left head Water chanels for the left head Merry Christmas to all of you from Stefan
Stephan: Unfortunately, there isn't a answer to question without actually having the motor, pistons, cam, valves all together on a flow bench (or at least one cylinder with the same). You can come close but, the best location really depends on too many factors. The really fast flathead guys spend countless hours on a flow bench and the track trying to answer your question. Good luck.
You may want to follow leads on this old thread http://www.jalopyjournal.com/forum/showthread.php?t=138917
looks like a fun project for sure! if I had the inclination to make a set of heads for a flathead I think I would have to make an early looking set of OHV conversion units. something like an F head maybe
Hard to beat the old Weiand chamber design - one of the best flowing mass-produced heads out there. Offys are a close second. Plenty of limited production heads and all-out, one-of-a-kind race heads as well to look at. But if you want a decent chamber that you can actually put your hands on easily, look for a set of Weiands.
I believe that any max effort Flathead Ford needs a better angle of attack from the valve seat to the combustion chamber transfer area. The only practical way to do this is to "pop" the piston dome up high into the cylinder head. If you're going to all the trouble of machining billet heads you might as well get all you can get. link for good info...... http://www.btc-bci.com/~billben/popup.htm examples how it looks in the hole
Interesting cutaway of Cord/ Lycoming V8 showing a "better" angle of attack In my opinion the only way to practically duplicate advantage in a Flathead Ford is to get that piston dome up there where it belongs.....
I've got a set of Norm Frick 2piece heads. One side is 2" billet 6061 and the other is 1" 6061. I have 78cc's and the area in the head behind the valve is backcut. The plug has been moved a small amount. These are going on a 3-5/16+.030 X 4.125 stroke. I'm using lightened Ross pistons, C.A.T. H beam rods. The block was relieved around the combustion chamber only, not out to the gasket. It was step relieved, .050 on exhaust and .100 on the intake. Have never had them flowed, but should be bringing the motor to life soon.
Thanks for all the tips of the heads. I will post pics when the heads are ready but that can take some time before they are done
In the meantime, thanks for the cool new computer wallpaper!! Keep us posted on your progress, looks great! Flatman
The combustion chamber shape and piston design can have a big influence on performance, but there are so many opinions and methods of chasing horsepower - and the final engine application has much to do with the choices you'll make. Most of the guys who are really experimenting with pop-up pistons, custom chambers, etc -- are looking to make top-end horsepower for dry lakes racing. Just because a high-flowing head and combustion chamber design works at Bonneville (where you care nothing about low-end horsepower and torque) - doesn't mean that you'd like it one bit on a street engine. Running a blower changes this dramatically in that the "stuffer" at the top really helps the low-end horsepower, so you can get away with more radical chamber designs. Also, consider cost! The minute you decided to go high-dome like Navarro or pop-up like Baron, then you're having custom pistons made - which will be at least TWICE as much as standard Ross forged ones. If you have the $$$ and are going for records at Bonneville, then go for pop-ups . . . if not, you'll have a hard time justifying to costs. Are you going to generate the CNC toolpath/code information for them from the 3D models? I'm heavily into CAD applications -- have Pro/E, Solidworks, Inventor, etc.. If you're willing to share your CAD models, I'm willing to work with you one some of the different chamber designs. I have original Harley KR heads, Baron pop-ups, Navarro pop-ups, etc.. If you want to chat or discuss, let me know - I'll be happy to send detailed photos of each type. Your valve areas are similar to the original KR heads - which influenced the work that Barney Navarro did. The KR flathead made the most HP per cube on carbs of any flathead - but they also had the room for big ports, valves, etc.. Another consideration is the valves and cam that you want to run - these play as big or bigger roles than the heads. Best of luck! Dale eMail: [email protected]
Sizing the blower to the intended application is important as well. For an all-out engine, you can get away with a bigger blower. For a street engine, you're much better off copying the factory stuff - spinning small blowers faster vs spinning big blowers slower. There was a factory Harley pamphlet called Competition Harley Davidson Racers - or something like that. There was an early one and a later one - there's some stuff that's only in one or the other - the bulk is in both.
Moving the spark plugs nearer the studs would allow for more valve lift and that would help address one of the biggest problems with Flathead's, Not getting near enough air in and out. I remember seeing pics of race heads where they welded up the original spark plug holes and moved them over a tad to allow lots more charging of the cylinders thru added valve lift. It's a bit of work because you have to hug up real close to some stud bores to get the plugs out of line with the valves if I recall right... (or was this just a hallucination caused by my alzhimers medication) If you haven't gotten JWLs book yet, it may be of real interest here as he deals with the shape of the current chambers through cut aways of heads. Good luck in your quest. moe ------------------------------ The All New/Old Flathead Forum is On The Air.... join today to cement your name in the first pages of the membership roster
I sell two piece flat heads.Old patterns,1947ish .600 Australian ,unmachined .see my website at brightworksmetalpolishing.com
Definately look into the Harley KR info the guys are refering to. By the late 60's they were getting real power out of 45 cubic inchs. Most came from combustion chamber design. Good luck.
i have not done them but i gave the files to some one thet was intresed of to do them but i have not heared anny thing of they were done
hi i know that this thred has been here a while but I have been working on designing a set of flat head heads and was wondering if you would want to share your files thanks
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