Boring a flathead

[Karl Wolf]

You shovel it into an airstream, and watch the air flow through plexiglass parts...
I think... Karl

[Kahuna]

Mike
Bruce explained it back a few posts. Essentially it is the process of flowing Kitty Litter thru intake ports with a plastic/plexiglass combustion chamber to see what actually occurs during intake flow. This concept is not really new, as others have tried it using different media. I think it's probably a good idea, but takes a bunch of work to accomplish. I'd love to see a video of it.
Jim

[Vergil]

Originally Posted by Mike B

One serious thread I have been following, nothing to add..I'm not even worthy
to make asuggestion or a comment...but I do have a question, how are you guys "cutting apart" a block, for view?

I used a 4 1/2" hand grinder with a cutoff wheel to cut as deep as it would go then finished the cuts with a reciprocating saw. It wasn't as hard to do as I thought it was going to be, be sure to wear a dust mask.

Vergil

[flatjack9]

I used a sawzall. Cast iron cuts pretty easily. But it's still slow work.

[Ol' Ron]

I used a skill saw with metal cutting blade and a saws all

[Bruce Lancaster]

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Flatdog said that he smashed junk blocks with a sledgehammer, then selected chunks and started cutting til he got a neat edge where he wanted it. Some of his port pictures have been published on the HAMB.

[Henry Floored]

I have flowed baby powder through Flathead intake ports. On the exhaust port outlets I simply started a Flathead without the exhaust manifolds on to get an idea of what the exhaust flow was doing at the outlet area. In both cases the visual is very telling. It's very easy to see that at both of these visible points the charge "wants" to go straight. In the intake port it is shooting straight towards the center of the cyl head dome and on the exhaust port outlet it is blasting straight towards the center of the engine just like Bruce said that Flatdog found. The idea of a very center angled or even slash cut out ext header pipe is probably the best way to carry the charge out of all 4 outer ext ports. Precisely what Flatdog was doing.

[Henry Floored]

A few more thoughts on the intake porting and their ability to feed the larger displacements in the Flathead Ford. Certainly it would be nice to have the option of bolting on larger ports like our OHV bretheren can easily do. Unfortunately that's not an option for us. Ron gave us an excellent vertical cross section of a Flathead intake port. The area that appears to be "pinched" is actually the ramp that directs the intake charge into the combustion chamber. With the water passages above and below it looks like quite a bottle neck. In my opinion though it's not as bad as it looks. When I port the intakes most of the material I remove is from the sidewalls of the intake ports. I like the design of the intake port and I don't think I can improve on the Ford engineer's ramp effect. If you think about it ohv engines like the sbc have ramps in them to direct flow as the port snakes around the pushrods. I think the best way to approach Flathead intake flow is to optimize flow through the port just like you would on an ohv engine. Forget about making the turn down the cyl for awhile. After finding the practical limits of what the intake port can actually flow I'd build an area over the piston that could accept about 125% of that number. I'm talking a healthy cyl head relief. This is the approach I'd like to try on my next engine. Step one is getting a block section with the intake ports and getting the fixture built. Might even be able to talk the local race engine builder into flowing it on his Superflow bench.

[Ol' Ron]

I built a flow bench for my book, years later I had the opportunity to use a professional unit. This became addictive. I spent days, weeks themn months trying to find the holy grail of flow. I ran flow test with valves, without valves. I ground into the water jackets and shaped ports with bondo. I wish you luck, I hope you find it. But5 I'll bet you a steak dinner I can get as much flow in 20 minutes than you can in an hour or two..
I use a power file to machine the top of the port to about .100" thick measured through the water jacket. Grind down the lip by the guide and blend that in. Next fill the low spot between the guide and the mouth of the port with JB weld. 20 -30 minutes. This includes a 1.6 valve and the bottom of the valve is part of the port and should be quite flat 15-20 degrees .040" seat. I could go on but you get the idea.

[Ol' Ron]

PS use a 52-3 block

[Vergil]

I will be the first to admit I am not very knowledgeable about porting but I will throw up a few pictures of what I done to the intake ports (these are on the cut up engine) on my engine during assembly. The valves are Manley ProFlo.

Vergil



Before




After



Difference

[Ol' Ron]

Now remove an 1/8" from the bottom of the valve too. Most of the Hump at the bottom is still there. This is a good street port& valve It will pass more than eniugh F/A to run a 276 with a long cam to 4500+ befor the power falls off.

[Vergil]

Ron I have the engine redline set at 5000 rpm using a Schneider cam and pulls strong, should have had this post thread before building the engine, good information.

Vergil

[Henry Floored]

Guys thank you so much for sharing your knowledge. I find this subject fascinating and a real release from all the bad news we hear on the news everyday. Thankyou!

[HotRodmicky]

Originally Posted by Vergil

Ron I have the engine redline set at 5000 rpm using a Schneider cam and pulls strong, should have had this post thread before building the engine, good information.

Vergil

Hi Vergil,
which Schneider grind do you use?
Michael

[Vergil]

Originally Posted by HotRodmicky

Hi Vergil,
which Schneider grind do you use?
Michael

Schneider 270-F
Lobe Seperation 112
Intake Camlift .365
Exhaust Camlift .365

Vergil

[Lyndon]

My LB ended up being 0.100 over to clean up some bad rust pits on some of the non-cracked cylinder walls.

[Ol' Ron]

The 270 Schnider cam is a nice cam, sounds good and pulls well over 2599. Displacement and compression make up for any low RPM losses. I like a hot cam in a street machine,if your looking for mileage buy a Preis.
Vergil, for a street engine you don't want a very thin valve and you don't really need all that flow for a street.

[Vergil]

Originally Posted by Ol' Ron

The 270 Schnider cam is a nice cam, sounds good and pulls well over 2599. Displacement and compression make up for any low RPM losses. I like a hot cam in a street machine,if your looking for mileage buy a Preis.
Vergil, for a street engine you don't want a very thin valve and you don't really need all that flow for a street.

Thanks Ron, another note on the cam, I have advanced it a little, now the intake valve closes at 43° ABDC instead of 49°, thought it might bring the torque curve down just a little and so far I am happy with it but I didn't get to run it with the cam set straight up.

Vergil

[Blownflatheaddeuce]

Originally Posted by Kahuna

Thanks Bruce. I had heard that those litter tests were pretty informative. So sad that he passed away. Good guy
Jim

So true....he was a super freindly guy who even spared time for a flatheader for the other side of the pond.

Was shocked at his untimely passing.

Great info in this thread, lets keep it going.

Im currently in the throes of another blown engine build so its great to read the info in this thread.

BFD