Flathead valves and flow??

[revkev6]

Valve flow!

I know I should just order up a book as I'm sure it's in JWT's but I have a couple questions on valves and angles.

I've read discussions on valve flow in a flathead stating that 30 degree valve jobs flow better than 45 as they push the flow more parallel with the face of the transfer area (vs an OHV engine that you want the flow mostly parallel with the cylinder walls) this makes a lot of sense to me.... now thinking along those lines I have also read that a lot of guys are using SBC manley stainless valves in their motors.. they are undercut and flow better than stock ford valves.... BUT.. in looking at exhaust valves vs intake valves there is a pronounced difference in the radius that leads to the underside of the head of the valve. an exhaust valve needs to absorb more heat and doesn't need to flow as much (in an ohv, this has been somewhat debated in a flathead I believe) so the manley valves which still flow better than a flathead are a cheap easily available performance upgrade. but comparing them to the same SBC intake valve it appears that we could still gain some more...

the manley 11521 1.5" stainless undercut polished etc exhaust valve has a 12 degree under head angle vs the 10 degree under head angle of it's corresponding 11506 1.84" intake valve.. it seems to me that the under head angle would be as helpful to directing flow parallel to the deck as the valve seat angle. I'm guessing that I'm not hitting on anything new here.. but has anyone cut down a 1.84 intake valve to see what the gains are over using the exhaust valve??

[revkev6]

manley 1.5" exhaust valve:
Exhaust Valves

Type: Exhaust Valve XH-426 Material
Head Diameter: 1.500''
Stem Diameter: 11/32'' / 0.3415''
Installed Height: Stock
Overall Length: 4.911''
Tip Length: 0.250''
Underhead Angle / Radius: Pro Flo 12° x 3/8''
Margin: 0.060''
Seat Width: 0.100''
Top of Head: 7° Dish
Weight / Grams: 89




manley 1.84" intake valve:
ntake Valves
Type: Intake Valve NK-842 Material
Head Diameter: 1.840''
Stem Diameter: 11/32'' / 0.3415''
Installed Height: Stock
Overall Length: 4.911''
Tip Length: 0.250''
Underhead Angle / Radius: Pro Flo 10° x 3/8''
Margin: 0.060''
Seat Width: 0.080''
Top of Head: 5° Dish
Weight / Grams: 104




they both use a 3/8 radius but the underside angle is 2 degrees different as well as the seat width being larger for the exhaust valve. I'm assuming the seat is ground at 45 degrees anyway so this would be set to whatever you would like when the valves are ground

[Ronnie]

This should be interesting!!

R

[rotorwrench]

This is one of the reasons folks usually recommend you read JWL's book.

[Daryl Middlebrook]

30 degree valve cuts and/or various radius valves are not going to make a noticeable difference in performance. Yes it will help, but you will won't see it.

A professional port & polish will provide the most improvement.

[revkev6]

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Originally Posted by rotorwrench

This is one of the reasons folks usually recommend you read JWL's book.

yes... it's in my birthday wish list which my wife has said doesn't exist since I just bought a complete rusted out 46 ford for the driveline... she says that's my birthday present

Originally Posted by Daryl Middlebrook

30 degree valve cuts and/or various radius valves are not going to make a noticeable difference in performance. Yes it will help, but you will won't see it.

A professional port & polish will provide the most improvement.

the next flathead I build will be a large cube motor and is going to get as many flow improvements as I can manage on my budget. I don't pick and choose... I try to address everything as a system. It will be ported, possibly a larger intake valve with associated machine work required.

before I do anything on it I'm going to do a lot of reading... like JWL's book and fordbarn and the HAMB

[Bruce Lancaster]

A good thinking tool: Dave Vizard's "How to Build and Modify Chevrolet Small-Block V-8 Cylinder Heads."
DV might be one of the most sophisticated writers around, and his analysis of results for different sorts of mods to ports, seats, and valves is great transferable theory.
A Chevy port is kind like an upside down flathead port...but of course the relatively huge bowl and the upside-down entry into the cylinder allow a lot more of the curtain to be useful. But...the theory shown, discussed, and tested in this book is certainly transferable.

[Bruce Lancaster]

And...remember the Late, Great Flatdog's flow experiments...he developed clear plastic head chambers so he could watch, and did the flowing in his garage with a huge vacuum cleaner and kitty litter!
His 3,000 pound '34 got into the high 12's and was still a smooth, driveable street car. I was privileged to drive it for a hundred miles or so on a trip once, and it was astounding.
There was no curve in the torque curve...simply as much torque as you wanted whenever you wanted it.

[Ol' Ron]

Boy, I love this thread. In my book I have some pics of the valves we used in the stock cars. Many hours on a flow bench proved the value of this to increase flow. When building an intake valve O use a 3/4" round carbide incert to cut the underside of a stock 2 piece Chevy valve. I feel these are much better than The SS valves made by the aftermarket, except for the chrome stem unites. Along with the 30 deg seat angle. Unfortunately, the real problem with intake flow is the shape of the port, especially the bowl. For a stree engine, reliability is more important than high power. In Richards engine we used unmodified SBC valves and no port modifications. Just a tight combustion chamber and hi compression. (8.5) The heavy 53 HT Ford had all the low end power you needed. For a mild street engine mods to the ports just remove material from the top of the port. Use a micrometer to measure the thickness of the casting through the water jacket. I bring this down to .100"and radius the output. On the flow bench this increases flow quite abit compaired to other areas. Also filling the bottom of the port also improved flow. Yes Flat Dog was on the right track and gave me allot of Ideas. The biggest problem with flow benches is::: They are addictive, once you start, you can't stop. I do believe the "Holy Grail" of the port will be found, I keep looking for it but?? The stock flathead is a 4L engine in to days automotive world. Most of them make double the power. Increasing the displacement of the flathead, only makes the ports work harder. Blowers do work.

[Pete F]

Originally Posted by revkev6

Valve flow!

I know I should just order up a book as I'm sure it's in JWT's but I have a couple questions on valves and angles.

I've read discussions on valve flow in a flathead stating that 30 degree valve jobs flow better than 45 as they push the flow more parallel with the face of the transfer area (vs an OHV engine that you want the flow mostly parallel with the cylinder walls) this makes a lot of sense to me.... now thinking along those lines I have also read that a lot of guys are using SBC manley stainless valves in their motors.. they are undercut and flow better than stock ford valves.... BUT.. in looking at exhaust valves vs intake valves there is a pronounced difference in the radius that leads to the underside of the head of the valve. an exhaust valve needs to absorb more heat and doesn't need to flow as much (in an ohv, this has been somewhat debated in a flathead I believe) so the manley valves which still flow better than a flathead are a cheap easily available performance upgrade. but comparing them to the same SBC intake valve it appears that we could still gain some more...

the manley 11521 1.5" stainless undercut polished etc exhaust valve has a 12 degree under head angle vs the 10 degree under head angle of it's corresponding 11506 1.84" intake valve.. it seems to me that the under head angle would be as helpful to directing flow parallel to the deck as the valve seat angle. I'm guessing that I'm not hitting on anything new here.. but has anyone cut down a 1.84 intake valve to see what the gains are over using the exhaust valve??

Before you go buying valves you better decide if your going to change the cam,different base circles affect valve length and valve seat affects valve length
So if your rebuilding and updating the cam have someone cut the valve seats first than get the cam so you can get the proper valve length .
Your adjustments are limited with the lifters and also the gain in flow in 30 degree seats are so small and the longevity of the seat is less because of the shaper edge
And you ask how does he know this well after 45 years of building engines I decided to build a little simple Flathead Wrong there is more hidden secrets in these engines than building a Duesenberg
Good luck

[40 Deluxe]

Something to consider when doing mental port work before you get to sleep: Air is pushed into the cylinders, not pulled. It makes a difference. We sometimes think the air/fuel mixture is pulled into the engine by vacuum, but it's not. Atmospheric pressure pushes it in. So wherever there is a narrowing of the intake tract or sharp turn, the air "piles up", slows down and fuel drops out of suspension. The resulting turbulence also impedes air flow into the cylinders.
It's easy to visualize the piston pushing exhaust gases out, but maybe harder to visualize atmospheric pressure acting like a giant piston pushing air through the intake tract.

[revkev6]

Originally Posted by Ol' Ron

Boy, I love this thread. In my book I have some pics of the valves we used in the stock cars. Many hours on a flow bench proved the value of this to increase flow. When building an intake valve O use a 3/4" round carbide incert to cut the underside of a stock 2 piece Chevy valve. I feel these are much better than The SS valves made by the aftermarket, except for the chrome stem unites. Along with the 30 deg seat angle. Unfortunately, the real problem with intake flow is the shape of the port, especially the bowl. For a stree engine, reliability is more important than high power. In Richards engine we used unmodified SBC valves and no port modifications. Just a tight combustion chamber and hi compression. (8.5) The heavy 53 HT Ford had all the low end power you needed. For a mild street engine mods to the ports just remove material from the top of the port. Use a micrometer to measure the thickness of the casting through the water jacket. I bring this down to .100"and radius the output. On the flow bench this increases flow quite abit compaired to other areas. Also filling the bottom of the port also improved flow. Yes Flat Dog was on the right track and gave me allot of Ideas. The biggest problem with flow benches is::: They are addictive, once you start, you can't stop. I do believe the "Holy Grail" of the port will be found, I keep looking for it but?? The stock flathead is a 4L engine in to days automotive world. Most of them make double the power. Increasing the displacement of the flathead, only makes the ports work harder. Blowers do work.

wish you were just a tiny bit closer ron! I'm in the springfield mass area and would love to be able to pick your brain in person as I went through a build. with a first time port job I'm going to be nervous about water...

[Ol' Ron]

If your building a street engine, don't bother. ANY Porting is only beneficial at higher RPM's. The forum here is discussing methods for improving flow, and we compare notes for better ideas. Over the past 80 or so years, some of us have tried to get better volumetric efficancy from these engines. And as one person has said, air is pushed in amd bloweres do just that. Porting a street engine is a basic waste of time. If Roller cams with 450 lift and re placing the present ports can't do it, then why bother.

[Kahuna]

Kev
If you place an angle finder or straight edge at the same angle as the valve face area (30 or 45 degrees) and make a measurement to the combustion chamber on "most stock or after market heads", you will readily see that the 45 degree is closest to being correct to direct the charge to "bounce" off the chamber and into the cylinder.
Next, it's probably impossible to put a 1.84" valve into a flathead, but easy to use a 1.72" valve, which are available.
If you accept that as a possible improvement, then the next step is to provide as much net lift as possible. The lift is probably much more important than the valve size.

Also agree with OlRon re porting. Unless you are building a real power house (like Dale B&S)
who has tremendous patience, just cleaning up the stock ports will be just fine.
If you have the time, look up some of B&S's posts re porting. He's done a magnificent job.
Wish I had the skill
JMO
Jim

[revkev6]

bother because it's fun! this will be going into a 32 ford with a 39 box and a banjo with 3.78 gears. my 28 has a basically stock 8ba in it with heads and intake... runs like a top although she's long in the tooth at 25 years since we built it. that one I'm tearing down and checking it out and just putting it back together. gaskets paint and valves adjusted... maybe a valvejob and a cam if the leakdown is excessive.

[saltracer]

I am currently building a turbocharged flathead to race at Bonneville. 1.8 intakes and 1.625 exhaust. Those are cut down from the 1.84's you described. Waiting for my block to come back from the machine shop. 3.268 bore with really small metric rings.

[revkev6]

Originally Posted by saltracer

I am currently building a turbocharged flathead to race at Bonneville. 1.8 intakes and 1.625 exhaust. Those are cut down from the 1.84's you described. Waiting for my block to come back from the machine shop. 3.268 bore with really small metric rings.

What are the rules for your class? Not really clear on rules but thought they limited most flathead classes to superchargers

[saltracer]

we are running our current flathead in a 1985 Mustang body, which is not considered Vintage.......so as such we are allowed to do must anything to the engine, like supercharge, turbocharge, centrifugal, electrical fuel injection, move the ports around. Pretty much the same as a streamliner I guess. XF/BGALT flathead blown gas altered

[JWL]

As everyone knows, searching for the maximum potential flow involves much more than seat angle and stem design. In addition to port and bowl shaping the cylinder head must also be considered.

The better seat angle after major port and bowl modifications are done is around 37 degrees. However, custom machined valve underhead designs can closely reach the same potential with 45 degree seats.

Actually, net valve lift is NOT as important as valve size. The REAL truth is the stock valve can be COMPLETELY REMOVED and flow changes little after around .350 lift and from .400 to .500 the measurements are only necessary to help the operator believe what he is seeing. If porting work is successful a bigger valve and larger diameter bowl, with a good shape, can be used and will step up the low lift flows to almost double the stock valve. But, even this begins tapering off at around .400 lift.

With all that said, there is the "quality" of the flow to be considered. Maintaining a completely homogenous mixture gulp into the cylinder can outweigh the maximum flow system when searching for power.

[revkev6]

Originally Posted by saltracer

we are running our current flathead in a 1985 Mustang body, which is not considered Vintage.......so as such we are allowed to do must anything to the engine, like supercharge, turbocharge, centrifugal, electrical fuel injection, move the ports around. Pretty much the same as a streamliner I guess. XF/BGALT flathead blown gas altered

Sounds fun. How small of a ring pack will you run with that turbo? Psi? Anymore specs you would like to share on the motor?

[Henry Floored]

Hey gang I recently attended a local truck and tractor pull. It has been about 20 years since I went to my last one.

Everything there was cool but I was most interested in the"Garden Tractor" pullers because I happen to have a cherry vintage Wheel Horse which is a prized possession of mine.

My Wheel Horse is powered by a "K" series Kohler single cylinder flathead engine. These little engines are things of beauty and when stock mimic the smoothness and deep baritone sounds that our lovely Ford Flatheads exude.

Why do I mention this seemingly waaay off topic subject? Well it's because we Ford V8'ers could do well to take a look under the bonnets of these little puller garden tractors.

First it sounds like they turn north of 7000 rpm. (I think)

They are based on the bigger bore 14 and 16 horsepower block which I think have about a 3 3/8" bore.

The intake port on a stock Kohler is adequate in size but lacks the shape they need so that is addressed.

They run a billet head with a flat top piston and some sort of block relief.

They have an impossibility small base circle diameter camshaft just like a Ford V8 in stock form.

They run a long intake runner with some kind of motorcycle carb on the end.

By now y'all might be thinking "who cares" and that's a fair question because this is a Ford V8 forum. Well I care because these little flatheads turn out about 45-55 horsepower!

I think that is incredible for a small antique one lunger. If one could duplicate that kind of performance in a Ford V8 wouldn't that add up to a 400+ horsepower engine?

Now I realize that's pie in the sky but those guys are doing it and the principles between those little Kohlers and our Ford V8's are much the same.

Food for thought and submitted for your enjoyment.

https://youtu.be/GvPbtUOfQ54

[revkev6]

JWL, If you noticed, I never mentioned "max flow" I'm trying to make flow improvements. keep the port velocity high and use components that will work efficiently within the constraints of the flathead. I have a couple 59a blocks I'm planning to use for a build. I'm really going to do some research to build a big cube engine that works well on the street. I found some plans online to build a flow bench and a calibration plate to give me CFM data. one of the 59a blocks is cracked with factory relief so I would like to use that as a flow bench mule. what I would like to start with is some valve and seat work to determine what works... is my understanding that once this is determined it should remain pretty static as far as angles and undercuts?? Or will I be hindered by the stock ports before the flow improvements on a stock size valve can be realized fully? I was thinking of putting in a plastic valve seat that I can quickly and easily swap out and make changes to. possibly cut the head off a valve and do the same there... use plexyglass to create a quick and easy swappable valve. In my thinking Valve work on a flathead is kind of a no brainer... you have to buy new valves, you have to do a valve job... why not determine the best flowing combination before you pick them out. I'm sure different chamber shapes will work slightly differently with different valve configurations?? say a head with a higher transfer port might work better with a 45 degree seat than a lower transfer area when compared to a 30 or 37 degree seat or when a relief is cut...

next I would try to move on to porting... this I would need to have some guidance on as there are so many variables that having a starting point would be a HUGE time saver

thoughts??

[Tim Ayers]

Originally Posted by Henry Floored

Hey gang I recently attended a local truck and tractor pull. It has been about 20 years since I went to my last one.

Everything there was cool but I was most interested in the"Garden Tractor" pullers because I happen to have a cherry vintage Wheel Horse which is a prized possession of mine.

My Wheel Horse is powered by a "K" series Kohler single cylinder flathead engine. These little engines are things of beauty and when stock mimic the smoothness and deep baritone sounds that our lovely Ford Flatheads exude.

Why do I mention this seemingly waaay off topic subject? Well it's because we Ford V8'ers could do well to take a look under the bonnets of these little puller garden tractors.

First it sounds like they turn north of 7000 rpm. (I think)

They are based on the bigger bore 14 and 16 horsepower block which I think have about a 3 3/8" bore.

The intake port on a stock Kohler is adequate in size but lacks the shape they need so that is addressed.

They run a billet head with a flat top piston and some sort of block relief.

They have an impossibility small base circle diameter camshaft just like a Ford V8 in stock form.

They run a long intake runner with some kind of motorcycle carb on the end.

By now y'all might be thinking "who cares" and that's a fair question because this is a Ford V8 forum. Well I care because these little flatheads turn out about 45-55 horsepower!

I think that is incredible for a small antique one lunger. If one could duplicate that kind of performance in a Ford V8 wouldn't that add up to a 400+ horsepower engine?

Now I realize that's pie in the sky but those guys are doing it and the principles between those little Kohlers and our Ford V8's are much the same.

Food for thought and submitted for your enjoyment.

https://youtu.be/GvPbtUOfQ54

Thanks. I also love all type of small engines. It is amazing what these guys can do. I'd be curious to hear how much they spend on these one lungers to put out that much H.P. I bet the number would be surprisingly high.

[Henry Floored]

Originally Posted by revkev6

JWL, If you noticed, I never mentioned "max flow" I'm trying to make flow improvements. keep the port velocity high and use components that will work efficiently within the constraints of the flathead. I have a couple 59a blocks I'm planning to use for a build. I'm really going to do some research to build a big cube engine that works well on the street. I found some plans online to build a flow bench and a calibration plate to give me CFM data. one of the 59a blocks is cracked with factory relief so I would like to use that as a flow bench mule. what I would like to start with is some valve and seat work to determine what works... is my understanding that once this is determined it should remain pretty static as far as angles and undercuts?? Or will I be hindered by the stock ports before the flow improvements on a stock size valve can be realized fully? I was thinking of putting in a plastic valve seat that I can quickly and easily swap out and make changes to. possibly cut the head off a valve and do the same there... use plexyglass to create a quick and easy swappable valve. In my thinking Valve work on a flathead is kind of a no brainer... you have to buy new valves, you have to do a valve job... why not determine the best flowing combination before you pick them out. I'm sure different chamber shapes will work slightly differently with different valve configurations?? say a head with a higher transfer port might work better with a 45 degree seat than a lower transfer area when compared to a 30 or 37 degree seat or when a relief is cut...

next I would try to move on to porting... this I would need to have some guidance on as there are so many variables that having a starting point would be a HUGE time saver

thoughts??

Kevin, where abouts are you in the world. I'm in west central Florida. If we happen to be neighbors I'd do whatever I could to help you, which honestly and coincidentally would help me too. 😉

Just a FYI. There is a guy in this forum who is in the west coast, I believe his name is Pete. He has built some big inch Flattys. Like in the 320" range.

He has stated on here that he revs them pretty high which I assume means north of 6000.

Keep in mind that the '48 and earlier blocks have valve locations that are, I believe, .090" closer to the edge of the stock bore which is the right direction for breathing in my opinion.

I have an 8BA block at home that is bored to 3 7/16". Believe me the valve seat to cylinder bore distance is pretty on that block. Imagine if you could find a 59A block that could take that large bore.

That's half the battle I think. Maybe more importantly in a Flathead Ford we are asking the flow to make two abrupt nearly 90 degree turns before it can fill the cylinder. Think about that and what can be done to overcome some or all of that.

[Tim Ayers]

That's half the battle I think. Maybe more importantly in a Flathead Ford we are asking the flow to make two abrupt nearly 90 degree turns before it can fill the cylinder. Think about that and what can be done to overcome some or all of that.[/QUOTE]

Slapping on an OHV conversion is what can be done to fix those two pesky 90 degree bends.


Sorry, I couldn't resist

[Henry Floored]

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Originally Posted by Tim Ayers

That's half the battle I think. Maybe more importantly in a Flathead Ford we are asking the flow to make two abrupt nearly 90 degree turns before it can fill the cylinder. Think about that and what can be done to overcome some or all of that.

Slapping on an OHV conversion is what can be done to fit those pesky 90 degree bends.


Sorry, I couldn't resist[/QUOTE]

Actually Tim you're on to something. Let's think about the flow path on an OHV. In the latest carbureted and central fuel injected OHV V8's the intake manifold was squished way down into the valley to allow for hood clearance.

This is a big reason why those last of the breed engines were lazy pigs. It wasn't until Ford did the SEFI 5.0 V8 that things started to wake up. Next time you have a chance look at the intake runners on even the lowliest 5.0 SEFI Ford. They actually align very nicely with the intake ports in the cylinder heads don't they?

On our Flattys what's going on? Really the exact opposite isn't it? The fuel and airflow source is up way to high. In any L- head you'd want the intake manifold to enter the ports in the block at a very low position.

This isn't a practical idea some would say and most would rather be able to bolt a conventional intake manifold on the block anyway. I get it, BUT!

Now how could we accomplish a better flow situation? Hmmmm

[awelker]

Originally Posted by Henry Floored

Keep in mind that the '48 and earlier blocks have valve locations that are, I believe, .090" closer to the edge of the stock bore which is the right direction for breathing in my opinion.

I have an 8BA block at home that is bored to 3 7/16". Believe me the valve seat to cylinder bore distance is pretty on that block. Imagine if you could find a 59A block that could take that large bore.

The 59A blocks have the same valve geometry as the 8BA blocks. It's the pre-WWII blocks that have the valves closer to the bores.

Andy

[Henry Floored]

Originally Posted by awelker

The 59A blocks have the same valve geometry as the 8BA blocks. It's the pre-WWII blocks that have the valves closer to the bores.

Andy

Thank you my bad. I guess my 1941 Mercury block with the early valve geometry and bigger bore is a good starting point for a hot rod engine.

Maybe you know but I was under the impression that Ford moved the valves away to lessen the propensity for cracking in those areas?

Am I on track or totally mistaken?

[revkev6]

Originally Posted by Henry Floored

Kevin, where abouts are you in the world. I'm in west central Florida. If we happen to be neighbors I'd do whatever I could to help you, which honestly and coincidentally would help me too. 😉

Just a FYI. There is a guy in this forum who is in the west coast, I believe his name is Pete. He has built some big inch Flattys. Like in the 320" range.

He has stated on here that he revs them pretty high which I assume means north of 6000.

Keep in mind that the '48 and earlier blocks have valve locations that are, I believe, .090" closer to the edge of the stock bore which is the right direction for breathing in my opinion.

I have an 8BA block at home that is bored to 3 7/16". Believe me the valve seat to cylinder bore distance is pretty on that block. Imagine if you could find a 59A block that could take that large bore.

That's half the battle I think. Maybe more importantly in a Flathead Ford we are asking the flow to make two abrupt nearly 90 degree turns before it can fill the cylinder. Think about that and what can be done to overcome some or all of that.

I'm out of western massachusetts. about as far from florida and california as I can get! not too far from Ron though (wink wink).

as for engine size I'm not looking to go THAT big! it really depends on how it sonic tests but I would like at least 3 5/16 bore maybe up to 3 3/8's if possible with the 4.250 inch crank. 304 would be nice.

[Henry Floored]

Just to put a cherry on top of this bloviating of mine I'll add this....

There are many fellas that will say (and rightly so I might add) that this or that won't do much good on a Flatty. A single change like exhaust headers or porting won't be worth the effort etc. In some ways that's right especially since you may not feel a "seat of the pants" difference in a low rpm street engine.

The consensus seems to be that tight piston to head clearance and the best ignition system you can afford are the dollars most well spent.

I wholeheartedly agree with that but I must add that porting changes and even cam and carburation changes are hampered by a he aforementioned road block.

Figure that out and watch your expectations of Henry's venerable V8 rise.

[Tim Ayers]

Originally Posted by Henry Floored

Slapping on an OHV conversion is what can be done to fit those pesky 90 degree bends.


Sorry, I couldn't resist

Actually Tim you're on to something. Let's think about the flow path on an OHV. In the latest carbureted and central fuel injected OHV V8's the intake manifold was squished way down into the valley to allow for hood clearance.

This is a big reason why those last of the breed engines were lazy pigs. It wasn't until Ford did the SEFI 5.0 V8 that things started to wake up. Next time you have a chance look at the intake runners on even the lowliest 5.0 SEFI Ford. They actually align very nicely with the intake ports in the cylinder heads don't they?

On our Flattys what's going on? Really the exact opposite isn't it? The fuel and airflow source is up way to high. In any L- head you'd want the intake manifold to enter the ports in the block at a very low position.

This isn't a practical idea some would say and most would rather be able to bolt a conventional intake manifold on the block anyway. I get it, BUT!

Now how could we accomplish a better flow situation? Hmmmm[/QUOTE]

I think that was the premise of the Ardun heads with some trade offs of course. I'm not well versed on Arduns and would defer to guys like Ronnie the Roadster on this topic.

Since the hemi-head was a proven winner in the pre- and post- WWI European engines, it seemed natural to turn a poor breather like our flatheads into a better one.

Engines like the Bugatti, Renault, Miller (and the later Offy's), and Alfa Romeo are genius in the simplicity of their valve trains and their intake and exhaust paths.

Fuel comes in very efficiently and exits very efficiently all with relatively light weight valve train since it all sits directly over the combustion chamber. Also, since the valves are canted, this allows for the use of a high dome piston to get a fairly high compression ratio to help boost power as well. Add a supercharger like Miller or a turbo like Offy and you are making some serious H.P. out of a smaller c.i. engine.

Cast all of this out of aluminum and you have a light weight, powerful package. There are other things like Miller's and Offy's use of caged ball bearings for the cranks and the combination of ideal bore & stroke, permit them to spin at crazy high RPM's.

Arduns use the hemi design or a modified hemi design(I think), but are limited to the cam in block design. I think C/T Auto made a few sets of DOHC heads for our flatheads. I'd love to hear one of these engines running.

Certainly a lot to think about when designing OHV conversions.

[Henry Floored]

More food for thought: This was the expensive solution for improving valve in block VE in the 1930's.Just saying......

[HotRodmicky]

I built three 304ci engines. Three different cams , but otherwise nearly the same, big ports, big valves , big cams.
They all perform very good.
But i really think a 304ci engine with little or no port work, stock size valves , 74cc edelbrock heads , or EAB heads and isky1007b or L-100 cam , would give the same fun or maybe even more !!

High compression means high octane gas, big cam mean high rpms ....

You loose more at the bottom rpms than you gain at the top rpms.

Ah and all engine where in 32 roadsters , and had the same induction(3x48)
So i can compare a bit

[Tim Ayers]

Originally Posted by HotRodmicky

I built three 304ci engines. Three different cams , but otherwise nearly the same, big ports, big valves , big cams.
They all perform very good.
But i really think a 304ci engine with little or no port work, stock size valves , 74cc edelbrock heads , or EAB heads and isky1007b or L-100 cam , would give the same fun or maybe even more !!

High compression means high octane gas, big cam mean high rpms ....

You loose more at the bottom rpms than you gain at the top rpms.

Ah and all engine where in 32 roadsters , and had the same induction(3x48)
So i can compare a bit

HRM:

If I remember from your posts, you've used the 404-A and the 425 Eliminator cams.

So what you are saying, you've gotten good results with the 1007b and L-100's which have approx. .250" less lift and less duration than those cams?

[awelker]

Originally Posted by Henry Floored

Thank you my bad. I guess my 1941 Mercury block with the early valve geometry and bigger bore is a good starting point for a hot rod engine.

Maybe you know but I was under the impression that Ford moved the valves away to lessen the propensity for cracking in those areas?

Am I on track or totally mistaken?

I'd say you are right on track. On the 39-41 Mercury blocks the valve eyebrow cut is just that it intersects the stock 3.1875 bore on the drivers side. This creates a sharp corner which is more prone to heat stress and crack.

[revkev6]

Originally Posted by HotRodmicky

I built three 304ci engines. Three different cams , but otherwise nearly the same, big ports, big valves , big cams.
They all perform very good.
But i really think a 304ci engine with little or no port work, stock size valves , 74cc edelbrock heads , or EAB heads and isky1007b or L-100 cam , would give the same fun or maybe even more !!

High compression means high octane gas, big cam mean high rpms ....

You loose more at the bottom rpms than you gain at the top rpms.

Ah and all engine where in 32 roadsters , and had the same induction(3x48)
So i can compare a bit

what cams have you run?? what components did you use to get the 304 cubes??

[Bored&Stroked]

This is a picture of a 42 Merc block - with 1.72 intake valves (and new larger hard seats) - and 1.6" exhausts. If it is a street engine and you still want to run a hard seat, this is about the biggest you can go. I use a 1.72 Manley SBC Chevy intake Pro-Flow valve that they use in some super-stock heads from the 50's. Nice valve to start with (though I mess with the undersides a bit more).

This block has extensive porting and relief work - and I'm doing a bit different relief work than 'normal' - just an experiment that mimics some of what the top-end Harley KR reliefs were doing. It is running a very large duration roller cam, with .420 lift.

DeckComplete copy.jpg

IntakeValveAssembly-Complete copy.jpg

DeckPicture-AllDone copy.jpg

[Henry Floored]

Originally Posted by Bored&Stroked

This is a picture of a 42 Merc block - with 1.72 intake valves (and new larger hard seats) - and 1.6" exhausts. If it is a street engine and you still want to run a hard seat, this is about the biggest you can go. I use a 1.72 Manley SBC Chevy intake Pro-Flow valve that they use in some super-stock heads from the 50's. Nice valve to start with (though I mess with the undersides a bit more).

This block has extensive porting and relief work - and I'm doing a bit different relief work than 'normal' - just an experiment that mimics some of what the top-end Harley KR reliefs were doing. It is running a very large duration roller cam, with .420 lift.

Attachment 304791

Attachment 304792

Attachment 304793

B & S you do beautiful work! Wow that is some very well thought out stuff and it looks so consistent from port to port. I know that represents hours and hours of work especially in cast iron!

Do you have flow numbers on this type of port? How much have you been able to do with the short side radius? I can't tell because I'm looking at these pics with my phone but is that relief the same depth for intake and exhaust with a baffle that favors the intake charge?

Using a long duration roller cam kinda sounds like you are building a race engine. Is this a land speed engine? Sorry about all the questions but your excellent work has me giddy like a child. Lol! How does a max effort Flathead Ford compare in terms of airflow and power to the FlatCad project you were involved in a couple years ago?

Anyways that's all the pestering I'm gonna do for now. Hats off to you man!

[Tim Ayers]

Originally Posted by Bored&Stroked

This is a picture of a 42 Merc block - with 1.72 intake valves (and new larger hard seats) - and 1.6" exhausts. If it is a street engine and you still want to run a hard seat, this is about the biggest you can go. I use a 1.72 Manley SBC Chevy intake Pro-Flow valve that they use in some super-stock heads from the 50's. Nice valve to start with (though I mess with the undersides a bit more).

This block has extensive porting and relief work - and I'm doing a bit different relief work than 'normal' - just an experiment that mimics some of what the top-end Harley KR reliefs were doing. It is running a very large duration roller cam, with .420 lift.

Attachment 304791

Attachment 304792

Attachment 304793

Dale:

Hard to tell from the picture, but do you use those O-rings on all the guides?

Thanks,

Tim

[revkev6]

Dale, your build thread on that motor is something that I drool over every few months. sadly I have had some inappropriate dreams about it lol.

now that you have that beast on the road how happy are you with the KR cam?? which grinds do you have?? E or F in the car now and an H on the shelf??

[HotRodmicky]

Yes, 404a , 425 and a schneider cam.

404a works best, with wide powerband, but is alot of work to set up.

I havent used a 1007b or L100 in a big motor , but i think it will work as good
In a street engine ( around 4000 -4500 rpm) without all the hassle with big valves , porting
And drivetrain setup (spring preassure, valve grinding,etc)

Flathead engines are torque engine , not rev monsters.

[revkev6]

Mickey are those all radius lifter cams?

[Ol' Ron]

I have an L-100 in a 296 I built 15 years ago, Driven on the street in front of a C4 got great mileage on the road. Owner was pleased with the preformance.

[Bored&Stroked]

Originally Posted by revkev6

Mickey are those all radius lifter cams?

No, the 404-A is a radius cam, the 425 is a Potvin Eliminator (flat tappet) and the Schneider - who knows, but probably flat tappet.