To Build a BAD not-blown Flathead

My first "official" post !

I've been reading through some of the threads on building flatheads, and I must first say, this is HUGE !!! Fantastic information !

I used to run a 248 inch 59A block, ported ( stock crank, .060" over ), Isky Max 1, using Offy heads, 3X 94's, my own tube headers. I liked the way the shorter stroke engine revved. Used a wide ratio Saginaw 4 speed, to a 57 Chev rear, with a 3.55 posi. The car was a primered 48 Ford 3 pass ( businessmans ) coupe.
I sold the rolling shell in 1991, to help pay for the 35.
GAWD I miss that car.

Anyhow, I was pretty happy with that combination, and it was VERY good on fuel.

Now, I want to build a REALLY BAD carbed flathead.
I read over some of thr postings regarding cams, and it seems that most are running the tried and true Max 1, or 400Jr. Doesn't seem to be much enthusiasm about a modern roller profile ?

This is just my take on it... But a roller lifter will follow a much more aggressive ramp. That much is fact. This means that the valve can get to an "flow-effective" opening, much earlier, and stay at virtually fill lift, for a MUCH longer time. Now, going to excessive lift in the flathead... say .450" or more, can only be done at the expense of compression ratio. It would seem to me, that a modern, radical ramp roller profile, with around .430" lift, just by it's very design, would HAVE TO out-flow even the best flat tappet cam ?

I'd sure like to hear from experts on this

The other area that I was hoping to get advice on, is intake manifold.
I have an old Weiand 4 carb piece. Polished, in very nice shape. I planned on using it as the base, and building 3" risers to mount on the carb mounting bases, and design/fabricate a common plenum for the top... using 4 model 94's ( sorry, I like them better than Strombergs ! ), in progressive linkage.
Does this sound like a viable intake arrangement for power ?
Or should I make something from scratch ?

Hope to hear some ideas !

thanks guys !

Aubrey

 

I've never heard of any kind of roller lifters for Ford Flatheads.

 

do you mean radiused tappets?

 

Absolutely available from Crower. They are $600 a set. Need a roller cam to boot @ $450. You got over $1K in just these parts. Aint't this fun!

 

DAYYYUUUM!

So these are probably the kind you have to have a groove machined into the litfer bore to keep from spinning on the cam? I expect there isn't enough room to use a vertical or horizontal link to do the same.

What would that cost (to add into the cost of going roller)?

 

At least one HAMBer is running a roller.
Manifold--common plenum will likely make four carbs way too much for anything but a gigantic flathead. Keep'em on the weiand setup feeding individual cylinders!

 

The rollers are considered race only. There was one car at Bonneville with a radical roller cam, but the motor would only run from 5000 on up. Not street worthy at all. The old 400 jr. makes a good mid range streetable motor with three carbs on a progresive linkage. Talk to Ole Ron on Ford Barn about reworking heads for clearance and flow.

 

Let's keep this thread going. I'm hunting a buildable flathead block now and I've been thinking about some of the same things. One thing I've been wondering is has anyone adapted modern low-tension piston rings to a flathead? It would seem to be a worthwile mod that would decrease the rotating friction.

 

Oh, I forgot, the tool to groove the lifter bores for this application is another $100. I'm still kicking myself for I found a new set at a swap meet with the tool for $100. I thought that was outrageous in '94.

Silly me.

 

I am gettting ready to build a 284 ci flathead with a Isky 404-A radius-tappet cam. These cams need a special set of tools to drill and install a key in the lifter bore,it looks like a overgrown copper staple. These cams are on ebay from time to time. You will also need a set of 404-A lifters. I would contact Crower Cams and see if any street friendly roller grinds are available. Good Luck

Jessman49

1949 Ford

 

I have a few 'hindsight' type instances of that (all O/T) sucks don't it?

I would have to believe the top guys that are running the Flatmotors in competition have already been using the 'new' ring tech. I have to believe J&E and their competitors have the data from other engines, as long as the cylinder walls are stiff enough (being preped properly too) and the pistons are fited for them, why not.

 

I have been talking with Crower about their roller set up for Flatheads, they are available and pricey too! The interesting thing is that when I talked with them, they made it sound as if you could get any cam profile you want in the roller cam. You could order the Max 1 or 400 jr profiles that have been modified for the roller lifter, essentially they would build what ever you want since the roller cams are special grind/order anyway.

 

The Crower roller setup will work on the street and can be ground with the help of Crower to your motor specs, Flatdog ran a 4 carb setup with a Crower roller with no problems at all, in fact ran pretty dam good before he put the blower on, the tool that Crower supplies is a simle jig so you can bore channels down the lifter bore to hold the roller is place, pricey yes but just another piece of the puzzle for a full out Flatty. Also what Ole Don said about making sure your heads are clearanced for valve lift and diameter if you intend on going with larger valves.

 

I am with Kevin on this, this is exactly why I am considering ponying up the $1100 for the roller set up. I am going to have about $8,000 in my motor and why would I risk the state of oil lubrication and such wiping out my cam when done? I am on the fence also, trying to decide if an additional $1100 for the security of my valvetrain is worth the expense.

 

You have to ask yourself, what are the biggest bottlenecks in a sidevalve engine design. On a typical sidevalve inline engine the ports can be pretty well designed or if not easily modifed. The other side of the coin, when you start adding cylinders the whole package starts getting huge. Usually longer and very tall because most inlines are straight upright.

The beauty of Henry's V8 is you got a very compact 8 cylinder mill that sits in the same space as the 4 cylinder it replaced. You have all the intake ports sitting there close together right near the fuel/air source so fuel distribution is decent. The intake ports are actually quite nice, and with a little work are pretty efficient to the valve seat. But that's precisely where a sidevalve loses to an overhead. That restrictive transfer area and the extra 180 degree turn into the cylinder. What to do? Well the camshaft profile certainly is compromised here. You can't put too much lift in there because the cyl head above does not move away like a piston does in the case of an OHV. Furthermore you don't have a rocker arm there to multiply lift so the cam profile has to do all the work.

Solutions? Well personally I've only ever built Flatheads with conventional "street" type parts. But along the way I have been trying to pick up ideas that may be better. Now you say you want to build a "BAD" Flathead, which tells me that you're willing to put up with with the temperament of an all out engine. The first thing you should think about is getting that valve off the seat quick. (The valve design should be carefully considered as well). Next you hold it open as long as possible then slam it shut. The problem? Flatheads have small diameter lifters that will "dig into" the cam lobe when going to radical profiles. The early racers used to modify their blocks for "mushroom" tappets. You get a nice wide footprint that does not expose the edge of the lifter to the cam lobe. I believe the tool used to modify the block is still available from Isky. Next what valve seat angle is optimum? On a typical OHV a 45 deg seat is best with two to four different angles surrounding that to ease flow around the valve seat. Are the requirements of a sidevalve the same? No not in my opinion. Most experts say that they try to get the valve to flow all the way around and relieve the valve pockets in the heads to promote this. The thing is, you are actually trying to get the charge to flow sideways in a Flatty when in reality it tries to go up smacking the transfer area. Now comes the big restrictive turn that is the real menace to any sidevale engine. I'd like to consult an expert like Mark Kirby who has done a ton of flow work on these engines to see if a 30 deg seat helps this problem. A Flathead typically does not require the big spring pressures that an OHV does due to the lower mass of the valvetrain. It's possible that a 30 deg seat may provide a little better low and mid- lift on a Flathead and still live. I believe a 30 deg seat will cause flow to move more radially than a convetional 45 deg seat. All theory on my part but I firmly believe it should be investigated and tested.

The next thing I think that would really help a Ford Flathead is really a very old idea coming from the mind of the great Barney Navarro. He pioneerd the "pop-up" piston in Flatheads. The theory behind it I think was to raise the transfer area and combustion chamber. This giving the fuel/aire charge a better shot at filling the cylinder. The pop-up piston then came flying up and fit tightly into this raised chamber. This cased the fuel/air to really homoginize through turbulance and it was forced to the area right under the plug to be lit off and burn effectively. It is my understanding that this system requires less ignition lead, a good indicator of efficient combustion.

Further remember there are two ways to think of compression ratio, static and dynamic. In the static sense you simply have a mathmatical calculation of two volumes. One with the piston at BDC, and the the other at TDC. The difference between the two gives you static compression ratio. Now dynamic is a more real way to think about it. Frankly I'm not sure exactly how it can be measured other than cyl pressure. The theory is the better the cyl fill the higher that dynamic compression. You are "squeezing more volume in a given space". This is what a supercharger does for example. It simply forces more charge into a cylinder than it could otherwise inhale by itself. The two benefits are more fuel and air to burn and higher cylinder pressure to provide more energy when ignition occurs. You want the best N/A Flathead you can build, right? Well that's what you need to think about. First I'd build the biggest cubes you can afford. This will improve everything. Static, dynamic compression and also be inherently torquier due simply to the better leverage of a long arm crank. Maximize port flow. Talk with cam experts that are familiar with the requirements of this unique engine. Same with the valve seat question. If you really want to go all out try a Navarro "pop-up" engine . I think these things along with good basic engine building techniques will help you get well past the 200 hp mark with torque figure that will make the sbc's jealous. Good luck!

 

Thanks for the replies, guys !... and Henry, your info covers most of the issues I was hoping to address here !
I agree on the valve seat angle. Also, I think custom made "directional valve guides are absolutely mandatory, in order to help address the 180 deg turn into the cylinder.

I was already planning on the "pop-up" piston, of my own design actually. My new Offy heads will be modified to accept them.
Oh, I actually have a set of ancient Navarro "marine" high compression heads on my old boat !... it's a factory relieved 59A block, with an Isky 3/4, and a pair of Strombergs on a Navarro "racing model" manifold. The boat is a 50's Chris Craft kit... 18 1/2 ft Utility.

Money
I couldn't help but notice that many members are commenting on the cost of the roller valve train parts.
HHHMMM....
You think THAT's expensive ???!!!!!!
Try building an actual modern day 409 Chevy Stock Eliminator engine !
The bare cylinder head castings are north of $3000. My tool-steel flat tappet lifters are $1150 alone. Pistons in excess of $1400.
My own headers that I built... $650 in materials, and 40 hours labour, and they're still not coated !
Now THAT's expensive !

Not nickel & dime'n here. Not going to settle for the old tried and true routine, with 50+ year-old technology. Tony Baron told me that 1 HP per cubic inch can't be done with a natuarally aspirated flathead... well I'm keeping the engine at no more than a 4 inch stroke, in the area of 274-276 inches, so at least I don't have a big number to overcome in my quest for 1 HP per CI !
I like RPM. To me, low end torque is for a diesel. Someone mentioned that a roller cammed engine used in racing, didn't do anything until after 5000 ? Has anbody ever spun a flathead past 7000 ? I don't think so.
I don't have any illusions about this thing buzzing like a cammed 283. 56-5800 shift point, I think is realistic. I have absolutely no concern about power below 2000 RPM. I want the engine to run HARD between 2500 & 5500.

What about headers ?
Is there a benefit from splitting the centre exhaust port ( one over, one under.... or at least a variation on that theme ) ?
Tubing diameter / length ?

Oh yeah... ring packages, coatings, clearances, along with oiling / windage tray... all areas that I addressed with my Stocker build. Would like to apply this technology to the flattie.

 

The thing that worries me about the steep cam, radiused/roller/grooved lifters is the side loads on the lifters for that type of cam. On a flathead you have the weight of the valve assembly resting on the lifters as well as the spring pressure which will have to be substantial for that type of cam. Then you remove the lifter's abillity to spin by pinning them and it seems to me you would have a recipe for scrubbing and exagerated wear on the lifters/bores...

I know that's all irrelivant on a race-only flatty but if you plan on driving the car at all, it might be an issue?

 

A couple more things. That center port divider issue. Well the commercially available ones I would'nt use. I would however melt some pistons down and fill the exhaust crossover chamber past the valve pockets. I would then grind a decent back port wall that directs flow out the center port. I think by using a stud in that one center hole above this area that goes all the way into this area would alleviate any risk of the filler material coming loose and moving. Maybe there is a better material that can be used also?

Another thing to think about is piston speed as it relates to degrees of crankshaft rotation. A good way to jerk the pistons down faster through the first part of the intake stroke would be to use shorter rods. This means custom pistons with a different pin location. You give up a little dwell time at BDC, but this could really help in getting that charge to move at a high velocity and filling those cylinders.

Lastly, if you're gonna go all out either move the outer exhaust port exits over and in line with the port box, or grind out the edges and build a set of headers that are "W" shaped and help the out ports continue their inherent exhaust path. Most headers come straight out and this is yet another change of direction for the exhaust gasses to encounter. Downstream an abbrupt turn may be less detrimental, but I believe that it is very restrictive to flow to have this unneccesary dog leg while the exhaust is still super hot and traveling very fast.

 

If money isn't nessecary an issue for this build, that is entirely different ball of wax.

I think the reason it was brought up is that a lot guys dealing with flatties, the total amount spent on the overall rebuild is a major concern during parts sellection time.

Like Smokey said, "Speed cost money. How fast do you wanna go?"

 

BTW I have a pretty rough late Flathead block with a poor relief job. It's been bored to 3 7/16". The pistons I have are made for the 3 3/4" Ford crank. It's got a couple sleeves and who knows what else wrong. You're making me think about pulling that engine out of storage and fixing it up. I know one thing is that with that big of a bore the area between the back water passage and the cylinder wall gets pretty thin with not much area to purchase on the head gasket. Might have to plug and redrill that baby.

 

First off you said you want a "bad flathead".
Then you put all sorts of limitations on it like intake manifold risers and 94 carbs.
You are actually just describing a street engine.
Roller cams work fine.
Flat and radius lifter cams work equally well.
Same price range for "all out".
Someone said Tony Baron said one hp per ci was not possible
naturally aspirated.
I have talked to Tony several times and we agreed that it was possible as many have done it many times.
You need at least 315 ci to do it though.
When you talk "all out" with a flathead, you are going to spend 15K.
Funny thing is, a flathead that does one hp per ci is perfectly streetable if you can live with a 1200 rpm rough idle.
These will turn 7500 but we usually never go over 6800
Here's a good example of what I'm talking about.

http://www.jalopyjournal.com/forum/showthread.php?t=190430

 

Note to self...

wait until Bruce has responded to a flathead post before you post something you think is correct and step on your dick...

 

one hp per ci was not possible
naturally aspirated.
I have talked to Tony several times and we agreed that it was possible as many have done it many times.
You need at least 315 ci to do it though.

What???

You get MORE power per cubic inch when you enlarge the displacement?
Patent that method real quick - I don't think the Nascar, Formula 1 people have heard about it.

 

ah yes, an "in your face" post !
Thanks Pete !

Set all sorts of limitations ?
No. That's EXACTLY why I brought up the intake manifold. I'm perfectly willing and able to design and build my own. I merely asked about the Weiand 4 carb, because it was the first automobile hot rod part I ever bought ( in 1977 ), and I still have it... and I too, am not convinced that it is by any means, the ultimate choice.

Crankshaft ?
I've been setting things up with Moldex, for a steel billet unit.
Aluminum flywheel is a given.

Cubic inch ? ... has to be HUGE to make 1 HP per inch ?
I think the opposite. While the huge engine will make more torque, the limitation is still the breathing ability.
Tony Baron DID tell me a few years ago, that it hadn't been done.

A 7000 RPM flathead ?
Is there someplace I could hear that ?.... perhaps on "youtube" ?
My gawd !... if I ever DID hear that, I'd probably have to be institutionalized !

Can I live with a 1200 RPM idle ?
My Stocker idles at 1300.
I am just trying to have a realistic expectation. I have difficulty imagining a flathead that doesn't "come on" till 4000 RPM.

My guidelines ( limitations ) for this "bad-ass" build:
Must cool-able. No restricted water jackets, due to severe port relocating, ect.
Conventional water pumps... 59A style.
No more than .125"... MAYBE +.030" overbore. Longevity IS a concern. It's a 60 year-old engine ( I DO have respect for these things ! ), and I don't want to machine it away to within an inch of it's life.
I DO want to be able to drive it for extended periods on the highway. Where I am located, my nearest street light is 50 miles away in one direction, and over 140 miles in the other. I have 4 highways to choose from, so "idle quality" ?.... would be IDEAL being absolutely radical, "quick rap" ( tight lobe centre ) at 900-1000 RPM.

Those are pretty much my only ground rules for myself.

Don't know if I've mentioned here... my car is an original 1935 3 window. Already have the Offy belly housing for the modern "Chevy" 4 speed. Yes, 5 speeds and stuff CAN be done, but I don't want to shred this car

 

Also, don't forget that you are going to have to step up to the pump and get valve springs for a roller cam(start at about $250.00 for most engines) and also machined retainer and locks(stamped steel wont handle the extreme spring pressure that is required for rollers)add another $100+ bucks for that.

 

Backtoflatheads,
I didn't mean for my post to come across as "in your face".
I meant it as information.
Sorry,
Pete

 

been busy will try to conment tomorrow

 

Many production engines as early as the mid-80's had roller cams from the factory. Gm and Ford both were available in their 5.0 Mustangs and 350 Camaros. Even though they were the hydraulic type instead of the solid roller type of the race style rollers, they still moved up and down in a fixed(non rotational)position, and many of those engines went well over 100K+ miles with no issues. I have over 20 years experience building every form of race engines imaginable, form Pro Stock to Winston Cup and every thing in between. I have had many guys want to put huge rollers(.650 lift or more)in their street cars just because their buddy did. And have seen quite a few put 10- 15K miles on them with no ill effects. Since a Flathead doesn't have any rockers or pushrods to compound the momentum of the valvetrain, it actually will be easier its valvetrain(what little it has), and spring pressures are not going to have to be as high because it has no rockers or pushrods to overcome to get the motion started....Roller cams in a Flathead for the street is very do-able and will give trouble free driveability....