To Build a BAD not-blown Flathead

no no no, Pete... NO offence taken at all. I was glad you got to the details. I do mean thank-you.

I hear you, CNC Dude... my thought exactly. These engines have a fraction of the valve-train weight to contend with. In fact, I'd suspect spring requirements with a 6000 RPM flathead, using 5/16" stem valves, titanium retainers, wouldn't be any more than about 100 pounds on the seat... maybe 200 open ( remember, lift will be around .420" at the valve ). Obviously though, I wouldn't consider those pressures, without the use of a steel billet cam core.

 

I have been running a radiused cam from Crane for five years now. It is in my 29 roadster land speed car. Turn the motor 7 grand with no problems. I have fourth exhaust out the top and W headers. Tried several systems and this was the best.

 

Now I'm really interested in this. Was this an old Crane set-up or did they make it up for you 7 years ago?

When you say, radius you mean Johnson-type lifters with a radius ground into base? Thanks.

Really interested in this.

 

7K Flattie V8, DAAAAAANG!

How fast do the folks out there that know figure you can turn one before you put the bridge truss looking girdle on the bottom (or any other that I may be unfarmiliar with)?



This may be a hijack, but I don't think so, as I figure 1 HP / CI W/O boost is gonna take some revs.

 

Ron St. Giovoni in [email protected] put rollers in his ardun. He is happy to talk to anyone about it.

 

I think it still is on the subject of building a maximum effort Flattie! I am currently building a Bonneville Flathead project myself using many unconventional methods and techniques. I will be using roller cam bearings, dry sump oiling system, belt drive cam and crank setup, roller camshaft, one off billet heads(2 piece design), and I will probably at the least be using 3 billet steel main caps of my own design and manufacture. Even though the girdle might be overkill for an unblown Flathead, I still will probably make one, because I intend to install eventually a Vortech or Procharger centifugal supercharger. Especially, if the R's are going to start reaching a much higher level(say over 5K), you probably will be increasing crankshaft flexing, and with just 3 mains, the girdle wont hurt, it can only help and be extra insurance....

 

Well I was always taught that the force was increased by the velocity squared. So I figured a girdle of some sort would be necessary sometime, just no idea when (on a flatty).

 

As to manifold design: the Hilborn (pretty much the most serious) shows that individual runners work. IMHO the question of "how much carburetor does a flathead need" can be resolved by examining the engine on the basis of vacuum rather than total power. It's still a 239-300" V8 despite the low volumetric effiency, and until it runs out of breath is going to have similar demand to an OHV engine in the low to mid-range. This means that it can use about the same total venturi area as a streetable 260, 289, etc. Windsor - like a 390 or 500 CFM 4 bbl., even larger with spread bore or vacuum secondaries.
I'm not familiar with the market (haven't driven a flathead since late 1960's) - is there a single modern 4 bbl. manifold available?

I've never seen a "tunnel ram" manifold for a Ford, beginning with the original port openings (like the bottom of any manifold) extended up separately as far as possible, and ending in a plenum, then (your choice of carbs).
Other than the height problem, this should be do-able using any aluminum manifold as a basis.
This gives a tuned length (although too high for anything but race), some inertial fill ABDC, and the maximum carb area without distribution problems.

 

Ah, that's one of the stats that I was looking for Ryndboys !
So, you haven't seen a benefit of a roller cam ?
I know with my Chevy 409 Stocker, I am limited by the rules, to a stock lift ( .508" / .518" ) flat tappet mechanical. No radius or mushroom tappets, just the original .842" diameter ( which is substatially smaller than a flattie lifter ). This cam that I use, looks like a roller profile. The ramps are ridiculous. Even with the low lift, it takes ungodly spring pressure to control the valve train to 7200... like 265 seat, 475 open. The cam has 265/272 duration @ .050". At TDC, on overlap, the valves are off their seats by about .205" !
Reason I mention this, is to recognize, and point out that a modern flat tappet profile can be VERY aggressive indeed... and perhaps there is is not much advantage to a roller ?

An Ardun ?
Expensive, powerful, and BEAUTIFUL.
But not a flathead.
It's just a hemi, with an under-square, weak bottom end

 

Hey Panic, you read between the lines of my postings.
That IS precisely where I was going. A manifold that would increase momentum of the charge.

I will never forget my first experience with a tunnel ram.
It was 1980, on a 12:1, .060" over 283. mild port work on a set of 461 heads, Crane .561"/.583" lift, 262/272 dur @ .050" mechanical cam, 1 3/4" tube hooker headers. The engine was shifted at 7500.
At first, the manifold was an Edelbrock Tarantula, using a Holley 4778 700 CFM DP carb.
Engine ran pretty good.
Change to an Edelbrock TRYX ( or something like that... it was the lower RPM version ), tunnel ram, using a pair of 550 CFM Holley carbs, mounted in-line.
HOLY S#!T !!!!!!
Felt like a hundred(100) freaking horsepower !
Yeah, I've seen the effect of a tunnel ram manifold !

 

That is what iI thought untill I profiled all my cams.Just because you have a roller cam doesn't mean it has to have a greater rate of lift(it may(can?) have). When I profiled my cam some of the flat tappets were wilder then my rollers.

 

My one roller cam has 5 years street use on it

 

Credit where credit due Tony Baron is generally credited wiht the idea.

 

Good info here

 

There is (or was) a tunnel ram manifold for a flathead. Aussie Mike Davidson (DBA-Flatattack Racing in the USA and available through Red's & other sources) made a base that allowed you to bolt either a 2X4 or 1X4 Offy top to it. He got some good HP/flow numbers with 2X4 set-up, debunking the over carburation "myth" that flatheads only run well on 2X2 set-ups.

If you don't have his books, I'd suggest picking them up or borrowing them from a flathead buddy.

He profiles the build up of a "built" (aka BAD) flathead in this books (I think the 2nd one).

 

Thanks Flatdog.

Banjo, that is good to hear. Sounds like a great idea, using the Offy top.

I'll have to get those books too.

 

This might not be the place to mention this but I have a flat attack intake for 2 four barrel carbs. Crower rods that take chevy bearings to offset grind a crank. Crower roller cam and lifters and jig. MCF filter setup. Aftermarket main caps. Navarro heads and stud kit. I collected these parts over the last 5 or so years to build a nasty flatty but it never happened. My machinist has my deposit for the machine work but now doesn't want to return it. I want out of the flathead and want to sell my parts. IM me or email [email protected] for info. Thanks!

 

Why would you need to get higher spring rates? Doubtfull you will need higher seat pressures.

Please explain why you think higher spring rates are needed.

 

Roller cams require greater spring pressure than a Hydraulic or Solid flat tappet of the same lift. The opening and closing ramps are so much more aggresive, they try to sling the lifters off the lobes. Even the difference between a hydraulic and a solid flat tappet of the same lift will also require greater spring pressure on the part of the solid tappet camshaft. Look through a cam catalog some time(Crane,Comp) for example, and look at hydraulic,solid, and roller cams of about the same lift and see what springs they require and the spring pressures that are needed for each and it might give you more explanations as to why they needed more pressure for each of these classes of camshafts....

 

^^^^^^Pics????^^^^^






Hey Aubrey, Great first 'Official' post.
You have rattled the old brain cells here with some unconventional thinking.

BTW, nice to see another 'Local' Flatheader in the south of the province.




moe




.



.

 

Sorry if I'm mistaken here. The research shows that Tony's dad Frank was one of the first to make commercially available "pop-up" equipment. This tells me that they must have been pretty satisfied with the results. I think some credit goes to three persons really, maybe more. Frank Baron, Barney Navarro, and of course Ed Winfield. I also think one needs to look at the work done by Harry Ricardo. Sorry if I credited the wrong person with the original idea.

 

I agree with you that higher spring rates are required for the applications that you are refering to, but this is a flathead. In overhead valve motors the spring rate is much higher because there is alot more mass being moved. That mass of the pushrods, rocker arms, and valves moves and creates inertia that needs to be controlled through higher spring rates. In the flathead you do not have those additional masses to be concerned with.

Look at the cams charts for an overhead cam motor. Pick a fairly aggressive cam and you will see that in many cases they call for new OEM springs. This is because they do not have that additional mass to move around during the valve stroke.

I argue that the same principles of spring seat pressure for a flathead should be the same as those of an overhead cam motor. When I researched the use of roller cams and cams in general, I found that the use of the higher spring rates are a function of valvetrain mass and valve train velocity not a function of the valve lift. Since there are very few street flatheads that are running overhead valves and rarely run beyond 6000 RPM, I believe that higher spring rates are not needed and if applied will only serve as potential HP robbers.

 

Thank you, Moe
Hey, unconventional thinking ?... ALWAYS gotta go faster !

It won't be my flathead coupe yet, but I should be in Medicine Hat with my 409 Chevy Stocker in mid-late May... testing.

 

I'm only speaking from experience, plus untold many conversations with both Bruce Crower and Richard Iskenderian on the very topic of roller cams in flatheads, and they both say that higher than stock spring pressures are required for the Flathead as well as any engine using a roller(solid roller)cam. One point is true, and that is because of the lack of valvetrain pieces(rockers and pushrods)the mass working against the springs isn't as great as an OHV engine. You still will have to use a stronger spring than stock, but not as much spring pressure as a pushrod engine...

 

Don't know why I ran into this old thread - came from a WEB search while NOT on the HAMB. Anyway, I'm running a big duration roller cam in my 284 cube flathead - have not had it on a dyno, but it runs extremely well with the tall Eddie Meyer manifold.

Specs: It has about a .420 lift and over 270 degrees of duration at .050 (a lot, just like a Harley KR), and has similar opening ramps as say a 404-A radius grind. I made the billet and managed to twist Ed Iskenderian's arm to grind it about 35 years or so ago (had didn't believe in roller cams in flatheads - I debated it with him saying that every darn Harley KR race flathead has a roller cam in it!). Have had the cam sitting in a box all these year - never got around to making lifters. Crower to the rescue on that -- heavy and expensive, but glad to have them.

Anyway, just saw Ed at the PRI show in Indy in December - he and I chatted about the cam - as I'm finally running it. Let him know that I finally put our "experiment" into an engine and love how it runs. The overall engine package has a LOT of serious porting, valve and flow work done to it - much more in the realm of a full-out Bonneville engines (except the small cubes).

Here is a picture of the cam - here I'm adding some more side-clearance to the lobes on my baby lathe:


Here is a profile analysis - overlaid on top of an Isky 404-A profile . . . pretty close in the end!



Brief video of the car on it's maiden voyage - about a year ago:



PS: Going to put some bigger carbs on the motor - as having just two 48's is not quite enough. I'll dyno it in the Spring and try out a few things!