Technical Is my Flathead Tuned Correctly?

I know this question is going to have a lot of different ideas and opinions and that's ok. I would like to hear them.
Just finishing my AV8 roadster build and am now driving it. I question if I am getting the power out of my old flatty that I should expect. I don't any experience with very low horsepower engines to say "yeah she is running good!"but I know you guys do.
So with that said, what kind of seat of the pants performance would you expect out of my cars setup? RPM in high gear? Top speed? Climing hills? I just so happen to live in a very hilly area is bring this up.
Or something else. Just enjoy it and not care......maybe but it will find a new owner and I am trying to make sure it's not a disappointment to them.

Facts:
1931 Ford Roadster full fender hot rod.
8ba 53 Flathead. Merc crank 276"
3x2 progressive 97's
High compression Eddy heads
L-100 cam
Mallory Petronix Dist. Advance corrected for a flathead.
Lake headers which sound awesome by the way.
Banjo 3:54 gear
36 3 speed
7.00x16 Firestone rear tires

 

Killer car. I have a '28 AV8. My car is fenderless, but on a deuce frame so weight is similar.

Without hearing your engine run, this is a tough question to ask, but I'll speak from experience with my motor.

292 ci 59L, 1.6 intake and 1.5 exhaust valves. Heavily ported and factory relieved which I did not mess with. Potvin 3/8th cam (similar to your L100) & Edelbrock Slingshot with 97 carbs. Petronix converted crab dizzy.

I also run open headers (headers to split '36 driveshaft) under the car. I agree, the sound is really incredible. People can't believe it's a flathead.

I do run and aluminum flywheel mated to a '39 box with a 28 tooth cluster, 3.78 banjo rear with 7.00X16". Firestones as well.

This combo runs super strong. It will spin the tires in 2nd if you get on it.

I am very impressed with how it performs. That said, my engine builder had to fool around with the timing gear in order to get the cam timed correctly. I forget which way it was just stabbed in, but he said it would have been a real dog if left as is. The cam was ground by Bill Jenks @ Moon back in the 90's.

I haven't fooled with early transmissions, but do you know what gear set you have in it? You will give up some off line performance with the 3.54's, but you should feel it with top end speed.

Even with 3.78's, the engine is screaming at 75-80 mph.

 

My 3 speed is all stock
Main Drive Gear
1st Gear: 2.820
2nd Gear: 1.604
3rd Gear: 1 to 1
I am noticed the rear gear is lugging the engine a little at low speeds. Maybe 3:54 was not the perfect choice.

 

Your build specs sound great and should be a blast to drive. The 3:54 screw might be the performance killer with the stock ge****t in the trans.
Do you have a aluminum flywheel so the motor revs up faster …

 

Could be. With my motor and 3.78's, I'm able to take off in 2nd in a slight roll coming to a stop light. I mean it will just take off. No bog.

After you checked the timing?

 

I do feel using an aluminum flywheel in a roadster is the only way to go. For all of the flathead's short coming, I am impressed with how quickly my motor revs up. It is unlike any flathead I've ever driven and I've driven a few in my time.

 

I have a '41 pickup that is under construction now but I was able to drive it for a season and a half. It has a 3.78 rear with 8.20 X 15 rear tires and a stock displacement 8ba. After replacing the diaphragm on the distributor and rebuilding the Loadamatic dist. it was pretty snappy. I adjusted the initial timing to factory specs. I also have a Pertronics 6 volt conversion in the dist. I would think about maybe bringing the end carbs in sooner. I am familiar with a '32 highboy roadster with 286 FH that runs non -progressive 3X2 97s very successfully . BTW 15 mpg @ 65 mph to and from Louiusville.

 

One simple thing will help you with the engine tune...
Get yourself an air-fuel ratio gage, hook it up and follow the instructions...
https://www.summitracing.com/parts/inn-39240

This will get your carburetors where they NEED to be.
The rest is up to you.

Mike

 

John, no I have a stock 10" BUT I do have an aluminum clutch from Schiefer. It helps a little I bet. But I couldn't afford the $400 on a flywheel.

 

Here is what I have so far in order.
1. Work on the two end carbs to bring in sooner in rpm.
2. Sync the carbs air flow to be the same. I just so happen to find a flow meter in my tool box from a 48 IDA Weber system I tuned.
3. Look into a 3:78 gear. Maybe a trade for my 3:54.
4. Adjust floats wet with new grose valves. Change out well plugs with nylon washers. Just don't like my carbs dripping. Not a performance issue but just common sense.
5. Aluminum flywheel?

 

53stude, at what level are you setting those floats at? What psi for the fuel? Getting ready to work on my 97's so I am curious how others are setting up their carbs.

 

I have a very very similar combo in a 32 3W ,it runs great , a little slow initially with an L100 cam ,but once you are above 1000 rpm it hauls. We have 3.54 gears and 750 x16 so at 60 mph we are at 2444 rpm. With your 700x16 you should be at 2555rpm.

 

That will help a lot if you ever compared the weight of a stock Ford 10" and one of those aluminum clutches.

 

I hear there are two ways to set the floats. Charlie at Vintage Speed has a very good video on both methods. Wet is let the fuel bowls fill up with carb tops off. They need to be .500" below the machined surface. I am going to try this method tomorrow. Fuel PSI is set at 2.5.

 

Let us know how that goes. I watched that video. Some good points.

 

I don't think I'd go to the aluminum flywheel; part of the flathead ability to pull at low rpms is the heavy flywheel and in a hilly landscape , that is an advantage. I believe the single biggest performance/ drive-ability improvement to a FH powered car is overdrive. I'm using a modern O/D trans in my truck, but I considered a Mitchel OD . You can actually use the "neutral" in the Mitchel to shift your trans into 1st gear with the car still moving.

 

I see two different opinions in a nut shell. All great stuff.
1. Making what you have chosen for parts work as best they can and being happy with it.
2. The other is improving on your choice of parts if you are unhappy with its performance.
I am leaning towards #1 and maybe a gear change to 3:78.

 

My version of tuning includes the “reading of the spark plugs”. Briefly, start with a fresh set of plugs(Champion H10 is standard) run the engine briefly at a fairly rapid idle1000-1200-1300 or so. Stop engine,put car on road at or above 35-45-50keep a steady speed for a few miles. Push in clutch or go to neutral—-kill power to engine. Come to a stop and pull 1-2 plugs on each bank.Look at the plug(real expert plug readers have a devise that lets them look deeper than the surface of the plug) look at the outer ring—does it look clean—-oily—-light carbon—-if carbon does it appear light and fluffy with easy removal or oily. Look at the white porcelain fixture that is in the center of the plug( down deeper is where the professional “reads” the plug) but the upper part visible to the naked eye will do. Ideally, the porcelain will appear light tan to grey indicating things inside the combustion chamber are relatively fine. Whiteness indicates too lean and black or sooty is too rich. Bear in mind,carbs as a general rule have an idle circuit5-10-15 mph or so and the high speed circuit(depending on gearing) generally happens at 30-35 and above. If someone disagrees with these explanations for finer tuning, please speak up with your version if some wording appears to be not right. Flatheads Forever!!!

 

@Flatheadjohn47 yes spark plugs never lie and tell the whole story on what’s going on.
@53studecoupe the guy who was doing my transmission in my race car wouldn’t do it till he knew what cam I was using and the gears in the rearend. How’s the performance in the higher rpm’s in that pretty little roadster, I bet she pulls hard.

 

Well that's just it. I don't think it pulls as hard as it should. I can barely get 3000 rpm in high gear. It just runs out of poop. But I base that on my experience with my pro mod with 750 hp on E85 pump gas. Now that pulls hard is what I am used to.

 

Here is a shot with the new grose valves installed and the fuel bowls allowed to fill up on their own until the fuel floats shut the valves off. This would obviously be the "wet method". The fuel level should be 1/2" below the surface of the carb bowl. It also can rule out a heavy or leaking float with this method. They are all a little high especially the back one. Again that's the one that kept weeping fuel at the gasket surface. I guess it works. I am going to allow them to sit over night to see if they leak down.

 

Well, I’m not near a FH tuner at all. But two things come to mind, you should be able to surp*** 3000 in direct, the little stock 221 I had in my ‘42 pu would do highway speeds, and had some more left (never tried it). So tune, build, etc does need to be looked at.
The other thing, is say 125-135 HP engine now, can’t compare that to your beast that has at least 5 x the power
But I do think you shouldn’t struggle to get to 3k in direct, so your topic may very well be your answer.

 

I've yet to see a pic of a spark plug, so how are we supposed to know if it's tuned correctly??? Everything else is subjective...

 

I used to set the float level with a cardbofard rt angle gauge that came with a rebuild kit for Stromberg. Time p***es on, and it occurred to me :why not set the float level with the engine running. So I did that and continue to set the level of the fuel in the bowl with the topsection of the carb removed including the accelerator pump and hardware. With the engine running, the fuel level in a Stromberg 2 barrel should be 1/2 in below the top of the carb with the gasket removed measured at the front part of the bowl. Flatheads don’t do well with a lot of fuel pressure.2 1/2 psi is about the max safely to run and I try for 1 1/2- 2 for my max fuel pressure.Lots of people use an adjustable fuel pressure regulator as some newer pumps put out 4-5-6 lbs pressure. All one has to do to achieve lower fuel pressure is to raise the fuel pump ***embly simply by adding gaskets to the base of the fuel pump stand until the desired fuel pressure is achieved. Flatheads Forever!!!

 

I will get a pic of the plugs tomorrow but they were all tan.

 

Agreed. 3000 rpm in first and second no problem. In high it just falls on its face. I will keep looking for the cause. Everyone has been helpful with ideas. I will find it and report back.

 

I set the fuel level just a little below 1/2" --15/32"

 

Hello,

Nice looking roadster. The stance and at***ude is impressive. With the Flathead motor you have, it would have been a go to motor for my first 1940 Ford Sedan Delivery. When I saw the sedan delivery, it had a big 348 motor installed, sounded mean and it was for sale. A friend, then a teenager, from my old junior high school was mechanically minded and was always interested in hot rods. But, in high school, I was in the search for a hot rod I could use cruising around and going surfing weekly or daily in the summers.

But, alas, my pocket book did not meet the asking price of the 348 sedan delivery. So, after weeks of bartering back and forth, he lowered the price, but took out the 348 motor. He installed a 80 hp Flathead motor. It ran like a top, did not leak oil and took me thousands of miles of coastal cruising for our surf adventures from San Diego in the South to past Santa Barbara in the North.

The one thing I had mentioned in other posts was the lack of power in the Flathead motor at 80 hp. It was fine on level streets in our Bixby Knolls cruising area and to our high school. But, when we took it to the OC Beaches and further South, we always had a challenging run down Coast Highway (PCH) near Laguna Beach.

The El Morro Beach grade was quite steep and despite the 3rd gear downhill run from the other downhill slope (from the Corona Del Mar area), it just was not enough to fly uphill. Downshifting to 2nd was a common thing. In traffic, sometimes, it was down to first gear for going up and over the steep grade.

In Dana Point, coming home was always a 2nd gear run and a quarter of the way up to the top of North Dana Point, we were usually in first gear. Loaded with several teenagers, heavy longboards and beach stuff all contributed to the necessity for downshifting going up steep grades and highways. The 80 hp Flathead worked overtime, but, ran like a top. It just did not have the extra power.

Your motor with the build specs would have been a bonus in my Flathead powered Sedan Delivery. There was an offer from Reath Automotive to build a stroker Flathead motor for additional power, but the teenage money situation denied all access to the necessary build. Your motor in my old Sedan Delivery would have easily made those steep coastal hills and had power to boot.

Jnaki

So, why would you be questioning the motor build? The modifications seem like pure power for your roadster, to me. I would not have any qualms to have your motor in my old 40 Ford Sedan Delivery. It may not have had the original power of the 348 motor install, but plenty of power for any other situations. Perhaps, my flathead sedan delivery would not have been the “chuckle” at the Cherry Avenue Drags in the “slower car cl***.” Ha! It would have had the power to even go up the steep, Big Bear Mountain/Lake roads during the Christmas Vacation adventures.

In the review of your roadster, we all know the “look” of large rear tires for the “big/little” look. But, whoever started that trend probably had a big hemi and (to offset the large item in front), had larger rear tires.

Not that it may matter to you or others with larger rear wheels and tires, but, it does take more to power rotate the rolling, larger tires than, say the same size tires as the fronts. But, forbid that notion for the “big/little” folks with the set up… !!!

Just a note:
“…increasing tire radius without re-gearing, yields less force between the tire and the ground, and thus slower vehicle acceleration…”

 

When you say falls flat, its is stumbling or just runs of steam and won't get over 3K floored? Have you tried running without air cleaners to see what happens?

 

@banjorear I was thinking the same thing but see in early build pics he had scoops. My buddy Tim has a very similar build as Kens but a early motor and Max 1 cam . With a shelling type aircleaner it’s a dog and rpm’s drop when you put it on. His roadster runs Very Strong even with a single modify carb . He is running 3:78 gears and 39 transmission.
Ken when you said you reset the weights on the distributor could it not being advancing fast enough. As the plugs look ok and fuel doesn’t seem to be a issue. Do you want me to send you a distributor to try it.