I like some information of the classic hotrodding mod for the 1946 100 HP engines. The engine I might get is a standard and complete but as I work with engines all my life this motors has never crossed me. I guess best is to get a kit from Scat then one get 2” rods journals, forged pistons, modern rings etc. How much is this blocks good for overbore ? Is it worth overbore max ? I’m not after HP here but I like the sound and look and ‘some’ reliability ( more HP always get some issues ) I plan use 2 or 3 carbs and older finned race heads, or do one get better compression with new castings from ex Edel or Offy ? The more stroke and bore the better compression. I guess near 10;1 should might work if possible. What is the coolest heads one can get ( old ) ? What cam is proven to get power and the especially the sound. I will not drive this car long, just around where I live so I can has a rather ruff cam. Any other good new one need to look for get a older one besides cracks in block etc.
Hank, STOP! Sounds like you are putting the cart before the horse when it comes to building a flatty. Don't be so quick to spend your money on a SCAT crank and other big name expensive parts until your make a plan as to what you want to build based on knowledge, not on the cool flathead stuff we see in hot rod magazines. Read this thread and buy books written by experts who really know flathead engines. https://www.jalopyjournal.com/forum/threads/flathead-reading.770895/ Then join www.fordbarn.com and ask even more questions. The key is to buy parts that when assembled as a package give you the engine you desire. For one thing 10 to 1 compression is way to high unless you're going to race a Bonneville Salt Flats. Watch this video and then GOOGLE: How To Build A Flathead Engine for more knowledge. It's an 8BA but, the principles are the same as your 46.
Shore this is just the first insights. ( I has a car to build and right now no body.. ) I did read some here at HAMB now and theese motor dont gain much on cubics if breath is no there. The suggestion was a blower ( but my plans is not a blower ) Shore to press air in and sounds cool must be great but I has no need of 300 HP. And I think few street racers around 48 used blowers. My idea is a cool set of old heads and intake/carbs. And I like the look of it. Most engines like compression and cam. I cant say on experiance build engines since mid 80’s and own dragracing that a good crank and rods and nice ring lands is a waste. A OEM crank needs dip, magnaflux and maybe was grinded before, then old rods is often a issue and cast old pistons would had done their time. Now I has not seen the parts inside but I think it would be wear. Can’t say on stroke and bore ( need info ) but I dont think a Scat kit with ROSS pistons and modern thinner rings is ’expensive’ at around 1.5K. In the video he talk about a guy in Minesota. I might call him what to do for my aplication. I has all machines and I can make new main caps to if needed and line bore etc. But info on what to do tricks, cam etc are great help. ( Books will be on order )
19Fordy nailed it in spades, homework first and then build an engine that is actually usable in a street driven hot rod. I've got just about every how to do a flathead book that has been written in the past 50 years on the shelf behind me and one in particular is about useless for building a drivable street engine. It's great for building a race only engine though. As far as internal parts the first step after your block passes a health inspection is knowing what it's bore is now. X size pistons may not work if it already has a Y bore. Stroker kit, that depends a lot on your build budget but in the long run that may be more productive than hunting down a Merc crank and having it and the rods machined. Compression, been there done that with a 327 with 12.5 Jahns pistons back in the 70's. Damned truck was seriously picky about what premium it wanted to guzzle. It ran like a bandit and then some, but it only drank the finest gas you could find at the pump in Texas at the time and don't even think about stopping at the cheap off brand station. Cam? Same deal all too often we as hot rodders tend to over cam anything we put together rather than running one that actually fits what we want to do with it unless your plans involve a trailer and the doing the pro fairground rumpty rumpty around the event grounds every couple of hours thing and then back into the trailer for the ride home.
I'm satisfied with my stock flathead. But, if you prefer to build yours up, be prepared to spend some money and effort. Do a bunch of research. Figure out what you want and how you want to do it. You're in the right direction by asking questions. Try the FORDBARN. It's also part of the Jalopy Journal.
Hi compression isnt always the answer with L heads. Its about balancing compression and breathing (air flow).
Yes I need to talk with guys get me the combo on comp and breath. I like see old Navarro heads and Meyers intake on it. Inside I can use new stuff as for me it ’make sence’. Even if I’m not are into make 200HP and this car will not be raced I can run on better gas leadfree with oxegyn, as the small runs I will do is Ok. I shore like to learn on comp and a hot cam. This will not be a trailer car, just local and get me smile on sound, look and smell. Who dont get a big smile on leaded VP C12.
I note the Mercury crank was at 4” and did the guys on the late 40’s stroke them ? Its possible go 4.1/8 if one use a 2” rod pin. But if they did it back then what rods did they use ( bearings ) ? Or was 4” what they used max ? -For me, it must be era correct ( new or old crank )
Get a copy of Ron Holleran's book, Nostalgia. https://www.vanpeltsalesstore.com/L-1017-Nostalgia-by-Ron-Holleran_p_607.html I talked to him and several other flathead guys when I built the motor for my coupe. 59L block (factory relieved), 4" merc crank. I only did .30 overbore to start, as I didnt want to go right to the limit. Meaning longevity and to help with cooling. I am right around 265 ci. With a flathead, all the little things you can do add up. Porting and polishing etc. I'm running Weiand FR heads and a Litero L-100 cam. Edelbrock super dual intake and two 97s. Stock crab ignition. (By the way, I have 3 Saabs....)
Är du inte ute efter hästkrafter så ta vilka alu-toppar som helst, ett 2-förgasar insug och typ en isky 77B eller 400 jr kam så har du en snygg motor som låter gött. /Andeas If you’re not looking for horsepower just take any aluminum heads, a 2x2 intake and a isky 77B or 400 jr cam and you got yourself a good looking flathead that sounds cool. These things are crazy expensive to build for horsepower here in Sweden.
Andy, I'm into horesepower - but really don't need that many.. This car will not be on a trailer and and not for 'race' and seldom used but I might throttle here locally. It's more for the 'art'. I'm into sound and look and smell and pre 1950's. I should be Ok with a 4" Scat crank and new Scat rods and Ross pistons, but if I find a Merc crank why not ( a cool factor ) I read of a ol' Ron on Ford Barn forum ( is that Ron Holleran ? ) If so he talk sweat on the Kiwi L100 cam. I read various reports on the new Navarro heads as not that nice machined. I would really like one of Barneys own works. As I said I can run racing gas if that helps powers vs compression and it shore smell nice, but as far as I read now this engines don't like compression (?) I understand the breath here is the key so I will read more and ask more on that topics to find the right balance. Anyone knows how much the Ross dome pistons has for dome CC ? What CC had the Barneys heads 'normally' ? What head gaskets is best to use ( copper or fiber ? ) and what thickness is those and CC. I read on ex Feel-Pro and they was at 14 CC and thickness 0.062" ( semi copper/fiber ) I read open up deck in chambers might help flow etc 0.08" deep. -Anyone knows how to get in contact with Rick Snell from Twin City ?
3w hank, Flatheads like compression,,,,,it’s just hard to get the compression up there where you want it ,,,,,short of an all out race engine . They will run very well when built right . Tommy
And, the sweet sound of the flathead is easily lost with exhaust pipes that are too large in diameter. A flathead with 2 1/4" or 2 1/2" pipes just doesn't do it (ask me how I know). Nothing bigger that 2". 10 to 1 compression is a lot for a flatty. You have a lot of volume over the valves. You might want to aim for closer to 8 or 8.5 to 1.
max1 cam from isky, single 4bbl. intake, iron heads, red's exhaust system with headers & short smithy mufflers. then tell everybody about the stroker crank and 3-3/8 bore that they can't see...
'Ashland Grinding' in Hayward, CA. (? or San Lorenzo, they delivered) used to offset grind the '49-'53 Merc 4" cranks, to achieve the 4-1/8" stroke. Crankpins were ground to accept smaller #29-A rods, ('39-'48) simply using '39-'48 Ford full floating con rod bearings. Easy, genuine Ford parts. Jahns ('J-E') or Silvolite pistons were popular, (low $$) When boring to 3-3/8", I discovered mid-'40s Chrysler 6 cyl. cast iron rings could be bought from the machinist-jobbers for cheap, not in sets, but individually... I built a 296" flathead for a customer as late as 1983, mostly from collected Ford/Merc parts. Only deviation was the Isky Max-1 cam...customer's choice. He later changed it to the old Weber F-2 I had. Vrooom!
I'll just found out that information the dudes back then did use the Merc 4" crank ( era pre 1950 ) and offset them to 4.1/8" and used the 2" pin. If one can get a decent round big end on the ( my guess ) 7" long 91A rods that could be one way to go. I guess Scat sell the same crank/rods so it's a game on use Henry steel or China, but even if I 'heard' Scat has 'issues' - I think it should be decent parts. I read this 46 block can be bored 3/16" over but that depends on the cylinder walls, and I'm not planning on supercharger this one. So than means right under 300 cubics.
Take Ol Ron's offer shown below, to call him about what you are trying to build. He really knows his stuff. Whatever the cost of the phone call, it will be worth it to you. Otherwise, you may end up buying expensive flatty parts that will omly make your engine look pretty and NOT perform as you desire. Plant your feet firmly on the ground and FIRST develop a plan, not a list of expensive hot rod parts. Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,131 Re: Building a hot rod flatty. If you PM me I will give you my phone number so we can talk about this build. My eyesight prevents me from long conversations here. Too many red lines. Gramps
In my opinion, the most practical thing to do is to bore the block 1/8" (.125) over and use the Mercury crank with reconditioned (or new) stock rods. This will give you 276 ci which is only 8 ci than the same setup with a 4 1/8" crank. I think all of the BS required to get the extra 1/8" stroke is not worth the time and money. If you have a Merc crank, the cost of putting one of these together is just about the same as a stock engine. And don't worry about the next overbore (or three) as these engines have been taken out to 3 3/8" and even 3 7/16" bores. I've done it three times and the only problem I ran into is one block needed a sleeve when the machine shop ran into a casting flaw after the bore job. They actually said it didn't need the sleeve, but for the small extra cost, I didn't want to take a chance. I've had a MAX-1 and a stock Mercury camshaft in a couple of these engines, and quite frankly, I can't really tell the difference. The single most important factor in flathead performance is getting the quench right. You want .045-.050" over the piston top. This will require milling the heads to get them in the neighborhood and then doing some grinding to bring everything up to snuff. This can be done with either stock iron heads or aluminum finned aftermarket units. One thing you shouldn't do is just slap a set of finned heads on it without checking and modifying them. The tolerances from the factory are such that you can never be sure of what you have. Be doubly careful with used heads. A four BBL carburetor is fine as long as your car has a hood and you keep it closed all of the time. For a traditional "Hot Rod", you have to have multiple Ford type two BBL carbs on an after market manifold. In my opinion, Stromberg's look better, but Holley's work better and are a lot cheaper; your choice. (I prefer two carbs on a "Super" dual type of manifold.) For a distributor, either a modified SBC unit or, my choice, an old "Flattop" Mallory. They are still around, and if you can't find one, SBC Mallory's are more common and can be converted, just like a GM unit. For an undercar exhaust system, you can't beat cast iron Fenton's, although other variations (such as Lakes Headers) are available. If you have the money and resources to take it further, more power to you. Good Luck!
I can stroke the crank, but I get your message. But the 2" pin and the 91A rods might work well. I like the look of the finned heads but it can be cool to use std cast heads to a nice intake ( ex Meyers ) But as I read the Navarro should had the best flow. What about that going with the cast ones ? As I work with 426 Hemis I know... about dome and piston to head ( and piston to valve ) Was this engines green from factory, if so I might look nice under a 25 louvers hood on a black coupe whit a nice intake/carb set-up.
19Fordy, well it shore be great if I can talk to Ron. Maybe I will use Henry steel in most here.. maybe even the heads ? So let's see.
Call Mike (Jr or Sr) at HandH and talk to him/them if he/them has time. I did so and built a rip-snortin flathead that has not ceased to amaze me. It's no BBC but I'll hang with the normally asperated SB guys. Warning: It cost me $17,000 to build it!
As a engine builder I humble ask but prefer to do my engines. I saw Scats crank at 4.1/8” and bore at 3.3125” give me a piston dome CC at 12.65. I used gasketa at 0.045” and deck zero. Scat said comp at 74 CC head would give 9.6;1. But as gasket has a hole ( unknow CC ) it don’t really tell me if dome CC at 12.65 is correct. Might need call Ross.
I found the piston at Ross web #80572 but on info nothing is told on dome CC ? Dome height is told at 0.187” So if I calqulate a cylinder at 0.187” /2 vs a dome = ca ; 13 CC. I like to know gasket CC and the piston dome CC exact. This gaskets is not round.
A note on aftermarket heads : As far as I know, just about all aftermarket aluminum heads are about the same. The secret is reworking them to provide the proper quench and compression on the engine they are installed on. The only exception to this is Edmunds heads. They have the spark plug relocated just enough to move it from over the exhaust valve. This allows the use of extended tip spark plugs which I have found to be beneficial. I only have experience with 8BA style heads, so I don't know if the earlier versions share this feature, but knowing Edmunds, I expect it would be so. Stock heads also share the location of the pug over the exhaust valve. Since any heads you use will need to be fitted to the particular engine you are building, I don't see how any brand would offer any breathing advantage out of the box.
I has try look on pictuer on sparkplug location on Edmund vs Navarro but I can’t see they is not equal. Sparkplug is located right under a hole and litte over hole on its side on both. When one build a motor and try locate comp one just can’t say this head is ex told be 8 in comp, as it’s based on bore/stroke and piston pop up, gaskets. Piston to head is one thing, design in chamber is another. One do not need a exact CC tube, just something decent. Normally piston manufactor tell on dome CC or gasket CC, but one can figure that out but strange that Ross don’t tell. When I build stocker Hemis I CNC new chambers use a blueprint plate, then I know chambers is exact above the cylinder. I use 0.40” piston to head and piston pop upp is 0.536” and good rods from Crower as RPM is 8500 and rotaring is 1.800 grams. I like evry comp I can get out as its HP. Ok that is racing and not a Flatty but idea is the same. Maybe Ron can cheer me some lights in this.
I has talked to ol' Ron and a great phonecall ! ( Big thanks ) His idea of a good motor might get 175 HP and he like smaller piston to wall clearance and suggested a Mahle domed pistons as ex SKU: MAH-930074712, and that is 3.5/16" bore or 3.3125". This piston has 0.0015-0.002" clearance. Keep them less banging to wall as a race piston at 0.004-0.005" clearance. Weight is 338 gram and dome CC is 12.8 CC ( 1/16 rings and 3/16 oil ring ) That with a Merc crank at 4" ( not stroked ) and the Ford 91A rods. That gets a 276 cubic motor. Gaskets from Best ( 515C ) compressed at 0.052" Heads was angle milled stock cast iron ( angle milled 0.080" ) to around 65 CC and that gets compression around 9:1. If a alu head it was Edelbrock or the Navarro 65 CC head ( I suggested or asked about ) Cam might be a Isky 400JR, Winfield 1A if higher RPM HP. Intake 2 duece from Offenhauser and 2-port Rochester carbs.
If you are using a Merc crank at 4" you use 8BA rods. The 21A or 91A rods are the 2" version which are used to stroke the Merc crank. Harder to find bearings for, and harder to set up those floating bearings.
Engine is not appart yet and I bought it Ok, thats the deal. I found a Merc 4” crank here grinded and correct rods for it. Done at the 60’s never used. The Mahle 3.5/16” pistons will be good match ( small piston to wall clearance ) I might found a old Clay Smith cam to ( update #272-2 ) The intake is Offy #1073 Ron suggested, spred 9.1/8". I’m into get the H&H Navarro 65 CC intake, or the 'Canadian' scheater or mill of originals.
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