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Technical 4 banger motor re-build

Discussion in 'Traditional Hot Rods' started by Don Bamber, Jul 8, 2017.

  1. Don Bamber
    Joined: Jul 8, 2017
    Posts: 4

    Don Bamber

    I'm planning to re-build and hop-up my 1928 Model A 4 banger motor in a few months time. I want to be competitive at VHRA events and tour at reasonable speeds. I'm thinking about a lumpy cam, counterbalanced crank (new with modern bearings) oversized intake valves, Thomas 6:1 head and Thomas dual intake with 2 Stromberg's. I'm also considering a Mitchell Syncro box and overdrive, funds permitting.
    Does anyone have any useful thoughts or advice on this subject, my research says the above is the way to go but I'm trying to get a general picture of what's good or bad, worthwhile or otherwise.
    Any input will be very gratefully received, thanks.
  2. Model A Gomez
    Joined: Aug 26, 2006
    Posts: 1,051

    Model A Gomez

    Sounds like a good plan, I would install a Mallory too. I had a B motor with a counterbalanced crank, Winfield head, Ansen manifold, Holley 94, Mallory dual point and a header. ran fine but needed an overdrive if you were planning on running over 55 for very far. You should look into The Secrets of Speed Society and F.A.S.T. (Ford A Speed & Technology) lots of good banger information.
  3. Dan,

    My first suggestion would be to put your general location in your profile. There are some excellent engine rebuilders around the country but there are definite advantages to locating one that is close. There are also some to avoid. Be sure to consult the archives here and at when you are trying to decide. Note that if a company has a symbol in their name, such as A&B machine, you can to to GOOGLE and search for "A&B machine on HAMB" and you will get what you are looking for. The search engines on HAMB and Fordbarn can't deal with symbols so you need to use GOOGLE. For the cam be sure to check out Bill Stipe. You can get a new cam with oversize journals and then ream your block to fit the new cam. The attached picture taken at LARS couple of years ago shows what I think you want to build.

    Charlie Stephens

    Felipe Toltecatl, ls1yj and Hotrodmyk like this.
  4. winduptoy
    Joined: Feb 19, 2013
    Posts: 1,540


    Welcome to HAMB
    Might want to look at the Banger Meet and throw your question there too.
    6:1 seems to work well
    Inserts good idea in my book unless you already have good babbitt that will work with a standard diameter crank.
    I don't know why you'd go with a new crank and turn it undersize to match existing babbitt
    Counterbalanced crank come stock on later B motors. I like them the other alternative is pricy in a Burlington or some other names that get cussed on the board for breakage
    Lumpy cam seems to loose lower end torque. I don't like them and I have a buddy that runs one with a similar set up like my A engine and he gripes about his 'lumpy' cam all the time missing the lower end.
    I would go with a 'B' touring grind.
    I think oversized valves are a waste of money on an A engine...spend it on other things like overdrive. I run a Mitchell and like it.
    Mitchell transmission.....I like it for the most part but it pops out of gear. It has the stock first ratio, 30% higher second gear and 1:1 final. I like the split. Their quality seems to be very variable.
    Think about the rear end ratio 4:11 is too low for modern road speeds. I run a 3:78 9with over drive) and a 2:22 in the OHV conversion (no overdrive)
    Agree on a different dizzy. I also like the 'B' distributor that has weight work to get about a 28 degree total advance.
    2- 97's might be too much and I like a single Holly 94 on the warmed up A
    The OHV gets 2- 81's
    Consider tire and wheel selection for final drive massaging
    I wouldn't have another A banger that didn't have a V8 clutch and lightened flywheel those were the most drivable modifications I did
    I'd use a different front and rear seal from stock
    Two blade fan and
    New at least 3 row 10 fins per inch radiator
    Cast iron drums and proper set up of mechanical brakes now that you can go fast

    Good luck

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  5. Don Bamber
    Joined: Jul 8, 2017
    Posts: 4

    Don Bamber

    Hi Charlie,
    Thanks very much for your reply, without the red paint, that picture is exactly what I want to build.
  6. Don Bamber
    Joined: Jul 8, 2017
    Posts: 4

    Don Bamber

    Hi Larry,
    Thanks very much for your reply, it's really helpful. What about full flow/full pressure oiling?
    Anyone have any views or information on that?
  7. waxhead
    Joined: May 11, 2013
    Posts: 1,067

    from West Oz

    You should try and get a copy of Jim Brierley's book "4 Bangers and me", lots of good info in there on building a 4 banger. Lots of good info posted above as well. Good luck.
  8. denis4x4
    Joined: Apr 23, 2005
    Posts: 3,271

    from Colorado

    I've run old Strombergs as well as the new ones and even used a Mooneyes EFI on my bangers. Both of my cars are equipped with Weber 32/36 progressive two barrel carbs. Much easier to tune than a pair of 97's. Check out the FS ignition. IMG_0063.JPG
    burl and ls1yj like this.
  9. winduptoy
    Joined: Feb 19, 2013
    Posts: 1,540


    Oiling has been overlooked, thanks for bringing it up. It depends on what you want to do with the engine and I perceive that you aren't going into competitive circle track racing.
    Model A blocks take a lot of work to set up pressure oiling to the rods. Dippers on inserts seem to do fine in mine. Look at Antique Engine Rebuilders in Skokie, Illinois. A set of inserted rods and bearings are about $750.00 for 4 as I recall. Model A bangers are the engine you can spend the most money on to go slow.
    There is a Riley article that talks to the modification of an oil pump that I have done and run in the A.
    I personally am more concerned with Volume than Pressure. I will see if I can get permission from Charlie Yapp and post his re print of the instructions to modify the A pump. It consists of opening up some ports and galleys along with making the end clearance on the gears to the cover/housing are tight. On the OHV, it runs a modified V8 pump.
    The 'B' block is easier to pressurize the mains and rods.
    I'm thinking if I were you, I'd warm up the engine you have by taking up the rod and main caps to .0015" if the Babbitt is good
    Install a 6+:1 head and
    find you a 'B' intake and carburetor just to see how much it warms up your engine. Low bucks to start and get you some driving fun in.

    ls1yj likes this.
  10. Don Bamber
    Joined: Jul 8, 2017
    Posts: 4

    Don Bamber

    Thanks very much to everyone who's replied, it's really useful to have different input.
    I know it's expensive and still slow but so far my Model A has been the best fun car I've ever had, I'll start my build at the end of this season which, hopefully, will make it even better.
    Any more ideas are very welcome, thanks again, Bamber
  11. Your project straddles the charter for HAMB and Be sure to visit there also with your project. How about a picture of the vehicle this engine is going into? Since you want to be competitive at VHRA events I wonder if adapting a '39 transmission might be better than the Mitchell in terms of how fast you can shift? Sorry I don't know the answer.

    Charlie Stephens
  12. Binger
    Joined: Apr 28, 2008
    Posts: 1,592

    from wyoming

    Welcome to the HAMB! I have installed an S-10 4x4 T-5 in my coupe with a closed driveline adapter on the back and love it. It has a 15% over drive in 5th gear. A lot of guys will convert over to an open driveshaft and run a regular t-5. Running a single 97, Red's header and a Mallory on an otherwise stock engine I can cruise comfortably at 50 MPH in Wyoming at 6000' elevation. However I am not sure if that trans is legal for the events in which you want to participate. I am saving to be able to build a counterbalanced and bearing inserted engine. I am leaning towards running a cast iron head with 6.5 :1. There is a guy here and on the Fordbarn who has been producing Cast iron and aluminum Winfield crows foot heads. One of those is the one I hope to purchase eventually. Good luck with your project. Please post a picture of your project for us to look at.
  13. lake_harley
    Joined: Jun 4, 2017
    Posts: 618


    I recently bought a stock, running and driveable '31 A Coupe. I'm still trying to decide what direction I want to go with the car. I do what the car to be practical to drive at "highway" speeds.

    My first thought was a 2.5L, 4-cylinder Chevy, so I bought a S-10 pickup with a T-5 and pulled the entire driveline.

    Then, I got thinking about something more 'traditional", so I contacted a long-time car-guy friend who has a complete 59AB with 3-speed top shifter in his stash that can be bought for $400. It would need a complete going over/rebuild which I'm expecting to run $1500 to $2500 for a mostly stock rebuild. He also has some Edmunds heads and a 2-2 intake carb setup, but that's the stuff dreams are made of for now.

    Tonight I got wondering how practical it may or may not be to just run the original A 4-banger. With a budget of lets say $2000 to $2500 for engine freshening and modifications, could the car be made practical enough with the 4-banger to drive at "highway speeds"? (55-65 MPH?)

    I hope my question isn't going to cause too much thread drift, but I thought it fit into the discussion that has developed.

    I do realize that my current thoughts and options are really going in three different directions, but I am open to hearing comments and advice, especially those regarding the practicality of using the 4-banger.

    Last edited: Oct 13, 2017

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