For a long distance (drive distance) speedster.
1. Will all the inside guts (axle, bearing, gears, etc) in a 25 rearend go into a 26/27 rear end? I know the brake difference.
2. Engine advice: (no mag, coils, NH carb, std manifolds, std valves,otherwise stock engine.)
A. Which will produce more top end power but less heat and stress on the crank/engine -
High Compression pistons?
Standard aluminum pistons with shaved head?
High compression head?
3 Strip Cam. Are they worth the money as for increased power band?
4. Opinion of this new forged crankshaft sold by Mac's/Snyder?
Any other advice?
Consider the setup Chris Bamford has on his T that he just drove from Edmonton to Oregon and back. He's using a Z head with an NH carb, stock coils and timer. With no mag, I'd run a distributor or the E-Timer built by Mike Kosser which retains a stock look and sounds without the coil and timer adjustment issues. A modified cam grind is a great change. I've used the Stipe 280 and like it, others prefer the Chaffin or other grinds. The new forged crank is great if it fits in your budget.
Regardless of the part changes, balance everything for a smoother and more long term reliable motor.
1. yes, the innards will interchange.
2. I don't like the idea of the little pin going through the bottom of the valve stem.
I use Ford 6 232 valves, keepers and model a springs. Usually machine shops can give you keepers and retainers.
3. Stipe cam, great. You can't use a high performance cam, high comp. pistons or high comp. head & worry about crank load at the same time.
4. A counterbalanced forged crank is a must, if you can afford it.
Other advice: Get everything balanced, use a metal cam gear, and adjustable lifters. Use model A head studs.
Sorry Walt, it looks like I copied what you said but we were typing at the same time.
More proof that great minds think alike!
Aaron, I agree with you on using modern valves. I use Chevy V8 exhaust valves but same concept with modern retainers.
Tyrone, an improved carb would likely help as well. A Stromberg OF is real nice as are several other options. Still, the Montana 500 folks can average better than 55 MPH with a swayback NH so they can work well. How much spare change you have starts to drive choices. Not T but a good number of folks have used intake and exhaust from a Model A with either the stock Zenith or a Tillotson carb.
If you opt for the counterbalanced forged crank, consider the Prus head. Advertised compression is 8 to 1 vs. 6 to 1. I have a buddy who upgraded from a Z to the Prus and is very pleased. I wouldn't try 8 to 1 on a stock crank unless I had spare cranks for when they break.
There are many different combinations that will give you a reliable but more capable power unit. I would recommend you check out the technical page on the Tulsa web site at: http://mtfctulsa.com/Tech/index.htm . They not share what they like – they also have relatively unbiased testing to show how things compare. And they are straight forward about things like reducing weight increases the percent of grade the car can climb. If you only want to read one of the several great topics – I would recommend you check out the Power and Torque one on that page which is located at: http://mtfctulsa.com/Tech/power_and_torque.htm
I would also recommend that you look over the 1995 article “Dyno – Ron Kelley Tests the Model “A” Engine”. While it is discussing a 1928-1931 Model A Ford engine, it addresses about 13 different combinations of compression ratios (heads) , carbs, and even mufflers. One of the best items it clearly documents is that while theoretically if you increase the compression ratio you increase the horse power at a mathematical rate (see: http://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node26.html ) but it doesn’t work that nicely/ in the real world of “flat heads.”
And as the sign in the speed shop says, “Speed cost money…How fast do you want to go?”
And for Model T Fords the corollary is the stock Model T brakes are marginal compared to modern day cars. So the faster your Ford goes the more you will need additional braking capability (and might as well add steering capability etc.).
Good luck with your project.
Hap l9l5 cut off
Walt - Besides all the good things I've heard about the Prus Head, call me "old fashioned" but I like the idea of an iron head on an iron block,......harold
Walt - Besides all the good things I've heard about the Prus Head, call me "old fashioned" but I like the idea of an iron head on an iron block,.......harold
Oops,....WiFi trouble made me do it,.....sorry!
Herald, you can have your cake and eat it too!! He makes iron AND aluminum heads! Tyron have fun !!! MG
Any increase in performance will put more stress on the crank. The Scat forged crank is the best answer to this. If you are going to increase the compression ratio, the Z or Prus head is better than the hi comp pistons as they have a much more efficient combustion chamber design. Bumping the compression to 6:1 and beyond will push the stock ignition system hard. It will work, but must be kept in top condition. One of the best and cheapest things you can do for your engine is to balance all engine and transmission parts. Stipe or Chaffin cams are great parts, oversize valves also are good. All it takes is money, how much T do you want to build?
Years ago, I knew a fellow that built dragsters professionally. His shop was across from where I worked. He said "Speed was money, how fast do you want to spend?"
I know a lot of people bump up the performance for speedsters and other Ts, even with T crankshafts, with little extra trouble for it. But most of them do not really drive their cars a lot. Ed Archer's famous number 4 has a Rajo, big carburetor, and much more on a T crankshaft. He has been clocked at 95 mph a couple times, so is quite powerful. And he has driven it clear across the country a few times. He has also broken a crankshaft or two.
All the speedsters I have had have been nearly stock engines. All have had original stock T iron heads. A couple had larger carburetors (always era updraft). One had high compression pistons, one had very large valves. Several of them have had good original era overdrive transmissions, I like a good overdrive. I can run highway speeds all day long with a nearly stock engine.
Carburetion, cams, compression? Anything you do to increase speed or performance WILL add to the stress on a T crank and the entire bottom end of the engine regardless of any other crankshaft you use. If you drive Ts on T crankshafts a lot? The odds are that you will break a crankshaft (or more). However, if you don't push them too much? You may do a lot of driving for a long time without a major problem.
Drive carefully, and do enjoy! W2
I agree with Wayne on the use of an overdrive auxiliary transmission. Once you have a little extra pep in the motor, the overdrive lets you maintain moderate revs while cruising at higher speeds with standard rear gears. Other folks prefer to use 3 to 1 rear gears in conjunction with a Ruckstell rear axle to have both town and highway gearing options. I use a Chicago (T era) transmission with 4 to 1 rear gears in my speedster. In overdrive on the Chicago the final ratio is quite close to a 3 to 1. 2000 RPM yields right at 60 MPH.
With a Ruckstell or any auxiliary transmission, you need to add brakes that work on the wheels rather than the drive line. You probably also want to look at the steering and the rest of the suspension.
Whatever you do have fun and keep it right side up.
Stock head with high compression pistons will keep the heat in the combustion chamber for more power but if they make an iron high compression head that could be an option too. The combustion chamber shape may be better on the newer heads but i've never tested this myself.