238 mph
 

https://www.youtube.com/watch?v=DqopaEr4Er4

The wife has a Subaru, just wondering, a Burtz block and ...

Re: 238 mph
 

Clocked at 68 MPH in my stock '31 town sedan by one of them new fangled cars, not the smartest thing I've ever done, and I will not repeat it...I don't care how many beers you buy me
Had my '57 Chevy over 120, again not the smartest thing I've ever done, and since I gave my Harley to my Son-in law I won't bring up the stupid things I did on that beast.
I'll leave the racing to the pros (they're braver then I), and I'll just putt/putt cruise to go watch them.
Somehow being older seems to make you smarter, wish I knew this when I was younger

Re: 238 mph
 

Had my 29 all the way up to 60 yesterday and the thing felt like it would fly apart. I think I will stay in the slow lane.

Re: 238 mph
 

Interesting video, but I have no desire to go that fast in something that old.

I once got the 30 Fordor in the mid 60s, but only for a few seconds.

Re: 238 mph
 

That was my thought as well - but after doing some digging, it looks like the only thing "Model A" about the car is the engine block; there are a few good photos of the finished vehicle here.

https://www.fordbarn.com/forum/attac...1&d=1646694613

Re: 238 mph
 

I have had my 1930 Tudor up to 72 mph a few times. The front end starts to feel kinda busy at that speed but the car felt surprisingly stable.
SDJason, that streamliner sure is pretty. Thanks for posting.

Re: 238 mph
 

I have to admire what some people can do with a Model A. I'm lucky to just keep a stock model A running.

Re: 238 mph
 

1963 high school graduation fordor going from Big Bear Lake down to the Mojave Desert on the back road I reached a terminal coasting velocity of 70 MPH due to the wind resistance of the brick styling of the Model A. Couldn't go that fast under engine power.

Re: 238 mph
 

So it's the same as hanging a 1920 Dodge Brothers Radiator badge on the front of my brother's 71 Mach 1 Mustang then bragging about setting records in the quarter mile.
Honestly, I'm not impressed. I prefer my Model A Fords to look more like a Model A Ford.

Re: 238 mph
 

I agree that it is not a Model A. But it is interesting from an engineering perspective. Thank you Updraught for sharing. I am wondering what that streamliner would do with 40 horsepower.

The 3 valves in the head is a great idea. It provides a lot of valve area without crowding and places the spark plug in the center of a mostly hemispherical combustion chamber. The lobes on the camshafts are extreme.

Regarding the original question, the Burtz block was not designed for 6,500 rpm. It would take shorter connecting rods for one thing. Plus they did some modifications to keep the block together. As he said the Model A block is as breakable as a potato chip (when putting out 300 horsepower). And then there is the basic question of when is a Model A not a Model A.

Re: 238 mph
 

The big advantage of the three valve design over the 4 valve is that it leaves room for two sparkplugs.
The Model "A/B" basic design/layout is not performance oriented. The long stroke, small bore and narrow bore spacing all contribute to limited performance. Shorter rods will not help in extending the RPM range, but a shorter stroke will. Pete mentions doing this, some have gone further.

John

Re: 238 mph
 

John, Thanks for your comments. I missed the part where he used a shorter stroke. Pete did mention decking the previous engine by an inch to run shorter rods and when that was outlawed, he developed the heads that insert into the bores by an inch for the same reason. I personally don't understand why the shorter rods would help but I don't understand everything. I guess it cuts down on the reciprocating weight (mass).

Re: 238 mph
 

The rod length affects the piston acceleration and that affects cylinder filling.
I use std length rods and spin the motor in excess of 6500 rpm
There are too many contributing factors to the engines efficiency and potential output
There is a thread about doing something stupid, this is my story

John

Re: 238 mph
 

Interesting comments. I would have thought that with the stroke being the same, irrespective of rod length, that the piston must travel the same distance, and thus acceleration from TDC to BDC remains at 180 degrees and total distance travel is equal to stroke. With time and distance being equal irrespective of rod length then acceleration and deacceleration would be consistent with different rod lengths. Changing the stroke would affect acceleration and deacceleration as the distance travelled in the same time period (180 degrees of a revolution) the piston would have to accelerate quicker to move through the increased distance (increased stroke) in the same time period.

My thoughts, maybe my understanding of physics is skewed?

Re: 238 mph
 

The piston travels the same distance but it spends more time at the bottom of the cylinder with a shorter rod. If you plot out the piston travel per degree of rotation of the crank you will see how this works. You can do the plotting with a pencil and ruler on a sheet of paper. So with more time at the bottom there is more time for exhaust to exit and fresh air/fuel to enter.

Re: 238 mph
 

The piston dwell at TDC and BDC are different.
The longer rod typically dwells longer, then accelerates to a peak speed passing thru 90degs to rod angle.
The shorter rod also increases the rod angle in relation to the bore which can introduce more side loading on the piston.
In fact, I worked on a "B" motor recently with 8" rods, it will be interesting to see it run.

J