VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 Flywheel balance

In an effort to get my 26 running smooth, I have been working on a number of items, some are the subject of recent posts. I have an all original 28 survivor coach that runs great, 50 MPH all day long. However, my 26 Roadster, weighing in at much less, has a hard time holding 40 without feeling like a washing machine. I replaced the flywheel, and pressed on a new ring gear. The gear is within a few thousands of an inch concentric. However, does the flywheel need to be balanced to the crank?

Lastly, what should I expect for performance from a 26?

It would be ok to just have the flywheel balanced, by itself.
Back then not much was balanced as a unit.

On these old engines the flywheel will be 'zero' balance meaning there is not a form of counter weight added. In this case, the flywheel (with pressure plate) can be balanced without the crankshaft. You may want to look at the flywheel or pressure plate for signs of extra holes that someone may have drilled to lighten them up. Just a note: the farther the imbalance is away from the crankshaft centerline (such as the large diameter of the flywheel) the greater the vibration detected. You may also want to check to make sure all the motor mount bolts are tight before pulling the flywheel.

When I rebuilt me ’28 engine I found the components to be very close considering today's electronic balancing equipment. For the best engine ”˜balance’ the pistons and both ends of the connecting rods must weighed and matched to each other. Next, the crankshaft is spun in the balancer and corrected as necessary. Then the front pulley and flywheel are balanced as separate units and as a final check, they are assembled on the crankshaft and the entire assembly is spun again.

Your 26 has a lower ratio diff and your 28, assuming its a late 28 will have a higher ratio diff.
The 2 sets of diff gears are 46:11 and 42:11
If you change the diff to a late 28 (they should be interchangeable) your 26 should do 50 mph.
Saying all that I prefer around 45 mph as a few Aussies who did a lot of 50 mph driving busted their engines. And it's less stressful.
Chris

My 27 is unbalanced.
I sit on around 40mph just before the vibration sets in.If you push it to 45 the vibration then disappears but the motor doesnt sound as happy.At 40mph everything seems to run sweet.

It may not be the engine but universal joint or even too tight adjustment on ball housing.

All great input! I actually print the advice I receive, and post it on my windshield, having highlighted the items to be checked. I am starting with the motor mounts; this car has had a lot of bolt-loosening vibration over the years!

Thanks again,

Dave

PS: good call on the u-joint Chipper, it is an easy component to overlook, and it does have a natural eccentric tendency.

You would get a better balanced engine(which is hard to do,as the crankshaft is a single plane type)if you have the crankshaft balanced with the crank pulley,flywheel & pressure plate assembly
balanced as one unit.
That's how my '28 truck engine was done,and it runs with very little vibration.