New Engine "Builders Guide" update.

[Terry Burtz, Calif]

The latest "Builders Guide" revision is dated 22 Oct 2024 and can be found at www.modelaengine.com under the tab "Guides". Click on "Guides" and then you can click on "Builders Guide". The "Builders Guide" is long and 4 pages can be printed on a piece of paper by printing 2 pages on each side.

Changes include the availability of O-Ring studs, one-piece deflectors, and a button head bolt with a copper washer for the rear main oil galley plug available from John Lampl. Contact John Lampl at www.burtzblock.com These parts will be included with the cylinder block on the next production run.

A builder in MA was removed from the "Builders List". This is the third builder removed. The two previous builders removed were in VA and southern CA. Please let me know if you know of a builder that should be on the list or removed. Baril, Green Bay, WI (barilengine.com), 920 336-4600 was added as a builder.

An insert bearing part number was corrected, and some sentences were rewritten for clarity.

A paragraph regarding tolerances was added and is pasted below.

Our parts are made in factories that supply parts to manufacturers that assemble engines and only check a few dimensions during assembly. The tolerances of our parts are identical, and the “New Model A Engine” can be assembled without checking any dimensions. This guide is for those who want to verify many dimensions and tolerances.

A paragraph regarding Balancing was added and is pasted below.

Balancing
The new engine parts are made in factories that manufacture modern engines and the “New Engine” crankshaft, connecting rods, and flywheel are balanced to be smooth up to 6000 RPM.
Balance is related to RPM and could be better for higher RPMs, but it will never be perfect.
The connecting rods are balanced in sets to modern engine standards. Each of the 4 connecting rods has a weight that is within a few grams of each other, but the center of gravity is slightly different for each connecting rod. If you are building a race engine, please see the YouTube video https://www.youtube.com/watch?v=QLpiF0E0EJU
For a perfectionist, gyroscope rotors spin at 48,000 RPM and balancing is done with a laser that removes small amounts of material.
From a lack of understanding or to increase profits, some rebuilders want to rebalance our parts.
If our flywheel needs to be used as a holding fixture to balance a pressure plate, do not let a rebuilder remove material from the flywheel. Material can be removed from the pressure plate by drilling the bosses in the centers of the 6 springs. If you want to see if a pressure plate is balanced, look through the 6 holes in the cover for drilled bosses.
The Model A engine is a long-stroke engine and piston speeds above 6000 RPM become excessive. Paying a builder to rebalance the “New Engine” parts to a higher RPM costs money that could be better spent.

I thank everyone for their comments that help to make this guide better.

Terry Burtz

[Smokedtires]

With your Burtz cam and head, what kind of RPMs is a Model A with the new Burtz engine looking at realistically in normal day to day driving/touring? Is there a point where the air flow limitations defeat the need to turn higher RPM's?

The updated builders guide is great BTW. The continuous improvements for the community is much appreciated.

[Terry Burtz, Calif]

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Originally Posted by Smokedtires

With your Burtz cam and head, what kind of RPMs is a Model A with the new Burtz engine looking at realistically in normal day to day driving/touring? Is there a point where the air flow limitations defeat the need to turn higher RPM's?

The updated builders guide is great BTW. The continuous improvements for the community is much appreciated.

A stock carburetor can't support much above 3000 RPM's and the stock valve springs won't follow the camshaft around 3800 RPM. With speed parts, Fred Roberts in Australis routinely turns 5300 RPM.