Richard A. Day, Jr., Restoration, Maintenance, and Operating 'Notes for Palmer ZR Series Marine Engines. Published by the author, 6 Windward Dr., Severna Park, MD 21146, $5.00, plus $.70 postage. Maryland residents add 5% sales tax.
This book is the fourth in Dick Day's series on Palmer engines. The previous three were reviewed in the February 1986 issue of GEM. It is in 8? X 11 format and has 90 pages. Twenty-four of these are of his authorship and the remaining are reprints of Palmer, Bosch, and Zenith data.
The Palmer ZR engine was considered the Cadillac of work boat engines. It was built in one, two, three, and four cylinder versions; however, the best-known is the single-cylinder engine used without a reverse gear. It is a big, rugged, slow speed four-cycle engine with lots of polished brass. Unique features are- a 'T' head design requiring two cam shafts, dual spark plugs (one for battery ignition and one for an optional magneto), and a lever to shift the exhaust cam endwise during starting. This last device allows an extra bump on the cam to reopen the exhaust valve during the first half of the compression stroke. Dick Day writes of the ZR series because there were other similar models-the NL and PNR.
The book contains a great many pieces of information useful to the collector. To mention a few-design variations over the years, how to date an engine, the proper paint color, how to time the camshafts, how to remove the flywheel, tappet clearances and bearing fits. This is information not available elsewhere. In addition, Dick Day's book is fun to read.
With these good things said, I must mention some faults and omissions. Early in the book there should be a table describing the ZR and the other similar models-bore, stroke, weight, HP, rated speed, overall height, and years of production. Secondly, he states that the model D Schebler air valve carburetor was used on all but the last engines built. The only carburetor information included is the Zenith that was on the late engines. Similarly, he tells that the Bosch ZR magneto was used on most engines, yet the data included is for the MJB used on late engines.
Despite the flaws, the book is essential for anyone owning or hoping to own one of these engines. It is a good addition to any engine collector's library.
This book review was written by Max F. Homfield, R.R.1, Box 697, St. Michaels, Maryland 21663. Mr. Horn field is a mechanical engineer retired from General Motors where he worked on engine design and development. He now does volunteer work for the Chesapeake Bay Maritime Museum where he is directing the restoration of their antique marine engines.