You’ll never see another one. This unusual 1915 Buick V12 prototype was created by Buick engineer Walter Marr, and it’s still in his family today.
As much as Billy Durant or David Dunbar Buick himself, Walter L. Marr (1865-1941) built the Buick Motor Company. The Flint, Michigan automaker’s first chief engineer, Marr was responsible for many of Buick’s innovations, including the valve-in-head engine. As a response, in part, to Packard’s introduction of the 1914 Twin Six, Marr developed an experimental Buick V12 engine. Two prototype cars were built and one still survives in the care of Marr’s great-grandson, Paul Durant Marr.
Based on Buick’s production valve-in-head design, the V12 was laid out, under Marr’s direction, by a young Buick draftsman named Leo Goossen, who went on to design a number of remarkable racing engines for Miller, Offenhauser, and others. The big Buick displaced 384.25 cubic inches, boasting a decidedly undersquare bore of 3.010 inches and a 4.50-in. stroke. The basic architecture is typical for the period, with cast-iron cylinder blocks bolted to an aluminum crankcase. The Delco ignition system employs the same distributor as the Packard Twin Six, and the firing order is 1-12-4-9-2-11-6-3-7-10-5-8.
Many overhead-valve engines of the era sported exposed valve gear, in part for easy access since the hardware required frequent hand-oiling by the operator. The Buick Twin Six is a bit more advanced in that regard with automatic oilers, one for each cylinder. Note the outboard intake manifolds on each bank, which connect to a Stewart two-barrel updraft carburetor in the center of the vee.
The two prototype Twin Six Buick engines were installed in Model D55 production cars. The compact design, using offset cylinder blocks and paired crank journals like a modern V-type engine, was more than an inch shorter than the company’s production six. One of the prototypes was handed over to Buick executive Walter P. Chrysler for evaluation, and its whereabouts today are unknown. However, the other prototype has remained in the loving care of the Marr family all these years. Below, Paul Marr (left, in gray sweater) shares the Buick Twin Six’s unique story with the car’s admirers at the Old Car Festival at Greenfield VIllage, Michigan in September of 2018.
It is incredible that this still exist and even more so that it is in the care of the designer’s great grandson. I think that makes Paul Durant Marr a “great” great grandson.
I could not miss the man’s middle name. Were the two families mixed, or was the middle name “Durant” an honorary move? Also, missing from the description was the included angle of the VEE. Logically it would be 60 degrees.
Walter L. Marr named his son, Walter Durant Marr, in honor of William C. Durant.
Video i recorded several years ago.
https://youtu.be/HSpo2v1axAg
I am a Buick fan have three Buicks Roadmaster 1947 1948 and a 1953 love them all.
While this is a way cool engine, I can’t help but think that the Packard, with it’s all enclosed side valve layout, was a “cleaner” and quieter design. Buick made the right decision. I would love to have a car like this, but the changes are less than zero.
Exposed valve gear. Very common in this period (also used by Chevrolet among many others). Also common in period: dirt roads! What a bad combination!
We could build anything at one time long ago. What a beautiful engine. Too bad it didn’t use hairpin valve springs, since it’s all exposed.
From what I can see in the photo – the little red car to the right of the Twin-Six Buick is the sole surviving Marr car, built in Elgin, Illinois – also owned by the Marr family.