Given the frequency of the broken crankshaft topic coming up here, the thought just popped
in my head .... is this a "modern" problem .... "modern" being defined as since paved roads
have been common and speeds have increased, as opposed to back when T's were relatively
new and driven slower on rougher roads ?
I have seen no reference to broken crankshafts back in the day.
frymiller says he has had a few old broken ones ,he has had a lot more old motors than me, but i have never seen an old broken one. charley
Back in the day they were not 90 years old
Part of the problem is they are reground so small on the mains... and not designed to drive at today's speeds
And, back in the day,
A worn crank of .002" was replaced with a new one on engine rebuilds!
As a 90 year after-the-fact "detective" looking at the case, it seems to me that
Henry made no effort to balance his engines (or anything else) because speeds
never really reached a critical point of needing to do so. But as roads improved
and engines revved higher to go faster, a problem developed that wasn't a concern
in the T era .... hence the broken crank issue.
Of course, no case is 100%, and there were surely exceptions, but it seems that
in the main, this broken crankshaft problem was a rare occurrence when T's were
new and roads limited speeds and revs.
Lest we not forget flywheels are drilled . . .
Unfortunatly it goes to prove the there was no desire by Henry to balance them as what balancing was done was done before the magnets were installed . . .
I might add that when compression is increased through the use of high compression heads and pistons, or the HP is increased by other methods whale using a stock crank, definitely puts the odds in favor of a two-piece. Bouts of lugging the engine along with misalignment of the crankshaft and transmission shaft will up the ante too.
Based upon antidotal evidence, broken crankshafts were not unknown while the Model T was in production.
Evidence of this can be found in the change to the heavy crank in 1924, and the change to the EE steel crank the following year. Additionally, the improved cars of 1926-27 had the transmission covers bolted to the back of the cylinder and corner reinforcement brackets were added to the point where the cylinder and transmission cover come together on the pan.
In my research on Model T #710, it's original crankshaft broke sometime in its first 15 years of use, and was replaced before 1924. I have also run across pieces of two piece crankshafts in my own restoration work.
The two primary causes of broken crankshafts are 1) misalignment of the three main bearing and the bearing in the rear ball cap, 2) lugging the engine. Model T crankshafts are remarkably flexible - actually amazingly so. In one instance that I am aware of, the flex in one crank shaft at the #3 food throw was measured at .040". Lugging is a major contributor to this.
If you want to keep an original crankshaft in service, there are three things that you can do. 1) make sure your Babbitt is perfect, and that all four bearings are in perfect alignment, 2, use an EE steel crankshaft, and 3) don't lug the engine. Keep the engine rpms up and the spark lever down.
of several hundred T engines i have been thru ...many being old origional engines , i have only seen 2 broken crankshafts in engines that were "not in service" for a very long time ...i have seen 3 other broken T crankshafts in current rebuilds/restorations ...i would suspect that the service conditions as well as alignment was the major factor ...of the "old" engines both had severe use , 1 having the rear mount broken off the driver side of the pan ...always an optimist...gene french
In the twenty's my father 1906-1966 and a friend took a T roadster pickup full of fish to Landsing,Mi to sell.They broke a crankshaft spent all the money from the sale of fish,and did not get back for 3 days!
Trent, you mentioned that Ford went to a heaver crank in 24 then to a EE steel crank in 1925. Could you enlighten a relative novice like myself what to look for when trying to identify either a genuine 24 crank or an EE example? I assume that an EE crank is marked as such, although it's just speculation on my part.
Thanks in advance,
Charles: Unfortunately all cranks weren't made from the better EE steel from 1925 on - you have to check the markings.
Here's one way they can be marked:
Another version is a marking at the front edge:
Here's a comparison between a stronger 1924-27 style crank to the left and the thinner and more crack prone '09-'24 diamond style crank to the right:
And yes, they did crack back in the day on old slow roads too - here's a story from 1936:
"An interview with Vernon Evans (at center in photo) about how this picture came to be taken:
Well, we was all without jobs here [in South Dakota]. And the jobs was so few and far between at the time we left that you couldn't even buy a job. We had friends that we knew out in Oregon, and we decided we was going to go out there and see if we could find some work. We had $54 between the five of us when we started out from here to go to Oregon. And when we got to Oregon, I think we had about $16 left. We had absolutely no idea what we was going to do.
We all got in an old Model T and started for Oregon. We started out, and, I don't know, we got out six miles and broke the crankshaft. This old rancher, he had some old Model T motors laying around. He said we was welcome to a crankshaft if we wanted one. So, we went back and proceeded to tear the motor out of the old Model T and put the crankshaft in. And that night we made Baker, which is a matter of 24 miles from the night before.
Well, then we had pretty good luck all the rest of the way. (---) Anyhow, we got out there and I went to work on the railroad."