I ve seen 7 main bearing John Deere s snap a crank and still happily clatter away.
Heard stories of big cube MM s with big strokes flex the crank enough to touch the inside of the crankcase.
Met another fellow that ran an old diesel super stock built on a 401 ford. Spun it fast enough that the crank would flex and grab the rod by the sides. Wasn t fully counterweighted.
The issue with the 3 vs 5 main bearing 4 cylinder or 4 vs 7 main 6 cylinder is not the main bearing itself, but crankshaft flex. Which can show up in the mains.
Take a piece of channel iron and support it at each end and place weight at two places equal from the center, then place a center support and notice how much better it supports the weight.
If you were to increase the mean cylinder pressure high enough and barring any other failures you would eventually break the crank through fatigue. Providing the piston and rods are up to the task as they usually fail first in most cases.
Upload one or more videos to your post. Photo and video filesizes should be less than 8MB. Formats allowed are gif, jpg, png, ogg, mp4, mov, and avi. Be sure to use filenames without spaces or special characters, and filetypes of 3 digits lower case.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - Earthmaster Project Progress Just a little update on my Earthmaster......it's back from the dead! I pulled the head, and soaked the stuck valves with mystery oil overnight, re-installed the head, and bingo, the compression returned. But alas, my carb foiled me again, it would fire a second then flood out. After numerous dead ends for a replacement carb, I went to work fixing mine.I soldered new floats on the float arm, they came from an old motorcycle carb, replaced the packing on the throttle shaft with o-rings, cut new ga
... [Read Article]
Latest Ad:
1964 I-H 140 tractor with cultivators and sidedresser. Starts and runs good. Asking 2650. CALL RON AT 502-319-1952
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
