Fordiesel69 271 #1 Posted May 3, 2024 (edited) With tractor pulls, I notice a lot of guys fab up a brace, even on factory engines. I assume the one in the link is souped up beyond factory, but my question is when it comes to lugging and engine down, what is the difference if you are cutting wet thick grass, snowblowing, or dirt plowing and lugging the engine really hard vs. a tractor pull? Why the need for a brace? Edited May 3, 2024 by Fordiesel69 Share this post Link to post Share on other sites
wallfish 18,071 #2 Posted May 3, 2024 I'm no expert but guessing those guys are shaving the heads down and creating higher compression 3 Share this post Link to post Share on other sites
ebinmaine 72,426 #3 Posted May 3, 2024 3 hours ago, wallfish said: I'm no expert but guessing those guys are shaving the heads down and creating higher compression That and the pullers in certain classes run higher RPM. 1 Share this post Link to post Share on other sites
RED-Z06 2,567 #4 Posted May 4, 2024 Lugging an engine creates the most dynamic compression, the carb is wide open, the engine speed is low, so the entire fuel/air mixture is fully burning...maximum torque happens, this also means that the same forces pushing down on the piston, Rod, and crank, are at the same time, trying to push the head and cylinder off the block (newtons 3rd law). Add in higher compression ratios, exotic fuels, more aggressive timing...and you need to add rigidity to the engine. OHV kart engines will run twice the compression as a flathead, and turn thousands of rpms higher, they add a girdle across the head to accomplish the same rigidity. Ive seen a K341 send the jug about 6ft in the air, there was shenanigans involved, its not something a stock engine needs to worry about. 2 1 Share this post Link to post Share on other sites
Wild Bill 633 877 #5 Posted May 6, 2024 Stock blocks with high compression like to break between the base of the cylinder and the top of the crankcase. 1 Share this post Link to post Share on other sites
