Heymow - Lawnmower Racing Forum

Engine Help => Briggs Flathead => Topic started by: rene knoll on March 05, 2014, 09:56:01 pm

Title: oppy motor
Post by: rene knoll on March 05, 2014, 09:56:01 pm
cant seem to get figured out 20 horse oppys or the different stroke blocks,how do i know if ive got one of the longer stroke blocks,the tin is off of all 10 of mine ,from what ive heard im looking for 462 or 463 in the model number,anyway im trying to make biggest hp i can get
Title: Re: oppy motor
Post by: willenglish on March 06, 2014, 02:34:31 am
If you are trying to get the most hp you can get....then you sure need to get working on that oppy.
Title: Re: oppy motor
Post by: BIG AL 202 on March 06, 2014, 10:22:38 am
OPPY'S COME IN 2 DIFFERENT BORES, 3.4 AND 3.5 [I DON'T REMEMBER THE REST OFF THE TOP OF MY HEAD]. THE BIG BORES FROM BRIGGS ARE KINDA RARE. THE COMMON BORE, 3.4, ARE THE NORMAL AND CUBIC INCH IS DONE WITH STROKE. YOU HAVE 40ci THE SHORT STROKE TO THE 46 THE LONGEST STROKE WITH A 42ci IN THE MIDDLE. THIS ALL TAKE THE SAME PISTONS, WHICH IS THE SAME AS THE 28ci SINGLE. THE DIFFERENCE IS MADE UP IN ROD LENGTH. ALL THE BLOCKS ARE THE SAME DIMENSIONS. YOU CAN PUT ANY TINS ON ANY SIZE. THE BIG BORE BLOCK AND USING A 46ci CRANK IS AS BIG AS YOU GET [WITHOUT CUSTOM SIZING].