Man this is awesome im building one for my lawn mower. mines a non pressureized motor. just trying to make it run better. the carb thing you did im currently work on. basically matching what you have done.
You never want to shave a flat head heads down. Just tape a big sheet of sandpaper to a flat surface and rub the head on it to make sure the gasket surfaces are flat. Shaving a flat head engine will make it run hotter and it will not flow and when you lose flow you have less power. Do small porting to get rid of the roughness and sharp edges in the ports and dont mill the heads more then just making sure they are flat. You need static compression (flow)
I have a head for an 11hp single cylinder flat head and I was going to shave it now after seeing this should I even bother or what should I do to the head input is much appreciated
I know it's 5 years late anyway depends on bore size model 28 avs is for 3.44" bore and model 31 avs would be for bigger bore later year 01/09 and later model 46 opposed twin briggs
th-cam.com/video/xCFpeJcTMs4/w-d-xo.html same principal just double the cylinders. If the gap is too big the valve will need to be ground on a valve machine and the valve seat will need to be hit with a valve seat stone.
On the fly wheel there is no magnets for that stator. If you run a billet flywheel you have to remove the charging system because there won't be any room for the stator
I was wondering if you might could tell me how to time a model 46 back to factory, or possible one tooth advanced? I've looked everywhere online and haven't had a whole lot of luck finding any information.... thanks!
theres really nothing to time. once tou line up the dots on the cam and crank and put the flywheel on the crank with the key in place you should be out of time. you can try an offset key on the flywheel but if your looking for performance you wont feel it by the seat of your pants with a offset key. whats causing an issue?
So, dot to dot no matter what? Was told by a friend that going one tooth clockwise on the cam from dot to dot will help it spin up quicker... Thoughts?
+Ivy Byers not likely to do anything really beside advancing it too far. unless you have a ton of money in it and have it full built but if you were doing that then you wouldnt be using a factory cam. being stock theres not really a whole lot you can do to get gobs of power out of it. you may get 1 or 2 horsepower by doing a bunch of stuff but you wont feel much power. best thing to do for a stock engine is better flow. clean up the ports a little and try a bigger carb. without spending $$ it hard to get a noticeable power increase
Matt Yarolem around 10 extra hp and it was happy around 5500-6000 before the cam couldn’t keep up and the valves floated. Low end power was great coming out of the corners
Matt Yarolem the cam was a stock cam that was modified by an old Harley Davidson mechanic and was $50. I can’t remember how much the stock 46 rods were but I want to say around $100. The pistons were stock AVS pistons for single cylinder OHV briggs engines so they weren’t very much either. The springs came out of a vTwin briggs and I had them laying around from my vTwin build. I believe the biggest cost was the billet flywheel and it was $300-$350. I had the crank stroked .010” for $75 which gave the piston zero deck height at TDC. I used 40 ci oppy heads because they had the raised landing around the combustion side which lowered the compression but with the piston raised .010” and now the slightly longer stroke of the crank it equaled itself out to mostly stock compression. But it gave me positive compression which is where you get more air/fuel in due to a taller head and it will give you better flow and efficiency which leads to better burn and more power. All said and done I think I had around $900 total in the build. But it was a power house. Now all this was done on a pressure lubed engine and not a oil slinger engine. It carried #50 lbs of oil pressure at idle and nearly 80 at speeds. I’ve built a couple of slinger engines and even with oil mods they didn’t hold up.
@@haulngrassracing thank you .. mine in a slinger engine .. I suppose I will run it till its cooked the way I have it ... start with putting together a better base engine while I'm running this old one
am not sure if your still around these days../on the forum but should definitely get in contact with me. been reading alot of roosters old forums and mowbandits forums and i have a million questions i feel only you or any of the other guys can answer and rooster hasnt been around since 2014 by the looks of it
slinger engines dont hold up... to mower racing? the top rod suffers from oil starvation... especially at low speeds. i rebuilt my 18 hp oppy with new top rod, the old top rod was egg shaped and wud hang on its way around the crank. new rod didnt hang and spun freely around the crankshaft. got it together, started... after new coil and different carb that had water in it that rusted the brass float in the carb that made it leak and spew gas out the top of n the carb... . still KNOCKS BIG TIME (SIGH) even with 15-40/20-50 oil and 20% STP OIL TREATMENT that makes the oil THICK THICK THICK. oh well, run it on test stand for a few hours, change the oil, NO SYNTHETIC!!! 15-40/20-50 with STP oil treatment and wear hearing protection so cant hear the rod KNOCKING. i read somewhere that OPPY's splash lubrication like more rod clearance than .002-.003" ... more like .005" so i sanded the rod big ends with 1500 grit sandpaper ... a little bit. to get more oil clearance... well... i GOT MORE MORE OIL CLEARANCE now. its ok, for $ invested $60 or so just to get it to run is ok with me. compression... 80 PSI... not too good. exhaust temps are 100*+ different... head temps abt the same temp difference? so ... one cyl isnt doing too well. the exhaust temp fluxuates quite a bit/misfire? putting .010" rings on cyl that had .015 gap tween piston skirt and cyl... even had to file fit the rings to get them not to butt up . i put .015" ring end gap... might have been a little much... someone said .010" is plenty of ring gap. the online piston ring mfg's stated .0045" for each diameter of piston... piston is 3.4545" or whatever so that times .0045 = .016"
Wow it sounds like you had a heck of a time. Lol. Slinger engines are fine for racing but do require a lot of oil modifications. The looser the clearances the happier the engine is. Which is the down fall because that will make the engine wear much quicker. Back when I was still racing it wasn’t uncommon to rebuild a slinger engine mid through the season (20 race season). Or have a few built up to change out of one engine let’s go.
I have a head for an 11hp single cylinder flat head and I was going to shave it now after seeing this should I even bother or what should I do to the head input is much appreciated
Man this is awesome im building one for my lawn mower. mines a non pressureized motor. just trying to make it run better. the carb thing you did im currently work on. basically matching what you have done.
Florian, yes you can use the billet rods on a horizontal opposed twin.
You never want to shave a flat head heads down. Just tape a big sheet of sandpaper to a flat surface and rub the head on it to make sure the gasket surfaces are flat. Shaving a flat head engine will make it run hotter and it will not flow and when you lose flow you have less power. Do small porting to get rid of the roughness and sharp edges in the ports and dont mill the heads more then just making sure they are flat. You need static compression (flow)
I have a head for an 11hp single cylinder flat head and I was going to shave it now after seeing this should I even bother or what should I do to the head input is much appreciated
Where you get your rods? I been hunting for two years to find rods like that
Old School Repair Shop They are ARC billet rods I got from www.arcracing.com/6304-arc-billet-rod-briggs-boxer-mod-46-v-4-87x-801/
you should leave links to your racing parts
Where did you buy the Pistons and rods?
I have a question about the billet flywheel:
Does it have the magnets for the stator? To charge the battery.
Can I use the billet rods on a horizontally briggs opposed twin?
What AVS pistons did you use?
For the briggs stratton mod 28 or 31?
I know it's 5 years late anyway
depends on bore size model 28 avs is for 3.44" bore and model 31 avs would be for bigger bore later year 01/09 and later model 46 opposed twin briggs
How do you adjust the valves?
th-cam.com/video/xCFpeJcTMs4/w-d-xo.html same principal just double the cylinders. If the gap is too big the valve will need to be ground on a valve machine and the valve seat will need to be hit with a valve seat stone.
On the fly wheel there is no magnets for that stator. If you run a billet flywheel you have to remove the charging system because there won't be any room for the stator
@NuBz keep a charger near by lol make sure you run LEDs
I was wondering if you might could tell me how to time a model 46 back to factory, or possible one tooth advanced? I've looked everywhere online and haven't had a whole lot of luck finding any information.... thanks!
theres really nothing to time. once tou line up the dots on the cam and crank and put the flywheel on the crank with the key in place you should be out of time. you can try an offset key on the flywheel but if your looking for performance you wont feel it by the seat of your pants with a offset key. whats causing an issue?
you shouldnt be out of time that is
So, dot to dot no matter what? Was told by a friend that going one tooth clockwise on the cam from dot to dot will help it spin up quicker... Thoughts?
+Ivy Byers not likely to do anything really beside advancing it too far. unless you have a ton of money in it and have it full built but if you were doing that then you wouldnt be using a factory cam. being stock theres not really a whole lot you can do to get gobs of power out of it. you may get 1 or 2 horsepower by doing a bunch of stuff but you wont feel much power. best thing to do for a stock engine is better flow. clean up the ports a little and try a bigger carb. without spending $$ it hard to get a noticeable power increase
+Haul'N Grass Alright, thanks for the advice! Much appreciated.
Who can do this?
I'm curious about the power or rpm gains that u receive from doing this build ..
Matt Yarolem around 10 extra hp and it was happy around 5500-6000 before the cam couldn’t keep up and the valves floated. Low end power was great coming out of the corners
@@haulngrassracing pretty decent rev and hp gain.. if u dont mind me asking what do u have into the parts for cash
Doing one right now
Matt Yarolem the cam was a stock cam that was modified by an old Harley Davidson mechanic and was $50. I can’t remember how much the stock 46 rods were but I want to say around $100. The pistons were stock AVS pistons for single cylinder OHV briggs engines so they weren’t very much either. The springs came out of a vTwin briggs and I had them laying around from my vTwin build. I believe the biggest cost was the billet flywheel and it was $300-$350. I had the crank stroked .010” for $75 which gave the piston zero deck height at TDC. I used 40 ci oppy heads because they had the raised landing around the combustion side which lowered the compression but with the piston raised .010” and now the slightly longer stroke of the crank it equaled itself out to mostly stock compression. But it gave me positive compression which is where you get more air/fuel in due to a taller head and it will give you better flow and efficiency which leads to better burn and more power. All said and done I think I had around $900 total in the build. But it was a power house. Now all this was done on a pressure lubed engine and not a oil slinger engine. It carried #50 lbs of oil pressure at idle and nearly 80 at speeds. I’ve built a couple of slinger engines and even with oil mods they didn’t hold up.
@@haulngrassracing thank you .. mine in a slinger engine .. I suppose I will run it till its cooked the way I have it ... start with putting together a better base engine while I'm running this old one
Hola que buenos días tengo el mismo motor y no sé cómo puedo rebularle válvulas algien me puede ayudar o informar ...muchas gracias
I’m sorry I don’t speak Spanish and it won’t let me translate it.
Ok .how can i regulate the Valves of the brissg stratton 16hp saw cylindrical
If you are getting valve float at high rpm you need to go with stiffer valve springs.
where do u get your aftermarket parts for your racing engines
Thank u for that if I have any questions I will message you than u again
+thespeeddemon2 no problem bud
@EvanHartley I got both from www.eccarburetors.com
Florian Mittermaier, im running 28 CI pistons
am not sure if your still around these days../on the forum but should definitely get in contact with me. been reading alot of roosters old forums and mowbandits forums and i have a million questions i feel only you or any of the other guys can answer and rooster hasnt been around since 2014 by the looks of it
Shoot me an email at Haulngrassracing@gmail.com
I got a 18hp opposed vtwin for sale. It's a side shaft. In North east AL
thanks i got one
OICU812???
slinger engines dont hold up... to mower racing? the top rod suffers from oil starvation... especially at low speeds. i rebuilt my 18 hp oppy with new top rod, the old top rod was egg shaped and wud hang on its way around the crank. new rod didnt hang and spun freely around the crankshaft. got it together, started... after new coil and different carb that had water in it that rusted the brass float in the carb that made it leak and spew gas out the top of n the carb... .
still KNOCKS BIG TIME (SIGH) even with 15-40/20-50 oil and 20% STP OIL TREATMENT that makes the oil THICK THICK THICK. oh well, run it on test stand for a few hours, change the oil, NO SYNTHETIC!!! 15-40/20-50 with STP oil treatment and wear hearing protection so cant hear the rod KNOCKING.
i read somewhere that OPPY's splash lubrication like more rod clearance than .002-.003" ... more like .005" so i sanded the rod big ends with 1500 grit sandpaper ... a little bit. to get more oil clearance...
well... i GOT MORE MORE OIL CLEARANCE now. its ok, for $ invested $60 or so just to get it to run is ok with me. compression... 80 PSI... not too good. exhaust temps are 100*+ different... head temps abt the same temp difference? so ... one cyl isnt doing too well. the exhaust temp fluxuates quite a bit/misfire? putting .010" rings on cyl that had .015 gap tween piston skirt and cyl... even had to file fit the rings to get them not to butt up .
i put .015" ring end gap... might have been a little much... someone said .010" is plenty of ring gap. the online piston ring mfg's stated .0045" for each diameter of piston... piston is 3.4545" or whatever so that times .0045 = .016"
Wow it sounds like you had a heck of a time. Lol. Slinger engines are fine for racing but do require a lot of oil modifications. The looser the clearances the happier the engine is. Which is the down fall because that will make the engine wear much quicker. Back when I was still racing it wasn’t uncommon to rebuild a slinger engine mid through the season (20 race season). Or have a few built up to change out of one engine let’s go.
I have a head for an 11hp single cylinder flat head and I was going to shave it now after seeing this should I even bother or what should I do to the head input is much appreciated