You need to remember also that top rod bearing needs to be oiled so you need to idle your machine a minimum of 1800 I Idlemoore in around 2000 RPM, so like I said my 14 horse is 38 years old almost and it doesn’t have that run-of-the-mill knock that you usually get with these motors. Keep the idle rpm way up brother
I agree with that, I've got a model 42 from the early 90s and the oil has been changed every 25 hours and I have no issues. Most of the wear like that comes with extended oil changes. I do agree with the sorry oiling system they would have been significantly better with pressure lube system
The consensus I came to after doing some research is that the 40 and 42 cid engines from 12.5 to 19 (or is it 19.5) last a very long time, regardless of the vertical shaft issue you mention. When they moved to the long stroke on the 46 cid and went to 20+ hp, that's when reliability took a nose dive. I have two 80s 12.5hp verticals which I believe to be all original (just splash lube) and picked up a very clean ~93 18hp (so 42 cid) also vertical. I don't know about "they like to throw rods" when I have two 35 year old original vertical shaft opposed twins that run great.
vertical do last long time all the apposed twins are around 20 years old. Most vertical shaft twins don't last as long as horizontal shafts at least till pressure lube was added to them. They'll run with knock for years anyway😉
I agree Kevin I have a 16 hp running my "46 in White tractor, and just picked up an 18 hp on a "46 Noma. White motor was a transplant and was built in the the 80's the bigger 18 is a 92 model and I have had no problems with these great motors past a bit of surgeing on both at lower idle and when their not under load which is a common thing in these guys. Both motors still have over 100 compression not bad for such old motors. Oil changes after 25 hours or at least once a season helps the longevity obviously.
@@RFKFANTS67 Last time I had that I unscrewed the fuel shutoff solenoid and blasted the main jet a few times with compressed air. I know it's not the idle circuit but it seemed to make a noticable difference.
Bought a Murray in 2000. Still runs strong and no leaks or smoke But, I check my oil every time and top it off even if it's just a glug or two. Have a horizontal 18hp and put it in a golf cart. Seems that lubrication is the issue..... check and change the OIL
I love these motors, I found 3 of them for free, I pulled from 3 MTD mowers, all cast iron sleeves, I was thinking on putting in some of the marvel mystery oil to help with the lack of oil,
There was never a apposed bilt that was full pressure lube but when briggs designed this motor they incorporated everything you would need to do it yourself tho
These engines are a huge pain in the ass. I love em. Every tractor I have besides one(it has a kohler v twin) has an oppy, even my little Snapper RER. The trick is to not overheat them and keep oil in them. Or be like me and hoard every pressure lube oppy you can find. My most prized oppy is an 18hp pressure lube horizontal twin i picked up for $50.
I like the horizontal shafts never new they had pressure lube available for them, thats neat. Hope to build big displacement opposed twin briggs monster some day😉
@@overbuiltautomotive1299 old Wisconsin engine had piston pump driven by cam lobe squirting oil ontop of the connecting rods and to governor gears could try diaphragm pump or electric pump to get more oil to upper half of the block. Not sure if theres a nipple you can utilize if you have to drill and tap a hole be sure no metal chips are left in the crankcase afterwards
The way the Carburetor is built is also genius, love my Briggs, mines are 30 plus year old machines still working. anyway my neighbor thought his 2022 green sit down mower is cool in which they are, but my cast iron IC Briggs and Stratton sounds better than than most engines they are making at the moment, and more like Steel beats Aluminum anytime. your vids are so helpful, thanks for posting.
my 1986 40 ci splash lube still runs like the day it was new.by 2020 every seal & gasket leaked so when i replaced them i plastigauged the rods for curiosity.both .003 after 34 years of summer mowing & winter driveway plowing.all i do is change oil in the spring every year & keep clean air filter on it.it will most likely still be fine when im dead from old age.they are torquey & dont need high rpms to function properly.
Looks like all these opposed engine are evenly firing engine. This is a huge advantage, and is part of longevity. V-twin engines, (most that I have seen), all seem to use the same crank journal, which mean uneven firing. Why did Briggs not have a pressurize oiling system ? Engine would have lasted forever. What is needed is a way to pre lube the crank before start up.
They did have optional pressure lube in later years of production I believe they were I/C PLUS The opposed twin engine was cheaper to manufacture than OHV engine but they couldn't pass emmisions being a flathead that would burn oil so the opposed twin was discontinued. Thankfully Vanguard filled the space for long lasting engines. As for the shared crank journal it's to keep weight and cost down otherwise you'd have to add a balance shaft and twice as much machine work for a crank and second balance shaft to fit inside the engine. P.S. The vertical shaft engines are fine with an extea 1/2 qrt oil which helps lubrication the horizontal shaft engines fare really well so long as oil is changed regularly
Im using one and its 1982 on a Montgomery ward garden tractor I keep oil and air filter clean and I run rotella diesel oil also I now use it to move boats and seadoos around at my shop no issues st all ever other than carb cleaning. I have also had better luck on junk gocart engines running suzuki and yamaha motorcycle oil. both these oils are for extreme heat and use engines
There is a casting on most 46 blocks running up the outside heading towards the top bearing and in the general vicinity of the top of the cam shaft. Soooo if u take ur cam and drill a hole top to bottom and connect the top of the block to the bottom u end up being completely pressure lube
I hear a lot about that these Motors blow up, I have a 1985 14 horse It’s been in my family for 37 years, it doesn’t knock tick or bang Runs perfect, original carburetor original everything never changed any gaskets on it. The only gasket I changed was this year on the fuel pump I replaced all the gaskets because I didn’t want it leaking into my oil. I guess I’m one of the lucky ones
They're great engines not all engines have the same amount of use or care lot of people don't check the oil unfortunately. I had an 18.5 hp that burned oil always kept it full wond up loosing a rod knocked for a long time that is an engine I got for free had a known oil leak prior to me owning it and fixing it and may have been run low on oil at some point may have had something to do with me mowing on steep hills as well none the less it had a hard life.
@@willyck948 Mine is always on level ground, i use mine just to push snow I only wait until it is 3 to 4 inches I don’t want to push the engine, before me the first 30 years of life it’s just mowed my dad’s backyard maybe twice a year it doesn’t have too many hours on it . It’s a small half acre field behind his house I guess it gave him something to do
I think these engines hold up better than the new ones, with the compression release on the cam! If you change the oil in these , they will hold up.....
Hi! I need an advice since I got an opposite 18hp and I can't remember how I should assembly back the intake valve, the order of oil stem spring and retainer. Plus I need to know how bad can be that I made a govenor delete, since I can't assembly it back cause the thread for the pin(retainer) is shredded so needs I fresh thread to keep the governor assembly. Thank you in advance.
These flatheads don't rev high without modification so its kind of hard to over speed one to the point of failure if engine is under load. Model 40 would hold up better without governor as they're shorter stroke puts less strain on the rods. As for valves thetes a few styles older ones with pins but the rule of thumb is a shim againt the block, spring, valve, then retainer. I recommend 2 flathead screw drivers to install the retainer once done be sure to clean any burs off the gasket surface. As for keeping the valve closed, you can put rope into the cylinder between the valve and head before installing the headgasket.
I got a 16 hp opposed twin horizontal shaft on a 1979 Sears Roper tractor, I have a mid 90s briggs 20 hp vertical shaft that is blown up, is it possible to convert the 20 horse to a horizontal shaft for the Roper tractor? Or are the years just too far apart. There really is nothing wrong with the 16 hp but I thought it would be nice to upgrade it to a 20 horse tractor. I use it to pull plows and a dozer blade.
the 20hp crank makes up the difference in displacement with longer stroke The heads on the 20hp have better flowing chambers as well. As for adapting vertical shaft to horizontal its a pretty involved process especially if the 20hp has lost a rod the crank bearings surfaces would need to be machine for new shorter 20hp connecting rods or buy the 18hp Connecting rods with pistons and shave the pistons to clear the head. The crank would need to be shortened to fit horizontal application as well. Next issue is clearencing the block for the longer stroke and adding oil dippers to pick up the oil for lubrication. About as complicated a process as converting SB chevy 350 to a 383 cost about the same too minus 6 rods and 6 pistons
Interesting about how they mill the blocks out more is all for the longer stroke. Any other differences for the parts? Will have to look up the parts numbers to see the differences besides the crank shafts and cranks I'm assuming?
Great video! I love these engines. I'm planning on converting one to work horizontally for a kickass gokart, it should have about 40hp by the time I'm done with it.
theres a lot to be had out of the opposed twins theres a guy on TH-cam Twisted that runs one in lawnmower racing up against built 44 c.i. intecs. opposed vtwin has powder at low end wile vtwins need to get rpms up to make power at high end.
Lot of variables depending on the engine and application as to whats over full and if that can lead to issues. Over filling dip lube opposed twin with oil can cause oil to spit out the vent tubes to the air filter nothing harmful to the longevity of the engine, oil can saturate the air filter, maybe oil foaming can become an issue but a better oil would negate the excess aeration. More oil is better than low oil😉 As for other reasons for oil to push out the vents is blow by or bad check valves in the breathers. Ive seen a few broken breather check valves over the years lead to excess oil consumption as well. If you remove a valve cover you'll see pieces of the disc sitting in the valve galley if the check valve brakes.
Wondering if using some molybdenum or tungsten disulfide on those bearing surfaces before assembly, if that would impregnate into the surface and help over the long run? Wondering if there is some other surface treatment or anyone makes a better material connecting rod like for the racers? Thanks for sharing! Subscribed, liked and commented.
I am currently in the process of trying to change the valve guides on the intake valve cuz what was a completely sealed stroke is now leaking compression back through the carburetor the valve is not tight so the seat is not sealed anymore
@@danny88dh I haven't had to replace a valve guide on an oppy yet I'd imagine they're pressed in like the Vanguard engines. Have you checked the tappet clearance?
@@willyck948 the tappets are custom so they are longer than original when I built my engine I welded on the ends of them to make them longer so the valves would open farther this Said motor is strokedand bored to 31 ci cylinders it has a 42 crank and bullet rods with 31 ci pistons that are decked the pistons still come out of the block at TDC it has around 140 lbs of compression on each cylinder
yup pressure lube would require more mods splash lube engines at least need dip rods added to the Connecting rods. It's a good idea to drill a hole for oil to flow from the crankcase to the valve valleys. Be sure to wash out all the metal shavings before assembly.
@@micahwagner4154 I plan on doing a similar conversion will try to put a video together of the build. It'd going to be a while as I have projects ahead of it yet.
@@willyck948 Please do!! I'm currently rebuilding a 42 series for a go-kart and would really like to convert it to a horizontal shaft, but have no idea where to even start with the modifications and can't find any resources to guide me.
@@tularem That's what got me watching some videos again... rehashing my 42 & 46 projects since last season finally got another horizontal shaft parts engine that was good, other than missing some parts on the top end. Mainly wanted the crankcase covers and sump so can eventually 3D scan at the local fab lab or maybe do an open source photogrammetry so have a CAD file for 3D printing eventually to do a lost PLA or whatever casting... thinking using aluminum wheel rim alloy while at it... though I do have a few old blown blocks that could be melted down to use.
It takes a little bit of work but it is completely possible to make a 46 cube oppy make around 90 hp, and maintain running around 8000 rpms at full throttle and love every second of it
Appreciate you sharing. I have an 18hp twin opposed. Would you suggest using any type of additive or even adding a little extra oil? I am using SAE HD 30 but open to suggestions. Given its from 1993 and I live in Florida…perhaps full synthetic 5w30? Thanks
vertical shaft would benefit from extra oil keep in mind the oil could push out the vent and to the air filter. oil down the intake won't hurt anything just plug up the filter and the exhaust will push alot of smoke.
@@willyck948 Hey thanks for replying so quickly…I’ll certainly keep those things in mind. Also one more question. Given your experience with these, are you aware of if an oil filter is applicable on my 18hp twin opposed? I ask as I saw someone sharing a 20hp twin opposed one that operated with a filter. Thanks again for the tips.
Lol i’m back. I watched the video again, saw at min 4:02 you mentioned how it probably sat for a long time and the owner just fired it up (without tilting or ensuring the oil got moved around). I assume using a floor jack to lift front and back or side to side? What is your method of ensuring oil is moved around before turning it over? Thanks for answering these redundant questions.
@@Sheeeeeeeeeeeeiiitt If an engine has been sitting over a year best to shoot fogging oil into the cylinder before starting. If an engine has been sitting 5+ years its best to check the sump for sludge or water. You can drain old oil out to check or remove a sump cover. Once clean just flip the assembled engine cam side down maybe pump oil into the crank case while sump cover is off replacing and gaskets as needed. If an engine was rebuilt you can still flip the engine cam side down to get oil everywhere or pump oil onto everything while sump is off. Vertical shaft engines would be easier to flip cam side/ carb side down just need to remove the air filter first so you don't bend it briggs are usually bolted down with 4 bolts can jack up a frame high enough. Just cranking the engine without plugs for 20 seconds then letting it sit a few minutes would help sling oil around to lube the crank and cam.
i am using billet rods and a oil mod or two A++ video yep they need a good high end oil and zinc added i been using diesel oil synthetic and a bit of oil in gas never hurts 50:1 or so n a bit of a jet size increases on some
@@danharold3087 only in my rx7 rotary and in my go karts atv soom times if plan on being hard on it heck i figure it can not hurt i would on opposed twins with piston oiling issues easy to clean carbon rather that boring out rebuilding( synthetic thinner) 15w40 diesel oil i use in compressors and engines
so what happens when you set a piston up in cylinder with say 3 thou piston to cylinder clearance then the 2cyl oil builds up 2 thou carbon and piston swells to temp on your piston engines. 2 stroke company's call his flacking and causes scratching in cylinder walls. Evinrude mercury yamaha sell decarbon spray to remedy this issue and to be used once a year. But customers seldom know about it or use it. I too agree and use diesel oil Rotella
@@dgc940 yep i clean out heads it does aggravate with carbon .i most do the oil in gas with ATV as i start and stop engine a lot short tripping it to death ye know
@@dgc940 allways cleaning heads a bit all ways a trade off .i run lucas fuel injector cleaner as i tested it in a s10 that set fer a few years running ruff and darn it if it did not fix the junker thing just thought i throw that it fer fun.i mostly run 2 stroke in stuff that i short trip like my ATV never run it long
I just got a pressure lube 20.5 I/C for 150$ vertical shaft. Been looking for a 46 for awhile. I’m going to pull the heads and inspect the valves. My lower cylinder seems to be very black inside and fouling plugs. I’m guessing it needs rings or valves need reseating . I pulled the lower cylinder plug and it was just covered In oily carbon and the gap was bridged with trash. My upper cylinder is in good condition.
If cylinder looks good, I'd check the breather assembly. The disc valve in the breather can break and allow crankcase oil to push up to the intake. Kind of hard to check ring gap on them, but I have seen horizontal rings worn out before.
@@willyck948 I took the breather apart and cleaned it and I am rebuilding it and the disc appears to be ok thru the main hole on the outside looking in and I found no broken pieces. Just dirty sponge Brillo pad. I am installing a new Brillo pad. I noticed that the brown plastic doesn’t move much at all. I would think it should open and close when pressed like a spring door but it’s dam near solid. I did adjust the flat metal spring so the plastic door moves open now. Maybe I’m wrong here maybe the plastic door is supposed to be closed with force ?
@@willyck948 so it’s supposed to move then ? Is it supposed to move a large amount or a small amount ? Like it barely moves enough to slide a dime in between the disc and breather. I bent tte metal tab slightly to allow the disc to open more like now I can fit 2 quarters in between the disc and metal
@pontiachotshot Good question, I haven't peeled one open to investigate the design to know how it's supposed to function exactly. I've only ever replaced broken ones. Kohler k241-k361 breathers I've had to fix before as the spring would loose tension and the filter would plug up with dirt or even deteriorate.
@@jojojeep1 I was wondering about assembling with a thin coat of molybdenum or tungsten disulfide that might impregnate into the surface to help with the long haul? I know there are methods to do that otherwise and the more I'm thinking maybe the engine conditions aren't extreme enough to actually do that without eventually rinsing away.
All lawn mower engines suffer from overheating due to the cooking fins becoming obstructed with debris. With a simple shroud removal and a good blast of compressed air these engines live a very long time. Heat and lack of maintenance will kill any engine.
hard to say as traditional small engine service shops will not work on older engines. You'd have to call around to a machine shop that can rebuild it. They'd only want the block and probably won't be able to get an estimate together before Dissassembly, some parts may be hard to find if not available from dealer.
I'm here because my 20hp 2000 model puked 2 rods. Top broke on the camshaft, has aluminum transfer. bottom snapped the rod. Not sure if repairable. What a mess.
As far as the oppose twin design being a bad design BMW has been using it on their motorcycles for over 50 years and I see them with over 500,000 miles on them so maybe you should back up and punt on that comment and I also have a 17 1/2 hp Briggs oppose twin that’s been working hard for over 25 years and still runs great
@Lowpass76 There's a few factors that can cause or negate the rod failure. I run amsoil small engine oil as its designed for high heat splash lube engines. Id doesn't cook off and has anti foam adjents in it. Another thing you can try is ARC billet rods you can replace bearings on them probably softer on the crank as well granted they're not available under size so if the crank is out of spec it'll need to be welded
These old engines are FAR better than anything made today.
They're great engines especially horizontal shafts.
Vanguard are still made pretty good.
They are still junk.. They should have an oil pump.
You need to remember also that top rod bearing needs to be oiled so you need to idle your machine a minimum of 1800 I Idlemoore in around 2000 RPM, so like I said my 14 horse is 38 years old almost and it doesn’t have that run-of-the-mill knock that you usually get with these motors. Keep the idle rpm way up brother
I agree with that, I've got a model 42 from the early 90s and the oil has been changed every 25 hours and I have no issues. Most of the wear like that comes with extended oil changes. I do agree with the sorry oiling system they would have been significantly better with pressure lube system
@@calholli They are by no means junk
The consensus I came to after doing some research is that the 40 and 42 cid engines from 12.5 to 19 (or is it 19.5) last a very long time, regardless of the vertical shaft issue you mention. When they moved to the long stroke on the 46 cid and went to 20+ hp, that's when reliability took a nose dive. I have two 80s 12.5hp verticals which I believe to be all original (just splash lube) and picked up a very clean ~93 18hp (so 42 cid) also vertical. I don't know about "they like to throw rods" when I have two 35 year old original vertical shaft opposed twins that run great.
vertical do last long time all the apposed twins are around 20 years old.
Most vertical shaft twins don't last as long as horizontal shafts at least till pressure lube was added to them. They'll run with knock for years anyway😉
I agree Kevin I have a 16 hp running my "46 in White tractor, and just picked up an 18 hp on a "46 Noma. White motor was a transplant and was built in the the 80's the bigger 18 is a 92 model and I have had no problems with these great motors past a bit of surgeing on both at lower idle and when their not under load which is a common thing in these guys. Both motors still have over 100 compression not bad for such old motors. Oil changes after 25 hours or at least once a season helps the longevity obviously.
@@RFKFANTS67 Last time I had that I unscrewed the fuel shutoff solenoid and blasted the main jet a few times with compressed air. I know it's not the idle circuit but it seemed to make a noticable difference.
Bought a Murray in 2000. Still runs strong and no leaks or smoke
But, I check my oil every time and top it off even if it's just a glug or two. Have a horizontal 18hp and put it in a golf cart. Seems that lubrication is the issue..... check and change the OIL
I love these motors, I found 3 of them for free, I pulled from 3 MTD mowers, all cast iron sleeves, I was thinking on putting in some of the marvel mystery oil to help with the lack of oil,
Can try talking to an oil expert see what they'd suggest.
Probably a thicker oil would help,
Pressure lube was a big design improvement.
i use a little bit of stp oil treatment in all my go kart and mower engines.
Great video.
The I/C Plus engines have a full- flow oil system , with an oil pump and oil filter. Great engine.
I/C stands for Industrial Commercial indecating Cast iron cylinder sleeves nothing specific on pressure lube that I know of.
Thanks for the reply I did look it up thats neat
There was never a apposed bilt that was full pressure lube but when briggs designed this motor they incorporated everything you would need to do it yourself tho
Have 4 of these opposed engines. The 20 hp I have is full pressure lube with oil filter.
@@danny88dh I have a 14hp on a Bolens model 400437 that is pressure lubed
These engines are a huge pain in the ass. I love em. Every tractor I have besides one(it has a kohler v twin) has an oppy, even my little Snapper RER.
The trick is to not overheat them and keep oil in them. Or be like me and hoard every pressure lube oppy you can find. My most prized oppy is an 18hp pressure lube horizontal twin i picked up for $50.
I like the horizontal shafts never new they had pressure lube available for them, thats neat.
Hope to build big displacement opposed twin briggs monster some day😉
How do you ID the pressure lube versions?
@@wansolve2036 pressure lube will have a filter boss on the block
@@willyck948 i like one can get rods billet ones nice still learning about thesee i am thing of a oil feed on top via diy jets and a vane pump
@@overbuiltautomotive1299
old Wisconsin engine had piston pump driven by cam lobe squirting oil ontop of the connecting rods and to governor gears could try diaphragm pump or electric pump to get more oil to upper half of the block.
Not sure if theres a nipple you can utilize if you have to drill and tap a hole be sure no metal chips are left in the crankcase afterwards
The way the Carburetor is built is also genius, love my Briggs, mines are 30 plus year old machines still working. anyway my neighbor thought his 2022 green sit down mower is cool in which they are, but my cast iron IC Briggs and Stratton sounds better than than most engines they are making at the moment, and more like Steel beats Aluminum anytime. your vids are so helpful, thanks for posting.
your welcome
my 1986 40 ci splash lube still runs like the day it was new.by 2020 every seal & gasket leaked so when i replaced them i plastigauged the rods for curiosity.both .003 after 34 years of summer mowing & winter driveway plowing.all i do is change oil in the spring every year & keep clean air filter on it.it will most likely still be fine when im dead from old age.they are torquey & dont need high rpms to function properly.
Looks like all these opposed engine are evenly firing engine. This is a huge advantage, and is part of longevity. V-twin engines, (most that I have seen), all seem to use the same crank journal, which mean uneven firing. Why did Briggs not have a pressurize oiling system ? Engine would have lasted forever. What is needed is a way to pre lube the crank before start up.
They did have optional pressure lube in later years of production I believe they were
I/C PLUS
The opposed twin engine was cheaper to manufacture than OHV engine but they couldn't pass emmisions being a flathead that would burn oil so the opposed twin was discontinued.
Thankfully Vanguard filled the space for long lasting engines.
As for the shared crank journal it's to keep weight and cost down otherwise you'd have to add a balance shaft and twice as much machine work for a crank and second balance shaft to fit inside the engine.
P.S. The vertical shaft engines are fine with an extea 1/2 qrt oil which helps lubrication the horizontal shaft engines fare really well so long as oil is changed regularly
Im using one and its 1982 on a Montgomery ward garden tractor I keep oil and air filter clean and I run rotella diesel oil also I now use it to move boats and seadoos around at my shop no issues st all ever other than carb cleaning. I have also had better luck on junk gocart engines running suzuki and yamaha motorcycle oil. both these oils are for extreme heat and use engines
There is a casting on most 46 blocks running up the outside heading towards the top bearing and in the general vicinity of the top of the cam shaft. Soooo if u take ur cam and drill a hole top to bottom and connect the top of the block to the bottom u end up being completely pressure lube
Going to convert in to horizontal shaft dip lube. I don't have the parts for a pressure lube
I hear a lot about that these Motors blow up, I have a 1985 14 horse
It’s been in my family for 37 years, it doesn’t knock tick or bang Runs perfect, original carburetor original everything never changed any gaskets on it. The only gasket I changed was this year on the fuel pump I replaced all the gaskets because I didn’t want it leaking into my oil. I guess I’m one of the lucky ones
They're great engines not all engines have the same amount of use or care lot of people don't check the oil unfortunately.
I had an 18.5 hp that burned oil always kept it full wond up loosing a rod knocked for a long time that is an engine I got for free had a known oil leak prior to me owning it and fixing it and may have been run low on oil at some point may have had something to do with me mowing on steep hills as well none the less it had a hard life.
@@willyck948 Mine is always on level ground, i use mine just to push snow I only wait until it is 3 to 4 inches I don’t want to push the engine, before me the first 30 years of life it’s just mowed my dad’s backyard maybe twice a year it doesn’t have too many hours on it . It’s a small half acre field behind his house I guess it gave him something to do
I think these engines hold up better than the new ones, with the compression release on the cam! If you change the oil in these , they will hold up.....
Hi! I need an advice since I got an opposite 18hp and I can't remember how I should assembly back the intake valve, the order of oil stem spring and retainer. Plus I need to know how bad can be that I made a govenor delete, since I can't assembly it back cause the thread for the pin(retainer) is shredded so needs I fresh thread to keep the governor assembly. Thank you in advance.
These flatheads don't rev high without modification so its kind of hard to over speed one to the point of failure if engine is under load.
Model 40 would hold up better without governor as they're shorter stroke puts less strain on the rods.
As for valves thetes a few styles older ones with pins but the rule of thumb is a shim againt the block, spring, valve, then retainer.
I recommend 2 flathead screw drivers to install the retainer once done be sure to clean any burs off the gasket surface.
As for keeping the valve closed, you can put rope into the cylinder between the valve and head before installing the headgasket.
I got a 16 hp opposed twin horizontal shaft on a 1979 Sears Roper tractor, I have a mid 90s briggs 20 hp vertical shaft that is blown up, is it possible to convert the 20 horse to a horizontal shaft for the Roper tractor? Or are the years just too far apart. There really is nothing wrong with the 16 hp but I thought it would be nice to upgrade it to a 20 horse tractor. I use it to pull plows and a dozer blade.
the 20hp crank makes up the difference in displacement with longer stroke
The heads on the 20hp have better flowing chambers as well.
As for adapting vertical shaft to horizontal its a pretty involved process especially if the 20hp has lost a rod the crank bearings surfaces would need to be machine for new shorter 20hp connecting rods or buy the 18hp Connecting rods with pistons and shave the pistons to clear the head.
The crank would need to be shortened to fit horizontal application as well.
Next issue is clearencing the block for the longer stroke and adding oil dippers to pick up the oil for lubrication.
About as complicated a process as converting SB chevy 350 to a 383 cost about the same too minus 6 rods and 6 pistons
Interesting about how they mill the blocks out more is all for the longer stroke. Any other differences for the parts? Will have to look up the parts numbers to see the differences besides the crank shafts and cranks I'm assuming?
lot of variables to sift threw not very much to compare to as all different pto side dimensions of the crank have different part numbers
With a pressure lube base u have instant oil to th bottom of the motor but what about the top
Great video! I love these engines. I'm planning on converting one to work horizontally for a kickass gokart, it should have about 40hp by the time I'm done with it.
theres a lot to be had out of the opposed twins theres a guy on TH-cam Twisted that runs one in lawnmower racing up against built 44 c.i. intecs. opposed vtwin has powder at low end wile vtwins need to get rpms up to make power at high end.
th-cam.com/video/yI_1R2_a7vY/w-d-xo.html
Twisted R channel
If you over fill them would that cause it to not throw oil up ?
Lot of variables depending on the engine and application as to whats over full and if that can lead to issues.
Over filling dip lube opposed twin with oil can cause oil to spit out the vent tubes to the air filter nothing harmful to the longevity of the engine, oil can saturate the air filter, maybe oil foaming can become an issue but a better oil would negate the excess aeration.
More oil is better than low oil😉
As for other reasons for oil to push out the vents is blow by or bad check valves in the breathers.
Ive seen a few broken breather check valves over the years lead to excess oil consumption
as well. If you remove a valve cover you'll see pieces of the disc sitting in the valve galley if the check valve brakes.
Wondering if using some molybdenum or tungsten disulfide on those bearing surfaces before assembly, if that would impregnate into the surface and help over the long run? Wondering if there is some other surface treatment or anyone makes a better material connecting rod like for the racers? Thanks for sharing! Subscribed, liked and commented.
ARC racing had billet rods with replaceable bearings for standard size crank jurnals for opposed twin briggs engines last I checked
Arc! Makes some fantastic products to fit the apposed
I am currently in the process of trying to change the valve guides on the intake valve cuz what was a completely sealed stroke is now leaking compression back through the carburetor the valve is not tight so the seat is not sealed anymore
@@danny88dh I haven't had to replace a valve guide on an oppy yet I'd imagine they're pressed in like the Vanguard engines.
Have you checked the tappet clearance?
@@willyck948 the tappets are custom so they are longer than original when I built my engine I welded on the ends of them to make them longer so the valves would open farther this Said motor is strokedand bored to 31 ci cylinders it has a 42 crank and bullet rods with 31 ci pistons that are decked the pistons still come out of the block at TDC it has around 140 lbs of compression on each cylinder
So I converted a vertical to horizontal, should I be worried about oil getting to the valves on the #2 cylinder?
yup pressure lube would require more mods splash lube engines at least need dip rods added to the Connecting rods.
It's a good idea to drill a hole for oil to flow from the crankcase to the valve valleys.
Be sure to wash out all the metal shavings before assembly.
@@willyck948 ok thanks I guess for now my valves are gonna be manually lubricated until I get my horizontal block bored and I get new valve guides
@@micahwagner4154 I plan on doing a similar conversion will try to put a video together of the build. It'd going to be a while as I have projects ahead of it yet.
@@willyck948 Please do!! I'm currently rebuilding a 42 series for a go-kart and would really like to convert it to a horizontal shaft, but have no idea where to even start with the modifications and can't find any resources to guide me.
@@tularem That's what got me watching some videos again... rehashing my 42 & 46 projects since last season finally got another horizontal shaft parts engine that was good, other than missing some parts on the top end. Mainly wanted the crankcase covers and sump so can eventually 3D scan at the local fab lab or maybe do an open source photogrammetry so have a CAD file for 3D printing eventually to do a lost PLA or whatever casting... thinking using aluminum wheel rim alloy while at it... though I do have a few old blown blocks that could be melted down to use.
I know they have updated versions with full pressure lubrication, I would like to have one of those
not many but they're out there probably more prevalent on the Poulon Pro yard tractors
They never made a completely pressure lube motor but it's not hard to make it that way yourself
You either have lower end pressure lube or nothing
It takes a little bit of work but it is completely possible to make a 46 cube oppy make around 90 hp, and maintain running around 8000 rpms at full throttle and love every second of it
Can you make a full wiring video
Not much wiring on the engine here a video going over some wiring.
th-cam.com/video/g97i06hSS54/w-d-xo.html
Appreciate you sharing. I have an 18hp twin opposed. Would you suggest using any type of additive or even adding a little extra oil? I am using SAE HD 30 but open to suggestions. Given its from 1993 and I live in Florida…perhaps full synthetic 5w30? Thanks
vertical shaft would benefit from extra oil keep in mind the oil could push out the vent and to the air filter.
oil down the intake won't hurt anything just plug up the filter and the exhaust will push alot of smoke.
@@willyck948 Hey thanks for replying so quickly…I’ll certainly keep those things in mind.
Also one more question. Given your experience with these, are you aware of if an oil filter is applicable on my 18hp twin opposed? I ask as I saw someone sharing a 20hp twin opposed one that operated with a filter.
Thanks again for the tips.
@@Sheeeeeeeeeeeeiiitt pressure lube opposed twin briggs aren't common but they are out there pressure lube is known as "Plus" option
Lol i’m back. I watched the video again, saw at min 4:02 you mentioned how it probably sat for a long time and the owner just fired it up (without tilting or ensuring the oil got moved around).
I assume using a floor jack to lift front and back or side to side? What is your method of ensuring oil is moved around before turning it over?
Thanks for answering these redundant questions.
@@Sheeeeeeeeeeeeiiitt If an engine has been sitting over a year best to shoot fogging oil into the cylinder before starting.
If an engine has been sitting 5+ years its best to check the sump for sludge or water.
You can drain old oil out to check or remove a sump cover.
Once clean just flip the assembled engine cam side down maybe pump oil into the crank case while sump cover is off replacing and gaskets as needed.
If an engine was rebuilt you can still flip the engine cam side down to get oil everywhere or pump oil onto everything while sump is off.
Vertical shaft engines would be easier to flip cam side/ carb side down just need to remove the air filter first so you don't bend it briggs are usually bolted down with 4 bolts can jack up a frame high enough.
Just cranking the engine without plugs for 20 seconds then letting it sit a few minutes would help sling oil around to lube the crank and cam.
I've learned is they do not like idling because the top cylinder doesn't get enough oil at idle. I never idle mine because of that.
i am using billet rods and a oil mod or two A++ video yep they need a good high end oil and zinc added i been using diesel oil synthetic and a bit of oil in gas never hurts 50:1 or so n a bit of a jet size increases on some
Are you using 2 stroke oil in the gas ?
@@danharold3087 only in my rx7 rotary and in my go karts atv soom times if plan on being hard on it heck i figure it can not hurt i would on opposed twins with piston oiling issues easy to clean carbon rather that boring out rebuilding( synthetic thinner) 15w40 diesel oil i use in compressors and engines
so what happens when you set a piston up in cylinder with say 3 thou piston to cylinder clearance then the 2cyl oil builds up 2 thou carbon and piston swells to temp on your piston engines. 2 stroke company's call his flacking and causes scratching in cylinder walls. Evinrude mercury yamaha sell decarbon spray to remedy this issue and to be used once a year. But customers seldom know about it or use it. I too agree and use diesel oil Rotella
@@dgc940 yep i clean out heads it does aggravate with carbon .i most do the oil in gas with ATV as i start and stop engine a lot short tripping it to death ye know
@@dgc940 allways cleaning heads a bit all ways a trade off .i run lucas fuel injector cleaner as i tested it in a s10 that set fer a few years running ruff and darn it if it did not fix the junker thing just thought i throw that it fer fun.i mostly run 2 stroke in stuff that i short trip like my ATV never run it long
I just got a pressure lube 20.5 I/C for 150$ vertical shaft. Been looking for a 46 for awhile. I’m going to pull the heads and inspect the valves. My lower cylinder seems to be very black inside and fouling plugs. I’m guessing it needs rings or valves need reseating . I pulled the lower cylinder plug and it was just covered In oily carbon and the gap was bridged with trash. My upper cylinder is in good condition.
If cylinder looks good, I'd check the breather assembly.
The disc valve in the breather can break and allow crankcase oil to push up to the intake.
Kind of hard to check ring gap on them, but I have seen horizontal rings worn out before.
@@willyck948 I took the breather apart and cleaned it and I am rebuilding it and the disc appears to be ok thru the main hole on the outside looking in and I found no broken pieces. Just dirty sponge Brillo pad. I am installing a new Brillo pad. I noticed that the brown plastic doesn’t move much at all. I would think it should open and close when pressed like a spring door but it’s dam near solid. I did adjust the flat metal spring so the plastic door moves open now. Maybe I’m wrong here maybe the plastic door is supposed to be closed with force ?
@pontiachotshot disc in the breather is just a check valve.
@@willyck948 so it’s supposed to move then ? Is it supposed to move a large amount or a small amount ? Like it barely moves enough to slide a dime in between the disc and breather. I bent tte metal tab slightly to allow the disc to open more like now I can fit 2 quarters in between the disc and metal
@pontiachotshot Good question, I haven't peeled one open to investigate the design to know how it's supposed to function exactly.
I've only ever replaced broken ones.
Kohler k241-k361 breathers I've had to fix before as the spring would loose tension and the filter would plug up with dirt or even deteriorate.
Maybe run some sort of a Teflon oil like slick 50 or something like that to coat the bearing
Just keep them full with small engine specific oil they'll be fine.
@@willyck948
Willie I change my oil every 5 to 10 hours of use since I’ve had it maybe that’s why mine or knock Ha ha ha
@@jojojeep1 I was wondering about assembling with a thin coat of molybdenum or tungsten disulfide that might impregnate into the surface to help with the long haul? I know there are methods to do that otherwise and the more I'm thinking maybe the engine conditions aren't extreme enough to actually do that without eventually rinsing away.
Can anyone send me a link where I can get piston rings for a 17.5 opposed twin
www.partstree.com/brands/briggs-stratton/
@@willyck948 thank you
@@fearlesspancake9817 your welcome
All lawn mower engines suffer from overheating due to the cooking fins becoming obstructed with debris. With a simple shroud removal and a good blast of compressed air these engines live a very long time. Heat and lack of maintenance will kill any engine.
The model numbers tell u alot about an apposed briggs look into the big bore short stroke model 46 crazy things can be done with that model
I've got both versions of the model 46😉
They only vomit their rods and what not when they starve for oil so what happens when you come across a sump with a oil filter
I've only seen one pressue lube in person, not for sale
I Lucas it.🇺🇸😀👍
How about running it at around 8 grand running c16 race fuel making around 90 horse power gonna have to stroke it and put bigger pistons in it
Most pulls have rpm limmited to 4000-4500
Who could rebuild one for me around Dayton ohio
hard to say as traditional small engine service shops will not work on older engines.
You'd have to call around to a machine shop that can rebuild it.
They'd only want the block and probably won't be able to get an estimate together before Dissassembly, some parts may be hard to find if not available from dealer.
I'm here because my 20hp 2000 model puked 2 rods. Top broke on the camshaft, has aluminum transfer. bottom snapped the rod. Not sure if repairable. What a mess.
Thats unfortunate not much can be done once rods let go just save what you can👀
As far as the oppose twin design being a bad design BMW has been using it on their motorcycles for over 50 years and I see them with over 500,000 miles on them so maybe you should back up and punt on that comment and I also have a 17 1/2 hp Briggs oppose twin that’s been working hard for over 25 years and still runs great
mainly the vertical splash lube isn't as good as horizontal dip lube or pressure lube
If you can find a pressure lube, they last much longer.
Pure junk design
once pressure lube was added the engines were bullet proof.
What year they offer that
@@guypatts494 was an option I've seen it on an engine as early as 1999
@Lowpass76 I heard plus option included pressure lube.
So a 18hp Industrial Commercial Plus would have been cast sleeve pressure lube opposed twin.
@Lowpass76 There's a few factors that can cause or negate the rod failure.
I run amsoil small engine oil as its designed for high heat splash lube engines.
Id doesn't cook off and has anti foam adjents in it.
Another thing you can try is ARC billet rods you can replace bearings on them probably softer on the crank as well granted they're not available under size so if the crank is out of spec it'll need to be welded