Briggs Opposed Build 46ci

"T" into the oil drain tube, get a small 12 volt pump and run a line to each valve cover. how to get it out, i dont know

I don't want to mess with pumps really, I think it will get it there itself. But good idea.

Beal, I could do that. But I have no use for a horizontal. I was thinking about making a mini bike around this engine if it runs dependiy.

Figured out what I'm going to do so the head gasket doesn't blow into where the valve holes are. Just going to measure some stuff today, gunna be a pic heavy thread with lots of info.

I would like to see an oppy or v twin converted to horizontal... or even a larger single cyl.
I seen a few small 3.5 or something turned horizontal.

willis923 wrote:

"T" into the oil drain tube, get a small 12 volt pump and run a line to each valve cover. how to get it out, i dont know

drill a whole in the bottom of the cover so it can drain out!

Drill and tap in some nice brass fittings, and use copper tubing to get the oil around the engine.

TheBeal wrote:

I would like to see an oppy or v twin converted to horizontal... or even a larger single cyl.
I seen a few small 3.5 or something turned horizontal.

Id just use opposed horisontal parts and transfer them over if i did, lol.

Thunderdivine wrote:

Drill and tap in some nice brass fittings, and use copper tubing to get the oil around the engine.

Id do that, if i can figure out the oiling if it works first, like using rubber likes temporarily.

More stuff done, can some one tell me when the the spark plug fires? Like when the magnet passes the magneto? Before or after in the picture? Or is it a general area?



Wrote down some info, the strokes of it are different between the two cyls.



Some specs on  the opposed.



And pardon my chicken scratch, but this is when the valves open and close on the strokes, and what the length of the stroke is of the pistion is in the bore.

my head hurts... i get the jist though

willis923 wrote:

my head hurts... i get the jist though

I guess i wrote it up for me. but all the stroke measurements and stuff are when valves open and close, what point the pistion is in the cyl. like how far down from the deck it is.

Ok, now I see the thread... Someone should get working on the faux briggs and stratton sticker for the shroud, making it look like this was some kind of experimental engine from the factory. I guess the ohv head does hang out over the opposed engines bore quite a bit. Stupid guys can never make stuff line up so you can just bolt something together. If you need to fill in the flathead bolt holes at some point, a hack job idea would be to thread bolts in till they bottom out (but without snapping fins off of course) and then cut the tops off and grind smooth.

Alright! This is pretty much the good bye to this project. As i look at it more and more, it seems like id be wasting heads and a big bore block for a little project.... So, i cant bring myself to hack it up.

The Heads would have to get holes drilled in them for the head bolts, you cant just drill into the block. the head bolt holes in the block are molded in like so:



I feel bad for starting and ending a project that had potential, but it would just kill me to have a irreversible block and heads if it didnt work out.

Plans are more simple for this engine now, copper head gaskets, lap valves if needed, port and polish, internal gov removal.

Problem about the gov removal. The allen bolts at the bottom decided not to work with me and both stripped. They arnt left hand thread are they?

Anyways- i managed to drill the one head of the allen out with ease. the other one will not drill at all. i dont know why. someone can help me? I feel like if i use a easy out it will snap in there, this thing is stuck.

Drilled:


Not so drilled:



{EDIT}: i have already sold some of the v twin stuff, the cam and intake manifold are gone. The intek carb will stay on the opposed. If anyone wants some intek heads (COUGH stretch44785) then contact me.

try a 12hp flathead or something similar first to get a concept. that way if you screw up all is not lost.

Ahh, don't feel bad. There's no shame in coming to terms with the fact that a concept is impractical, not feasible, or just generally not the greatest idea. Was a neat concept- but in order to make it happen, you need access to tools, equipment, and skills that not too many of us (including myself) have.

You need to cast your own heads. Then no need to drill holes in the block. If you get the easy out in that bolt, just hold steady pressure on it while tapping on the block with a hammer. Might try a little heat too like from a propane torch, not like oxy acetylene melt through the block hot.

mr.modified wrote:

You need to cast your own heads. Then no need to drill holes in the block. If you get the easy out in that bolt, just hold steady pressure on it while tapping on the block with a hammer. Might try a little heat too like from a propane torch, not like oxy acetylene melt through the block hot.

Cast my own heads? Ermmm... And yea. I'll have to figure something out.

Yeah, you just make up some casting sand from a bag of play sand and some clay. Or buy actual casting sand somewhere. Then you just need a good hot fire and some half way rugged steel container. Aluminum melts at somewhere around 1200F with steel around twice that if I remember correctly. Of course you'll need some good quality aluminum, which is no problem, you can just melt down a push mower block or two. Find yourself some fairly stiff Styrofoam and carve out your head. There are different ways to do it, but you can pack the sand right around your Styrofoam and pour the aluminum right into that. The Styrofoam melts out of the way as the mold is filled with aluminum. All that's left after that is drilling a couple holes, pressing in your valve seats, and your good. Of course there's a bit of set up time involved maybe... I was thinking of making an ohv set up for a model 5s briggs at some point.

I think it's a lot more involved than that. Seats, guides, studs, flat, and withstand heat.

Well, you could figure out all the fine details after you cast it out... But anyway, I guess this thing has about the same stroke as my 18hp twin. I thought there were 3 different displacements/strokes on these things. So I guess my 14hp twin must be the shortest stroke with this 21hp being the longest made. I wonder where they come up with the extra 3hp if the displacement is the same?

mr.modified wrote:

I wonder where they come up with the extra 3hp if the displacement is the same?

I have often wondered the same thing, From what I have found in the (Same displacement engines with rated higher HP) is the carburetor jetting.

Kohler is notorious for putting larger HP labels on smaller engines. Most common that I have seen is the CVS14S Labeled as a 15HP. And this had lead me to think Briggs does the same thing only they label it with a new number.

There was a big law suit deal or something a few years ago that had something to do with lawn mower engines and HP ratings or something. Now mower stuff just has a torque rating on it. I'll have to look into it, I don't know what it was all about. I don't see what the difference really is for the average person. If you buy a mower and it cuts grass, should be close enough.

***THREAD NAME CHANGED DUE TO NEW PLANS***

Ok guys, insted of a new thread, ill go off this one, so its more of a story line of the engine and not links to other threads; ect.

Just building it up as i go here, worked on it today some. The bottom case took forever to get off, the centering pins at the bottom were STUCK.

But its off, gasket  juek.


Cam out

Gov removed. take the gear and pin off the bottom case, and e clip for shaft. might just cut the paddle off the shaft and stuck it back in to plug the hole.




Im wondering, can i shave a little off the timing key and advance it like 2-3 degrees? Dad idea? Dont touch it? Going to prob go in my offroader.

Filing 0.006" off the timing key results in 1° of timing advance (or retard). You can add a few degrees safely, should be a bit better in the higher RPM. All else fails, replace with stock key again. No harm.

Doc Sprocket wrote:

Filing 0.006" off the timing key results in 1° of timing advance (or retard). You can add a few degrees safely, should be a bit better in the higher RPM. All else fails, replace with stock key again. No harm.

Im thinking 2 degrees, i hear if you advance it to much it wont start to nice. i think the crackle in the exhaust is cool too. Taking the flywheel off to really clean up the block and check out the starting system.

Sounds reasonable to me!

A couple points worth pondering-

*You don't actually NEED a timing key. It's there simply to take all guesswork out of setting the timing
*If you've got a buddy with a degree wheel, you can set whatever timing you like without fooling with a key
*Remember to torque that nut back to spec, or you'll shear the key (if used) and lose your timing.
*Your timing may be retarded. If it IS, for the love of god, don't call it retarded. It's not politically correct, and the tree-hugging, beret-wearing, latte-sipping, poetry-writing, vegheads will burn you at the stake. Enjoy!

I like my timing Paris Hilton-style: rich and retarded