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Messages - garrywarber

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1
Briggs Flathead / Re: 28/31 pistons
« on: January 17, 2013, 03:23:50 PM »
In my opinion...Flatheads have been around forever, not alot has changed in the design. Experienced, professional engine builders have attempted literally every approach to increasing CR in them and no-one has been successful at it. Domes, shaving, quenching, port reduction....you name they have failed with it. Flatty's make compression with the Cam, not the piston! It has been tried in In-line engines, V Engines and yes, Briggs as well as other small engines. It always ends up the same, increasing compression reduces flow and cylinder filling thus hurting the power out put of the engine.
There is always the guy that comes along and says ;"What if we could increase CR without hurting flow?" - My answer to that is simply; "Then you will have done what no-one else has been able to achieve. If that is your goal, have it!"
While your out chasing that great white whale...I'll be fishing for HP in a pond full of bass!

There are many proven ways to make power from a Flatty....why waste your time messing around with the one way proven to hurt power?



I'm in over my head here Ahab!  You boggle me with making compression with the cam.  Obviously I'd best stay with stock parts and not get exotic.  In truth, I was just using the parts I had, and instead of trimming the piston top flat I was going to round it...  Doing mine on the cheap, which to me means as many cubes as possible with stock manufacturers parts.  An ARC flywheel is as exotic as I'm getting, and that's only to get the weight down.  Low compression also means one can run lower octane fuel, correct?  I'm just a regular guy... :doh:  

My thing is a flyrod for bluegills, but pond bass I could live with! :rockwoot:
Garry

2
Briggs Flathead / Re: 28/31 pistons
« on: January 17, 2013, 06:18:59 AM »
You won't ever get me to agree that raising compression in a flatty is a good idea.

Well, I misunderstood then...  I had thought you were against shaving the head causing even more flow restriction is all.    A domed piston shouldn't restrict much if at all I suspect.  What is the reason you would be against that approach?
Garry

3
Briggs Flathead / Re: 28/31 pistons
« on: January 16, 2013, 06:55:44 AM »
I guess I'm used to people saying "You can't do that!".  You know the conundrum I mentioned.  Increase the compression on a flathead, kill the flow. Both would be nice.  I think it was Barney Navarro who first posed the idea of using a domed piston to ease the flow transition between the valves and cylinder.To that end, I started looking at aftermarket pistons. Several have pins and bores that would work. Some even have a dome. Compression heights vary from 1.188 to 1.5, hence my question. There's a partial machine shop in the basement and garage (I wasn't about to pack a Bridgeport to the basement) and a flow bench being installed. It would be a fun quest, to see how much hp. could be rung out of an oppy without breaking the bank. I wish we had a data bank to keep all this kind of info but I suppose there must not be many who would use it.

Arr,
I'm a real neophyte at these projects, but from wiser guys here I have concluded you could put 42 rods in your 46, causing the piston to rise above the block and enabling turning a dome in its top.  That's my plan, so I hope my conclusions are correct.  I remember a post somewhere where a member recommended exactly that.  Rooster and Flatheadpuller, am I correct?  In my favorites I keep a link to topic "New ARC rods for opposed twin" that may answer what you are looking for...
Garry

4
Briggs Flathead / Re: which stock cam should i run
« on: December 18, 2012, 03:47:23 PM »
Run the one on the left, it has more duration.


Could you expand on that?  Is that what I should run for the best low (3500-4000) RPM torque?  How about the 46 camshaft?  What is unique on that, if anything?  In my 46 would the 46 cam be best for what I want?  Common sense, if I had some, would say the 46 cam would be best with the 46 crankshaft because my RPM is right in the factory design range, but it seems briggs is spooky-weird on that stuff sometimes...  Or I am, I'm kinda confused... :worried:
Garry :twitch:

5
Briggs Flathead / Re: Copper Exhaust..
« on: December 18, 2012, 06:22:24 AM »
lol I bought a stiff spring so we'll see what that does with some heat

Are you trying to bend hard-drawn?  If you got it at Lowes you must be...  Annealing while heating will help, but the muffler shop would do better if they will bend your pipe...  You can get soft in L-weight, but in a small ammount it will be hard to find.  Maybe we will both end up at http://www.robertsonstorquetubes.com/index.htm ?
Garry :spam: 

6
Briggs Flathead / Re: Copper Exhaust..
« on: December 17, 2012, 05:16:00 AM »
Well its copper pipe 1 me 0.  :lol: I'm not discouraged yet. Coming up with a new plan on bending it,  stay tuned!   :doh:

Well, I doubt it would be easy to find long-turn 90's, so I'd use two 45's and straight pipe pieces.  Or go have a muffler shop bend them with their fancy insertion bending tools?  Fittings may not look as graceful, but it'd work. :stickdance:
Lookin' forward to the pics!  Could you tell me the proper flux to silver solder copper pipes?  I have an oxy/act torch and some flat sticks (don't remember the silver %) of silver solder already.
Garry
[/quote
 you should not need flux with silver solder just make sure your copper is clean i would braze the joints if there not socket welds if you use copper wire for rod you could polish the joints they would appear seamless i think its very hard to weld copper with copper though, seen it done on tv one time

Yeah, braze sounds good to me too, at least pipe to mounting flange.  I may do a plumber's job and use fittings for turns... :uhh:

7
Briggs Flathead / Re: Copper Exhaust..
« on: December 16, 2012, 05:19:48 AM »
I just picked up some tubing at menards for $20. Its 1"X 5' type m .5 thick. I was looking for 1 1/4 to but they don't carry it even though they sell 1 1/4 fitting??? I think 2 1/2' lengths going into a 2" collector should be good. I already have the 2" collector so altogether so far I have about $25 in it. I need to pick up silver solder but I have the torch. Oh yeah I have the caps to close off  the end of the pipes so I can fill it TIGHT with wet sand so I can bend it without collapsing it in. Good thing I have a spare block for mock up since my engine is in pieces. I will try to get started on it tonight but I have a Christmas party tonight so it will have b e later. I will take pictures as I go

Lookin' forward to the pics!  Could you tell me the proper flux to silver solder copper pipes?  I have an oxy/act torch and some flat sticks (don't remember the silver %) of silver solder already.
Garry

8
Briggs Flathead / Re: Copper Exhaust..
« on: December 15, 2012, 06:20:21 AM »
You do realize this mower gets the name "Coppyrhead" right?

He's going to have to sing the song "Copperhead Road" all the time also.  So, it has worked out fine already...  I'm gettin' into the idea "big time!" :freak:
Garry :weefly:

9
Briggs Flathead / Re: Copper Exhaust..
« on: December 14, 2012, 06:37:51 AM »
Sooo i always seem to come up with crazy crap so here it goes. Me and a buddy from work were talking about how we are building up our Opposed twins for next year and the topic of exhaust came up. Me and my brother have made a copper exhaust on his Triumph using type K thick walled copper pipe and made it into a 3-1 exhaust system. That was 3 years ago. He has sold it but he says the owner keeps it polished and it looks great and sounds awesome to this day. He sees it every once in a while at car shows. I have done my homework and i know the melting point of copper is around 1980* and while running a stock opposed at full throttle (stock) the exhaust got to 1088*. No way near melt temp. I also know that it will get hard or some say it will get softer because of temp and exhaust doesnt mix well with copper but racing engines only run for about 30-60 mins a race day and kept in a garage most of the time. Using 1 piece from each cylinder at equal lengths going into a collector and brazing them together. Has anybody thought about doing this? I know theres better ways but im just throwing it out there  :werd: :rofl: :lol2:

I like the idea!  Gonna look into it, but I would use M-weight copper.  K is very heavy and how much did you have to morgage the house to buy a couple feet?  For my non-racing use it would look really cool, and that is important to me...  :crazy:

10
Briggs Flathead / Re: Re-use rods
« on: December 08, 2012, 04:08:54 PM »
get more popcorn, and some no-doze.... :lol3:

I have watched mine three or maybe four times now.  No-no on the no-doze. :roll:  You will be referring back on stuff, unless you are a lot smarter than me, which wouldn't take that much, I suppose... :crazy:

11
Briggs Flathead / Re: Re-use rods
« on: December 07, 2012, 05:38:08 AM »
Sorry Garry that's the one I'm getting.  :doh: he said he will bring it to me so he can break in his new engine in his car. I told him I would give him $50 for gas. I don't know if its 46 or 42? It doesn't  matter to me as long as it is a pressure lube.
I'm building a 42 splash but what concerns me is I have the engine sitting where the cylinders face front and back of the mower and the Carb sticks out of the hood on the left which puts the oil slinger on the left side of the engine. What's got me a little concerned is that when I go into a turn the oil goes to the right side of the sump pan and the splasher can't get enough oil to sling. So far I haven't had an issue but a pressure lube would make me feel better

Very cool!  It is going to someone that really wants a pressure lube.  Alex told me the 46 went right away, but he still had the 42, so it is almost certainly a 42.  Glad you got it; now it need not haunt my thoughts!   :lol:
Garry

12
Briggs Flathead / Re: Re-use rods
« on: December 06, 2012, 04:38:23 PM »
make us all feel bad.  :( :P

Last I knew, there is a 42 pressure lube still for sale in Kalamazoo, MI for 100 bucks...  The 46 pressure lube he had went fast though.  :-)  The owner is a member here, and has posted them for sale at least once, possibly twice so far.  I'll get it when finances permit, unless one of you guys does first.  I really don't care if it's pressure or splash, in fact I'm looking for 46's of the splasher persuasion, mostly.
Garry

13
Briggs Flathead / Re: oppy hp max?
« on: December 03, 2012, 04:39:24 AM »
what hp should i expect to have with a 42 splash lube oppy. camed arc rods and flywheel with avs pistons ported polished and carbed. is would be for an outlaw. guys with 50hp inteks say that 50hp is more than enouph even.

Look through search well.  It's possible to make 50 cubes using stock parts.  3.5 piston with 46 crank and 40 rods, I think, but shorter rods may be wiser?  You could maybe get 50 HP if you supercharged 8 or 9 psi, but you better use ARC parts then, most likely...  Is boosting legal in outlaw class?
Garry

14
Briggs Flathead / Re: Re-use rods
« on: November 29, 2012, 06:24:13 PM »
In addition, a longer rod increases ATDC and ABDC piston dwell, which can allow for camshaft duration/lift combinations, spark advance, and fuel chemsitry advantages.

I too have learned everything so far right here from you guys.  I read short rods for torque and long rods for RPM.  Is that still the rule of thumb?  I want a low-rpm "torque monster..." :-)
Garry :weefly:

15
Briggs Flathead / Re: Re-use rods
« on: November 29, 2012, 06:53:52 AM »
Also I'm trying to find Don's video for the oppy but can only find engines 101 or is that one for the oppy? It says for 8hp on up.

Go to the G-Team site if it isn't there in the eBay G-team store.  Same price in the end.  Mine states "Motor 101 opposed" on the dvd case...
Garry

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