They are all a little different. I think in the end they will all do close to the same. It is hard to say. I have had them vary from 7700 to 8550 when new. So 8150 is pretty high. once yours is broke in it will go higher than 8550 more than likley. One of the first ones I did is on my buddies Spce Walker. It started life at 7900 RPM. Now with 3 - 4 gallons of fuel it is up to 8600 - 8700. I am always changing little things trying to get more out of them. The one at 8550 has a little different porting again. I will run it for a while and be sure everything is fine before I do it to one I sell. plus I only tested the one prop on it. I will test others and see if the torq has changed as well as the HP. Somtimes more HP will lead to less torq. SO it may turn a bigger prop slower than yours. I have more testing to do. It is a constant trial and error process. But I make sure everything is up to snuff before I sell them after trying somthing new. You have to remember, if it ends up at 8600 + you ended up with slightly less power than a G26, at less weight, and half the price. Pretty good I think. You are getting the 33rd Toro I sold and the 37th Toro I have converted. So far everyone has been happy with them. They are a bargin.

Dude, I wasn't trying to bust your chops or anything. I was just wondering. I'm sure I'll be very happy with the engine, and your right, it is a bargin. I've ported heads for racing engines and you can't get them all the same. You try but it just will not happen. Unless you have a CNC machine. I'll bet you have one in the garage though.

No Problem Al. I wasn't offended or anything. I was just tying to explain why yours was a little lower than the one I mentioned. I tend to overexplain somtimes I just hope the USPS doesn't let me down and has it for you tomorrow. They are usually pretty good. Let me know what you think when you get it.
Oh, no CNC. Just a manual mill

Scott I'm glad you don't have a CNC. I couldn't afford to buy a motor from you.

I bet one of these would be great in my 1/4 scale Fokker DR1.

Hi,
The Torro would fly it scale like. Keep the weight down and the lifting airfoil should make it work well.

Dave

Hi Dave. I used to have a 1.60 FX in it. I usually only used half throttle. I was running a Zinger 18x5 with the needle set at 8100. Do you think this motor will spin about the same rpm with this prop?

Hi,
It should come close to 8,000 since the pitch is low. The rpm depends a lot on which version of Toro and what was done to it. If you flew at half throttle with a 1.60 FX, the Toro will fly it fine. It may take more throttle to do it though. They come in a 1bbl and 2bbl versions. Weight is 3lbs for the magnito version without the muffler.

Dave

If modified the Toro 2bbl will turn a Pro Zinger 18x6 at 7200. A 5 pitch may be slightly faster. 7400 or so. That is what my engines have done. So it should fly the plane well. But like Dave said, it will take a little more throttle and will not have the same top end thrust. You could help make up for it by repropping. It will turn an APC 17x6 at 8400. The zinger has alot more load than APC.

I GOT MY TORO 2BBL DONE THIS WEEK AND RAN IT FOR SOME TESTS. STOCK WITH NO MODS AT ALL IT TURNED 7400RPM WHICH IS 1000RPM MORE THAN A 1BBL STOCK. IT TAKES A LOT OF MILL TIME TO FINISH THIS 2BBL. I DID AWAY WITH THE REEDS AND MADE NEW COVERS WITH A BALL MILL RUNNER IN THEM AND MILLED THE BLOCK TO MATCH SO I HAVE A 7/16 RUNNER ALL THE WAY TO THE PISTON. HAD TO MILL THE SLOTS LONGER AND WIDER IN THE BASE OF THE CYC. TO GET THE FLOW OUT OF THE CRANKCASE. RAISED EX. PORT .060 AND MADE I AS WIDE AS THE CASTING ALLOWED. I LOWERED THE INTAKEAND MADE THAT AS WIDE AS CASTING ALLOWED. ALSO THE REAR POINTING TRANSFER PORT WAS RAISED .040. ONLY THING I DIDNT DO WAS LOWER THE CYC TO INCREASE THE COMPRESION, I THOUGHT IT WOULD HURT THE PORT TIMING SINCE THE ISNT ENOUGH MATERIAL TO RAISE THE EX. PORT ENOUGH TO COMPINSATE. MADE AN INTAKE MANIFOLD TO ROTATE THE CARB SHAFT TO VERTICAL AND A VELOCITY STACK AND MY MODIFIED STEEL MUFFLER. ON MY TEST STAND WITH A 18-6 CLASSIC IT TURNS 8400RPM THIS IS A LOT OF WORK FOR 1000RPM BUT ITS ALL FUN OR WE WOULDNT DO IT. I GAVE UP ON THE 16-6 CLASSIC BECAUSE IT DOESNT MAKE THE THRUST THE 18-6 DOES, ALMOST 2 LBS LESS EVER THO IT TURNS MUCH HIGHER. IM UP TO 14.2LBS AT 8400RPM. MY FINISHED WEIGHT IS 3.2LB (51.2OZ) COMPLETE READY TO INSTALL. MUFFLER, CARB, VELOCITY STACK FLYWHEEL IGNITION AND PROP HUB, JUST ADD UR PROP AND GO FLYIN. IVE COMPARE 4 ENGINES AND THIS IS THE BEST AND 2ND IS A G23 WITH 8000RPM AND MY 1BBL TORO WITH 7860RPM. I HAVE THE BEST RESULTS WITH A WALBRO #28 VENTURI CARB.
FARMER TED

The only way to get more out of the 1bbl engine is to mill the transfer ports. If you do it will be almost the same as the 2bbl. That 1000 rpm you gained with all the work is a big increase in thrust and HP. It moved it into G26 territory. I think it is well worth the work. Do 20 or 30 and it gets pretty quick FOr the 1bbl I just use a 5/16 mill end that has 3" of cut. I plunge it down in between the transfer runners on each side. Take away as much as possable without cutting through. That will boost the 1bbl up in power.

POCO
IM A LITTLE FUZZY HERE CLEAR THIS UP 4 ME. BY MACHINING IN BETWEEN THE TRANSFERS WITHOUT BREAKING THROUGH UR MAKING 3 RUNNERS OR UR TAKING OUT THE INTIRE CENTER AND MAKIN 1 LARGE RUNNER? I HAVE MILL THEM (ALL 4) WIDER, DEEPER AND HIGHER. IM 600RPM'S AWAY FROM THE 2BBL NOW BUT THE PORTING AND TIMING CHANGES HAS GOT IT INTO A REVERSION MODE AND NOW IM THINKIN ABOUT INSTALLING REED VALVES TO STOP THAT AND GET THE CHARGE MOVING INTO THE CYC. WHERE RU WITH CARB SIZE? IVE TRIED FROM 8MM TO 15MM AND SETTLED IN AT 11OR 12MM. WHAT ARE YOU USING FOR PORT DURATION NUMBERS AFTER 30 OF THESE CONVERSIONS? I LOWER THE CYC .040 ON THE 1BBL BUT NOT THE 2BBL HAVE YOU FOUND THE COMPRESSION INCREASE WORTH THE WORK. LOOKS LKE U DO UR TESTING WITH 16IN PROPS AND I USE 18'S CAUSE I GET MORE THRUST BUT LESS RPM'S. THRUST IS WHAT WERE CHASING! WHAT RU TURNING WITH AN 18-6 CLASSIC?
LOTS OF QUESTIONS AND IT LOOKS LIKE UR DOIN THE FOR MONEY AND IM IN IT FOR FUN SO MAYBE U NEED TO KEEP SOME SECRETS!!
FARMER TED

When I milled the transfers I cut the center out to make 1 large transfer on each side. I have not changed the port timing at all. I also did not change the intake on the 1bbl. Just the exahust. I opened it up a little without cutting up. Only down a hair. Mainly I squared off the port on the bottom. It is a little V shaped stock. I also have not tried to increase the compression by using a different gasket. I did not want to get into changing the port timing like that.
I have not tried a MAS classic prop. I test them with everything from an APC 12x12 to a Zinger 20x6. I just use the APC 16x8 numbers because that is what a G26 is tested with.
I do sell many of these engines. Up to 42 now. But I will tell anyone what I do to them. No secrets. I sell them to people who either can't do thire own, or do not have the time or tools to do them. For people like you, that do your own, I am happy to tell what I have learned about convering them. I found out this week, you can go too far on porting the 2bbl. I have 3 scrap cyls now

ID LIKE TO HAVE THEM TO MESS WITH I HAVE 1 GOOD BOTTOM END FROM 1 I BOUGHT THAT BROKE A RING AND DAMAGED THE CYC. WHAT DID YOU DO TO GO TO FAR ON THEM? GO OUT THE TOP OR SIDE ON THE PORT? IF YOU WENT TO HIGH I CAN DROP THE CYC DOWN CAUSE I WANT TO TRY MORE COMPRESSION ANY WAY. THE 1 CYC I HAVE HAS A SLOT CUT UP THE WALL FROM THE BROKEN RING. RU USING THE 2BBL CARB OR DO U GO TO A 1BBL IF SO WHAT SIZE DO U LIKE?
FARMER TED

To go to far I went down too low on the intake port. The idle was gone then. About 2700 was as low as it would go.
I use either an 11mm or a 13mm carb. The 11mm is best, but hard to find enough of them.

Hi Scott,
I always figured it would be easy to make the 2 bbl intake port too big, or move it too far, but when you look at the intake port on the 1 bbl engine it makes you wonder. The 1 bbl intake port is huge, isn't it? I lowered the intake on the 2 bbl engines pretty far, I thought. I remember lowering the bottom of the port to within 1/16" of the pulse hole. I used a 1/2" drill, lined up with the top of the port and a carb spacer with a 1/2" hole in it bolted on for a drill guide. The port came out as a 1/2" hole with square corners on top. With no mill, I wanted to keep it simple and this is how I got to within 1/16" from the pulse hole. I am now wondering how far down you went on your 3 problem cylinders? Maybe I need to change my thinking?

If you want to try something, how about machining an adapter with a flange on it to repair the 3 jugs you have, is this possible? The flange would make sure the adapter doesn't "fall into" the cylinder and can be designed to do several things. I haven't seen the cylinders, of course, only you can judge.

One thing I found is that you cannot drop the cylinders down into the crankcase very far at all without the piston hitting the "corner moulding" around the top of the cylinder. For reference there is only about .010" - .015" to begin with (its close). I suggest (for anyone) removing the cylinder gasket and checking this assembly to see if the piston hits, before machining the cylinder.

After looking at the jugs again, I think it is not so much that the intake was too low, He actually went up a little and down on the exahust too far. What ended up happening is when the piston was all the way up, I could see through the intake to the exahust. Not just a hair either. A good 1/16" I think thet is what caused the idle problems. I am doing them a little more conservitive now. It seems thier is a limit to what will create more power anyway. The last few I did, I milled more but the power was the same. I think 8300 - 8500 on an APC 16x8 new is pretty good. Also I think it was you or Dave that said maybe why the 2bbl has more power is a higher intake velocity due to the smaller port size. I think that may be the case also. Plus the transfer ports are nicer in the 2bbl. I have noticed the compression is much lower on the 2bbl. It makes no sence because the piston is even domed, but the 2bbl have 20-30PSI more, but less power. Can't figure that one out

in your video, i seen you use a drill for a starter. I'm assuming an 18 volt model. how did you make the "adapter" for the cone?

It is an 18volt Snap-On drill. I also have a 12 volt Makita that works good too. For the cone I just bought a replacement starter cone from Tower and ran an allen head bolt through it with a nut and tightend the crap out of it. It never slipps and works great. I allready had the drill and they do a great job as a starter The main thing is to have a good drill that turns 1000 rpm + in high. My Snap-On turns at 1700 RPM free and will turn over a 46cc at 1400 rpm. I think it would start my truck. The Makita is rated at 1100 RPM in high and will also start a 46cc. It was not fast enough to start a McCulloch 38cc so I use the Snap-On all the time now.

I was thinking of using one on smaller glow engines as well.

Scott,

Have you tried the electronic ignition on the Toro 25 cc engine yet?

Roger

I have. The engine is much lighter. Under 3 lbs with the ignition. I will be finishing one up this weekend on EI. Then I will have some numbers.

Scott,

Thanks, I'm looking forward to the performance numbers. I would also be interested in the price of your Toro with the EI.

Thanks,

Roger

I am working on a couple toros myself, following all the great info here.
I will probably be doing little or no real performance mods other than a muffler, and cutting some weight of course....at least to start, one motor is going on the GP super stearman and sounds like should be a good fit for the airplanes flight envelope....

I was real curious
if any of you had tested the thrust or have an idea of about how much could be expected from a stockish motor? It would be killer if it would pull it vertical, though I realize thats abit optimistic. thanks for any info....

Hi Scott, Just looking through the thread today and wondered if you have ever thought of trying the 2 bbl piston in a 1 bbl engine. I haven't compared them side by side lately myself, I am just thinking about the dome on the 2 bbl piston and whether it is enough of a dome to raise the compression in a 1 bbl cylinder? Think there could be anything worthwhile to this?