>>>>>I've read through 17 pages of messages and have tried to keep all of the info straight but it gets quite confusing with the conversation going in 10 different directions pertaining to half a dozen different engines......
I'm not seeing the point of spending $700-$1,100 on an engine and then throwing everything away except the cases ....and then spending $2,000 replacing all of the parts that were just tossed from a brand new engine.
So here's a few questions that will hopefully get answered without too much information drift.
So where does it stand at this point....???
1. Is 35-40 hp possible from a "stock" engine......no turbo,crank replacement,pistons and rods replacement,valves replacement or cam replacement......"stock" off the shelf engine..strip it down,bolt it up and fly ?
2. Reduction or direct drive ?
A. Reduction : gearbox or belt ?
B. Direct : pusher or tractor.....which end to mount prop on.....will the crank stay in the block without a thrust bearing ?
3. Weight of engine after all unnecessary parts are removed...
A. With electrical system...alt,starter and battery ?
B. Without electric system...no alt,starter or battery and just hand prop it ?
C. Flywheel.....needed or not ?
4. Horizontal or vertical shaft ?
1. No, there isn't a Stock Single or V Twin Engine I would just put on a Plane that makes 35-40hp.
2. Belt Reduction is Best. I haven't seen a Good Gear Drive Conversion yet, but may be possible.
3. Your going to have to figure that out, each Type of Engine will be different.
4. Yes, you want Electrics, with Electric Start, use a Lithium Battery.
5. Horizontal is easiest to convert.
There is a 35-40hp@3600rpm EFI V Twin Engine's out there, but you still need to Modify them for Airplane use. READ POST #336 of this Thread. The Big V Blocks you need to lose as much Weight as you can.
For Durability for these Singles & V Twins!
1. Valve Train, use Needle Bearing Roller Rockers, HD Valve Springs for Max rpm used, HD Valve Locks & Keepers, use HD Chrome Moly Push Rods, Billet Lifters, Stainless Valves. Even if using Stock 3600rpm, Upgrade the Parts.
2. Billet Rod.
3. Billet Cam
4. Billet Aluminium Flywheel. Stock Flywheel is Good for up to 5000rpm, but you Save a lot of Weight with the Billet Aluminum Flywheel.
5. Use a Good Full Synthetic Oil, like Mobil 1 ($7.88 qt) if Non-Filtered, means you have to change it more often. If Filtered I would use Mobil 1 Gold ($8.96 qt) 15,000 mile Oil, Walmart has it the cheapest in 5qt Containers. Some V Twins have Oil Coolers, I would use a Bigger one than Stock. Most Engines come with a break in Oil that needs to be changed shortly after Break-in Period they Specify. That would be a good time to Open the Engine and do the Mods needed for Airplane use, like Disable Governor, Disable Low Oil Sensor, Install Hi Rev kit, etc. Good Time to deburr and Polish all internal parts.
6. Use the different Engine Coatings to reduce Heat.
7. Take Out Heavy(4-5lbs) Balance Shaft & Balance the Engine Assembly.
8. Since most Airports only carry 100LL anyway, Design & Tune it to run that Fuel. Solves any problems from Detonation or Old Bad Fuel.
A Vegas Carts 625 Single, $850 is 626.3cc and rated 23hp@3600rpm. It could make your 35-40hp easy with the mods I listed.
The Small Block V Twins go up to 627cc 23hp@3600rpm!
The Big Block V Twins go up to 993cc.
Big Block Engines:
Vanguard® 25.0 Gross HP* 896cc
Vanguard® 27.0 Gross HP* 896cc
Vanguard® 29.0 Gross HP* 896cc
Vanguard® 31.0 Gross HP* 896cc
Vanguard® 33.0 Gross HP* 896cc
EFIVanguard® 35.0 Gross HP* 993cc
Vanguard® 35.0 Gross HP* 993cc
EFIVanguard® 37.0 Gross HP* 993cc
EFIVanguard® 40.0 Gross HP* 993cc
Vanguard® 40.0 Gross HP* EFI - Marine 993cc
Compare these 993 Engines probably just different CAM used.