Hot Rodding a Tec

[FOMOGO]

I see people posting about the H50 performance engine and parts. Can you, well I know anything can be done...., but can you hot rod an HM80? Just a mild build. Maybe 12 to 14 horse.

To much trouble? No parts? Whats the low down????


Thanks,

Doug

 

[Sixpac440]

I know next to nothing but I would think trying to get the RPMs up is where the problems would arise ... you would need a stronger rod and I'm guessing a different flywheel ..
Dollar for dollar a Predator would be the way to go ... but if your like me and like the Old Style motors get a NOS H50 Motorsports engine ($350 delivered) and build around it ...

 

[markus]

i think member roccosbike beefed one up awhile back, he might have some insight on them. I think Tecumseh made the Star 10hp for racing that should be in the same block configuration/dimensions but you rarely see them anymore.

 

[FirePowerMinis]

Sure. It's just the bigger frame, 305 or 318cc. Same height as a 5hp Briggs.
Points vs electronic, 1.187 or 1.375 journal.
Porting, tight quench, a little more timing, carb/pipe, same as any other.
The Motorsports starts off with some nice parts, but the 60% displacement advantage is tough to beat.
They're sorta wide. VKE billet side cover gives more room.
Flatties Forever!

 

[jeffdubb8]

I've been down this road...Here's my take. I have a worked 10hp Tecumseh Star engine that puts out 20-23hp on gas, but it's a real b*tch to start sometimes even with the compression release. I also have 2 Mike Clements worked H50 Tecumseh Motorsports engine pushing 13-14hp on gas. Much easier to start but less torque down low...it still rips though. He knows his stuff. Lastly, I have a BONE STOCK Tecumseh 10hp with the govern taken out that honestly is MORE than enough to haul you around. It'll easily do 50-60 mph, and the low end torque is very impressive.

So, what's my point? Get a new 10hp Tecumseh for $250...'maybe' take the govern out...gear it properly and you likely won't want or need anything more. As for those other two engines above...the Star was $1800 and the H50 Motorsports engine was $900. Yes they are 'nastier' but the stock 10hp is easy, clean and still loads of power. That's my take.

Fyi, You can get an H50 Motorsports engine for $350 shipped to your house...then you have to build it. I sent mine to Mike Clements for some extra power...The 10hp Stock Tec. is still the cheapest, most reliable option IMHO.

 

[Dr. Shop Teacher]

JeffDubb offers good advice. ARC makes some billet rods for lawnmower racing that may or may not fit a horizontal shaft HM80 (probably not). 8-10 hp and oodles of torque without getting your arm ripped off trying to start it makes plenty of sense. I haven't even thought of building a bigger engine, but I can tell you the Frankenmotor I just finished that has an H70 piston in an H60 block is a quite a challenge to turn over even with a compression release (really over square). I kept this engine governed and the TAV that's going on it will harness the power.

 

[owend]

I've been down this road...Here's my take. I have a worked 10hp Tecumseh Star engine that puts out 20-23hp on gas, but it's a real b*tch to start sometimes even with the compression release. I also have 2 Mike Clements worked H50 Tecumseh Motorsports engine pushing 13-14hp on gas. Much easier to start but less torque down low...it still rips though. He knows his stuff. Lastly, I have a BONE STOCK Tecumseh 10hp with the govern taken out that honestly is MORE than enough to haul you around. It'll easily do 50-60 mph, and the low end torque is very impressive.

So, what's my point? Get a new 10hp Tecumseh for $250...'maybe' take the govern out...gear it properly and you likely won't want or need anything more. As for those other two engines above...the Star was $1800 and the H50 Motorsports engine was $900. Yes they are 'nastier' but the stock 10hp is easy, clean and still loads of power. That's my take.

Fyi, You can get an H50 Motorsports engine for $350 shipped to your house...then you have to build it. I sent mine to Mike Clements for some extra power...The 10hp Stock Tec. is still the cheapest, most reliable option IMHO.

That is great info Jeff:thumbsup: Now I need to get some of mine off the shelf!!

 

[joshua. c.]

I thought I red on an old thread that the hm80 could use the star billet rod. but I could be wrong, I would have thought some of the experts on this subject would have piped up by now with a list of modifications that could be done and info on how to do them.