Why use a modified engine?

[modelengineer]

I've been thinking about this for a while and have been wondering about what drives people to use a modified clone/honda/tec./industrial engine/lawnmower engine for a power plant?

Advantages:
- Good learning experience building up an engine
- Fun taking apart and rebuilding the engine to better understand how it works
- Can spend money gradually by replacing parts one at a time
- 'Cool' factor ("Yeah, it's got cams, header, flat top piston" )
- Easy to mount and connect. Just throttle linkage and chain

Disadvantages:
- By pushing the engine past design limits life of the engine *can* be shortened
- Quite expensive to get hop-up parts for these engines
- Needs a separate clutch/gearbox/torque convertor
- Lot's of work and time to build up an engine (Can be a positive if you enjoy engine work. I know I do!)

This is far from an exhaustive list, just what I could think of in 5 minutes. Feel free to add anything you want.
So, what made you choose to modify an industrial/lawnmower engine?

 

[jr dragster T]

Cause we like building our own engines and they sound sick!

 

[Russ2251]

I rarely modify. Only for form, fit, and function.
For you guys to pass me (let alone catch me)...modify you must.
Take that my Otto cycled friends!!!

 

[jr dragster T]

Well from a stand start Russ I would beat you.

 

[Russ2251]

Not possible.

 

[newrider3]

Anyone can go out and buy a bigger engine. It takes some skill to build up an engine, and then you get to see the look on the other guy's face as you smoke him and his huge stock engine with your tiny mill.

 

[ZnsaneRyder]

Easier to hod-rod than a car engine.

Learning about smaller engines is fun.

Lots of power in a small size.

Cool factor.

Cheap to change oil and good gas mileage.

 

[Kenny_McCormic]

I rarely modify. Only for form, fit, and function.
For you guys to pass me (let alone catch me)...modify you must.
Take that my Otto cycled friends!!!

I have some motors that will pass you. Even your double E.

 

[scar]

its in our dna every man wants more power and more speed

 

[jr dragster T]

Russ I think it very is possible for me to be you. I've seen some of your vids and I dont realy care how rich your low end or high end is your LB bogs and accel's very slowly. I dont think you have seen what a go kart with a live axle and a torque converter will do.

 

[modelengineer]

I think it very is possible for me to be you. I've seen some of your vids and I dont realy care how rich your low end or high end is your LB bogs and accel's very slowly. I dont think you have seen what a go kart with a live axle and a torque converter will do

Ooooooh, them's fightin' words!

OK, I have another question:
Would you rather have a highly modified engine which makes 20hp, or a stock motor which makes 25hp?
All other things being equal.

 

[scar]

stock but only because it has a better chance of lasting longer

 

[jr dragster T]

I'd rather have a modified engine making 20 hp. Because if I wanted more power I would just go and buy a 15-20 hp engine. But you see I want more overall RPM AND power. So having a mod'd engine is better IMO. Plus you built the engine and you know where to get new part's and so on. You also get the great feeling and reliability because you personally tightened every single fastener on it. And even my built engine most of the time I'm just cruising along the pit's at 5-10 MPH. But I wanted the billet rod and flywheel for when it's safe/room to open it up. So realy most of it's life its doing LESS than desihned maximum RPM.

 

[Russ2251]

What it comes down to is, with all things being equal, your clone cannot and will not ever pass me in it's stock configuration. My goal was/is to keep things as stock as possible and still be able to kick butt.
I have a clone and have never been less impressed with any engine (other than a Chevy Vega 2.3L). The only thing good about the clone is the price, and for what it is, is overpriced. Why do you think they give away new ones when failure occurs with no questions asked? Their true value is probably closer to $25 or less.

 

[jr dragster T]

Think what you want Russ. Your using a lawnmower engine. I dont know what you hate about clones but your lawnboy looks awfull sluggish from a dead stop. Centrifugal clutch's just dont have what it takes to lock up and get up and go like a CVT does. But I do agree if my clone was stock on the top end you would start to catch up.

 

[Russ2251]

I dont know what you hate about clones

Never said that.

lawnboy looks awfull sluggish from a dead stop

No choice. No other clutch will fit without getting expensive.

Centrifugal clutch's just dont have what it takes to lock up and get up and go like a CVT does.

I don't disagree.

Like I said (and stand by it) with all things being equal, you don't have a chance.

 

[jr dragster T]

Dont have a chance stock. Not stock anymore. Now a dependable thumping race engine. Someday we should all meet up and I'll show you how it's done. I can gurantee you 15-18 HP @7000 RPM and your toast. You wouldnt even come close to me. By the time your clutch lock's my secondary is already opening up in the engines powerband!!!! And your not even going to complement on all my hard work on my engine!

 

[Russ2251]

I'll show you how it's done.

XD...XD...You're a few decades late my friend.
When I was your age, I dropped a 3/4 race cam into a 312 cu.in '58 T-bird engine. That in turn went into a '51 Ford convertible.
I still see it once in a while.

 

[jr dragster T]

I dropped a 3/4 race cam

You know dropping cam's is not good XD XD So what are you saying? A young teen cannot beat your lawnmower kart?

 

[Russ2251]

Yup.