Longevity in Race Engines

Wil

New member
I found a very cool Kart track where they have not only race chassis classes but 2 separate classes for yard kart frames. The idea is that you take a random kart frame, strip it and rebuild with race components. One class is 6.5 HP and the other is completely open. Tech is simple, kill switch and brakes. Everything else goes. Most are running old Manco Dingo frames. My question is, where is the tipping point between usable power and just blown motors? I run the 6.5 class with either predator or clone engines and I build them up a little more all the time. Cam, springs, flywheel.... still gravity feeding a stock but re-jetted carb. Just looking for a little direction. I blew one up last month and will probably blow one this month (old block). But as I restock with predator motors I’d like to get a full season out of the next couple....
 

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sundog

Member
The problem with racing non racing equipment is you have failures in the braking and steering systems and sometimes wheels come off any one of which can kill.
 

Wil

New member
Thanks for your reply and I can understand your concern. The track is a short dirt roval to keep speeds manageable and we are aware of the risks of racing. However, it doesn’t really address the question....
 

flattop1

Dawg 89
What engine part is giving up ?
 

Wil

New member
So far I have only ever blown a rod. I know I need to upgrade, but the motor was mostly stock except for a flywheel and intake/exhaust. I hadn’t even upgraded valve springs. I’m guessing the rod needs replaced as soon as I pull the governor?
 

flattop1

Dawg 89
Yea. That would be best.
 

Jimbo

You can fool some of the people some of the time
I have sprint racing customers with LO 206 engines that have 9 seasons on them.
Yes they still have the OEM seals intact.
Divide the cost of the engine by 10 years (makes the math simple) and see if you can beat that.
 
Yea, I'd agree with Jimbo on his comment.
A local backyard group here switched to the 206 when they were first introduced and some are disappointed that they won't be able to take their current almost 10 year old engines to the actual kart track and race next year because of the seal rule change. 10 years! That's dependable, especially considering the level of maintenance these guys DON'T do.

But, the LO206 won't let you tinker with the engine, and that sounds like what you are wanting.
The Chinese Predator engines certainly offer plenty of room for improvements.
Yes, as soon as you disconnect that governor, replace the flywheel and rod.
If you're replacing the rod anyhow, then you might as well replace the piston with a real one as well (higher compression height for a longer rod combination, etc.)
Next get rid of that fuel tank and restrictive carburetor and bolt on something that will let it breathe.
Then get a matched exhaust to go with your cam and carb.

The whole engine build has to work together.



-----
?Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 

Jimbo

You can fool some of the people some of the time
Just cut the seals off.
Yep, now it's not a legal 206 but it doesn't sound like this guy could care. Tinker to your heart's content.
The point is to start with a good foundation and don't go nuts with the modifications.
For the second time this season we had about an hour delay because one of these other brand of engines spilled oil around the entire track and it needed to be cleaned up before racing continued. Because of the noise curfue the rest of the race program needed to be cut short.
 

Bob Evans

Administrator
Proprietor
Why should he buy a $500 motor instead of a $150 motor if he's going to tinker with it? :)

Probably would be best to let the clones run the 18 lb Honda spring anyway. There ain't no way they're going to twist them to the moon with a .615 carb anyway, and it would make them more viable on sprint tracks.
It would also save the tech man a whole bunch of time and several pounds of valve spring testing equipment. :)
 
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Jimbo

You can fool some of the people some of the time
Bob
Because it ends up being cheaper in the long run.
Here's a couple of examples:
He won't have to buy a billet flywheel.
He won't have to buy a good ignition system.
It has a larger carb as well.
Even though it has a RPM safe flywheel it has HD blower housing for additional safety.
It comes with the fuel pump.
 
Bob
Because it ends up being cheaper in the long run.
Here's a couple of examples:
He won't have to buy a billet flywheel.
He won't have to buy a good ignition system.
It has a larger carb as well.
Even though it has a RPM safe flywheel it has HD blower housing for additional safety.
It comes with the fuel pump.
And will last many years. I have one that is 11 years old and still will win any race.
 

Bob Evans

Administrator
Proprietor
:) So the problem is that there aren't enough different motors to choose from? Because I was kinda thinking in the opposite direction.

The simple 4 stroke karting facts of life are:
Road Course- LO 206
Dirt Oval- Clone or Predator (or both)

Just how it is.
 

paulkish

old fart
" My question is, where is the tipping point between usable power and just blown motors? "

It depends on the level of competition your racing against.

Deal offered to us was motor, clutch and engine oil to use would show up in a box for us on Friday to use racing the weekend. All we had to do is make sure it was shipped back by Tuesday so engine and clutch could be gone over, so we could have it by the next Friday.

In return we were expected to win. so... it all just depends ... :)
 
:) So the problem is that there aren't enough different motors to choose from? Because I was kinda thinking in the opposite direction.

The simple 4 stroke karting facts of life are:
Road Course- LO 206
Dirt Oval- Clone or Predator (or both)

Just how it is.

I'd disagree.
Yamaha and piston port = sprint and road course circuits
Briggs flathead = dirt ovals.

;)

I think we need a "new" clone - a clone of the Predator to be imported and that will solve ALL of our problems.
One more engine, 10 more classes...yep, that ought to do it. No more problems.
 

Jimbo

You can fool some of the people some of the time
The LO 206 has eliminated the clone in sprint racing because???
I'm going to a race this weekend that is all LO 206 powered. No 2 cycles, no clones, no Tag's, no Shifter karts etc
There will probably be somewhere around 150 to 200 racers there. No $$$$$$ to win but tremendous door prizes donated by sponsors.
The classes are:
Kid Kart
Gold Slide
Sr
CIK body only
Masters (old farts)
 
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