[LilysDad]

On Brian's site there is info about how to modify a Kohler Carb. How much of this do you think is still relevant? Any tips of your own?

I have a K341 that I am using in a parade/yard tractor. It is ported and polished, K361 cam, milled head. I am interested in anything that will increase performance without hurting yard performance.

 

[Horse_Nuts]

His carb modifications work very well for an engine like yours.

 

[LilysDad]

Only one reply??? You all are keeping your top secrets to yourselves, huh??? I've noticed that it's hard to pry any info out of a puller. Some of them even put panels on the sides of their hoods so we can't see what's in there.:fing32: I bet they are running hydrogen engines and don't want us to know.

I've even been told that Mater's T-Rex runs on raw meat!

Carry on!!!

 

[marcuskelley35]

To be honest 1/2hp to 1hp gain is not much improvement vs the cost. I've checked out his site in the past, it's a lot gadgets and "tricks" that will not improve the performance of the engine anymore than stock.

 

[gray wolf]

I,m gunna Run a 341 on pure oxygen,don,t tell anyone.'

 

[LilysDad]

To be honest 1/2hp to 1hp gain is not much improvement vs the cost. I've checked out his site in the past, it's a lot gadgets and "tricks" that will not improve the performance of the engine anymore than stock.

??? By cost, do you mean buying one of his? Or cost to do it yourself?
What I have done so far is estimated to increase my 341s power by 4hp +or-. That's more than stock.

 

[Johnnyby68]

i myself dont like to modify carb... if anything have the carb reworked to get some more hp.... means having it sent out.... also cam wise there is a few companies that regrind your stock cam and get a couple hp and few ft lbs torque.... shaving the head also helps hp some.... after market coil... and creating the least resistance inside the motor... but i wouldnt run your yard tractor on the least amount of oil possible... pulling tractors they do but they run 2 min and their shut off

 

[searstractorfan]

Port and polish does alot..then send ur cam out and have a goo grind put on it..Small engines of Seymour is the best grinder I feel..Guys name is Greg Hackman...why not just buy a good built carb? Might call some of the engine builders and see how far they feel u can push a modded motor before u pass up the lawn use...I know long rod/short piston makes gobs more torque over stock...HP isnt what ur chasing..u want the torque...

 

[LilysDad]

I don't understand the physics of that long rod/ short piston.

 

[searstractorfan]

Keeps the piston up or down in the cylinder at TDC or bottum which is what BTDC?? and that helps get more air into the cylinder supposedly...Im not a professional engine builder just back yard, but when I started my NQS stock altered, i turned to a pro...and thats what he said everyone is doing...

 

[Horse_Nuts]

Modifying your carb yourself won't cost you a thing if you do it right. You'll use more fuel but, fuel = horsepower. There's no way to tell how much you've gained without having someone dyno the engine, but every little bit helps. Tractor pulling can be a game of inches and 1/2 horsepower more than the other guy can sometimes make the difference. Anybody that tells you they're consistently winning with a stock carb is pulling your leg.
I agree Greg Hackman's cams are the best out there right now.

 

[searstractorfan]

U might call Vogel Mfg...they are out in Illinois...they have a dyno and make these kinda parts..dont know how much help they'd be...

 

[Weaverama]

I don't understand the physics of that long rod/ short piston.

I don't get it all either but I have rationalized that the once the horsepower gets those pistons sitting on the longer rods spinning, the longer length of the rods cause the pistons to travel further. That longer travel length is what creates more torque; once you set those "long stroke" pistons in motion, they are harder to stop than a short stroke piston (which can rev higher) but have less torque. Probably has something to do with centrifugal force and bodies in motion tend to stay in motion and all that.

BTW my best advice with regard to Brian Millers site is to proceed with caution. Some info on there is very good but be careful and verify with another that what you are about to is correct.

 

[LilysDad]

Keeps the piston up or down in the cylinder at TDC or bottum which is what BTDC?? and that helps get more air into the cylinder supposedly.....

So, the piston doesn't come up as far in the cylinder, creating a larger chamber? Because it goes farther down in the chamber, the comression is still the same.

the longer length of the rods cause the pistons to travel further. That longer travel length is what creates more torque;

Only the crankshaft throw determines how far the pistons travel.

BTW my best advice with regard to Brian Millers site is to proceed with caution. Some info on there is very good but be careful and verify with another that what you are about to is correct.

I guess verifying is what I'm trying to do here. Where do you go to verify?

 

[geoz]

With a long rod, you need the proper piston. The pin height of the piston will need to be different, so the piston does not make contact with the head. A long rod gives a few advantages. A better rod ratio is one. (Less side loading of the cylinder/piston, = less wear, better ring seal, piston not rocking in the bore etc..) And longer dwell time to pack the cylinder with more air and fuel.

Im sure theres other advantages, but those are the main ones. High perf Chevys is what Im most familiar with, but the principal is the same. More fuel and air = more power.

 

[antiqueetc]

With a long rod, you need the proper piston. The pin height of the piston will need to be different, so the piston does not make contact with the head. A long rod gives a few advantages. A better rod ratio is one. (Less side loading of the cylinder/piston, = less wear, better ring seal, piston not rocking in the bore etc..) And longer dwell time to pack the cylinder with more air and fuel.

Im sure theres other advantages, but those are the main ones. High perf Chevys is what Im most familiar with, but the principal is the same. More fuel and air = more power.

What he said!!!

There is no difference in the length of piston travel. In addition to the items listed above, the piston 'dwells' at TDC a millisecond or so longer thus allowing more complete combustion before it starts moving down and reducing the pressure on the piston. That pressure = torque.

 

[Bigkrank]

It gives a more favorable torque angle to the crank throw also.

 

[Tater305]

:not_worth:not_worth:not_worth:not_worth:not_worth High performance chevy
:trink39:

 

[LilysDad]

As far as the carb, I didn't bore it out. I don't think that would work well on a work tractor. I did alter the high speed needle and plug and drill the bowl vent. I'm not sure I can tell a difference.

Has anyone tried a different carb other than the aftermarket Kohler types? The Harley guys used to love SU carbs for example. The smaller ones off of a MG would be about right.