Author Topic: Model 28 for pulling tractor.  (Read 963 times)

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Offline dagwoodz

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Model 28 for pulling tractor.
« on: March 17, 2017, 11:46:53 AM »
I posted over a year ago about building a Briggs 28 for an unlimited RPM pulling class. I have since built a Kohler K301 that is totally legal but just like the 10 other tractors I pull against.  Hecky doodle, one guy built 5 of the motors.  Anyway I am looking in to building a Briggs 28 for a stock class pulling tractor.  Stock means stock.  On the governor at 3850 RPM.  I am confused after reading a lot of posts.  So I want to run a combination by the members here.

model 28 block. Porting and polishing not allowed.  I will clean out the casting flash.
stock crank polished(?)
OHV rod polished(?) Do I need a billet rod at this RPM?
Stock Piston. Flathead or OHV?
Stock Cam and Lifters
Stock valves
Stock or better springs?
11 HP head play doughed and milled for max compression
Stock head gasket.

A couple questions.
Does the internal balance mechanism rob power?  Should I use the brass balancer?
Are all the stock flywheels the same weight? Will a heavier wheel of another engine work?  Kohler wheels are 19 lbs.

Thanks in advance.

Offline flatlanderfornow

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Re: Model 28 for pulling tractor.
« Reply #1 on: March 22, 2017, 04:20:40 PM »
Shave the head if you can and advance the timing.  No need for lots of fancy stuff at that RPM level with a stock cam.
Do a GOOD valve job on it and set the lash right. I'd be more concerned with getting the chassis to work good, as this is more important.   

Todd Potter

Offline nip 19

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Re: Model 28 for pulling tractor.
« Reply #2 on: March 23, 2017, 07:39:00 PM »
So are you planning on running stock or modified.  Most of the questions you asked should be answered on what your sanctions rules would allow.  Anytime you polish, change rods, flywheels, springs, remove balancers, and above 3650 rpms should be modified.  Anything above 3650 as anyone on  here will say should have a billet flywheel .
2011 GLMRA FX champion
2011 SRUSAAO FX champion.   Kevin