My lil' 5HP guide...

[oscaryu1]

http://www.arcracing.com/

Take a look for yourself.

 

[Russ2251]

I'm still looking!

 

[oscaryu1]

 

[jr dragster T]

Finally ARC has finally made the splined clutch post so we can use a billet crank with a splined PTO.

 

[Magice]

Okay I need a *little* more clarification!

Here is a picture of my new 5hp block. (not so new)

Can someone please shave the areas I need to shave?

ALSO - how deep to I shave?

 

[ed1380]

i never shaved and it runs great

you wouldnt knotice without a dyno

 

[oscaryu1]

Okay I need a *little* more clarification!

Here is a picture of my new 5hp block. (not so new)

Can someone please shave the areas I need to shave?

ALSO - how deep to I shave?

Don't touch the seats. That's how deep. And don't go so crazy you start seeing the rings.

 

[oscaryu1]

Pistons

I've just decided to add this in now. For people who are really building (or trying to) build up a Briggs 5HP flatty, start thinking about using Raptor pistons. Stock 5HP pistons have a tendency to break by the wrist pin area and crack the piston and allow the wrist pin to get ripped out. Raptor (3?) pistons solve this by having a much beefier area around there. Also, stock 5HP rings are large and steal lots of power. Raptor pistons on the other hand, have much smaller rings, so much you can turn the engine by it's PTO shaft when done.

 

[Jblankster]

VERY GOOD! i like it!

 

[oscaryu1]

Thanks

 

[Leem1994]

Is the number on the inside of the five horse head.

 

[oscaryu1]

Is the number on the inside of the five horse head.

?

Dunno whatcha talkin' about, but a 5HP head should have a #13 printed on it. A 4HP has a #10 (it may gain compression and low end, but kills mid and top)

 

[oscaryu1]

By the way... if anyone even reads this thread anymore, I just found this interesting:

Raptor 1 Engines - 3HP
Raptor 2 Engines - 4HP
Raptor 3 Engines - 5HP

So yeah... don't go around buying stock Raptor 1 parts thinking they're made for bad*zz stuff and then dump a few thousand RPMs into its parts...

Suprised? So was I... 3HP?! A racing motor?! PLEASE Briggs...

 

[Kaptain Krunch]

yea i learned the raptor 3 was only 5hp the other day...its pretty pathetic, i mean maybe a junior racing engine or something. So whats the parts difference in your standard flatty and a raptor?

 

[oscaryu1]

Well... Raptor 3 has a piston that has less skirt area, so less friction = more power, thinner rings...

A rod with integrated dipper that can supposedly hit about 7000RPM before breaking...

Alot of things that supposedly "increase" power but it still makes 5HP... fail...

But still, I expected 6-8HP at least... 5?!

 

[jr dragster T]

Oscar, A shorter skirt is ok with a stock stroke engine. But when you throw in a short skirt piston with a stroker 3" stroke crank or so its very hard to keep the bore and piston in good order for long. If its a aluminum bore forget about it. Every single Raptor engine I've seen on a Junior Dragster has blown to peices first pass.

 

[greasemonkey85]

you guys are taking this stuff way to seriously. the raptor 1 2 3 is what they have been using in karting for years! jr dragster is a different story, i won t even go there. but a stock flywheel is good for at least 9000 rpm if taken care of. that means no banging with a hammer or anything like that. the stock rods, just forget them, for $50 you can get a billet arc rod and turn it as hard as you want. the pistons holds true, raptor 3 pistons are far superior to the older stuff. we have to follow strict rules concerning engine parts. we run billet rods and raptor 3 pistons. a "stock" class motor turns 7000 rpm give or take. my "controlled stock" i have turned 9000 rpms with it and race EVERY WEEKEND and turn it 8000+ running a methanol, which is worse for a engine then gasoline.

i also don t agree with some stuff in this thread, but that is just me. the eyebrows really don t make that much of a difference. if it was me go INVEST into a clone. far better motor than a flat head. plus in a few years you ll be lucky if you can still find parts for the flatty's

 

[oscaryu1]

and turn it 8000+ running a methanol, which is worse for a engine then gasoline.

Not if you flush it out of the cylinder every race and use methanol mixable oil.

the eyebrows really don t make that much of a difference.

This was a more "bang for buck" type of thread. If the clones had eyebrows, I have honestly no doubt that you and everyone would be all over that.

Sorry, cheap power is just as good as methanol burning billet power. Put both together and you have something brilliant. Just because it's easy power doesn't mean it doesn't work.

go INVEST into a clone. far better motor than a flat head. plus in a few years you ll be lucky if you can still find parts for the flatty's

All the better to do mods that don't require too many parts.

I have already invested plenty in a Clones, heck, maybe more than you have. Billet flywheel, 8 degrees advanced timing, ARC Billet rod w/ bearings, Flat Top Piston, 14cc head, thin head gasket, Stainless Steel valves, indexed spark plug, billet retainers, automotive style keepers, 26lbs springs, metal lash caps, 1.2:1 ratio rocker arms, chromoly push rods, Robertson TorqTube, Super Dyno X 275 .265" lift cam, UNI filter....


Built that when I was 13. Took a while, but I think that's plenty for "investing in a Clone"... don't you?

It's people like you who hate on the Briggs 5 horse because of it's older design... the design that restricts major power output.

Stop a'hatin boie

 

[Kaptain Krunch]

Greasemonkey, the point of this thread was to get your cheap power like Oscaryu said. Some people dont want to buy a $100 clone then go ahead and put another $400 into it. Briggs flathead engines are so popular you can often get them for free (i've gotten 2 that run fine for free, not counting the free verts i've gotten), and if you have it why not build it up a little, especially if you can make a decent motor for under $100.

Secondly, if you want to invest in a "far better motor" you should just get a sled or mc engine, because for the price of a decent 440 (i can find them for under $100 easily) you get the power of over 8 flatties, and 8,000 rpms out of the box, plus a torque converter!

And lastly, i highly doubt that flathead parts are going extinct at all. Do you know how many of these things are out there? you go to a junkyard and look at all the snowblowers, edgers, and tillers, and tell me how many of them have a briggs flatty on them.

 

[jr dragster T]

Well said guys.