Needing advice for honing a connecting rod.

[Andrew05]

Right now I'm finishing up a basic 5hp Briggs flathead build, and one of the parts I replaced was the connecting rod. I got a Raptor 3 rod (Briggs part #555208), and I made the mistake of not realizing that it's designed for a 0.020" ground crank. I saw that they can be honed out to the factory specs, but I'm not sure how to do it. Does anyone have experience with doing this using home tools? I've done some looking around and from what I've seen most people have them done on a lathe. Is this something I need done at a shop?

Here's a link to the rod:
Briggs Motorsport Connecting Rod 555208 Raptor 3 | The Drag Racing Blog (wordpress.com)

 

[Master Hack]

. Does anyone have experience with doing this using home tools

It is not possible. It takes accurate equipment to size it right and keep it concentric and perpendicular. If the bore is not right it will cause catastropic failure..

it's designed for a 0.020" ground crank

Ya can’t hone out .020 Size matters as does contricity. (See reason above)

Is this something I need done at a shop

Yes, better yet buy the correct one.

 

[Darren]

I imagine, the cost of getting the rod polished out to the correct size would be higher than a new rod.
Won't the shop take the rod back and exchange it?

 

[Andrew05]

Sorry for responding late, I've had the rod for a little while now and it's past the return date. I'll probably just use the stock rod, I don't plan on running the engine much past 5k rpm's anyways. ARC has a billet one for $70 if I do upgrade, and I bet that getting mine honed would be roughly the same if not more. I appreciate the advice, guess I've got to find something to do with this raptor rod then lol.

 

[Rat]

Right now I'm finishing up a basic 5hp Briggs flathead build, and one of the parts I replaced was the connecting rod. I got a Raptor 3 rod (Briggs part #555208), and I made the mistake of not realizing that it's designed for a 0.020" ground crank. I saw that they can be honed out to the factory specs, but I'm not sure how to do it. Does anyone have experience with doing this using home tools? I've done some looking around and from what I've seen most people have them done on a lathe. Is this something I need done at a shop?

Here's a link to the rod:
Briggs Motorsport Connecting Rod 555208 Raptor 3 | The Drag Racing Blog (wordpress.com)

It's ill advised but you can bolt the end on tight as if you were installing it and spin something that just barely fits through wrapped 1000g and work it slowly. It is possible to knock it down a little faster with 400 or 600 as long as you work it wet and leave some meat to polish with 1000 or higher.
You have to make sure you spin it and use no sawing motion or apply any directional pressure.

I've done it, it ran fine and never had issues, so the method CAN work for small clearance issues under 0.030" but again don't mistake this as a suggestion or advice, I'm not an amateur with engines despite certain aspects of minibikes and karts being a more recent learning experience.

 

[Denny]

Just use a wheel cylinder hone. Make sure to torque the bolts on properly. Best done on a drill press.

 

[Master Hack]

Just use a wheel cylinder hone. Make sure to torque the bolts on properly. Best done on a drill press.

Well, maybe rethink that. .020 is a lot!

Connecting Rod Honing Basics

Over the past few weeks we’ve been talking about Connecting Rod Reconditioning in Tech Notes. Thanks to our friends at Sunnen® Products Company, we’ve been able to share material from their book, Sunnen’s Complete Cylinder Head and Engine Rebuilding Handbook. Unfortunately, this book is now out...

goodson.com

 

[Thepartsguy]

Sorry for responding late, I've had the rod for a little while now and it's past the return date. I'll probably just use the stock rod, I don't plan on running the engine much past 5k rpm's anyways. ARC has a billet one for $70 if I do upgrade, and I bet that getting mine honed would be roughly the same if not more. I appreciate the advice, guess I've got to find something to do with this raptor rod then lol.

A .20 rod would mean .20 has been taken off the crankshaft and a hone will not help you here. Are you on the briggs facebook page? You mentioned a billet rod? They are $25 for a stock length billet arc rod. He had well over 10 of them for sale.

 

[Andrew05]

@RLS_Underground I figured you could do something like this, and if it was only a couple thousandths off I would've tried it. I would be worried about ruining the rigidity of the rod. Also @Thepartsguy, can you send me a link to that? If they've still got some for sale I'll get one today lol. The only groups I'm a part of right now is this forum and a minibike group on Facebook. Do you know if they ship to Tennessee?

 

[Denny]

Tennessee is that some kind of foreign country?

Of course they probably do, for a price.

 

[Thepartsguy]

@RLS_Underground I figured you could do something like this, and if it was only a couple thousandths off I would've tried it. I would be worried about ruining the rigidity of the rod. Also @Thepartsguy, can you send me a link to that? If they've still got some for sale I'll get one today lol. The only groups I'm a part of right now is this forum and a minibike group on Facebook. Do you know if they ship to Tennessee?

Join briggs performance and fun page on Facebook open to anyone who would like to join. Scroll down the first few posts you will find it. you have to join that group to see the posts though. His prices are usually as listed so you would pay $6 shipped. you need PayPal

 

[Master Hack]

Just use a brake hone they say. Ya don't need no stinkin expensive machine.
Process is the same on both ends. ( I actually know a little about this machine)

 

[Denny]

Did you see the runout in that shaft? He was boring out the big end probably for a bigger pin or full floating pins. Ok, use a rigid hone then and lots of honing oil!

 

[Master Hack]

Thats an old school machine, like me. Now a days the youngns use some new fangled CNC crap. Push a button sit back and sip on yer red bull.
I remember when (said in my best geezer voice) when ya had to know more than how to push start!
The mandrels for that machine were accurate to within .0002 if the bearings were accurate and the machine was setup properly.

 

[Denny]

Don’t worry Terry, I’ve been yanking your chain the whole time! No way on God’s green earth would I hone out a big end with a wheel cylinder hone!

 

[Master Hack]

S'all good! I just like old machines, they are soooo much fun!
An I been yankin yer chain. I have no idea what that thing is or does. The pic looked cool tho!

 

[Denny]

That machine bores the small end of rods. Could probably do the big end too. Then a rigid hone is used for final size. That’s an old machine and the shafts have too much run out for my engines! Not a hone though that I recognize.

 

[Master Hack]

Ok, the point is it needs to be more accurate than a drill motor and a hone.

BTW, the machine does both ends and has zero runout. Yer seeing the pneumatic clamps and the plug screwed into the end. It is a boring machine not a hone. Single point boring. Just another example of engineering of yesteryear!
that old s**t fascinates me. done without computers.
Technology has vastly improved machining quality, but mankind has made some impressive machines, with pencil, paper and gray matter.

 

[Andrew05]

Ok, the point is it needs to be more accurate than a drill motor and a hone.

BTW, the machine does both ends and has zero runout. Yer seeing the pneumatic clamps and the plug screwed into the end. It is a boring machine not a hone. Single point boring. Just another example of engineering of yesteryear!
that old s**t fascinates me. done without computers.
Technology has vastly improved machining quality, but mankind has made some impressive machines, with pencil, paper and gray matter.

It honestly amazes me how simple older tools were, yet how precise they could be. I got an old set of tools from my great-grandfather after he passed, and I've got some old rachets and whatnot that honestly feel nicer than what I see today. Also @Master Hack thank you so much for letting me know about that guy with the rods, I got one ordered.

 

[Master Hack]

lso @Master Hack thank you so much for letting me know about that guy with the rods, I got one ordered

Not me. I believe that was the the parts guy. Thats what he does, parts.
l just throw in useless info, stupid jokes, and waste everyones time.
l expect an eviction notice any day now!