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bp131 05-26-2013 01:10 PM

Question about connecting rod polishing
 

I started in on cleaning up a set of triumph 650 connecting rods. I noticed at the top of one of them there are a couple little nicks, on both sides. I sanded on it a bit but don't know how much is too much. The other rod is in good shape. And yes, I plan on putting in new small end bushings. Do any of the resident experts think that this is OK to run.

http://i1018.photobucket.com/albums/...psf44c6eb9.jpg

http://i1018.photobucket.com/albums/...pse7c7ed44.jpg

Tony the torch 05-26-2013 01:13 PM

Re: Question about connecting rod polishing
 

if your not building an 8k rpm race motor you be ok.
clean them up and polish 'em.

BCOWANWHEELS 05-26-2013 04:10 PM

Re: Question about connecting rod polishing
 

nice polish job, no worries on those little defects unless your going all out in the compression and rpm's , magniflux them !!!!!!

HRC 05-26-2013 04:43 PM

Re: Question about connecting rod polishing
 

As said, just polish out the sharp nicks, but remove as little material as possible.

I bet you a dollar you'll have a hard time finding someone to mag them...;)

Hans

HRC 05-26-2013 05:04 PM

Re: Question about connecting rod polishing
 

Quote:

Originally Posted by Dragstews (Post 925225)
I was thinking the same....

http://youtu.be/109-Uzu2ihw

Magnafux doesn't work on Non-ferrous metals so a dye pentrant must be used.

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And on that note, if you go to the trouble of getting them dye pen'd, make sure they use flourescent dye penetrant...mucho bettero.<script type="text/html" id="overlay_tmpl">
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bp131 05-26-2013 05:23 PM

Re: Question about connecting rod polishing
 

Thanks for the responses. Of course in my mind I'm building the baddest motor ever but in reality it will be just a bit better than stock. This build is going to be pretty straight forward as it's a stepping stone for a future build. There is a guy close by that can magnaflux the crankshaft. Maybe he equipped to do the rods.

Tailbreaker 05-26-2013 06:24 PM

Re: Question about connecting rod polishing
 

It's probably not necessary unless you are building a race motor but I like to ensure that they are both the same weight which helps to balance the lower end.

JAWS 05-26-2013 10:09 PM

Re: Question about connecting rod polishing
 

Definitely check weight if you remove any material, like polishing. I mean that if you are taking the time to polish and finesse them, why not make sure the weights are the same, hell do the pistons too...all to half a gram difference.

Daddy Boy 05-27-2013 03:23 AM

Re: Question about connecting rod polishing
 

What you're doing is right. You're gonna ride it flat out from time to time, that's the same as racing. Every little nick or scratch (especially around the small end) is a 'stress raiser'.
From 69 the meat below the s/e eye is beefier.
Do it to all stressed parts. Lightened rockers, pushrods, big end bolts.

bp131 05-27-2013 07:14 AM

Re: Question about connecting rod polishing
 

At the time I built the 64 I didn't really have any money so lot's of down time. I polished and smoothed out a lot of stuff before assembly. The rods for that were in really good shape. Just needed to go through the process of getting them shiny. Knowing I was going to put it through its paces. The 64 is not a daily rider, more of an up early on the weekends and ripping around back roads and cutting through fields kinda thing. I hate typing. maybe I should just start a new build thread with a lot of pics.


These are the polished parts from my 64 TR6 SC
http://i1018.photobucket.com/albums/...1/HPIM1488.jpg

http://i1018.photobucket.com/albums/...1/HPIM1531.jpg

http://i1018.photobucket.com/albums/...1/HPIM1589.jpg

drainsurgeon 05-27-2013 10:06 AM

Re: Question about connecting rod polishing
 

WOW!!!! Nice job on the head. If you don't mind me asking. What was your way of doing this? Were the pistons done by hand? Did you polish the skirts on the piston? Grits? Sand rolls? Scotchbrite?

Mr.Pete 05-27-2013 02:59 PM

Re: Question about connecting rod polishing
 

Knock the sharp edges off the valve pockets on those pistons;it helps.I use a 1/8" radius where possible.In some places,you'll have to settle for a little less than 1/8" radius.

bp131 05-27-2013 03:35 PM

Re: Question about connecting rod polishing
 

Mr Pete....too late, those pistons are already installed and running on this bike. That did cross my mind but my thinking was that I'd probably botch it somehow.

https://www.jockeyjournal.com/forum/s...ad.php?t=63643

I'll most likely do it on this new build.

drainsurgeion....I started with a little 120 grit flap sander for the dremel tool. Being very careful of the valve seats. 200, 320, 500, 800, 1200 wet sand and if I remember right 2000 wet sand, then steel wool and WD40. Then broke out the jewelers rouge. Like I said I had a lot of time on my hands.

I even smoothed out and polished the exhaust ports and matched up the manifold to the head so there is not any lip where they meet.
http://i1018.photobucket.com/albums/...1/HPIM1497.jpg

JAWS 05-27-2013 03:37 PM

Re: Question about connecting rod polishing
 

That's racecar right there.....good work.

OnVacation 05-27-2013 07:26 PM

Re: Question about connecting rod polishing
 

I'm envious of your patience. I should have taken the time to polish my heads last time I had them off.

but the next bike I'll build...

Alan Sputhe 05-27-2013 09:17 PM

Re: Question about connecting rod polishing
 

It sure looks like a crack to me. I wouldn't run it unless it passed Zyglo inspection. And then I would polish any nicks out. (A nick is the beginning of a crack and a crack is the beginning of a catastrophic failure.)

When I have a part that fails Magnaflux or Zyglo I often do a distructive test to see how close to failure it was. In any case I distroy the part so that it can't be accidentally reused.

HRC 05-28-2013 12:43 PM

Re: Question about connecting rod polishing
 

Be sure NOT to polish the piston skirts, the roughness/machined ribs is what holds the oil there....and dont do the intake ports either...port them, port match them, raise the floor, etc etc, but the slight roughness creates minutte turbulance right at the surface which keeps your fuel in suspension. Polished intake ports can lead to fuel dropping out of you A/F mixture on the slow side of the port....this means poor performance and possible washed out rings in severe cases.

Hans

magnum45pete 05-28-2013 01:28 PM

Re: Question about connecting rod polishing
 

Quote:

Originally Posted by HRC (Post 927921)
Be sure NOT to polish the piston skirts, the roughness/machined ribs is what holds the oil there....and dont do the intake ports either...port them, port match them, raise the floor, etc etc, but the slight roughness creates minutte turbulance right at the surface which keeps your fuel in suspension. Polished intake ports can lead to fuel dropping out of you A/F mixture on the slow side of the port....this means poor performance and possible washed out rings in severe cases.

Hans

I was going to say that Jerry Branch did some work on Polished intake ports Verses Un-polished ports, and I seem to remember he found that contrary to popular belief,rough tracts gave more power than polished ones................I think he put it down to the roughness would tend to swirl/mix the fuel with air better..........

bp131 05-28-2013 06:12 PM

Re: Question about connecting rod polishing
 

I didn't polish the skirts or the intake. After smoothing and contouring the intake I went over it with 120 grit. Someone compared the gas going down a polished intake like rain water running off your windshield at highway speeds. How it just sticks to the glass and creeps along. That same person said that 120 will work fine and it does. The bike I did that stuff to performs really really good. I wont do all that stuff on the new build as the head I just scored is rebuilt and ready to run.

I'm definitely gonna get the rods checked out.......better safe than sorry.


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