Question about connecting rod polishing - The Jockey Journal Board

Go Back   The Jockey Journal Board > General Discussion > The Board

Reply
 
Thread Tools Search this Thread Display Modes
Old 05-26-2013, 01:10 PM   #1
bp131
Senior Member
 
bp131's Avatar
 
Join Date: Nov 2009
Location: New Orleans
Posts: 375
Default 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.



bp131 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-26-2013, 01:13 PM   #2
Tony the torch
Senior Member
 
Tony the torch's Avatar
 
Join Date: Oct 2008
Location: still in so cal.
Posts: 3,691
Send a message via Yahoo to Tony the torch
Default Re: Question about connecting rod polishing

if your not building an 8k rpm race motor you be ok.
clean them up and polish 'em.
__________________
Possibly the finest private collection of Whitworth screwdrivers in the U.S.
Tony the torch is offline   Reply With Quote
Old 05-26-2013, 04:10 PM   #3
BCOWANWHEELS
Senior Member
 
Join Date: Jan 2011
Location: TENNESSEE
Posts: 553
Default 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 !!!!!!
__________________
I BELIEVE IN JOHN 3:16
BCOWANWHEELS is offline   Reply With Quote
 
Old 05-26-2013, 04:43 PM   #4
HRC
Senior Member
 
HRC's Avatar
 
Join Date: Dec 2009
Location: Texas/Norway
Posts: 359
Default 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 is offline   Reply With Quote
Old 05-26-2013, 05:04 PM   #5
HRC
Senior Member
 
HRC's Avatar
 
Join Date: Dec 2009
Location: Texas/Norway
Posts: 359
Default Re: Question about connecting rod polishing

Quote:
Originally Posted by Dragstews View Post
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.

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.

Last edited by Dragstews; 05-26-2013 at 05:17 PM.
HRC is offline   Reply With Quote
Old 05-26-2013, 05:23 PM   #6
bp131
Senior Member
 
bp131's Avatar
 
Join Date: Nov 2009
Location: New Orleans
Posts: 375
Default 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.
bp131 is offline   Reply With Quote
Old 05-26-2013, 06:24 PM   #7
Tailbreaker
Member
 
Tailbreaker's Avatar
 
Join Date: Mar 2010
Location: Pensacola, FL
Posts: 38
Default 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.
Tailbreaker is offline   Reply With Quote
Old 05-26-2013, 10:09 PM   #8
JAWS
Senior Member
 
JAWS's Avatar
 
Join Date: Jul 2007
Location: la la land
Posts: 8,512
Default 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.
__________________
60% of the time, it works every time...
JAWS is offline   Reply With Quote
Old 05-27-2013, 03:23 AM   #9
Daddy Boy
Banned
 
Join Date: Aug 2008
Location: Melbourne, Australia
Posts: 980
Default 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.
Daddy Boy is offline   Reply With Quote
Old 05-27-2013, 07:14 AM   #10
bp131
Senior Member
 
bp131's Avatar
 
Join Date: Nov 2009
Location: New Orleans
Posts: 375
Default 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




bp131 is offline   Reply With Quote
Old 05-27-2013, 10:06 AM   #11
drainsurgeon
Member
 
drainsurgeon's Avatar
 
Join Date: Apr 2011
Location: So Subs Chicago
Posts: 78
Default 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?
drainsurgeon is offline   Reply With Quote
Old 05-27-2013, 02:59 PM   #12
Mr.Pete
Senior Member
 
Join Date: May 2010
Location: Victoria,Australia
Posts: 498
Default 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.
Mr.Pete is offline   Reply With Quote
Old 05-27-2013, 03:35 PM   #13
bp131
Senior Member
 
bp131's Avatar
 
Join Date: Nov 2009
Location: New Orleans
Posts: 375
Default 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.
bp131 is offline   Reply With Quote
Old 05-27-2013, 03:37 PM   #14
JAWS
Senior Member
 
JAWS's Avatar
 
Join Date: Jul 2007
Location: la la land
Posts: 8,512
Default Re: Question about connecting rod polishing

That's racecar right there.....good work.
__________________
60% of the time, it works every time...
JAWS is offline   Reply With Quote
Old 05-27-2013, 07:26 PM   #15
OnVacation
Senior Member
 
OnVacation's Avatar
 
Join Date: Nov 2010
Location: Petersburg, VA
Posts: 334
Default 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...
__________________
Land of the Free, because of the Brave
OnVacation is offline   Reply With Quote
Old 05-27-2013, 09:17 PM   #16
Alan Sputhe
Junior Member
 
Alan Sputhe's Avatar
 
Join Date: Mar 2013
Location: Grass Valley, CA
Posts: 26
Default 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.
Alan Sputhe is offline   Reply With Quote
Old 05-28-2013, 12:43 PM   #17
HRC
Senior Member
 
HRC's Avatar
 
Join Date: Dec 2009
Location: Texas/Norway
Posts: 359
Default 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

Last edited by HRC; 05-28-2013 at 12:43 PM. Reason: Poo
HRC is offline   Reply With Quote
Old 05-28-2013, 01:28 PM   #18
magnum45pete
Senior Member
 
magnum45pete's Avatar
 
Join Date: Jan 2013
Location: Brighton England
Posts: 1,618
Default Re: Question about connecting rod polishing

Quote:
Originally Posted by HRC View Post
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..........
magnum45pete is offline   Reply With Quote
Old 05-28-2013, 06:12 PM   #19
bp131
Senior Member
 
bp131's Avatar
 
Join Date: Nov 2009
Location: New Orleans
Posts: 375
Default 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.
bp131 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -5. The time now is 09:50 PM.