Topic: Piston pin clip index position?

[Hannibal Smith]

Just about ready to button her up, and I need to get this tidbit confirmed here-

Never messed with this type of wrist-pin retention before, is the correct method as pictured (seems the most logical to me) that the opening of the clip is centered over the access opening in the clip groove, so as to not have unsupported clip area (knees in the breeze, if you will). Or, do you guys rotate the clips so that the opening of the clip is within a portion of the groove?

Pics show clips installed with clip ends at the border of the relief cut within the clip groove-

[754]

Pointing down, if anything the force of combustion will spread it tighter..

 And top ring 180 degrees from midpoint between plug & exhaust valve...

[Hannibal Smith]

Pointing down, if anything the force of combustion will spread it tighter..

 And top ring 180 degrees from midpoint between plug & exhaust valve...

I am talking about the little "C" clip that stops the floating pin from going left/right! sorry if I wasn't clear!

[754]

 Yes, if it is affected by downforce, the gap being at 3 oclock could close slightly. Whether it actually does , I dont know..

[Hannibal Smith]

Yes, if it is affected by downforce, the gap being at 3 oclock could close slightly. Whether it actually does , I dont know..

It is a clip that acts in shear to retain the 15mm piston pin, downward force isn't applicable, at least to any degree that would factor in, I am just curious as to how the system was designed, and if rotating the "opening" to a spot other than the relief is correct-

[dave500]

spin the clip so the ends are within the groove.

[Hannibal Smith]

spin the clip so the ends are within the groove.

Just out of curiosity here-

The clip ends are "wider" when installed within the groove than the relief is wide, so they are in fact still supported with the groove, so why would one want to effectively double the span of un-supported (and non-effective in shear) ring?
Granted, we are splitting hairs here, as it would be reatined with 1/10 of what it has now, but it does make me wonder...................

We have a "compressed" (installed) gap of 4.2mm, if we rotate the clip, we now have 8.4mm of unsupported (in proper shear configuration) clip, the ring that spans the 4.2mm gap (if rotated) is no longer in shear as it is unsupported. It is only in shear where it is retained via the groove in an engineering sense. Purely academic, I know!

[MCRider]

If you do it this way, and leave it, the clip will span the opening, with the opening of the clip itself in the groove. The instructions say nothing about turning the clip, once installed, to align the clips opening with the install cutout of the piston.
http://atvconnection.com/departments/atv_tech/tech-tip-5-proper-piston-circlip-installation.cfm

I think it is a non-issue. I'd leave the clip in whatever position its in once installed.

Same here:
http://www.bigboyzcycles.com/showthread.php?t=82

[Hannibal Smith]

This is a JE piston from my Lotus racecar, fully supported spiral lock for the pin, if there was a relief, the spiral lock would be technically unsupported-then it would have to be engineered to account for this.

Doing Google searches doesn't get me anywhere, I guess nobody is concerning themselves, and just popping them in, but this kind of stuff drives me crazy.

[Hannibal Smith]

If you do it this way, and leave it, the clip will span the opening, with the opening of the clip itself in the groove. The instructions say nothing about turning the clip, once installed, to align the clips opening with the install cutout of the piston.
http://atvconnection.com/departments/atv_tech/tech-tip-5-proper-piston-circlip-installation.cfm

I think it is a non-issue. I'd leave the clip in whatever position its in once installed.

Same here:
http://www.bigboyzcycles.com/showthread.php?t=82

Thanks, I won't sweat it. Funny, when I first put them in I had them rotated past the relief, then a few beers later, I started thinking maybe I should rotate them back over the relief..........

[MCRider]

I used "piston pin clip install" as my Google search request to get the sites I posted. Also much more reading of forum type hits. Mostly non-issue. A few people would say put the clip opening at 12oclock or 6 oclock, but that would have to be more for the motion of the piston than for the area of the install cutout. As the cutouts can be other than 6 oclock. I've never seen one at 12 oclock, seen some at 3 oclock and elsewhere.

bottom line... non-issue at least to me.

[mystic_1]

IIRC, Hondaman's book says to have the clip's gap opposite of the relief in the piston, so that's what I did when I installed my pistons recently.

Prior to this rebuild and reading HM's book, I never worried much about the location of the gap, and it was never a problem.

mystic_1

[gnarlycharlie4u]

o... that's what those little clips are for.

oh well, bike seems to run fine without them.

[BLUE71TURBO]

 GEEZ !!  If your paranoid about the clips just run spiral locks or buttons.   

[754]

 If you have tapered wristpins, you can use cigarillo tips trimmed with a penknife..

 So sayeth Grumpy Jenkins........

[HondanutRider]

To be definitive, consultation of the Honda Common Service Manual gives this advice:

[MCRider]

To be definitive, consultation of the Honda Common Service Manual gives this advice:

Very interesting. I know there may be restrictions in time and space in a manual, and even though I basically agree with it, when someone tells me "do not do..." I want to know why. The only real reason I can think of for not aligning the gap with the cutout is that it will make it difficult to remove the clip later on. It may get baked in place, and you won't be able to get a pick under it as you would if some of the clip were exposed in the cutout.

A side issue, we are told to space ring end gaps 180deg apart, upon assembly. I've read extensively on this and my conclusion is this is an old wives tale. The reason being that piston rings rotate in their grooves when the engine is running, so what possible difference could it make upon assembly. I ran across a rather extensive test of this issue which proved definitively that rings rotate during operation. Its elegant and I'll likely do it for the rest of my life out of habit, but... you see what i mean?

Or... maybe I'll align them all on top of each other next time just to be ornery. 

[Hannibal Smith]

I know, I know!

I am not worried about it not doing it's job, but I only button up so many motors in my life, and this makes it a little more fun.
I just showed the piston to a gear head employee, and he hadn't seen this type either-his best reasoning was that by rotating the clip past the cutout, it would minimize the chance of one of the "C" legs popping up and "unwinding"................anyway, thanks for all the input fellas.

I will remember the cigarillo trick for the post-apocalypse.

[MRieck]

Try getting the clip out of the groove with the gap in the open area.

[mec]

Try getting the clip out of the groove with the gap in the open area.

+1
a friend of mine helped me reassembling an engine and mounted the gap in the open area. next time disassembling the engine i had to fabricate a special tool to be able to rotate the ring a bit.

mec

[MCRider]

Try getting the clip out of the groove with the gap in the open area.

+1
a friend of mine helped me reassembling an engine and mounted the gap in the open area. next time disassembling the engine i had to fabricate a special tool to be able to rotate the ring a bit.

mec

diing ding
"The only real reason I can think of for not aligning the gap with the cutout is that it will make it difficult to remove the clip later on. It may get baked in place, and you won't be able to get a pick under it as you would if some of the clip were exposed in the cutout."

Guess I was right too.      

[754]

Heyy, I was kidding about the cigarillo tip.. pretty good eh??
 I heard a few stories of Grmpy tossing his cigar butts in V-8s being revved up  at the end of tuning and pronouncing them, good to go...

[MRieck]

Try getting the clip out of the groove with the gap in the open area.

+1
a friend of mine helped me reassembling an engine and mounted the gap in the open area. next time disassembling the engine i had to fabricate a special tool to be able to rotate the ring a bit.

mec

diing ding
"The only real reason I can think of for not aligning the gap with the cutout is that it will make it difficult to remove the clip later on. It may get baked in place, and you won't be able to get a pick under it as you would if some of the clip were exposed in the cutout."

Guess I was right too.      

Absolutely MC

[gnarlycharlie4u]

Heyy, I was kidding about the cigarillo tip.. pretty good eh??
 I heard a few stories of Grmpy tossing his cigar butts in V-8s being revved up  at the end of tuning and pronouncing them, good to go...

...well i suppose it'll eventually burn up...

...or get sucked into the valvetrain and require an immediate oil change