Topic: Piston pin to arc rod clearance

[crazycraftsman]

These are brand new parts and was wondering what the max clearance is. If you can get movement is it junk?. I haven't measured it with a micrometer yet but I would say pin is atleast .002-004 tho play.
Thanks for any info
Got my mic
Alright factory used pin size is 0.669 fits nice on arc rod.
New Aftermarket pin is 0.666 has some movement .
Is this ok ?

[chavez]

Reckon if you can feel it.....always went with free movement but no perceptible play on auto parts....I'd be nervous

[crazycraftsman]

Ya I'm nervious , that's why I'm asking.im going to be reving this thing atleast 8500-9000rpm.

[chavez]

I wouldn't trust it in anything. I know one needs oil clearance but not sure about that one on a mower mill. I may very well be wrong....splash lube needs to be loose to live, but.....I'd like to hear from the experts too

[cycloneracer]

What engine?

What parts?


That will help you get your answer.  And help me put it in the correct section.

[trbinrat]

Call ARC.  I called them when I was resizining my rod to a new pin and they gave me the clearance needed.

[Cromwell C4]

Owen, in performance engines we normally run .0008" - .0012" clearance on the wrist pin but i have heard of some people using .002" .003" for more oil retention in certain applications depending on the type of oiling system used. I would say no less than .0008" and no more than .0015"

[crazycraftsman]

  . Not having any luck at all.

[George Herrin]

Save the headache, get an oem pin aint but 7 or 8 bucks. And be done with it.

[crazycraftsman]

The factory pin is 1/4" shorter than the one that fits piston . The (piston) pin bore would need to be opened up .004. So custom pin? Machining of piston?This is a 35 cube vanny twin stock bore. I have the arc long rods. Is there a direct fit aftermarket piston that will work with the long rods? With the correct pin clearance for arc rod. Someone that's run or is running this setup now, can you help me out. I don't care about cost of pistons. I have no access to any machine shops that will or have worked of small engine boring so , direct fit would be nice. Part # and where to buy. I would really appricate some honest help.

[George Herrin]

What pistons are you using  now!!! that everything is so different.

[Rocket Ron]

Thats why all parts I have mfg. I leave everything a few tenths of a thouy. under size can always resize up but hard to put material back!

[Cromwell C4]

Al Hodge at Performance V-twins is the only other person I know of who sells drop in aftermarket pistons for the 4.262" long rods. He has some Wiseco and Arias pistons, but they aren't cheap. Call him at 704-291-7825 and tell him what block you are using (bore size) and your rod length.

[crazycraftsman]

I do not have a part #as they are not on box , nor did I get part #, but was told they were high compression dome top scotter pistons. They have a much shorter skirt. The pistons fit perfect in bore , .010 from top deck height with long rods. The seller has (refunded )me the money back and now I'm looking for the right set!!! I'll phone performance v-twins and hopfully he can help me out using the arc rod as he has his own rods. 17.03 mm stock vanny pin, Chinese or whatever they are are 16.96 mm. Pin was listed as 17mm. I just wanted to know what spec for clearance I should have and now I know it's to much!

[Rocket Ron]

FIY PVT 6061 no inserts