Rod side clearance

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oldkimmer

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I have .008 with factory rods. Would a light sanding on the big end work? Or mill some off? If not what’s the best way to gain some. This is a 318 poly crank going into a 340. Thanks. Kim
 
.008 is on the thin side. I'd rather see .020 or more. As long as the rods don't touch when running you're ok.

Contrary to popular belief, a wide side clearance doesn't over oil the cylinder walls. Oil control is a function of bearing clearance, not side clearance.
 
I've raced (long endurance use in rallying) with that little rod side clearance on other motors and never any issues. If you sand, place the paper on a known super flat surface (machinist's flat or granite counter), apply pressure all around the end, and move the rod end in a circular fashion both CW and then CCW to try to keep the sanding even.
 
Make sure not to use standard sand paper. You can't put it back once you take it off. Extra fine wet/dry or crocus cloth.
 
I like at least .010, and a ton isn't a problem.

Right. I've seen .060" and more. I've even seen Jim Laroy comment that "a lot" of side clearance isn't critical. He oughtta know.
 
Don't sand the chamfer off, lay it on a surface plate, use a figure 8 pattern...........if you are brave, I've seen seen rods done on a Craftsman belt sander...........Or, if you have access to a surface grinder with a magnetic chuck, fast and accurate
 
You can use sandpaper glued to a piece of glass. I use a window glass from a '35 Ford.
 
Spec is .009 to .017. I use a glass plate, WD-40, and 320 then 400 wet or dry sandpaper. Lay the wet or dry sand paper starting with 320 on the glass plate and WD-40 and do a few figure 8's to clean both sides up, then finish with a few more figure 8's with 400 and WD-40 and be done.
 
Don't sand the chamfer off, lay it on a surface plate, use a figure 8 pattern...........if you are brave, I've seen seen rods done on a Craftsman belt sander...........Or, if you have access to a surface grinder with a magnetic chuck, fast and accurate

Zactly!

And you can pick up a decent enough surface plate on craigslist. You can't have too many tools!
 
where can I get a 35 Ford?
and hone oil not wd-40 wd-40 tends to embed tiny grits

Never had a problem with WD-40. A whole lot of engines lasting 200,000 to 300,000 miles. Polished cranks, valve stems, bearing surfaces, and the sides of rods. Is honing oil better? Maybe, but not much that I can tell.
 
Zactly!

And you can pick up a decent enough surface plate on craigslist. You can't have too many tools!

I've got four granite surface plates, and they are all utilized in different parts of the shop. For this type of work a cut off from a granite counter or a granite floor tile is plenty flat enough and cheap. I have one granite that I use for this type of lapping and depending what is on hand I'll either slop some oil between the paper and stone to hold it in place, or use a light coat of spray adhesive to hold it on. The paper moving around is a PITA. For steel I like a light 10W oil and for aluminum I typically use WD40 in a squirt bottle. Random pattern or figure eight is important.
 
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