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How much piston to wall clearance can I get away with?

T

TetanusShot

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See title for question

The pistons are second hand, never used .060 over Arias pistons that were swap meet specials, I assume they're forged. I've got a couple shallow shrapnel grooves in two cylinders in the block. Should I dingle-ball hone it and move forward or go another .005 over and run the pistons loose? I don't give a rip if they slap & make noise.

Its an .060 over Hemi with a couple skirt blowouts in its past life + some short milled decks. Its not worth the price of new pistons or sleeves. Just throwing it all together with the parts I have on hand for fun to see what it will do.
 
All i can offer is a personal experience.
A good friend and i worked on his 440,727, dana 60 duster. He had traded a built 454 chevy engine for the duster, running, staight across. (454 was a BIG chevy at the time.) We raced it at the backstrech dragstrip at the old riverside raceway.
When it was time for a freshening-up, we took it apart. It had .008 piston to wall, with CAST pistons. Yeah, it sounded more than a bit sloppy in the morning. And heck, it barely ran. It would only go mid elevens at only 116.
Almost forgot. I ran a .060 over maxwedge, that had so much piston to wall, i put .070 over forged (standard bore 440) in it without touching the bore other than a dingle ball hone. It did run better with the .070s in it.
 
33 IMP said:
All i can offer is a personal experience.
A good friend and i worked on his 440,727, dana 60 duster. He had traded a built 454 chevy engine for the duster, running, staight across. (454 was a BIG chevy at the time.) We raced it at the backstrech dragstrip at the old riverside raceway.
When it was time for a freshening-up, we took it apart. It had .008 piston to wall, with CAST pistons. Yeah, it sounded more than a bit sloppy in the morning. And heck, it barely ran. It would only go mid elevens at only 116.
Click to expand...

Personal experiences are the responses I'm looking for THANK YOU!
 
One more thing. I seriously doubt that Arias ever made any cast pistons. I have Arias 12.5-1 in my max now, and i htink they are in at around .008, one or two thou more than perfect. They are seriously down in the hole though, really a measured 11.25 to 1.
 
Thanks again. That's especially useful given they are the same brand. They only do 4032 or 2618 aluminum. My part number is outdated, but I'm sure they could tell me what they are. And yeah, they only do forged.
 
early days i ran a 440 with .... .014 it made noise cold ran great 13:00 110 mph 1/4 had a .488 / .292 racer brown cam .
 
Call Arias; they should have old specs somewhere. Piston clearance depends on how it is going to run (n/a, blown, alcohol, etc..), piston grind and skirt design, and the alloy. I am sure they can guide you for a good clearance. We did have them make a set of custom pistons for a Bently (RR engine S2) and the clearance spec was 0.004" to 0.007" for them.
 
the bores are good except for a couple of grooves
do the dingle or a little solid hone no need to go .005
and that might not clean up the grooves anyway so why go big
RING SELECTION is key here
nice soft rings
 
They used to knurl the piston skirts if the gap was excessive.
 
still do
I even knurl new pistons sometimes (to hold some oil mostly for endurance applications)
you can also just knurl the minor thrust side but in this case both should work
What would total seal or some other ring expert say about the rings
I'd go plain iron and not a molly face with that scratch
IDK about any plain iron ductile or stainless or ...
barrel or taper face?
lots of question that must be asked for every build
maybe ask the dirt track guys
pm Krooser
 
There’s way better alternatives to knurled skirts.
https://www.johnheard.com/line2line-piston-coating-followup/
My understanding of this situation is it’s a low buck build, so there may not be cost justification in this instance. If you have access to a hone, buzz a couple thou out and run it. A ball hone wouldn’t even knock down a high spot so not an option in my book.
 
Had .010 clearance in a 440 with ash can Jahns pistons. The car ran 10.60's @ 126.
 
same with classic fordgetrues cranky
I have a few knurlers so I'd knurl
but key here is rings
I agree about rigid hone there are usually raised edges next to the groove
 
Sounds like running em loose wouldn't be a problem, but if I can knock down the grooves myself, I might as well do that instead. I do have a stone hone also, but was worried about chipping it on the groove. I had already bought cast .060 rings a while back since they're cheap.

Thanks for the input guys
 
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