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Rebuilding the 230 - NOS vs New Pistons?


Bob Riding
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Go to solution Solved by MarcDeSoto,

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Good news from the machine shop - the 230 cid motor that I pulled from the '56 Suburban passes muster for the block, rods, crank, cam, valves, valve seats, springs and head. Unfortunately, there was enough vertical scoring on the pistons that they needed to be bored over 0.040, which means I need to buy new pistons. I did some research between our favorite vendors based on price, but then I wondered if there were any significant quality difference between them on pistons and rings. I tend to think that "Made in the USA" get's you a superior part. NOS is, of course, cast iron- new are typically aluminum alloys. Not sure where each vendor sources their parts but I'm assuming that Roberts and Bernbaum are using NOS, while Egge makes their own in the US, or used to.  Here's what I found on price for pistons+rings:

Small piston in photo is Summit Racing's offering, which looks different from the others.

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Screenshot 2022-11-18 at 8.02.27 AM.jpg

Screenshot 2022-11-18 at 8.39.32 AM.jpg

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Cast iron pistons....nope...don't use those!

Leave those for old GM cars.

 

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1 hour ago, Bob Riding said:

 

Small piston in photo is Summit Racing's offering, which looks different from the others.

 

Screenshot 2022-11-18 at 8.02.27 AM.jpg

Screenshot 2022-11-18 at 8.39.32 AM.jpg

 

There is so much dimensional difference of rings to pin that I suspect the Summit photo is just a generic image.

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I suspect the cast iron spec is in error.  Never have I encountered cast iron in a Mopar, only 216 chevies.    NOS stuff in .040 is hard to find as that was not used often, most stopped at 30 and if more was needed they went up to 60.   I was lucky, I had a 56 plymouth engine that was bored 40, had good bores and pistons.  And, I found a set of NOS .040 rings in original Dodge branded boxes.

 

 

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The old ads for Mopar made pistons was they were cam ground. I took that that to mean out of round on purpose to make up for the thrust of the movement in the bore and helped with wear/performance?.

 

Is that still a deal that means something.?  Did ever?.

 

Cast Repos or Newer NOS, New Aluminum - - still do this?

 

DJ

 

 

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I'm with Kencombs as well......I don't think 23/25" mopar pistons were or are cast iron........aluminium alloy since the 1930's.........as for whether NOS or new made I suppose it depends on the cost and condition.......if NOS and in GOOD condition, ie, have not suffered from any corrosion or abuse and reasonable cost then use them but if cost is not an issue I'd pick a nice new set from a reputable maker with a corresponding set of rings, ideally balanced to suit as well..........when I was getting all the bits for the 230 I intended to install in the 41 plymouth the pistons were the last things to get, I had found a set of NOS .60thou over alloy ones & had also found a place in Oz that made pistons as well as a couple in the USA so that was my next & last thing but ended up selling the lot...........back then, around 2013 a set of custom made but stock size pistons was going to be around $8-900.00 Aus, now would probably be at least $1500.00 Oz now.......maybe $900.00US...........andyd  

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My parts list from Dec 2020. Most of it. Not all.  All from Vintage Power Wagons.

 

 

Screen Shot 2022-11-18 at 4.57.32 PM.png

 

I see they have increased a bit. But not much. $235 today for a set. I have no complaints. Engine is running great.

 

 

 

Screen Shot 2022-11-18 at 5.01.27 PM.png

Edited by keithb7
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I stand corrected! Proof from a 1941 owner's "How To Fully Enjoy Your Beautiful New Plymouth booklet. It states:

 

"Among the many features that make the Plymouth engine outstanding are...aluminum alloy pistons"

 

scan1.pdf scan2.pdf

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14 hours ago, DJ194950 said:

The old ads for Mopar made pistons was they were cam ground. I took that that to mean out of round on purpose to make up for the thrust of the movement in the bore and helped with wear/performance?.

 

Is that still a deal that means something.?  Did ever?.

 

Cast Repos or Newer NOS, New Aluminum - - still do this?

 

DJ

 

 

As I recall the cam grind was used to counter the uneven expansion of the piston as it heated.  The heavier side, pin bosses, expand differently than the thinner side.  The cam grind was intended to assure it was round at operating temp.

 

Later designs use a steel strut cast into the piston to accomplish the same result.

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From what I've read from various sources, new production pistons could offer performance advantages. They might be 3 ring vs 4. But I've also read of quality issues. I also think of last year, when I shopped for a set of rings, some of the places that listed them on their website were actually out of stock. Personally, I'd hunt around just a bit and see if I could come up with NOS at a decent price. 

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9 hours ago, MarcDeSoto said:

Where did you get the $710 price from AB?  I clicked on your link and they are $210.  

Uh, because I used poor math skills!

I used their ring set price - $85  - as a single price, which I multiplied  x 6

Here's the new prices, and we've established that they are all aluminum alloy...

Good catch Marc!

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