Piston specs

[Hickory]

Looking for piston measurements for 3 1/8 bore engines. Plymouth 201 is an engine that comes to mind. Any others also. I need the pin diameter and pin height, piston length ect. Trying to find a reasonable price replacement for my DeSoto pistons. Ty.

[desoto1939]

Hickory: To be more helpful we need to know what year desoto that you are looking for. Is this for the 29 Desoto?

 

I have several catalogs that go back into the early Desoto years so I need to know the specific years.

 

Rich Hartung

 

Desoto1939@aol.com

[Hickory]

This is for the 29 174.9ci but the 29 has a 3.00" bore and there are no pistons out there oversized without having some made up. I was told the 3' bore was bored out to 3 1/8 for the 189.8ci engine. The cylinder walls are thick enough to bore over sized. I'm trying to see if the 201 pistons would work or not. They are readily available.

[Sniper]

To be honest, sonic checking is the only real way to determine if your block can handle a .125" over bore.  Not like you can run down to the boneyard adn grab another if you hit water.

[kencombs]

2 hours ago, Sniper said:

To be honest, sonic checking is the only real way to determine if your block can handle a .125" over bore.  Not like you can run down to the boneyard adn grab another if you hit water.

I thought that's what sleeves were for!

[Sniper]

Six sleeves are pretty expensive though.  And if I were going to go that route I'd see what he larger diameter I could run.  Wonder what the Freewheeling Tony Smith might have to say about this engine?

[kencombs]

4 hours ago, Sniper said:

Six sleeves are pretty expensive though.  And if I were going to go that route I'd see what he larger diameter I could run.  Wonder what the Freewheeling Tony Smith might have to say about this engine?

You''re right about the expense!   Auto machine shops are a dying breed, and the survivors are charging for their knowledge, time and machine investment.  Take a look at the pricing for head machines, boring and surfacing machines and it is obvious that the price is justifiable, but it doesn't make me like it.  In the old days our local guy used a bolt to the block type boring bar, manual seat  replacement tooling, washed the hot tank junk down the drain, seat grinding tools(stones) and charged very little.  Those days are gone forever.

 

 

[Dodgeb4ya]

Those were the good days I like to remember....oh and the smell of fresh hot tanked engine parts!?

[Hickory]

The expense is the driver here. I'm already dumping $1000s of dollars for babbitt and really can't afford $1000s more fore custom pistons and bore work. Slaves may be cheaper I will have to check. 3.00" bore is rare breed.

[Sniper]

I almost hate to say this, but have you looked at metric pistons?  76.2mm is 3".  I found several that have a bore than might work, compression height and pin diameter though, that might bite you there.

 

https://www.summitracing.com/search/part-type/pistons?N=bore-mm%3A76-200mm_76-250mm_76-500mm

[Hickory]

The real issue is it's a rod pinch bolt on the piston pin. Which I guess our Bridgeport and a good bit may fix that.

[Sniper]

Oh wow, I didn't realize it used a pinch bolt.  Any odds you can adapt a later style rod in there?

[Hickory]

Rods are out to the babbitt shop so I can't even measure them, I guess I didn't have a plan there.

[Hickory]

I do have the pins and pistons so I can measure the pin. But I do know that they are much smaller than my 251 Chrysler.

[Hickory]

So my pin is a wore out 3/4" and pin height is 2.00"

[Sniper]

52 minutes ago, Hickory said:

I do have the pins and pistons so I can measure the pin. But I do know that they are much smaller than my 251 Chrysler.

 

Well, those metric piston's have pins that are likely much smaller too, so that might work out in your favor?

 

Unfortunately, the pistons in my link are way too short.  Tallest one has a compression height of 1.279", pin diameters are very close though

Edited April 13, 2023 by Sniper

[Hickory]

[Hickory]

I just checked out those Nissan and Mitsubishi pistons and their compression height was 1.2 and 1.1 

[desoto1939]

have you contacted Egge engine and Piston Parts in Texas. They have piston and parts for the older cars.

 

Give them a call

 

Rich H

[Hickory]

I have and they can't help me out 

[Hickory]

Does anyone know if otto engine works is still open. I've tried calling them several times with no answer. Egge is who referred me to them.