Technical Can a cracked piston be welded?

These are old Chevy 302 Pistons pre DZ. I pulled them from a small journal 327 that had a steel 283 crank. It was in my 57 Chevy that I found in garage parked in there since the late 70's. I wanted to sell the Pistons then noticed this crack. Can it be welded? I am not certain if they are forged. They have a weighted steel plate one each side were the pin goes through? Which is behind the crack in the 1st picture.




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It wouldn't be worth trying. Would you feel comfortable with an engine that could possibly grenade on you?

 

i'm sure they are cast

 

Nobody want to buy a welded piston.

 

Yes, I have heard of people welding pistons.
Generally, holes in domes.
Distorting ring lands is a potential problem.

 

Don't chance it. You are lucky you have a motor that has literally dozens of piston manufactures offering a white array of options. I image stock class racing requires pistons similar to what was stock.

 

Cast piston. Most common small block crack ever. I've seen all 8 cracked on early 265/283s 'back when'. The steel strut inside is for expansion control and is one of the many reasons welding is a bad idea.

 

The cause of the notorious “Piston Slap” unlike the more common “Rod Knock” (bad bearing)


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Looks like it had a little"kiss" too

 

That piston is nothing more than a .125" over 283 piston...
Egge probably sell those....

 

Ok Thanks - I was under impression it was a specific piston for the 302 stroker only. They are pretty expensive. If it's just a 283 piston then it's just another piston.


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Sure, bring it over I'll weld it up. I'll also strongly advise that you do Not try to use it again in a motor. In the over all cost of building Cars the cost of pistons is relatively Cheep.
The Wizzard

 

The cast material being of this age and being run has sooooo much contamination inbeded into the material that the weld becomes garbage and pitted, welding the crack will expand the alu and then when it cools will shrink it more then when it was expanded

 

That is even pre "MO" 302!

 

This is a bad idea to even consider doing.
You have to know when to say forget it!!!
Jimbo

 

Burt Munro would weld it up....and go over 200 mph with it!

 

In my day a .125 over 283 was a 301...

 

Thanks! Glad I had noticed the crack before I tried to sell them. Paper weights, trophy art 4 sale lol like you guys don't have a few of these laying around lol thanks


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Same bore/stroke as the 302 Z motors. Chevy didn't want it to look like the hot rodders came up with it years before they did, so they upped the 301.? to 302. LOL

 

NO! And even if you did the skirts look like they're trashed anyways.

 

Yeh, at 8000 rpm what possibly could go wrong!

 

New SBC cast slugs don't last long enough!

 

Same thing!.....

 

Well you can do like a buddy of mine did with hundreds of them in his shop. pull the rigs off smash them from the side, take out the steel piece and sell the broken pieces for scrap by the five gallon bucket load. He did it because it paid a few cents more a piston when he hauled a load of scrap. With the skirts scuffed up like that the decorative item thing might be the other way to get a buck or two.
Genuine .125 over 301 Piston from the late 50's for use as a paperweight.
In the early 70's you could buy a 302 Chevy block from Chevrolet for around 300 bucks that was a new 302 block with Z28 pistons fitted to the bores I helped a friend in Texas put one together and it ran like a bandit. He used a 283 crank and rods along with a pair of 202 camel hump heads. He had less than 500 1973 dollars in that engine when it was done, new cam lifters and all.

 

Ya, but only once!
The Wizzard

 

Some of Burts pistons. From World's Fastest Indian

 

Anything can be welded, but why would you even think of building an engine with a repaired piston. I wouldn't trust it. If it lets go think, of the consequences.

 

That must of been a tough piston, most that I have seen, the skirts are laying in the pan.
Take it to your local fair and have that guy that welds up those soda cans do it for you.

 

I would like to have a set of .020 or .030 oversize 302 pistons. so I could bore a small journal 327 block and use a 283 crank. A famous engine builder once stated if you can turn a 1000 RPM more than everyone else. All other things being equal you will beat them. I suppose I will just use the 327 pistons I already have.

 

301= pi as 3.14.
302= pi as 3.141590265359 (although it can be taken out to 1 million digits).
take your pick, it's only math. They both had a 4 inch bore block.
Really old cast pistons, and the first design small journal rods also.

I am Butch/56sedandelivery