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Re: Collapsed skirts on used pistons
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Forum Ambassador
 
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What is involved in a CNC operation on an already made piston which is close in size to a 374? I would think there are some pistons already in mass production which could be used as a starting point. It would seem that starting with a finished piston, a CAD program could be developed to trim off a few thousandths here and there so a few dozen pistons instead of a few hundred could be done on a relatively short run not break the bank basis. Pay for the program up front and copy and change that one as needed for oversizes. Pay some setup and hourly time when a run is needed. Buying finished brand X oversized pistons in bulk I wouldn't think would end up as much per set as a forged set costs or be as tedious and expensive as doing them individually in a lathe.
Egge might not sell enough to be profitable but what about a specialty machine shop. Aren't there places that do that kind of work and charge for setup time plus an hourly charge for the machine and operator?
Posted on: 2016/12/14 22:48
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Howard
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Re: Collapsed skirts on used pistons
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Home away from home
 
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Or I bet Egge would be happy to do a run of 80 or more.
Posted on: 2016/12/14 23:01
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Re: Collapsed skirts on used pistons
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Home away from home
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We reproduce over 100 different pistons and a few are made economically possible by altering the mold of an existing piston we already make.
There are no pistons (or molds) we currently produce or are produced by anyone else that can be used to make a 374" piston. If there were we'd already be making them. An important dimension is the pin centerline to deck distance.
Posted on: 2016/12/14 23:32
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Re: Collapsed skirts on used pistons
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Forum Ambassador
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I guess I got lucky back those few years ago. No slap on the ones you sold me on initial start up. I really probably should start that motor again sometime soon.
Quote:
Posted on: 2016/12/14 23:50
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1937 Packard 138-CD Deluxe Touring Limousine
Maroon/Black 1090-1021 [url=https://packardinfo.com/xoops/html/modules/registry/View.php?ID=232]1955 Packard |
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Re: Collapsed skirts on used pistons
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Forum Ambassador
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Quote:
What about Chrysler 413 pistons. Are they or the molds still available? IIRC, those are what the late Steve Williams suggested and installed in my 374. Other than the block overbore of .060 I don't know if anything else had to be done to the piston to make them fit. They have been in since the mid 80s and the reason the Chryslers were used is at the time Egge was the available option. I had just had a local rebuild done with a set of Egge's and on the way back from the first long trip (400 miles) one or two failed. At least one had a collapsed skirt which damaged the cylinder and another was close to failing. Not wanting anything more to do with Egge, Steve suggested the Chryslers so I shipped him the short block and he did another rebuild. If they are still available could they be turned down and rings sourced so the block overbore is not necessary? I also remember something with the rods but not sure what was done -- but they are the Packard rods
Posted on: 2016/12/15 0:10
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Howard
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Re: Collapsed skirts on used pistons
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Home away from home
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Pin size.
Badger made them. I bought a set. But went wirh JE pistons. Cause 413 sit 80 thou below deck. But. With today's gas you can use 87 oct.
Posted on: 2016/12/15 7:12
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Riki
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Re: Collapsed skirts on used pistons
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Home away from home
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I am a bit perplexed by Egge. When I called as I have 3 374's to be rebuild, told me that they have not produced any 374's in five years. I told John I was a bit perplexed because last year I need a .060 set and they had not stock. They made a set and had it to my door in one week so what did they produce?
Secondly when I was at Egge this past June, I was given a tour by Bob Egge. We discussed the 374's and Bob told me they were no problem as he has a truck piston that he keeps in stock that he can machine. I have reached out to to Bob to re-verify his statement but have yet to hear back.
Posted on: 2016/12/15 12:57
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[url=https://packardinfo.com/xoops/html/modules/
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Re: Collapsed skirts on used pistons
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Home away from home
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Quote:
I guess I got lucky back those few years ago. No slap on the ones you sold me on initial start up. Same effort went into selecting the pistons I sold you. That's why I don't advertise used 374" pistons for sale for 352" rebuilds. It takes way too much labor to make sure they're good to go. Quote: What about Chrysler 413 pistons? Are they or the molds still available? IIRC, those are what the late Steve Williams suggested and installed in my 374. Other than the block overbore of .060 I don't know if anything else had to be done to the piston to make them fit. Quote: There are no pistons (or molds) we currently produce or are produced by anyone else that can be used to make a 374" piston. If there were we'd already be making them. An important dimension is the pin centerline to deck distance. Quote: What is involved in a CNC operation on an already made piston which is close in size to a 374? I would think there are some pistons already in mass production which could be used as a starting point. It would seem that starting with a finished piston, a CAD program could be developed to trim off a few thousandths here and there so a few dozen pistons instead of a few hundred could be done on a relatively short run not break the bank basis. Pay for the program up front and copy and change that one as needed for oversizes. Pay some setup and hourly time when a run is needed. Buying finished brand X oversized pistons in bulk I wouldn't think would end up as much per set as a forged set costs or be as tedious and expensive as doing them individually in a lathe. Short answer, "No." Easy to speculate, incredibly difficult to find a shop to do it. I know first hand, because I have NLA Studebaker and Packard parts manufactured. First, I've been combing the catalogs for fifty years. AFAIK, there are NO existing catalog pistons close enough in dimension to modify to fit the 374" without an unacceptably low compression ratio and/or also modifying the connecting rods. I have approached every manufacturer domestic and foreign, asking who'd sell small volumes of pistons. Most didn't even want to discuss it. The smallest quantity I was quoted was 1000 units; enough for 125 engines. Then, they'd only be in one oversize. Ask Fred for confirmation, but knowing old car owners, that would mean listening to a half-hour of whining about the good old days when Packard parts were everywhere and selling for scrap prices and then why the oversize they absolutely had to have wasn't the one chosen. Then, they'd go away mad without ordering, because the cast pistons cost almost as much as custom forgings. BTDTNA jack vines
Posted on: 2016/12/15 13:51
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Re: Collapsed skirts on used pistons
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Forum Ambassador
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Starting to sound like there is no reasonable approach and anyone with a 374 needs to baby them, park them or be prepared to shell out big $$ when time for a rebuild. How much would one add to a Egge or Kanter piston rebuild vs the custom forged piston route? Another question might be if nothing is made that is close to a 374 and there is not much demand, how long are custom pistons going to be available.
I'll show more of my ignorance here but am curious -- can anything be done to a piston with the pin holes and location or is that area too reinforced or maybe not have much extra metal around the holes? For example, could something like the 413 piston with an incorrect pin to deck distance have the pin location holes bored a bit larger and at the same time offcentered lower. If it could be bored are there such things as oversized thick wall bushings which could be installed to accommodate the Packard size pin? The oversized and offset hole would raise the deck height to take care of the compression issue at the same time. Could something like that be done on an individual basis at a less than custom forged piston cost.
Posted on: 2016/12/15 14:57
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Howard
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