Packard Forum Index » V-8 (1955-56)

I guess this would be the next tool for a good Packard Mechanic?
Wes

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Just the thing for the rebuilder who has everything. Lets start a collection and send one Jacks way. Of course there are a few more minor things needed such as blueprints, aluminum billets and someone to operate the lathe but those are just details.

Howard, ever seen the movie Worlds Fastest Indian? In the movie he poured and machined his own pistons, so how hard can it be?
Wes

Never saw the movie but did see an episode of How its Made where a CNC machine was making pistons.

Seems like it could be a business for a specialty machine shop where one could have pistons or many other parts made in small batches by "renting" the machine for an hour or two. Have a CAD program for the operator to plug in and make a few dozen pistons instead of a few hundred. Am surprised some of the shops here don't offer that service but maybe our Chinese or Indian friends will offer it someday where economies of scale are less of a hindrance.

No idea how much setup and teardown time is involved so paying for the operator to do that part might be expensive. Upfront costs for a few hours of draftsman time would be needed but once the program is done it is there for future use. If any of the old blueprints are available I would think half the planning work was done and would not be a horrible drafting charge to transfer to CAD.

After that part is out of the way, surely there are raw billets available for other cars in a size that would work for Packard pistons.

See Jack Vines statement about using Ford pistons and rods in the following from about 8 years ago.

packardinfo.com/xoops/html/modules/newbb ... rum=12&post_id=45628#forumpost45628

Wonder if the Ford pistons could be used as a starting point and whether it would be feasible to build off a stock of those. Have the CAD drafting work done to modify the Ford pistons in various oversizes and could it be done on a CNC at a low rate at reasonable cost.

Quote:
" .....370
Ford truck pistons were the closest
possibility. After extensive engineering
design, the machine work was undertaken.
The piston top deck had to be machined
shorter. The pin boss had to be machined
wider inside. The rods had to be ground
extensively to lighten them to compensate for
the much heavier pistons, then the bushings
had to be removed and the pin bore honed for
the Ford pin. Finally, the entire rotating
assembly had tobe rebalanced. Because I
can do all this in-house, I did it just to see....."

"pin boss machined wider" I'm not sure what that means.
"rods ground to lighten" Probably not necessary at all.
" Entire rotating assembly balanced." Pistons and rods do NOT rotate. They reciprocate.

So the process is probably much easier and more simple:
Just deck the piston crown and machining needed for the pin.

The quality of ANY REPRODUCTION piston is solely dependent upon the MATERIAL used to manufacturer the piston. (there is a period at the end of that statement). Machining is secondary. (thereis a period at the end of that statement too).

Therefore, it behooves us to find a PRODUCTION type piston to modify.

Going back some 6 or 8 years ago (i can't find the thread) there was some discussion of using and SBC piston WITH somekind of custom made rods.

I don't recall the entire analysis but IIRC the cost of the rods + cheap SBC pistons was about equal to a new set of custom forged pistons for packard.

Bottom line:
There might be some up-front expense for custom made rods, but would allow for cheapfuture replacement of pistons (SBC).

Found it: (this mite b something a bit more availaable "off the shelf")
" After some web research, I found that Chevy
Big Block 402 pistons are 4.125 or larger with
apiston comp ht of 1.77. The "low
compression" version has a 0.200 dome on it,
but this could easily be milled off flat. Also,
Eagle SP makes a Chevy Big Block con rod in
7.100 length. I'll get to the adaption mods
later. Anyway, adding up the stack heights,"

See the very FIRST post of the thread link i cited in post #15 above. I think it was Craig that the quote is from.