Engine: 1956-58 289" pistons were full skirts?

[PackardV8]

On another thread it was mentioned '56-58 289"s had full skirted barrel-shaped pistons and '59-64 changed to slipper skirts.

Obviously, there was some reason/benefit to the change to the later piston. However, AFAIK, the 259"s kept the full skirted pistons through '64 end of production. Since Studebaker was building far more 259"s than 289"s, wonder why the lesser production got the newer design piston, but the higher production 259"s didn't.

Another WTF?, the 259" full-skirted pistons have a different piston pin than the 289" slipper skirt pistons. The 259" is a straight wall pin and the 289" is a tapered wall pin. Does anyone have a '56-58 289" piston pin at hand to confirm whether it is straight wall or tapered wall?

Another WTF?, but in the other direction; all of the several 320", 352" and 374" Packard V8s we've had apart came with slipper skirt Bohnalite pistons. Recently, I got a set of NOS Egge Machine 374" +.040" pistons which have a barrel skirt. Hey, Joe, you used some Egge back in the bad old days; ever seen those?

jack vines

[doofus]

seems like the slipper skirt piston came out with the R series engines, all 289 based. the slipper skirt caused less friction, supposedly, and a performance boost? lest we forget early slipper skirt pistons, all brands, were bad to crack the skirt with or without a steel reinforcing strut. the pin difference might be due to different pin loading caused by different stroke lengths? maybe there is an ASE paper on this somewhere? Luck Doofus

[JoeHall]

On another thread it was mentioned '56-58 289"s had full skirted barrel-shaped pistons and '59-64 changed to slipper skirts.

Obviously, there was some reason/benefit to the change to the later piston. However, AFAIK, the 259"s kept the full skirted pistons through '64 end of production. Since Studebaker was building far more 259"s than 289"s, wonder why the lesser production got the newer design piston, but the higher production 259"s didn't.

Another WTF?, the 259" full-skirted pistons have a different piston pin than the 289" slipper skirt pistons. The 259" is a straight wall pin and the 289" is a tapered wall pin. Does anyone have a '56-58 289" piston pin at hand to confirm whether it is straight wall or tapered wall?

Another WTF?, but in the other direction; all of the several 320", 352" and 374" Packard V8s we've had apart came with slipper skirt Bohnalite pistons. Recently, I got a set of NOS Egge Machine 374" +.040" pistons which have a barrel skirt. Hey, Joe, you used some Egge back in the bad old days; ever seen those?

jack vines

Hello Jack,
As I recall, the old EGGEs were near identical in outward appearance to OEM Packard V8 pistons. Problem was, their quality control was pathetic back then, and the piston was not much more than a machined slug; no expansion plates cast in; up to .002" difference between largest and smallest in a set of eight, etc.. Because of the size difference, a machinist I used in California said he has to re-set his boring machine several times, and mate each piston to a specific hole. Even then, if bored to .0015" clearance, they'd run hot because the EGGEs had less expansion control. Till now, even though I know EGGEs have came a long way, if installing a new set, I'd want .0025" clearance.

Yep, Bohnalites are the only OEM Packard V8 pistons I ever saw.

[PackardV8]

seems like the slipper skirt piston came out with the R series engines, all 289 based. Luck Doofus

Actually, most of the dished-top 289"s we've rebuilt came with slipper skirt pistons.

To this day, the Silvolite 289" replacement pistons are all slipper skirt and the Egge Machine 259"s are still barrel skirt.

jack vines