Engine: Top of piston relative to deck height on 259's

[CarCrosswordDan]

Did all 259's incorporate a design that stopped the piston short of the block deck, or was that only when utilizing a 289 block ? Did all 259's also incorporate dished pistons ? If either of these questions can be answered yes, can anyone provide the insight considerations required to do so ? Thanks, Dan

[DEEPNHOCK]

Almost all engines stop short of the top of the block.
In manufacturing there is always some 'plus and minus' tolerances.
Also, you need to leave a little bit of material for future rebuilding (even though that is not a prime factor in an engine design.
The block and connecting rods are the same for both the 259 and the 289 engine.
The difference between a 259 and a 289 is the crankshaft and the piston.

Did all 259's incorporate a design that stopped the piston short of the block deck, or was that only when utilizing a 289 block ? Did all 259's also incorporate dished pistons ? If either of these questions can be answered yes, can anyone provide the insight considerations required to do so ? Thanks, Dan

[41 Frank]

Additionally non "R" 289 engines have dished pistons, 259 engines have flat top pistons.

[Flashback]

I thought a 259 piston stopped .070 from the deck. This is more than most engines ? right.

[Mike Van Veghten]

Yes...for some reason, the Stude engineers put the piston way down the bore. Much more that the "big three" did.
As I recall, mine was in the .060" range.

There are three ways to fix this problem (and it is a problem !)

1. Deck the block to match the piston height.
2. Buy custom pistons with .xxx" taller deck height.
3. Buy custom connecting rods that are .xxx" longer.


All are acceptable methods.

Mike

[Tom Bredehoft]

My understanding is that the 289 pistons approached the top of the deck, and were dished, while the 259 pistons were flat topped and stopped .070 away from the deck. Same compression volume.

[DEEPNHOCK]

I'll bet a donut that it had more to do with how much, or how much less material there was in the piston(s)....
Or what mold the low bidder had around to cast a zillion pistons.
Studebaker did more with less than most manufacturers.
And remember, the Stude V8 only had a build run of eleven some years.
It probably wasn't some high tech SAE white paper technical reason.
More like some product manager budget constraint.
Not a slam, but more a prudent view during a struggling car manufacturers final few years.
Jeff

My understanding is that the 289 pistons approached the top of the deck, and were dished, while the 259 pistons were flat topped and stopped .070 away from the deck. Same compression volume.

[Chicken Hawk]

Specs I have for the 259 deck is.082"; the standard 289 .031"; the R 1 and R 2 .019". R 3 .011" to +/- .023". NHRA lists the R3 as .017" (which is right in the middle of the .011" and .023"), and for the R 4 +.227" which would be the dome on the piston.

Get this: The deck on the 232 engine is .109" and they don't run too bad for what they are. I'm guessing on this but I think the 259 deck of .082" is so the 259 and 289 will have the same compression with the same heads used on either.

Ted