BADGER PISTON ?'s

fifesjeep

My buddy just gave me an old un-used set of .030" Badger pistons... He said that he is uncertain what they are for... I measured the pistons and this is what I found...
O.D. @ ring grooves is 3.750"
O.D. @ or around the skirting is 3.780"
1st and 2nd compression ring grooves measure .82" (Using dial calipers)
Oil ring measures .187"
Wrist pin Measures .930" (Using dial Calipers)
The top of the pistons have the eyebrows cut into them... the deepest measurement in the eyebrow is .150"...
The center of the piston is dished and the depth is .050"
From center of the wrist pin to the face of the piston measures 1.585"....
These are Aluminum pistons that need to be polished... on the inside of the skirting it says B-834... I can't find anything on this number.. Maybe some of you might know... Compression Ratio... are they AMC, GM, FORD etc... Here are a few pics of the pistons...

jeepsr4ever

Looks like a cast .030 304 piston

fifesjeep

That's what I figured but I can't find any info on these pistons... I'm not sure the compression ratio etc..

Rogue Racer

Replacement 290 pistons.

AMX69PHATTY

Yeah they do look like 290 pistons, 290 & 304 are same bore. Those pistons in a 304 block ought to give some real good CR :t:

fifesjeep

I found some info... on the 290 & 304 etc... I would definitely say that these pisons are for the 304... here are some numbers for the 304 BLOCK HEIGHT = 9.208" CONNECTING ROD LENGTH = 5.875" STROKE = 3.440" AND ON THESE PISTONS THE COMPRESSION HEIGHT IS 1.585" This is how I figured it... 9.208" (block height) subtract half of stroke... 1.720" = 7.488" I then took 7.488" and subtracted the Connecting Rod length 5.875" = 1.613" I took 1.613" and subtracted the known compression height of 1.585" = .028" The .028" represents the Deck Height... which in my opinion is sitting kind of deep in the hole... If my math is incorrect somebody please feel free to jump in and correct me.

jeepsr4ever

Rogue Racer wrote
Replacement 290 pistons.

How long were 290 rods? :mrgreen:

AMX69PHATTY

From the Perf American Style book 1.601 looks like the stock C.H. for both 290 & 304. Aftermarket replacement pistons are usually about .020 shorter than stock to allow .010 mill to heads and block deck, yet maintain stock CR. Con Rods were 5.875 in both 290's & 304's Stock Deck clearance: 290 = .060 --- 304 = .012 Deck Hieght: 290 = 9.175 --- 304 = 9.208 which you most likely know already. Anyway, wouldn't 304 pistons have a larger dish than those ? There were ( 2 ) 290's, 2V @ 9.0:1, 4V @ 10.0:1. Believe the 10:1 was a flat top, 9:1 was small dish. I would think if they were 304's they would have a larger dish since the .012 deck clearance is so small. a piston dish volume of 17 or 18 cc's would give a CR of 8.5:1 in a stock 304 with 58cc heads and a piston dish volume of 7 or 8 cc's would give a CR of 9.0:1 in a stock 290 with 51cc heads Wonder if the piston dish & eyebrow volume on those pistons is 17-18cc's or 7-8cc's ? 16.387 cc's per 1 Cubic Inch. hmmmmm.........

Rogue Racer

Actually, the 290 2-bbl piston had a 1.581 compression height and the 290 4-bbl had a 1.610 compression height. All 290-304-343-360 engines used the same rods. 343s had a 1.581 compression height on both 2-bbl and 4-bbl versions.

jeepsr4ever

;) IIRC the 304 replacement Badgers had a higher compression. They realistically could be either. Dwight I just like to hear your input :wink:

AMX69PHATTY

Looked in a year 2000 Badger Piston Catalog.

#P834 = 290 pistons = .040 deep dish - 9.0:1 CR

#P890 = 304 pistons = .140 deep dish - 8.4:1 CR

1.588 Comp Ht for both

Looks like probably 290's since "B-834" is cast in'em and a .05 dish.
The dish volume oughta be about 10.5cc's.

Those pistons in a 304 .030 over with 57.92cc heads milled .010
& .028 head gasket oughta give about .025 deck clear & 9.2:1 CR.

If the block is deck milled .020 to 9.188, 005 D.C., CR would be about 9.6:1.

fifesjeep

Thanks people... this helps a lot!!!

AMX69PHATTY wrote
Looked in a year 2000 Badger Piston Catalog.

#P834 = 290 pistons = .040 deep dish - 9.0:1 CR

#P890 = 304 pistons = .140 deep dish - 8.4:1 CR

1.588 Comp Ht for both

Looks like probably 290's since "B-834" is cast in'em and a .05 dish.
The dish volume oughta be about 10.5cc's.

Those pistons in a 304 .030 over with 57.92cc heads milled .010
& .028 head gasket oughta give about .025 deck clear & 9.2:1 CR.

If the block is deck milled .020 to 9.188, 005 D.C., CR would be about 9.6:1.

This is great Info... I'm not sure if iwant to build a junk-yard 304 or just sell these to somebody for that needs a cheap set of pistons...
Now if I were to build a junk-yard 304 and I milled the heads .010" and skimmed the block to meet or match 9.188" would I have to cut the eyebrows a little deeper?... (Depending on the amount of valve lift)... Hmmm, I'd also have to mill the intake in-order for the runners to match or line-up. (no biggie) the set-up will take longer than the cutting.
Personally I'd like to mill the top of the pistons about .020" to .025" to have a dish around .020" + .005" I'd like to zero deck the pistons but I'm assuming if I do all of this I'll definitely have cut the eyebrows deeper. And with that set-up run a 280H cam ..... 1.6 roller rockers on the intake and 1.7's on the exhaust... toss on a torker and a 670 carb and some 1 5/8" headers... and that little puppy will be a stout 5.0... But then I guess it wouldn't be a junk yard motor then :razz: and if i go that far I might as-well do the full oil groove bearings etc... Hmmm, the more I actually think about it, I smile... then I think about the $6000 I dumped into the 360... and how I hear about it every other day from my ole' lady.. 🙁: 8) hahaha I told her the reason i spend my money on the Jeep instead of her is because the Jeep doesn't talk back, it treats me good and it vibrates my NutZ while I drive down the road... She's hates it!... i honestly think she's jealous of my Jeep! :t: