SP Breathers ? Jahns Pistons

The strange stuff keeps coming.. Anyone ever hear of either of these companies ? These breathers are HUGE !! amazing how dirty stuff gets when sitting 20 years lol and the walls on these pistons crazy thick,,think the pistons are for flathead

 

Jahn's pistons have been around since O/S pistons have been available. I believe he had the actually idea to bore out a cylinder vs. junk it in favor of a new piston.

 

Speed Products is the SP... notice their logo on the Stromberg top. Your breather is in the same 1958 Honest Charley's catalog.

 

Cool thanks ,,thats a neat lookin carb

 

Jahns Pistons are still in business.2662 lacy St.Los Angeles,Calif

 

The wider breathers with no logo came a little later. I've seen some with Offenhauser in the lid and the smooth type that you have. The tops will interchange so I'm betting that there was one supplier.

 

I have never seen flathead pistons with valve reliefs in them. Yours must be very rare. They are cast pistons. These days we are much more used to seeing forged pistons, which are much stronger hence thinner and lighter. And better. Still I have heard some old guys say the cast pistons expansion is more compatable with block expansion when up to temp. I don't know

 

Im guessing at what they are for,,and it was there beefiness that prompted me to ask

 

A lot of Jahns pistons have a casting number on the underside--if yours do, I might be able to I.D. them.

 

I would agree. No need for valve relief in a FH piston and it would lower compression, very little, but every little bit counts.

 

if they were for a flathead... maybe they're setup for the Ardun heads?

were they marked flathead or are you just guessing?

-keep finding this stuff... the sp breathers RULE.



Tuck

 

Ardun is a hemi head and still no need for reliefs unless they are for some crazy stroke like 4 1/2".
I believe you'll actually need a pretty healthy dome to get the compression up in a Ardun.

I agree the SP breathers are the ***s

 

If it was for a flathead the diameter would be some where between 3 1/16 and 3 3/8 in all likelyhood. It's hard to guess at what the diameter is even with the tape on it. If we knew the exact diameter at 90 degrees to the pin holes and the diameter of the pin we could make an edjucated guess.

 

Theres boxes of em so ,,i think most of em are labeled so thats a plus

 

Those look more like Pontiac or Buick Pistons.
Buick (not nailhead) maybe an Olds. Buicks seemed to have that big round skirt.

Mike

 

Please let me know if have any Cadillac 331, 365, 390 Jahns piston sets and you are selling.
Thanks

 

From your posted pictures,those look like small block chev pistons,They made three styles for the small block,the flat top,one with a small hump on one side and one with a larger hump on the side....Small block pistons were a 980,980H1 and a 980H2.All Jahns that ever saw were of the full skirt design..Used to sell tons of them during the fifties and sixties.

 

Why are these breathers SOOO much bigger than others ?? Ddid it help the motor ?? found some Eelco ones as well and they are like 2 inch tiny things

 

The Jahns pistons are most likely for a 265/283 Chevy. Are the breathers for sale?

Frank

 

I ran Jahn's 12 to 1 cast pistons in a couple of y-blocks I built back in the day. Good stuff for the money, glad to hear they're still in business.

 

id be intrested in some 301/302 chevy pistons.....

 

As far as the Jahns stuff goes post a part# and I'll look it up in the catalog >>>>.

 

Damn dude... You've got one of everything in that shop of yours!!

 

Theres nothing on the box and could'nt see anything inside the piston though the top is stamped 030 so I figure that means 3rd over or 30 over