Question on Twin H Air Filters

HornetSpecial

Does anybody out there in Hudson land know the story of why the Twin H air filters are designed like they were? I get that question a lot at car shows,Seems like just a lot of Air filter that are empty. Maybe they were made like that for looks. They do look neat.
Paul

Lance

Paul, This design of air cleaner actually goes back into the 1930's . It was a design made by the AC division of GM. Many cars of the day other than GM built cars used them. Since AC was a seperate division of GM they had no problem selling components to the independents. Buick as well as Studebaker and Hudson all had similar designs. Hudson actually had used  that type of air cleaner before It was on the 8 cylinder stepdowns. It was black and had a larger air horn opening to accomodate the 2 bbl.carb. Later it was  an identifier of a 'twin H'car. Standard oil bath or oil wetted air cleaners were black and round so the red air cleaners on a twin h really made them stand out. Could round filters been used-well yes but how sexy would that look next to a set of long twin H filters? lol. 

StillOutThere

The '33 Terraplane 8 uses a long cylendrical air cleaner that is similar.   Of course back then we did not have paper elements (hadn't been tried or invented !)

Frankvintagefullflowcom

Actually, it's not just a lot of empty housing. There are carefully designed tubes inside that act as a silencer, much like a muffler. No stuffing, though.
F

Ol racer

FYI

I 'heard' that air cleaners on cars back then were designed to help silence the induction system....

PAULARGETYPE

ALSO THE TWIN H AIR CLEANERS ARE BRINGING IN COOLER AIR FROM THE DRIVERS SIDE OF THE CAR ON THE PASSENGER SIDE YOU HAVE THE EXHAUST 

HornetSpecial

Thanks guys !! You are always helpful. What Paul says make's a lot of since to pull cool air from drivers side.
Regards Paul

Chris Smith

Good looking engine in the photo. FYI the heat shields under the carburetors are mounted backwards.

HornetSpecial

Thanks Chris for pointing the mistake on the heat shields. Since the photo that has been corrected. They should also be painted red, but could not resist polishing them.
Paul.

RL Chilton

Original heat shields were steel and painted.  Reproductions are sometimes stainless, sometimes aluminum (sometimes steel)  and look great when polished.  

I always thought it would be different if you have a polished radiator top tank, then it would be cool to have polished brass heat shields to match.  No one else would have some (at least for a while).  

54Hollywood

Doc,

I use Fram CA-372 filters in our '54 Twin-H.  They work just fine.  

Tim in WI.

ivanz62

Actually, the really great thing about the Hudson style of air filter is not just silencing (which is accomplished). The inner tube is a functional air horn extension or "velocity stack" common on high performance engines. This tuning component adds about 5 BHP over the standard carb with no air cleaner as I could measure on the engine dynamometer. And increased low RPM torque as well. Attached photo of recent dyno run showing the velocity stacks used there.

Kdancy

Looking for some Twin H housing info and saw this color question wasn't answered.
Here- from another post
308's Filler tubes were engine color
Twin H linkage and single carb linkage were engine color
Twin H air cleaners-
Dupli-Color Ford #1605
Hudson
Twin H air cleaners were manufactured by FRAM. The color of these items
is a red that is generally not found today. The color is Colonial Red
provided by Rustoleum in their new spray can paint line.

super-six

This is the original decal on the Twin-H air cleaners that was on my '54.

Park_W

Ivan, great pic's of your dyno setup.  A question on the engine:  I note the big vibe damper.  I've never quite understood . . . does the damper need to be tuned to the specific crankshaft design, or can one be "universal"?

dwardo99

Ivan, what is the effect on HP if one uses twin-H air cleaners with a proper paper filter? It would be no trick to use larger ones or stack a couple of them. I'm intrigued by the possibility of 5 free HP but don't want to run without a filter. 

Glowplug

Ivan... Thanks for sharing your valuable knowledge. Like that head too!

EssexAdv

Super-6 (Larry)  I have had several lowmileage 54's and have never noticed that decal ( not to say they weren't there).  Where is this decal located?

Save
Draft

Lew

RL Chilton

I'm far from an expert on the air cleaners, but you have to remember that their were two different maufacturers that Hudson utilized, and I'm reasonably sure that either company couldn't meet the demand, hence the need for multiple vendors.  Some were AC filters and used AC stickers, and some were United Air Filters and used United stickers.  

ivanz62

Kerry--Thanks for the reminder to check in here.  First, the stock Twin H air cleaners have the tube as shown on the dyne built in and the HP gain is not hurt by the air filters if they are clean.  Second, the crank vibration damper.  The one in the dyno picture is a modification of a Chevy Big Block done by BHJ here in California.  The damper would have been designed for the engine by Hudson "in the day", but aftermarket people like Fluid Damper and BHJ ask a few questions and give you the closest thing they have.  The sublets of the engine harmonics and the proper design seem to be beyond the scope of what is done in the aftermarket.

A note about stock air cleaners--the early Twin H style (as shown on the engine at the start of this thread with their flattened tube going to the body of the air cleaner) work quite well and the later "Hash" style (with round section tubes going to the air cleaner body) are thought to be restrictive of air flow for maximum performance.

RL Chilton

Thanks for posting, Ivan.  That's interesting info, especially about the earlier-styled air cleaners. 

SuperDave

I had the opportunity to work on an original 54 Hornet.. Late Sept build date. The twin H filters had American Motors decals and were of the "hash" variety.

RL Chilton

Doesn't surprise me, Dave.  Towards the end especially, I'm sure the folks on the line grabbed whatever was available in order to finish cars.  

super-six

Super-6 (Larry)  I have had several lowmileage 54's and have never noticed that decal ( not to say they weren't there).  Where is this decal located?

Save
Draft

Lew

On the back side (with them mounted on car, looking from front to back) centered, towards the bottom of the curvature.

railknight

Here's an interesting tid bit of information regarding Twin H air filters.  My '53 Super Wasp, built late in '53, apparently has the Twin H air filters of the Hash type.  On the canisters is a decal that reads about using Fram paper air filters, how often to clean and replace them and at the end of this decal it reads, "Hudson Motor Car Company" Detroit, MI....nothing about American Motors anywhere on the decal.

Dan 

Park_W

Deleted

Kdancy

ivanz62 said:

Actually, the really great thing about the Hudson style of air filter is not just silencing (which is accomplished). The inner tube is a functional air horn extension or "velocity stack" common on high performance engines. This tuning component adds about 5 BHP over the standard carb with no air cleaner as I could measure on the engine dynamometer. And increased low RPM torque as well. Attached photo of recent dyno run showing the velocity stacks used there.

Just bringing this back up for the info concerning the difference between the two air cleaner styles.

cchancel

There were two styles of Twin-H air filters (oil bath and element). I assume the 5 hp boost is good for both?

The access to cooler air and ability to adapt a large element is why I adapted an oil bath style air cleaner to my 262 with the 2-barrel Carter WGD. Do you think that this would see the 5 hp gain you discussed?