EBAY Aluminum Terraplane Head

allan

This is unusual.  Anyone ever heard of such an animal before?

http://www.ebay.com/itm/1936-1937-1938-Hudson-Teraplane-Aluminum-Head-/111550454709?pt=Motors_Car_Truck_Parts_Accessories&hash=item19f8ecdbb5&vxp=mtr

Jon B

Might be aftermarket or a homemade casting.  I think Hudson did offer a high compression aluminum head "in the day" but I thought it said "Hudson" on it!

Frankvintagefullflowcom

I believe it's the lower half of the two-piece Aluminum/Iron head. The "Hudson" name would be on the top of the upper half which isn't there. The top view you see is the top of the lower half showing the internal structure and coolant passages.
That's a guess since I've never actually seen one, however the bottom side is a match for the Splasher Six so I think it's a good guess.
Not much good without its other half but great Hudson "wall art".
F

Ric West IN

You are correct  Frank.  I had one for an 8 cyl. for a while.  Sold it to Pete B.

"Ric"

Huddy42

Yes, I agree, I have both halves of a 1935 Terraplane two piece cylinder head, it has the raised centre ,very corroded, but nice wall art

StillOutThere

Agree it the lower half of the two-piece high compression head.  Totally useless without the other half.   Should have a Bohnalite Aluminum casting mark on it somewhere.   The other half is cast iron.  And then one you have the other half, you need to find the totally UNIQUE center sandwich gasket between the two halves of the head !

Jon B

I don't grasp the concept here.  Why two "stacked" heads? What was the intended benefit?  When originally installed, did they perform as promised?

barrysweet52

I also have one of these (top and bottom parts) for a 1934/35 head. The water pump mounts on the front of the head. My understanding is that they were a high compression head, and looking at it there seems to be better water flow for cooling - which is what you would expect considering the water pump location. Yes a special gasket is reqd but its only a water seal gasket so not to hard to make. Barry

StillOutThere

Has anyone ever measured the chamber volume of the standard production head versus the vol. of the high compression head?   I would expect that will show the difference in compression ratios.  Less volume, more compression.    One could block the water passages to the block of a stock head as well as bolt a two-piece together and then fill both and see which, if either, holds more water after filling through the water pump mount.

Frankvintagefullflowcom

Quoting Butler's writings regarding the three available sixes in '34, "With C/I head of 5.75:1....." . With a two piece Fe/Al head and 6.25:1,......" or "A Super Power Dome 2 piece head with 7.0:1......"
So, apparently there were 2, two-piece heads offered. I suspect the downsides of the design out-weighed the advantages, the latter likely being improved heat transfer from the combustion chamber to cooling system.

F

allan

Just to keep the discussion going, I have 2 cars with the 3X5 that I installed NOS traveler heads on and both cars have spark knock issues forcing me to burn premium fuel all the time.  The power difference is tremendous though!  The premium fuel eleviates the spark knock in driving conditions where the temp gauge reads half or below.  But, even with premuim fuel, I have spark knock at highway speeds.  I attribute this to poor heat transfer. If i retard the timing comensurately, I sacrifice power and starting.   In other words, premium fuel compensates for the increased compression in all but highway driving where I cannot eleviate it.  If I had an aluminum head, I think the improved heat transfer would do the trick.  I can't imagine running a true 5.75 to 1 compression ratio - the traveler head is 6.25 to 1 if I recall correctly.

dwardo99

Somebody else will jump in here because I am not a splasher guy, but I believe the Traveler was 175 cid? And a 3x5 is 212? The Traveler head may have been rated at 6.25 to 1 on a 175, but on a 212 the CR will be very significantly higher. 

53jetman

The CR would be identical because both engines are running a 3" bore

Ric West IN

The large difference in stroke would result in greater CR when used on a 212 engine.

"Ric"

Geoff

Simple  mathematical equation meas a 175 head used on a 212 would give a compression ratio of 7.34:1 which is almost the same as the standard  7.5:1 iron head on a Jet 202 motor, which is prone to pinging when hot as well.  The optional alloy head for a Jet was 8:1, the highest in the whole  Hudson engine range for 1954.

Geoff 

terraplane8

I have a 112 cast-iron head on my '36 212 Terraplane and it goes perfectly on the higher compression of around 7.3:1. I haven't noticed any detonation on the basic grade petrol here.

There are a couple of old threads on here detailing what I did.