F-head high altitude head?

[56willys]

Okay another random Willys question that came to mind today. I searched the forum and didn't find anything.

So I know there was a high altitude head for the F134 that had higher compression. How, or is there a way to tell if it is from the outside? Between my two hurricane motors I was wondering if one might have the high altitude. And if there were any markings on the head to tell.

Thank you, just a geek trying to learn stuff that school doesn't teach!

[gmwillys]

Great question! I do not know off the top of my head, but will do some research to see. I know on the L heads, a common "upgrade" was to use the head off of a Kaiser Super Sonic head. Our Heep just happens to have one. It's good for a couple more ponies.

[bmorgil]

It seems I did read somewhere about a "Higher Compression" head for the F134. gm will find it. The way to tell is to measure the combustion chamber volume and compare. The higher compression head will have fewer cc's of volume. You could achieve the same result by "Milling" a stock head to a desired cc volume. Like gm has on his, there was a "Super Sonic" head for the L134. I think it bumped the compression up to 7 to 1 or so.

[gmwillys]

The only thing I could find was that there were 7.4:1 or 7.8:1 compression heads for the mountains. The casting would have a number cast in it as 7.4 or 74, 7.8 or 78 on the top/passenger side of the head. The stock numbers were 6.48:1 or 6.9:1.

https://www.oldwillysforum.com/forum/index.php?threads/high-compression-head.14947/

https://forums.g503.com/viewtopic.php?t=72926

If anyone that may be interested in adding power, here is a snip it of a source I ran across.

https://www.speed-talk.com/forum/viewtopic.php?t=65959

I had forgotten about the aluminum heads for the L head from Australlia. The Willywilly head. I threw it in just for kicks.

http://www.ewillys.com/2022/05/16/willys-willy-aluminum-head-northeast-ar-1000/

[56willys]

Thank you for the information! I'll have to check to see if I have one. Maybe if I ever build a hurricane a little more compression would be nice. That second link is interesting, gets the gears turning in my mind! I wonder what a little boost would do to a 134?

I really appreciate the info! It's cool to learn more about jeeps!

[gmwillys]

A little more food for thought;

http://www.earlycj5.com/xf_cj5/index.php?threads/87622/

https://www.jeepforum.com/threads/the-building-of-the-turbo-ready-f-head.760165/page-2

https://www.youtube.com/watch?v=te1NFZzELa0

https://www.thecj2apage.com/forums/boosted-willys-f134-engine-swap-with-a-twist_topic45792.html

[bmorgil]

56' I truly enjoy "hopping up" motors. I have been at that since I was 6 years old. Some motors lend themselves well to a hop up. Some do not. A 4 cylinder 134ci flat head motor wont yield much. A slight compression increase probably wouldn't even be felt. It would however be good for the engine. For today's gas, the 134's compression is very low. A bump in compression certainly wouldn't hurt. Just don't expect anything but a little easier starts.

I like to think of horsepower increases in a percentage perspective. If I add 20% power to a 350 cu in 300 horse motor, I get 60 more horsepower. If I do that to my 134 cu in 60hp Willys, I get a staggering 12 more horsepower. An aggressive cam and intake with a full flowing exhaust will usually get you 10% to 20% of a power increase. The better the engines heads and other design criteria, the better the return. Flat Heads are the worst. To get 20% from a 134 flat head, would take a Lot of work. I would guarantee after you squeezed 20% out of it it would be a fussy, hard to start and rough idling little thing. If I had a high compression head lying around, I would use it for sure. Why not! But I certainly wouldn't spend any money on "hopping up" a L134. I am sure someone has though! To get more horsepower you increase the RPM potential of the engine. Everything about the 134 says keep the RPM's low.

[gmwillys]

Bmorgil would know better than anyone when it comes to hopping up engines. His daily runner pickup sounds amazing with a great throaty note.

As with the links provided in my previous posts, there has been a lot of effort put into increasing the performance of the 134, but most just put the effort into just making the engine reliable and smooth running. Those aspects are worth a whole lot more than any performance gain you may ever get.

[56willys]

I think reliability would take a major hit. And for probably not much gain. Although experimenting would be a fun project. But Flossy will stay stock and reliable. But in the future if I build another jeep I might consider something crazy (and probably stupid) Being that all my family members who are into cars and all my buddy's are all into mustangs, V8s and other fast stuff. I'm the only one who just sits back and has a low horsepower cruiser. So it's really easy for me to get crazy ideas about keeping up with the horsepower!

As always I really appreciate you guys giving me information. The main thing I can see about having higher compression would be for today's higher octane fuel. I believe back in the day they only had 70 or so octane? So the little compression gain might be worth it today.

[bmorgil]

56', I promise you I have seen more boy's passed on the track that didn't understand the basics, than I have seen those that did understand get passed. When you start where you are starting, things make a lot more sense when you jump into the advanced stuff. So many today want the answer not the process. You can rest assured the day will come when those who rush in with money and incompetence, watch from behind those who understand how the whole thing works from the very basics, finish in style. When you build your first Hot Rod, it will be a winner. Flossy is showing you how it all started.

[LarrBeard]

" ...back in the day they only had 70 or so octane.."

Check the octane rating on this overhaul plate from a German Overhaul Depot after WWII.

[bmorgil]

Yikes! 68 Octane... sounds like dishwater from the greasy spoon.

[gmwillys]

Fuel has come s long ways since then. I had a John Deere B that had a small gas tank to warm the engine up then you turned the main tank which was for distillate, (low grade fuel). The deuce and a half military trucks would run multi-fuel engines that could burn anything flammable.

[56willys]

56', I promise you I have seen more boy's passed on the track that didn't understand the basics, than I have seen those that did understand get passed. When you start where you are starting, things make a lot more sense when you jump into the advanced stuff. So many today want the answer not the process. You can rest assured the day will come when those who rush in with money and incompetence, watch from behind those who understand how the whole thing works from the very basics, finish in style. When you build your first Hot Rod, it will be a winner. Flossy is showing you how it all started.


I can agree, the journey is always the most fun. I can think of soo many examples, like I am into model trains and model cars. (Or used to be, lately jeeps have been taking time/money away from other hobbies) but I always think as I'm building a new train layout or model car, how much I want to see it finished. But when it's done the thing I truly enjoyed the most was the process of building it. I could care less about having it done, the real fun is building it.


Wow, 68 octane,. That's just a little different then the 110 my friend runs in his cars!!

That's why I was thinking higher comp. might be a good idea since now the lowest is 87. Although I don't think it will hurt anything in the motor to have higher octane.


I looked over my spare head and didn't find markings that match what gm found. The only thing similar was an 8.07. Backwards of what it should be. But after all it is a willys part! I did learn something new, so if I ever find a head for sale I can see what compression it is. So I appreciate the help!

[56willys]

Fuel has come s long ways since then. I had a John Deere B that had a small gas tank to warm the engine up then you turned the main tank which was for distillate, (low grade fuel). The deuce and a half military trucks would run multi-fuel engines that could burn anything flammable.

Oh yes, I always wanted an m35. It would look so cool with a willys pulled up into the bed. And yes, running it off of vegetable oil would be so neat! The only problem is the fact that it's the size of a house. But they are such cool trucks! That john deere is like a lot of antique tractors/hit and miss engines. That would start on gas to warm up then switch to kerosene for running . (Okay I might have the two backwards but it's something like that).

[gmwillys]

The building is half the fun. The other is the years of smiles you'll get from driving Flossy.

[LarrBeard]

"...Yikes! 68 Octane... sounds like dishwater from the greasy spoon...."

If I can trust my failing memory, in Germany during WWII, much gasoline was derived from coal, not crude oil. During the restoration period, local gasoline might still have been from coal stocks and could have had an octane rating about that number.

[gmwillys]

I am certain you are spot on Senior Chief. Cooking oil is a good fuel source if it is warmed up, but it makes everyone riding and passing by hungry for French fries.

[bmorgil]

Since we are going on an octane journey here, I like this chart. Notice how even though we "got the lead out" and octane ratings stabilized, compression ratios continued to climb. In fact some of the newer engines approach 11 to 1 compression on 87 octane fuel. This is a testament to the design of modern cylinder heads and combustion chambers. As the combustion efficiency goes up, the tendency to detonate goes down. We make some good motors these days.

https://www.energy.gov/eere/vehicles/fact-940-august-29-2016-diverging-trends-engine-compression-ratio-and-gasoline-octane

[LarrBeard]

There are several old airplanes flying today (Doc and FiFi, The SuperConnie and numerous B-17/24/25's) that can't fly above about 12,0000 feet because above that altitude they need boost on the engines and with "just 100-octane" fuel, they detonate and gag.

Although I don't understand the complete octane rating, WWII AvGas and fuel for the last generation of radial engine aircraft was rated as 113/130 octane. They were called "aromatic fuels" because the molecular structure looked more like perfume than conventional fuels.

[51 CJ3]

How the octane rating is determined has changed over the years as well.

[gmwillys]

That is a very interesting chart Bmorgil.

[bmorgil]

It really does show the evolution of combustion technology. A GM "Gen V" L83 Engine has 11 to 1 compression and runs on 87 octane fuel with 32 degrees of ignition timing. That is just Wow!

[51 CJ3]

I think the computer controlled electronic fuel injection systems have more to do with the ability to run low octane fuel in high compression engines. “By guess and by golly” was all it took in the past to get an old carbureted engine to run good. Now it’s all very precise.

[bmorgil]

Yes the precision of the fuel delivery is important but, you still see the best "all out" horsepower from a carburetor. As old as that design is, on the dyno a well tuned carb has been proven over and over to make the maximum power. We have now seen the latest design heads make awesome power, with a carburetor and 11 to 1 compression on 87 octane. The emulsification of the fuel and air mixed well and far ahead of time is the key. The other tell tale of the efficiency in the combustion chamber design is the total timing required. As the combustion chamber efficiency increases the amount of total timing required for complete combustion decreases. This is also a huge help in preventing detonation. A Gen 1 GM small block would usually make the best power approaching and sometimes exceeding 40 degrees of total timing. A modern GM LS doesn't need any more than 30 with racing engines running around 34 on race gas. The newest design combustion chambers combined with the precise timing and fuel control of injected computer controlled engines, provide the unbelievable "best of both worlds" we now see from autos. Great power, smooth drive-ability in all conditions, fuel economy and low pollution. Now keep in mind, if it does start to detonate on a computer controlled engine, it will adapt. Power will be reduced. On a non computer controlled engine, you may want to back that 11 to 1 down a bit just in case!

[51 CJ3]

Thanks for the extra info. I remember when we started switching to electronic ignition and EFI. I didn’t want any part of it but 235,000 miles on my current truck, my EFI boat motor and even my last motorcycle has made me a believer in the newer tech. I turn the key and it starts ready to drive. It’s bad when it screws up because no one knows how to troubleshoot what the computer doesn’t tell them in plain english. Fortunately, the issues show up a lot less often while needing a lot less maintenance to get there. Who would have thought 100,000 miles would be the normal spark plug change interval 40 years ago? I still get to do old school maintenance on flat fenders, lawnmowers, old 2-stroke boat motors, airplanes and the like.

[56willys]

This could solve all the problems with the 134! https://www.facebook.com/marketplace/item/998037391666684/?ref=marketplace_pdp_share Definetely looks tempting, maybe its a good thing i dont have 2 grand to spend right now. One could do some really neat stuff with this head though. It would be a fun thing to play with, and could have some crazy results.

I dont know, i think Ham's 48 needs an aluminum head!!

[gmwillys]

7,500 rpm on the bottom end would definitely make for an oil pan failure. '56, your welds look a lot better than the ones on that intake.

[56willys]

7,500 rpm on the bottom end would definitely make for an oil pan failure. '56, your welds look a lot better than the ones on that intake.

It is sketchy that's for sure. I can just smell the rods twisting already. But hey, it was a cool experiment. And I appreciate you complement on my welds!

[bmorgil]

I have to agree gm, at nowhere near 7,500 rpm we can expect to see many holes in the oil pan! Very clear what to do with that cylinder head. Leave it on Facebook. Note its " Never been run, Outlaw status". I think someone is trying to recoup some costs on a bad mistake. Lets think about 7,500 rpm on a motor that only has one cam bearing...

[TJones]

WOW
It would almost be worth the $2,000 to see the video he has of it doing 7,500 rpm’s!!!
Just seconds b4 it had a scrap iron fit and granaded:cool::cool:

[LarrBeard]

"I dont know, i think Ham's 48 needs an aluminum head!!"

I don't theenk so. That pile of aluminum is so ugly you would have to sneak up on it in the dark. Cast iron works just fine in the '48.

I wonder if goat aroma corrodes aluminum?

[bmorgil]

You do have to chuckle at the stuff you see on this Internet sometimes! I think someone forgot about the exhaust. The cylinder head may flow enough, the in the block exhaust valves however never, ever will.