Performance Options

I have a 1960 CJ5 with F-head (good condition), T90, 5.38s, 11" brakes, Elect ignition, and 31" tires. Looking for options to make it a better road driver. I have no desire to do a engine swap but I would like to get a little more out of it. I drive up and down mountains a lot and going up is painful. I constantly have to shift back and forth between 2nd and 3rd to maintain 45mph and I cant take it on the highway for fear of getting run over.

I don't think there is anything I can do to get more out of the F-head so what is the best option? Considering an OD, thinner tires (non directional???) Maybe a T98 4 speed? (think this can be an easy swap)

As you can see below, it is a pretty stock (restro/mod) and I would like to spend more time in it...... Even considered selling it to get something that I could drive more but don't know that I could let it go. Too much blood sweat and tears in the rebuild...

 

4 speed won't help with fdr. Overdrive and Weber 2bbl carb swap might do some good.
Oh and nice jeep.

 

Do what the factory did 50 years ago....V6
The 4 speed is unlikely to help your situation much, the overdrive will help a little bit (and even more with the V6)
Great looking CJ!

 

Would LOVE to have a 225 but I want to keep it basically stock....

 

Looks like photo from the Skyway near Sylacauga AL.

 

75 hp in a 3000lb Jeep.
Options are small and very very limited.
Overdrive about all you can do.

 

Buildflycrash Looks a lot like the same place but my photo is in Huntsville.

Guess I need to look a Herm to see what the options are.

 

Turbocharger

 

If you are hunting between 2nd and 3rd, having the overdrive will let you split the difference. I am also a big fan of narrower tires... I really like the 7.00-15s on mine. IME they are much better both on and off road than 31x10.5x15s for a stock jeep.

 

I put 3:73 axels in my Tux, from a 66 V 6, has 10"x 2" brakes, and 750 15" tires on 15" x 7.5 " wheels. It can go 60 mph Flat out, don't do that very often, but it can cruise at 50, 55mph on flat roads. I have a hard time getting up long slow hills, it gets slower and slower until I have to shift down to second, unless I am paying attention. If I am paying and make sure I am going 45 mph when I get to the hill it will climb it OK. I think I read in the FSM that the column shift T 90 has different ratio second gear too. Just something to consider. Good luck.

 

The main problem with the 134 is the very long stroke for the displacement. This gives you lots of torque at low speed, and makes the Jeep responsive, but limits the top end. Power is force times velocity, or with an engine, RPM times torque. The larger the stroke ratio (stroke/bore), the lower the RPM of the torque peak generally. F134 torque starts falling off at a low 2100 RPM, and rapidly after that.

Another problem with the long stroke design is piston velocity. The longer the stroke, the higher the piston velocity at a given RPM and the more stress on the rod bearings. Even though the engine has a sturdy forged steel crank, the factory limited RPM to under 4000 ... that's for a new engine in top condition.

F4 Engine Dyno Test on CJ3B.info

An overdrive will give you more gear choices, but won't give you much more top speed. The top speed is limited by the air resistance barrier ... the engine does not have the poop to push much faster than that, regardless of the gearing. Realize that the newest F134 is nearly 50 years old, and this engine design originated in the 1920s with Willys-Overland.

If I really wanted to hot rod the F134, I would look to literature for old engines like the Ford flathead V8 for insight regarding hop-ups. The general principles should apply better than modern sources. The old hot rodder's formula was the 4 Cs: cam, carburetion, compression, cubic inches. To make more power, you need to push more fuel and air into and out of the cylinders, and compress it more to make a hotter, faster combustion.

Likely the easiest path for this is forced induction - ie super or turbo charging. Look for the Dick Datson books on forced induction for old oddball engines.

Considering all these issues, you have to be really dedicated to want to hop up the F134 rather than swap to a more modern engine. Unless you have a large auto machine shop at your disposal, and lots of time, I don't see how you can economically choose the F134 over swapping-in a more modern engine. You don't have to go with a V-engine. There are modern 4-cylinders that have been successfully swapped in to these Jeeps with good results, resulting in a more original appearance. Look for engines from RWD cars like the Chevy 153 and Mercruiser/Industrial 181, GM/Pontiac/Jeep 151, Ford Lima 2000/2300, Jeep 150, and likely others if you dig into the automotive literature.

 

Its the nature of the beast to go slow...enjoy the smell of hot oil and roses........wanna go fast get a JK,my wife has one and its stable and flies down the road,but you can't beat a ride in an old jeep....

 

Your Jeep, being around a '59/'60, should have 5:38 gears in the axles. Sometime around '63, the factory changed the axles to 4:27 gears, along with a slight change making a slightly lower 1st gear in the T90. The F134 was still the same.
If you have access to a later set of axles with the taller gears, it may help your situation.
-Donny

 

Is this picture takin near the high tension wires on Green Mountain just up Jones valley. I seem to remember meeting you at Tellico years ago although your name escapes me right off.

 

F-head Engine Hop-Up on CJ3B.info

Check this out. It is by a guy that built one for better high altitude performance.

 

I think Jim's reply is spot on, Pretty much all you need to know right there...................75 hp on a good day @ sea level , much less at altitude in thin air when gravity is not your friend............Overdrive may help a little in the splits between the lower gears but not in high gear. And since you already have 5:38's no other benefit for gear multiplication.................at elevation a little more compression would help........and a few more degrees of timing......

 

This topic is about as old as the F head its self. There should be numerous threads addressing it. But other than raising the compression a bit with one of the, at least in my experience, rare "high" compression heads, cam & carb swap along with headers, not a lot can be done. Those mods are not going to net a significant amount of additional torque and usually hurt bottom end performance. Forced induction usually doesn't end well.

Jack Clifford' Performance Products inc. - Headers Intakes Cams For Inline Six Cylinder Engines, Inl

The T98 is not a bolt-in either. and requires modification of the floor, driveshafts, and cross member although you may be able to acquire those parts from the same donor vehicle as the sourced transmission. That transmission will make a big difference on rocky trails but will be little help anywhere else.

Baring an engine swap, I would just leave it stock and get the overdrive. If you do decide to do an engine swap, I would not use the Buicks. A 4.3 Chevy is a much better choice.

 

yep, that is the spot and we did meet there. Scott is my name. I live on the top of Green Mountain so any time I take it out, I have to pull the hill to get back home. Does OK in the valley, I can run 45-60 without much of an issue. Wish there was another Tellico type trip somewhere around here.

based on this and some other research, looks like I will be looking for OD and maybe some headers. Also, read a thread about advancing the timing a bit over factory.