Connecting Rods

Were there ever a decent set of upgraded rods for the Willys 134 motors? I figure at some point someone would have hot rodded these a little.

 

I have an F-134 out of a specific-class racing Jeep used in Naples, Fl. The engine had pretty major carnage in cylinder#4, but is impossible to tell what turned loose first, though I suspect the piston failed with the wrist pin pulling out the bottom. The rod is bent, but absolutely intact. This engine was turning around 6500-6700 rpm at the time, and had commonly seen 7000 rpm in other races.
I don't think rods are a particular weak point, and don't think upgrades are necessary. If anything, better quality bolts would be all (my blown engine has upgraded bolts).
Does this answer your question?
-Donny

 

Sorta. What all did you have done to it? That wrist pin seems sketchy as hell for any decent RPM. I've been reading up on options for engines and power, and I wanted to see what the F134 could do. The rods scare me more than anything. I figure a decent modern set of rods and a good balance job, this motor may wake up a bit in the mid-range until it runs out of air. Mine is propane right now, and I think significant timing, or boost, or both would be an excellent addition to the rig. I'm not looking for a power monster at all, or monster RPMs for that matter, which is why I'm still researching the F134. I like the idea of an undersquare motor in a Jeep. I'd like to investigate some significant power boost in the 2000-3000 range. I know I can swap a 4.3 or (insert motor here), but I'd like to take a healthy look at what the exhisting options are.

 

I bought the engine discussed above in non-running condition, mainly to see what the old-time racers did to make them hold together, as well as make them turn the revs they do. I've been to the races on the west coast a couple times, and have been amazed to hear a 134 screaming for 5 minutes at a time without grenading. In my case, the remains of the piston was an NP88 which I believe was a cast piston, rather than forged.
The intake valve was bent, piston shattered, crank broken across the rear journal (opposite side of journal from the flywheel), and cylinder wall shattered, though it was pretty thin due to an .080 overbore.
This engine was running a 4 bbl carb fed through a custom manifold feeding through the side of the head, and had a custom ground Crane cam. All four rod bearings were spun on the big ends, but the crank journals were still clean.
This engine was balanced, and used the crank with the bolt-on counterweights.
A weak point seems to be the crank likes to fracture at the rear journal though a drilled oil feed. The racer had several more cranks broken in the same location, and I have broken one here too.
I have briefly driven a Jeep with one of these engines, running up to around 5000 rpm, and the power is amazing. It is all but useless for crawling, but on the street, makes for a very lively Jeep.
I will be rebuilding another block with the remaining custom parts (roller rockers, modified head), mainly as an excercise to find out what the real power numbers actually are. There is a ready market for these highly-built 134s if I get tired of playing with it.
So far, I don't see the rods as a limiting factor, and the wrist pin could almost be reused, except for a gouge from the water jacket.
The best way to wake up the F134 is through a hotter cam and raising compression a couple points higher. The stock cams are ground strictly for low-end pulling. I'm trying to find some of the milder race cams that are sitting under workbenches around my area.
-Donny

 

You would gain considerable horsepower "power boost" just by running it on gasoline.

 

Thanks for the info!! I'd love to see a picture of that intake setup.

 

Power was similar before and after, actually.

 

Interesting. It was my understanding that gasoline is much more energy-dense = more BTUs = more heat value.
I have read that propane generators are de-rated 10% from the same engine on gasoline

My comment was also based on knowing that dual-fuel "woodgas" vehicles experience about a 40% reduction in Horsepower when running on woodgas.

 

Woodgas is a whole different beast due to the amount of inert stuff in it and other effects. I do want to eventually play with it on this motor though. It's part of the reason I went to vapor fuel.

While per unit weight, yes, propane is less BTU than gasoline, it is a higher effective octane fuel as well (like e85 and others). Now in a 7:1 motor, that doesn't mean all that much. Some other important aspects of fuel in this case, are atomization and burn completeness. Specially when considering liquid fuels and simple carberated fuel delivery. A overgrown chainsaw carb will not reach super high burn levels, where as vapor fuels have an easier time naturally achieving more even given a similar mixer since they are in a burnable state prior to entering the chamber. Long story short, there is more to it than BTU alone. All things equal, however, you are right, but things are not equal here.

I have not altered my timing yet, and it was on the low/stock end before, which I think will be huge given the octane rating. The fact that I have equivalent power already, leads me to believe my gasoline fuel setup was decently below optimal (easy argument). The question becomes can it be close to optimal without moving to a better carb setup. My bet is no, and I'm not going to venture down that route (I have a stock YF CJ5 already equipped that way). I went propane since the previous owner had no fuel system in this rig and my steering conversion negated the mechanical fuel pump. Keep in mind, this is my test dummy rig (not my restore candidate), so I don't much care about originality.

 

Thanks for the info.

I have a six cylinder Hercules I run on propane as a woodsplitter. Very smooth. And interestingly, a notably quiet exhaust note.

I also have a woodgas generator. Someday I might try making a wood-powered wood-splitter, if that doesn't tear a hole in the space-time continuum.

 

For what its worth, the grenaded F134 I detailed in post#4 had about 0.120" milled off the block deck, and the piston crowns were machined leaving nearly half the top (combustion chamber area) about 0.180 above deck level. Add to this a milled head (haven't measured against another stock head yet), there is a substantial compression ratio increase.
I haven't cc'ed the chambers yet, but saved the old head gasket, so I think I have enough to go back and calculate the CR.
-Donny

 

Milling on a F head will be more effective then on an L head since the area above the piston in an L head is flat level with the deck of the block the "Chamber" is over top of the valves.

 

Does this mean stock deck height is already .060 above? I was hoping to gain some CR by getting to zero (showing my ignorance to these motors here). That being completely under the assumption it was under.

 

That is awesome! I too wish to complete the cycle lol. I'm hunting down a monroe to rig up a tractor style splitter on the back of the 57.

 

I've mentioned on here before how I spent hours getting kicked in the kidneys in the passengers seat of an old 2a with a hot F-head screaming at 7000 rpm. Those engines can really move with the right cam and balanced parts. They sound sooo sweet too.

 

In stock form, the piston at TDC is more or less flush with the top of the deck, if I recall. My grenaded engine essentially has "pop-up" pistons where the piston crown is well above deck height, fitting into the combstion chamber in the head. Keep in mind, when seriously decking the block, there are still 4 exhaust valves/seats that need to be dealt with.
-Donny

 

That kinda why I want to rebuild an old F-head back to racing spec. I have most of the unique parts for the build, and I think you could actually drive one on the street and trails.
-Donny

 

Diggin up an old thread. Keys, you ever get that FHead rebuilt? Better yet, dyno'd?

Also, I'd be interested in cam specs and their related mods and overall torque curve changes (TQ holding up to 4k would be nice even if it drops below 2k). My gut tells me this motor will love a small turbo and a mild cam. I'm in the decision phase of whether to stick with the FHead or go somewhere else with easier proven paths.

 

Life has recently been too busy to stay on top of this. I have picked up another whole race Jeep with another one of these engines, and have it nearly parted out. The engine is still in the frame, but at least this one is not grenaded like my other.
When I get the time, I want to pull it apart to freshen it up (it ingested some rain water in the hurricane last fall).
I may still have some hand written cam specs copied from the Crain card, but the original card was lost to that storm.
I remember many years ago seeing forged pistons for the 134, but they seem nonexistant today. That is the item I am hunting for.
The GM 151 and variants are a good, solid engines hat should be a big improvement over the 134. I have another engine down in the garage that you could also consider; Kiekhaefer Mercruiser 470/485. It is an aluminum block 3.7 liter 4 cylinder with a Ford 460 iron head. It uses a Chev bellhousing pattern too. Lots of grunt in a compact package!
-Donny