It's been a few years since I've posted on AusJeep and a lot of things have happened in that time.
Finally trying to get my flattie back on the road after 9 years of gathering dust and 4 workshop moves
I've owned FrankenJeep since December 2000
When purchased it wasn't ready for any off road, 4WD didn't work due to no front driveshaft and the Go Devil engine was tired.
Early 2001 it received an F head engine and other minor upgrades and saw regular action until 2007 when the chassis and body started to come apart, chassis crossmember broke and numerous rips and tears in the floor.
I reluctantly pulled it apart for a rebuild and as I feared other work and private issues took over and the Flattie has sat around waiting for a rebuild.
The final specification in 2007 was as follows
Specifics:
MB 2989** (this is on the registration)
1946 CJ2a chassis
1944 MB front sheet metal and grill / 1946 CJ2a tub
Engine and Gears:
Jeep Kaiser F-head
M38 waterproof ignition system
SU HD6 1.75 inch Carburettor
4-into-1 headers
MSD5 Multi Spark Discharge ignition
75mm dia snorkel air intake with K&N filter
2 Electric fuel pumps and fuel filter (Holley Blue main pump and electric diaphragm type auxiliary pump)
Fuel pressure regulator
400mm BMW electric main cooling
300mm Mercedes electric auxiliary cooling fan
T-90 3 speed
Dana 18 transfer case, interlock pin removed for low range 2WD
Warn 25% overdrive
Suspension and differentials :
2.5 inch spring lift, 2 inch shackle lift
Dana 25 with Lock-Right locker and AVM hubs
Dana 44 19 spline with Detroit 'No Spin' Locker
Pro Comp shock absorbers
Rancho steering stabilizer
Wheels and Tyres :
7" x 15" 5 spoke alloy
Simex Extreme Trekker 32"x9.5"x15"
Other :
Warn 8274 8,000 lb electric winch
Dual battery system
120 Amp Bosch alternator
6 point roll cage
High back competition seats
Crow 5 point harnesses
Pioneer tools [ shovel and axe ]
Black out light
Hella Comet 450 reversing light
Rear tool chest and 2 ammo storage boxes
Roll bar mounted carry rack
Swing type spare tyre carrier
2 Jerry cans and holder
A frame tow rig [ mounted on rear floor ]
Front and rear tow hooks
Hi Lift Jack
Snorkel exhaust system
Battery cut off switch
Canvas radiator cover for water fording
Heavy duty steering components and CJ5 steering box
Sump and transmission guards
GARMIN GPS
ICOM VHF radio
Fire extinguisher
Off road first aid kit
Two overhead Camelbacks on the roll cage (drinking water)
Electrical 'missile switches' to isolate the starter motor , alternator and switch off the electric fans for water crossings
Full instrumentation including engine oil and gearbox oil temp and fuel pressure gauges
Some photos of FrankenJeep in it's heyday
I've have been mulling over an engine replacement and initially bought a Chev 350 4 bolt truck engine out of a Chevy Blazer (hard to find here) but then I was concerned about the rest of the drivetrain and wanted something that was a bit kinder to the stock drivetrain than the V8.
A few weeks ago I bought a mid 90's BMW 318 5 speed manual as a donor car. I will repower the Jeep with an M40B18 1800cc fuel injected 4 cylinder from the BMW.
It doesn't sound like much of an engine but the torque is about 20% more than the F head , power is 113 hp (up from 70hp F head) and I have a 6,200rpm rev limit to work with the 5.38 gears. The engine weighs about half of the F head engine. If it's underpowered I can find a bigger BMW engine later or turbo this one.
I've searched a few times on google and seen lots of Pinto, Chev and Toyota 4 cylinder petrol swaps but never a BMW engine.
I'm reversing on 2 wheels in this photo thanks to the front and rear lockers
Quicksand with a thin hard crust on top
Camelbacks , VHF radio, overhead switch panel
BMW M40B18 , this will be the next engine for the Willys Jeep. 6.2k rpm limit compared to 4k for the 50 year old F head Willys engine. This will help at highway speeds with the standard 5.38 diff gears. Need 3k rpm to do 90kmh and the old engine didn't like it , it was happy at 70kmh. It was dangerous on the tollway with big trucks a few metres off the back of the Jeep.
I've been driving and modifying old E34 BMWs (early 90's) the last 4 years so this tipped me towards using a BMW engine.
I have another Willys body and so that might get the 350 chev and a beefier drivetrain in the future as a separate project.
Detailed ideas on the build later but I will change the suspension to a coil over / link set up.
It was hard for me not to go for a huge V8 (I love V8s) but I think once you go down that route the Jeep starts to lose it's character and drivetrain reliability , the T90 and the 5.38 gears have their own unique sound and they are fragile behind a V8. I think this is a 'sensible swap' (a first for me) and well within the design power and torque margins of the drivetrain
Willys Hurricane F-134 4 cyl weight : 470lbs / 213kg. Power : 72hp@4k, torque : 100ftlb@2k
BMW M40B18 4 cyl weight : 286lbs / 130kg* Power : 113hp@5.5k, torque : 122ftlb@4.25
The BMW engine has 104,000kms on it so it should be in good shape and nobody wants them so they are cheap to buy. This one will cost me a few hundred dollars or nothing once I part out and sell the rest of the $1,000 donor car.
The E30 BMW weighs about the same as a stock Willys Jeep and it has reasonable 'modern day' performance with this engine. Meaning it can drive on the road without causing a traffic jam behind it.
200lbs out the engine bay / front axle area has to help handling and general on and off road performance. The drivetrain mass should be between the axle centres concentrated near the drivers feet (engine, trans, transfer case) making the Willys behave like a front mid engine vehicle.
Overall the BMW engine should be a good match for the Willys, a bit more power and torque, wider RPM band to help with highway speeds and much better fuel consumption.
The Hurricane engine was shocking in this area. Around 12 mpg on the road and 2 or 3 mpg off road. I had a 60 liter tank and 2 x 20 liter jerry cans.
The one thing I really liked with the F-head was with the M38 waterproof distributor, leads and plugs I could go into 3 or 4 feet of water. This will be a challenge to match this with the BMW engine.
INITIAL IDEAS ON THE BUILD V1.0
Engine
Swap in the BMW M40B18 using a custom adapter plate
Waterproof the ignition system
Look at the oil pick up system and modify or increase oil capacity for extreme angles
Engine uses a computer so a lot of thought needed on waterproofing sensors and wiring
Engine computer mounted in a waterproof compartment
Snorkel intake and exhausts
400mm BMW electric main cooling
300mm Mercedes electric auxiliary cooling fan
Big radiator
Oil cooler
Clutch
Willys clutch plate (I hope)
BMW pressure plate
Trans and Transfer case
T-90 3 speed
Dana 18 transfer case
Warn 25% overdrive
Fuel System
20 US gallon / 80 liter fuel tank (position to be decided later)
Twin electric fuel pumps on separate circuits
Extreme angle fuel pick system
Braided stainless lines
Truck style spin on element fuel filter
Electrical
Aircraft push to reset circuit breakers
Aircraft copper nickel wiring (salvaged cable)
Twin 100 amp batteries
Bosch 140amp alternator (ex BMW 750i)
Battery cut off switch
Suspension and differentials
Custom fabricated suspension using BMW coil/shock units
Dana 25 with Lock-Right locker and AVM hubs
Dana 44 19 spline with Detroit 'No Spin' Locker
Steering stabilizer
Power steering
Wheels and Tyres
7" x 15" 5 spoke alloy before, I'm thinking of using a bigger diameter with more offset for a better turning circle. Need to consider what tyre size selection is available for 15 , 16 and 17" wheels.
Simex Extreme Trekker 32"x9.5"x15" ? Hmm, the Simex were a great value for money tyre but they didn't have much lateral grip compared to Boggers. I had 2 off road roll overs where the Willys went sideways off an inclined road. I may go for a set of Boggers on this build
Other
Warn 8274 8,000 lb electric winch (existing, great unit)
6 point roll cage (new cage to be built)
High back competition seats (probably Sparco)
Crow 5 point harnesses (already purchased)
Pioneer tools [ shovel and axe ] ... a must have
Black out lights converted to driving lights
Hella reversing light
Rear tool chest and 2 ammo storage boxes
Swing type spare tyre carrier
2 Jerry cans and holder
A frame tow rig [ mounted on rear floor when not attached to the front bumper]
Front and rear tow hooks
Hi Lift Jack
Canvas radiator cover for water fording ... simple but very effective
Sump and transmission guards
ICOM VHF radio
Fire extinguisher
Off road first aid kit
Two overhead Camelbacks on the roll cage (drinking water), this was a great idea before.
Electrical 'missile switches' to isolate the starter motor , alternator and switch off the electric fans for water crossings.
Full instrumentation including engine oil and gearbox oil temp and fuel pressure gauges. These are a great help , especially the fuel pressure gauge. Great for troubleshooting.
It won't be a tyre burner but it should be a good little engine for a flat fender.
Some of the reasons I chose this engine for the swap
1. They are cheap , nobody wants them
2. They can sustain moderate to high rpm
3. Reasonably light
4. Similar length and width to the Hurricane and Go Devil but about 3 inches shorter due to the slant 4 design (I'll confirm this accurately later when the engine is out) which will help lifting the gearbox and transfer case further into the chassis rails
5. The donor E30 318i is a similar weight to the Willys and ran 3.64 gears, I haven't done the gearing calculations with 5.38 gears and 32" tires but below 60 mph I should get reasonable performance out of this engine in the Willys
The goal is to get mildly better all round performance than the Hurricane engine plus cruise capability of 50 to 60mph on the open road with the stock drivetrain and Warn overdrive. The M40B18 will sit on 4 to 5k rpm all day without complaint.
With 20% more torque, 50% more power and 150lbs less weight it should give a good result.
Back in the day with the Hurricane installed I saw a touch under 70mph on the GPS with a slight downhill and absolutely flat out in overdrive (windscreen down) and the Jeep was stable enough , just don't sneeze, swerve or brake. I felt like Chuck Yeager trying to break the sound barrier and the engine didn't like sustained high rpm at all.
Gearing
Initial research shows a 60mph cruise at 3,400rpm in direct 3rd gear with 5.38 gears and 32" tires. Not sure if the little slant 4 can pull that speed off in overdrive 3rd , we will see. At 3,400rpm the M40B18 will be real happy and it's in the sweet spot of the torque curve (peak torque at 4,200)
Jeep 5.38 diff gears and 32" tires compared to the stock BMW E30 3.64 gearing and 25.2" tires
With 5.38 gears this will give good all round performance with this engine
A stock E30 M40B18 could do 116mph , with similar weight, 15% lower gearing and the aerodynamics of a butter box the Willys should be able to pull 80 to 90mph , not that I'd ever want to go there. I'm happy if I can keep up with traffic.
Theoretical top speed in overdrive third if sufficient power available is 142 mph (no thanks)
Weights
I'll be putting the weights of all the components of the build into a spreadsheet and posting them on the thread as the project progresses. It will be interesting to see what these parts weigh in the real world
Some photos off the internet of the M40B18
The only potential problem that may occur is clearance of that front mounted oil sump
The distributor will need to be waterproofed also
The Return of Java Jeep's FrankenJeep BMW M40B18 slant 4 powered
XJ Cherokee
HG Premier
