Thread: 3.9 accessory drive

i've been googling it .... Gee's, nothing is ever simple. So the serpentine belt motor has a longer crankshaft. So I can't swap over front covers. So to put the Vbelt motor in I'll need a new radiator, new oil cooler lines.... not forgeting the A/C compressor has been open to the air for a couple of years and I've used the Vbelt alternator on my tractor..... Damn it. So none of the parts I have here fit together .... AAARrrrrhhhhhhh.

From my understanding it was the 4.6 with the longer crank shaft.
I thought you could change the front covers and accessories over to convert it as I converted a serpentine 3.9 to V belt for my Rangie so you should be able to do it the other way.
I would swap the distributor drive gear over as well as it will be a matched wear to the distributor.
All the best mate.

Trav Man

NOOOOOOO.
all RV8s are backward compatible.

The engineers were not clairvoyant so did not know that one day in the future V8s with a front oil pump would have a longer crankshaft. So they are not forward compatible.
You know I have posted this pretty exact post about 15 years ago.

You can put Vbelt timing case and accessories on a 4.0-4.6L Block by using a spacer but not vice versa.

Look I would guess that NZ would have a die to clean up the thread on the radiator. I would have it rodded at the very least anyway.

Then a couple of oil cooler hoses and bob's your aunt.

It's your fault that you used to alternator on a tractor. Surely you knew one day that the LR hex would get you.
Regards PhilipA
I guess if the crank is OK in the bent conrod engine you could switch cranks, but there lies madness. ( and expense) There is always some detail that will derail you, but AFAIR the bearing sizes are the same.

Originally Posted by PhilipA

NOOOOOOO.
all RV8s are backward compatible.

The engineers were not clairvoyant so did not know that one day in the future V8s with a front oil pump would have a longer crankshaft. So they are not forward compatible.
You know I have posted this pretty exact post about 15 years ago.

You can put Vbelt timing case and accessories on a 4.0-4.6L Block by using a spacer but not vice versa.

Look I would guess that NZ would have a die to clean up the thread on the radiator. I would have it rodded at the very least anyway.

Then a couple of oil cooler hoses and bob's your aunt.

It's your fault that you used to alternator on a tractor. Surely you knew one day that the LR hex would get you.
Regards PhilipA
I guess if the crank is OK in the bent conrod engine you could switch cranks, but there lies madness. ( and expense) There is always some detail that will derail you, but AFAIR the bearing sizes are the same.

Yes, you can drive yourself crazy going in circles. What is less amusing is I did a compresson test on the motor (that ran really nicely a couple of years ago when I parked it under a shelf in the shed) ..... 75 -> 120psi across the cylinders........ ER, maybe the rings have gone to sleep and will recover as soon as its started.

Another option is to find a conrod from somewhere and throw that into the motor ..... after all the rest is good! .... or maybe find another disco 1 that's cheap with a good motor and jsut move the thing across..... You could drive yourself crazy going around in circles

Sump off conrod out new one in seems to be simplest option. I mean heads are off motor out sump gasket is cheap you know that engine is all good other than one conrod. No swapping anything

You could have done that with engine in the car

For context many years ago guy turns up at engine reconditions I worked at in 289v8 Ford Fairlane. Sounds ok just a slight miss. Turns out he was in Cairns (the shop was Melb) and had a piston fail. So - they pulled head off dropped sump. Removed one faulty piston/conrod. Cut conrod off so there was only a lower section which was rebolted back onto crank. Re installed head minus pushrods for that cylinder. Then drove Cairns to Melb with no issues. Minor increase in fuel consumption and slight loss of power. We thought that a clever fix to get vehicle back for repairs at reasonable cost

For context many years ago guy turns up at engine reconditions I worked at in 289v8 Ford Fairlane. Sounds ok just a slight miss. Turns out he was in Cairns (the shop was Melb) and had a piston fail. So - they pulled head off dropped sump. Removed one faulty piston/conrod. Cut conrod off so there was only a lower section which was rebolted back onto crank. Re installed head minus pushrods for that cylinder. Then drove Cairns to Melb with no issues. Minor increase in fuel consumption and slight loss of power. We thought that a clever fix to get vehicle back for repairs at reasonable cost