Rover V8 help - converting to serp belt
Discussion
Hoping someone can offer some advice here. I have posted over on the V8 forum, but it seems rather quiet there.
Story is, I had an SD1 based 3.5 in my Triumph mated to an LT77. Running an Offy intake manifold and Weber 500 carb. The engine had the old style Vee belts.
What looks to be an oil pump failure has meant this engine has expired in a rather big way.
I've bought a 3.9 EFI unit off ebay, this is out of a circa 1996 Discovery and came mated to the autobox and transfer box.
The engine seems to be a very late 3.9 as it has the serpentine belt arrangement, crank driven oil pump, but still retains the distributor.
I need some help in getting the 3.9 to fit with the other components I've got.
I'm not going EFI with the install, but will be retaining the Offy manifold and 4 brl carb.
Problems/questions:
1. Water pipes. On the old 3.5 there was a pipe out of the back of the water pump and there used to be a pipe running under the intake manifold to the heater matrix. The 3.9 doesn't have this. What solutions are there for this?
2. Pulleys and belts. I won't be needing the PAS pump on the Triumph. And there was another pump of some kind on the right hand cylinder head (air con???). What idlers/pulleys can I buy to allow me to remove these?
3. Sump. The 3.5 had a short sump pan, the 3.9 is much longer and looks like it'd foul the subframe. Are the sumps interchangeable even though the front covers are different?
4. Flywheel and clutch. I assume I can simply swap on the flywheel and clutch plate from the 3.5 onto the 3.9 and that these haven't changed? And on this note, should the 3.9 mate up to the LT77 without any issues?
5. Anything else I should be wary off while doing this engine swap?
Thanks.
Story is, I had an SD1 based 3.5 in my Triumph mated to an LT77. Running an Offy intake manifold and Weber 500 carb. The engine had the old style Vee belts.
What looks to be an oil pump failure has meant this engine has expired in a rather big way.
I've bought a 3.9 EFI unit off ebay, this is out of a circa 1996 Discovery and came mated to the autobox and transfer box.
The engine seems to be a very late 3.9 as it has the serpentine belt arrangement, crank driven oil pump, but still retains the distributor.
I need some help in getting the 3.9 to fit with the other components I've got.
I'm not going EFI with the install, but will be retaining the Offy manifold and 4 brl carb.
Problems/questions:
1. Water pipes. On the old 3.5 there was a pipe out of the back of the water pump and there used to be a pipe running under the intake manifold to the heater matrix. The 3.9 doesn't have this. What solutions are there for this?
2. Pulleys and belts. I won't be needing the PAS pump on the Triumph. And there was another pump of some kind on the right hand cylinder head (air con???). What idlers/pulleys can I buy to allow me to remove these?
3. Sump. The 3.5 had a short sump pan, the 3.9 is much longer and looks like it'd foul the subframe. Are the sumps interchangeable even though the front covers are different?
4. Flywheel and clutch. I assume I can simply swap on the flywheel and clutch plate from the 3.5 onto the 3.9 and that these haven't changed? And on this note, should the 3.9 mate up to the LT77 without any issues?
5. Anything else I should be wary off while doing this engine swap?
Thanks.
Lucky find – 3.9 Interim engine.
Does the Offy have a feed out of it's rear face (Edelbrock does). Feed heater from there then tee into bottom hose for return.
TVR have an installation of that engine which uses idlers in place of redundant ancillaries. Easiest is: bottom pulley to alternator on one head, across to idler on other head back to bottom pulley via w/pump. Alternatively, but not ideally, mount alternator in the V and run the belt straight down to bottom pulley and back running against w/pump pulley. Doesn’t give you much wrap on the w/pump but I’ve seen it done like that.
From memory 3.5 sump will not fit. Bolt pattern on bottom of front cover is different on crank oil pump covers. Oil pick up is still into the block skirt though. You’ll need to mod the 3.9 sump to clear.
Flywheel and clutch are direct fit. You may need to remove a dowel in the crank rear face though. And you’ll need a new spigot bush.
Does the Offy have a feed out of it's rear face (Edelbrock does). Feed heater from there then tee into bottom hose for return.
TVR have an installation of that engine which uses idlers in place of redundant ancillaries. Easiest is: bottom pulley to alternator on one head, across to idler on other head back to bottom pulley via w/pump. Alternatively, but not ideally, mount alternator in the V and run the belt straight down to bottom pulley and back running against w/pump pulley. Doesn’t give you much wrap on the w/pump but I’ve seen it done like that.
From memory 3.5 sump will not fit. Bolt pattern on bottom of front cover is different on crank oil pump covers. Oil pick up is still into the block skirt though. You’ll need to mod the 3.9 sump to clear.
Flywheel and clutch are direct fit. You may need to remove a dowel in the crank rear face though. And you’ll need a new spigot bush.
Max_Torque said:
Do it properly, stay with the injection manifold and go Megasquirt III etc!
Why re- invent the wheel? Bosch / Lucas did this 20 years ago with a perfectly good 14CUX ECU. Its even got switchable fuel maps 
If hes running a stock motor there is no shortage of maps available (Think TVR). These boys who fit MS spend more time fiddling with the multitude of variables than driving the car......Max_Torque said:
Because Lucas didn't do it properly! They forgot the important bit, the mapped ignition! (the bit that actually makes more power!)
Ummm- point taken about the ignition and all its mechanical bits. I think the Aldon Amethist at £200 to make the dizzy mappable is a reasonable update without breaking the bank. Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff