I have a 94 Disco and I was told by the PO that he had a 4.0 installed by the dealership. How do I tell if this is really a 4.0 or if it is a 3.9? The reason I ask is because by serpentine belt tensioner pulley crapped the bed so I need a new one and a new belt and I want to make sure I order the right parts. I am pretty sure the the 3.9 serp belt and the 4.0 serp belt are different but maybe someone can correct me if I am wrong. Thanks in advance for the help!
Is my engine a 3.9 or a 4.0?
- Thread starter teledan
- Start date
3.950cc or 241 cu ins is the engine size, Land Rover 'upped' the size to 4.0 for the late D1's and the D2's.but it was effectively the same engine.
If you have a Disco 1, it is a 3.9
If you have a Disco 2 it is a 4.0
Same engine in both, but ancillaries are different, so try and detail what you have on the engine, rather than by engine number. Mine has a D1 3.9 block fitted with Thor equipment to make it into a 4.0 engine.
Peter
If you have a Disco 1, it is a 3.9
If you have a Disco 2 it is a 4.0
Same engine in both, but ancillaries are different, so try and detail what you have on the engine, rather than by engine number. Mine has a D1 3.9 block fitted with Thor equipment to make it into a 4.0 engine.
Peter
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I am almost sure the later 3.9 and 4.0 serpentine belts are the same.
The check is ridiculously simple - if you have a distributor, it's a 3.9 (even if it used 4.0 block).
The check is ridiculously simple - if you have a distributor, it's a 3.9 (even if it used 4.0 block).
Peter - you are wrong.listerdiesel said:
1996-99 MY NAS Disco 1 have 4.0 (same displacement, but slightly different block, and distributorless GEMS EFI/ignition system).
teledan said:
The 4.0 blocks (gems D1 and motronic d2) have cross bolted main caps, and a provision for the crankshaft sensor.
But this won't really matter, if they replaced your 3.9 with a 4.0, they still would have most likely used all of your old accessories and stuff, so the belt should be the same as if it still had the 3.9
EDIT: I could be wrong on that... the difference in the two belts might be the crankshaft pulley... if that's the case, maybe you do need the newer belt... I'm not sure. Just buy both at the parts place and return the one you don't need.
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Serp belt is the same for 3.9 and 4.0. You for all intents and purposes have a 3.9, even if a 4.0 block was used. For your truck to have been converted to a 4.0 would have required rewiring your car.
FWIW, NAPA shows belts for 94/95 D1 and 96 D1 with different part numbers, but earlier D1's belt is longer by 7mm (which is probably less than the belt's stretch). Same width, same rib count.
Isn't it as simple as a dizzy v. coil packs? The 3.9 had the distributor front and center. My 4.0 simply has a casting where the dizzy used to live. My D-1 was the prototype vehicle for the '96 NA spec. model, with a build date of February, 1995. It has a block number of 000000017 and may be the oldest surviving 4.0 anywhere in the world. (Supposedly, the first 25 didn't survive testing....)
Cheers
Cheers
Thanks. I have a D1 (1994) but the PO said that he had a 4.0 installed instead of the original 3.9. From what I have been reading it sounds like the belts are different.
British Pacific has them listed as different:
http://www.roverparts.com/Parts/ERR5579.cfm
http://www.roverparts.com/Parts/ERR4623.cfm
That and this thread made me think that they are different:
http://www.discoweb.org/forums/showthread.php?t=2033&referrerid=16500
Thanks for the tip pm, I will check to see if it has a distributor or not.
British Pacific has them listed as different:
http://www.roverparts.com/Parts/ERR5579.cfm
http://www.roverparts.com/Parts/ERR4623.cfm
That and this thread made me think that they are different:
http://www.discoweb.org/forums/showthread.php?t=2033&referrerid=16500
Thanks for the tip pm, I will check to see if it has a distributor or not.
apg said:
Nope, the 4.0 block also has bigger crankshaft journals and main caps that bolt from the sides and the bottom.
jafir said:
Well, not really. I mean, you are correct that 1996+ 4.0's did have those journals and main caps as you mentioned. But so did the 1995 D1's, and that was considered a 3.9L. The 1995's also had a serp belt, but still had the dizzy as well.
The 3.9 and 4.0 both had the same bore, stroke, CuFt, etc... For all intensive purposes the 3.9 and 4.0 are the same engine, just one had a dizzy and the other did not when it comes to 1995 D1's.
That's not to say the parts are interchangeable. They're not. You can't put a 4.0 crank in a 3.9 block, or vice versa. But you can add a dizzy to a 4.0 by changing the cam and front cover - or a 4.2 or 4.6 for that matter.
PM - the alternator pulley diameter changed in 96, the reason for 2 belt sizes.
Rod length is different, so even though the 3.9 and 4.0 are the same size and casting, the torque curves and power bands are slightly different. Close enough for a 3.9 14cux setup to run a 4.0, but they are not the same engine.
Rod length is different, so even though the 3.9 and 4.0 are the same size and casting, the torque curves and power bands are slightly different. Close enough for a 3.9 14cux setup to run a 4.0, but they are not the same engine.
This difference I am aware of, but mainly between 95 Classics/96 D1s (which seemed to use the same alternator pulley) and P38A.robertf said:
hks3sgte said:
I will do that as soon as I get a chance. I am at work now and will be on the river all weekend
so I wont be able to until next week.1MITCH1 said:
Good call, the old belt is still in one piece and didn't actually look that bad so I am sure I can find a part number on it.
Thanks for all the help guys!
The serpentine belt is a slightly different length between the distributor engines and the distributorless ones, because the 3.9/4.2 alternator pullies were larger diameter. If you use a smaller pulley off a later D1 then you can use the GEMS 4.0 serpentine belt.