Vehicle & Technical > Range Rover
Swapping 4.2 for my tired 3.9-Any Info
kjj0506:
Exactly ...... E-X-A-C-T-L-Y what I was looking for !!!!!!
If I could get answers like that everywhere I would be a much happier guy! So did you notice any difference in the performance with the headers?
As far as the cam is concerned ... the reason I was considering changing it was that I come from a racer head/ hot rod back ground and even though I have no inclination on building any desert racer out of this rig I would like a little extra... just a little .. and that I hear these cams have a real tendency to wear. So I like the freshen up info you gave.
This truck will be driven from Oregon to Baja Mexico to watch the Baja 1000 ( I have raced in it a couple times but never been able to spectate and my Brother has never been to Baja so ... ) then ferry across to Mainland Mexico and up through Copper canyon , New Mexico, Utah ( Moab ) and back to Oregon . So Mileage and dependability are really up on the list . I also would rather drop my cash on gas and stuff. So that is the scoop on it.
Legally I can't use one here but how would a LPG system work with this set up? Does the cam choice or mapping particulars effect this potential option?
What do you think about the rocker reinforcements that are recommended by some ( D&D Fabrication in particular here in the the country of President Bombs-a-lot ) ? Are the needed for my non abusive driving and use?
Thanks again so much for your time and energy... really cool !
Range Rover Blues:
Ok I've been thinking about this for a few hours, and trying to remember back a while too.
<-------Blue, is a 3.9 Manual, I got the chance of a sports pipe in stainless second hand so rude not to really. It also allowed me to have the bigger bore of a sports pipe with the routing of the earlier 3.5 EFi where the pipes are less vulnerable under the gearbox, even if the crossmember sticks down a litte more, so it wasn't all about performance.
The 3.9 exhaust is bigger than a 3.5 and TBH the difference in power between the 3.9 and the sports pipe (tubular headers) is marginal. Even though when you modify you go looking for the improvement it's hard to find. Perhaps a little in the mid-range but I do remember thinking that if I'd paid full price for a new system on the grounds of performance that I'd be dissapointed.
Part of the trouble is that the V8 has a weird firing order so you can't do anything clever with the exhaust like the old 4-pot classic Fords I used to play with, no extractor manifolds or 4-2-1 headers, just 4 into 1 and try to let it breath better.
I decided not to bother with a sports pipe on my sister's 3.9 as that was an auto, given that you have to 'use' the engine to get anything from the pipe and an auto does the thinking for you, not worth it.
So, we then come to the LSE. On Wed I fitted the sports pipe I bought (again Second Hand) for it. Not expecting a massive surge in power but more because I have a reliability problem with the cast header, I am forever swapping gaskets either to the head or the downpipe and to fix one you have to do both, or risk the other bank playing up the week after. Every time I tow with it the same thing :roll: .
Now it could be due to vibration but I also think the cats are blocked, one symptom is poor starting and that had now improved so fingers crossed.
I guess once I have done a couple of tank fulls of LPG I will know if there is any improvement. Performance wise, well it just keeps running out of road so I don't know, but it sure sounds quick now, the sports pipe is straight through with no cats :twisted:
I have to say that being objective, the sports pipe is only better because my cats were probably blocked, yes the car seems faster but for me it was more that I had to do something and the sports pipe allowed me to do away with the downpipe joint.
My advice if you want a reliable car is stick with a 3.9 exhaust, you can wrap the downpipes on that but whether you would notice any gain in performance I don't know. You could try porting the headers a little though, matching them to the head.
As for a cam I don't honestly know, it wouldn't be the same cam as you would fit into a race car, the RR needs more grunt, torque if you like, but there are cams out there to do the biz if you want to go that way.
Cash wise I'd say stick with a stock cam or fit the 4.6 cam, an off-the-shelf unit that's about as lumpy as you would like anyway.
You will notice the 4.2 has more torque, the capacity come from stroking. You'l also notice it sounds smoother, not everyone likes that because it looses the V8 burble but this is perhaps a reason why the sports pipe seems better on my LSE. That BTW is stroked even further to 5.0litres :twisted:
http://members.mud-club.com/profiles/Range%20Rover%20Blues/gallery/LSE/0/7709b8895c6c6e3a7ef35f870f361cf0.JPG/
SO in short, I would "rejuvinate" the 4.2, stick a standard pipe on it with a K&N panel in the airbox. New cam but not too savage and if you fancy it go for a chip (remapping).
Am I contradicting myself now, well one thing I bore in mind is what a b****d of a job fitting a sports pipe was, if the truck needs to be reliable for your trip then standard parts every time. Add to that the extra noise of a sports pipe can be a bit annoying after 6 hours :?
Range Rover Blues:
Sorry bI just noticed a couple of your other questions.
LPG, hmmm. One for discussing over a beer on a long dark night. Sufficed to say that as design is always a compramise you never have the engine set up ideally as a dual fuel, you have to favour one or the other.
Blue is a single point draw through, so I loose power but it's economical, though it does use more LPG than petrol (gasoline).
I can gain some of thi sback by advancing the timing as LPG has an octane of 115whereas petrol is 97. You can also raise the compression ration to 12.5:1 or even 15 to one, but it'll never run on petrol. SO I have an electrickery box that advances the timing on LPG only and make do with that.
We tried the same on my sister's 3.9 with a multi point LPG system and it made little difference but you can't tell it's running on LPG so I wasn't expecting a lot. Multi point is so much better for power but not as good for economy I find.
The LSE is also multi point but I can get it to do 9 to the gallon (4.546 litres to an imperial gallon). with the air conn on and a caravan or trailer.
SO how to tell where the exhaust figures in all that, I guess the same rules apply, the less energy the engine wastes breathing the more comes out through the crank.
Reinforced rockers, ermmmm, hmm. Not onme I come accross but I think I know why you are asking. TBH not many of us rev Land Rovers quite that hard, I've not heard of a failed rocker shaft anyway.
On a full rebuild it is worth replacing the rockers. Apparently as the engine wears metal gets into all the bearing linings, when this happens within the rocker shaft it releases more metal from the shaft as it too wears, so if you put a worn rocker onto a new engine the rocker dumps metal into the oil and so trashes the new engine. So say the people selling new rockers anyway :lol:
kjj0506:
Is there any reason why I cant use the 95's serp belt set up on my 90?
Seems like the only real issue would be the AC.. is the compressor compatable with me older system?
Looks like I would have to use the intake manifold from the 90 in between the 4.2 motor and plenum due to the thermo housing and hoses .
Thoughts ? You seems to always have the info I need and I am in the need .
Range Rover Blues:
The engine that's going into Blue is a John Eals 4.6, this would have been built as a sertpentine type engine, the oil pump is no longer driven from the dizzy but from the crank IIRC, the belt is obviously different on the front as well as the PAS pump (not interchangeable :evil: ) the alternator (4 lug fixing, non-adjustable) and the viscous fan goes the other way round.
But that engine is fitted to a '93 RRC with the 4-belt front end and as far as I know the front end of the blocks are the same. One difference I am aware of is that later engines had a thrust half plate on the camshaft but earlier engines just had a thrust pad on the inside of the timing cover, apparently when you fit a performance cam this can be an issue.
I plan to fit the serpentine front end to the 4.6 from a scrap angine I have (blows head gaskets a lot) but then I need a couple of spares, like the PAS pump, water pump and alternator but I recon it's worth the grief to get a more reliable belt set-up with a 100 amp alternator, quieter etc etc and the airflow from the rad gets past the LHS of the engine better because the alternator isn't in the way, so it will relieve a hot-spot for me too.
As for the inlet manifolds I havn't got my head round that one yet, though I suspect I will be fitting the earlier one because I have one already fitted for the LPG conversion.
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