first things first i have been a long time lurker but this is my first real post so thank you for all the info over these last few years. secondly about 1 year ago i purchased my first LR. its a 1990 county swb, currently has a slight lift and 245/75-16 tires. it has its problems but runs pretty good and i think its a great rig, but i am at kind of a quandary moment and need some help.
i have been reading quite a bit about some of the problems that these 3.9L have; namely eating the cam and bad ignition and am hoping that i can begin to cure the most major problem with mine - extreme lack of power.
i have been doing an informal way of baselining and testing performance improvements which is a 0-60 time averaged both ways on a relatively flat track close to home, basically when i bought the truck it was doing 22+ seconds and now 18 seconds after plugs, filters, cap and rotor, gutting the cats - after finding material in the resonator "box of rocks" etc. if i remember correctly the compression was consistent in all cylinders around 135psi.
my question is basically this. what do i need to do in order to take the next step in determining anything?
and secondly what are my options to fix the motor within a limited budget?
my assumption is that the cam is shot - 126000 on the clock, and probably the timing set. i would love to just throw a cam in there and some lifters, fix the cv's - i think they are a little worn - and enjoy the vehicle until my budget can support some more mods but i am afraid of the bottom end and heads not putting up with all that, i also dont know if the ignition is up to snuff and dont really know where to go from here?
would love any suggestions - i dont mind spending good money on good parts but i am fairly limited right now and really just want to enjoy this thing.
Go through the entire power train and running gear ensuring they have sufficient, clean oil or grease. Ensure the brakes are not binding as the rear callipers have a habit of rusting. The parking brake can be hit and miss also. All bearings should be checked as well. The Rover V8s can go well even with high mileage but they do like clean oil. I would do all these things before looking at a cam replacement. You can check valve train lift, duration etc in the vehicle with a dial indicator if you have one.
Understand that a 1990 Range Rover is no rocket ship. Stock 0-60 was quite respectable for it's day but fast forward 22 years and it will not be any faster and you are running oversized tyres.
"Your only supposed to blow the BLOODY DOORS OFF" Charlie Croaker. The Italian Job. 1969.
sorry i forgot to mention, the oil has been changed regularly every 3000k since i have had it and when i bought it i put napa synthetic atf in the t-case, tranny. and clean 80w90 in the diffs. i think i should still do a flush on the tranny but have only drained and filled up to this point. i will check the brakes tonight and i have figured that there will be some loss in time due to the tires and age as well as the elevation - fort collins - from the claimed 0-60 times but were still talking a 63% increase from stock. i dont need a lot of speed, i just want somewhat stock performance and maybe a slight bump. is there a better way to determine my performance as compared to stock - baring a dyno run?
i will check the valve train lift with a dial - that makes sense. what should the lift be? i can probably get to that this weekend.
as a point of conversation if i put the cam in just to get a performance bump, would there be any major flags with the bottom end that i should worry about? how about head gaskets etc?
random, thanks for the reply. i jvae not had a chance to check the valve lift yet but i am still hoping that i will soon. i agree that the rover will never be fast, and thats fine with me but i feel that i can still improve its performance some and bring it up to an acceptable level.
does anyone else have a good way to determine how much performance i have lost?
also would you guys have much heart burn putting a cam in a 3.9L with this many miles on it? would it just be a waste of time and i should wait for the rebuild?
re-gearing the diffs would help more with your larger tires.
But they are not cheap and then you have to have them setup right. GBR (Great Basin Rovers) in Salt Lake City can give you more particulars.
Bill Davis is the owner.
i guess that i was assuming that since the new tires are only 1" larger then stock in diameter, that i would not need to regear?
i would love to throw a set of true tracks in there or at least in the rear but i just dont have the money to do that now.
it sounds like my best bet is to just run what i have now and wait until i have more major engine problems and do a rebuild then.
I just checked tire specs and was surprised that the 245/75/16 are only about an inch bigger.
4:10s would be nice for acceleration, but expensive to buy and install.
Sorry, if I muddied the waters - I was thinking they were 2-3" taller.
no worries about the water. i have been thinking about a gear change and a TT in the rear for a while anyway but i should wait until i get the 235/85-16's!
i guess my real question now is would it be worth it to put a cam in this older motor?
i was towing a toyota pickup yesterday on a tow dolly ~2500lbs (pickup had no motor or bed) total load and i couldnt even get going 45mph with a few small hills.
it just seems like its got no power?
Something doesn't seem right. I could easily tow that weight with any of my previous RRCs.
Maybe it is the cam. I guess they can go flat but I'd check fuel and timing first.
It could be a range of things. So I'd start with the cheapest first.
Any of your injectors leaking? Check this first because you don't want any fuel leaks when you are testing the spark
Pull some spark plugs. How do they look? http://www.centuryperformance.com/spark-plug-reading-spg-192.html
Is it running on all 8 cylinders? It will run rough at idle.
If so, start start pulling plug wires. Nothing will happen when you hit the bad plug/cylinder.
Fuel filter? Could it need replacing? This, by itself is probably not the problem, but it can add to other issues.
Are you getting a spark at the plug? Is it a strong spark?
Autozone (I think) has sparkplug testers or you can hold the plug near a ground and have someone turn the engine over. Make sure that you don't have ANY fuel leaks first.
Timing. Is it correct?
Is it advancing?
Is the vacuum line good and attached to the throttle body?
My guess is (and this should definitely be taken with a grain of salt) that it is ignition related. Bad distributor, timing set wrong, timing chain, coil.
Sounds like the motor is good, it just needs fiddling with and you'll be up and running.
Seems like 200k+ out of that engine is not unreasonable if it has been cared for, but the cams just seem to go away on them. I'd say go for the new cam, it should help. Of course, you will still be running around with less oxygen (and power) up there a mile above sea level.
2004 DII SE7, OME Lift, ARB Bumper, 265/75-16's, The Family Car
1999 P38 4.6 HSE, 128,800 miles, working EAS, Sold!
Did you check the Diagnostic Code Display under the passenger seat.
That should be first.
It is a black box about 2.5" x 3" x 1". There is a smooth face at top where problem codes will be displayed.
Turn the ignition on to read them.
no, i have not checked the diagnostic display, i will try that tonight or tomorrow night.
cdb i think that you might be right about the ignition. i have had my hunch but nothing to prove it. i will shoot for pulling the plugs and inspecting them, the spark, all 8 cylinders working and compression this friday - my next real open time to work on it.
i put a new fuel filter in it about 1 year ago, along with new plugs and cap and rotor. but that doesnt necessarily mean much. now that you mention it there was something funky about the plugs - like one bank was running differently then the others.
Could be bad O2 sensors too, but the diagnostic display will show.
It is easy and expensive to start throwing parts at RRCs and still not have it run right.
I really suggest diagnosis before treatment.
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