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· Workin' and Wheelin'...
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Discussion Starter · #1 ·
I just had to get htis one out there and over with. I got a few questions on modding a 94 4.2L in my RRC.

Can I use an MSD ignition system on the motor? i.e.: coil, wires, ignition box

Are there any types of exhaust upgrades? i.e.: headers, high flow cat. converters, etc.

Are there any kinds of fuel system upgrades? i.e.: Fuel rails, injectors, fuel filter,

Plus are there any miscellaneous engine mods out there for my 4.2L?:dunno:

These are just some ideas of mine for later investment. :buttrock: Once I get a hood straightened away, tires, and suspension parts, I'll pay close attention to the motor, and how to squeeze more power, possibly gas mileage out of it.:D Any input would be cool.
 

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Here are some.

RageRover said:
I just had to get htis one out there and over with. I got a few questions on modding a 94 4.2L in my RRC.

Can I use an MSD ignition system on the motor? i.e.: coil, wires, ignition box
I believe you can. I know one of my friend has the MSD ignition set up on his 95 LWB.

Are there any types of exhaust upgrades? i.e.: headers, high flow cat. converters, etc.
I have installed Borla SS catback and sound and quality are outstanding.

Are there any kinds of fuel system upgrades? i.e.: Fuel rails, injectors, fuel filter,

Plus are there any miscellaneous engine mods out there for my 4.2L?
I have installed Crane Cams and shortened the tappets and it gives very good performance. I had my mechanic do this while changing out the headgasket, waterpump, thermostat and so on. Acceleration noticeably improved and 60-70mph acceleration has improved dramatically.

Good luck.
 

· Workin' and Wheelin'...
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That's cool... a cam in a 4.2L...I did notice in one of threads on here someone said that the 3.9L and the 4.2L were made by GM. But anyways, and more opinions would be appreciated.
 

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First, the website says that those photos are for illustration only. The website also made no mention of their exhaust systems being made of stainless steel. Additionally, I saw no mention of headers as part of the system. Finally, due to it's dimensions, an exhaust system from the UK would cost more to ship than to purchase.

If you want a premium stainless system there are several reputable manufacturers available here in the US (NRP, Borla, ect.). I don't think you need to look to the UK for an exhaust. Frankly, I'd find a local hot rod shop with an excellent reputation and ask them for suggestions regarding an exhaust. I am lucky that I have a friend who specializes in stainless exhausts (he's currently fabricating a system for a 1937 Lincoln Zephyr with a V-12) and I'll bet dollars to donuts that what he can fabricate is every bit as good if not better than anything you can buy off the shelf.
 

· Workin' and Wheelin'...
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Discussion Starter · #6 ·
A stainless exhaust. I've never thought that they would make something for my RRC. For now, I'm gonna add a glasspack to replace that oversized muffler in the middle of the exhaust to get it breathing, then have to figure out how to get duals going.
 

· Workin' and Wheelin'...
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Discussion Starter · #7 ·
Has anyone put this on their RRC? If so, did you notice any increase in performance, fuel mileage, etc.? Need another opinion.:dunno:
 

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looks like the stock coil with a different sticker. I've seen people throw huge bucks against these engines and they never really improve. Get a 4.6 short block if you want to see real improvement and slap your front cover, heads etc on it.
 

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Discussion Starter · #9 ·
That would be cool to swap in a 4.6, but I don't have the kinda money and time to do that right now. What I'm really trying to get out of the motor right now is better mileage (if possible) and performance.
 

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You aren't the first one to try that- if there was a solution, it certainly wouldn't be kept a secret. Land Rover has a lot of engineers looking for the answer too- if they made the vehicles get better fuel economy, they would save millions since the US makes them pay taxes based on average fuel economy for their product line.
Keep the engine tuned, air filter clean, oil changed often enough, proper fuel, drive gently. The coil in there is fine unless it broke. You could maybe eek out a fraction of a percentage by buying a new coil, some fancy wires etc- but the return on investment will never happen.
 

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If you are truly interested in better MPG results, the only thing to do in the US is park your Rover, using it only when absolutely necessary. Buy a VW TDI, get between 40 and 50 MPG and use the money saved on fuel to turn your Rover into a real weekend warrior. Maybe if you were in other parts of the world you would have the luxury of choosing between gas and diesel. Then you might actually be able to get reasonable economy out of a full time four wheel drive truck that weighs close to two and one half tons. Otherwise, as Steve said above, there isn't much that you're going to be able to do that the manufacturer hasn't already tried.
 

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4.2 stuff

has anyone really attempted to improve performance as a system not just by component.

all engines are systems that act together.

has anyone used headers with a good exaust, and a new chip? what about a cam,headers and an exaust?

any one using a davis distributor?

any one with the mallory ignition upgrade from ab?

i would like real world data, not theories or speculation.

any one ported heads?
do you know any flow bench numbers from our mods?

i personally think that this engine has potential but as a system, not by each component.

al:beer:
 

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Sure, you could extrude hone the runners- install the DAP/Mallory ignition- headers, cam, etc etc. So you'd take a small V8 and make it slightly more powerful, emissions failures, cooling problems most likely.
I've got a 3.5 with SU carbs and 95 disco distributor in it and a 4 speed with overdrive- it gets better fuel economy than my 04 Disco. Installing a Mallory in my 95 Disco improved it only slightly, but replacing an old distributor with a new one often will give an improvement. The main benefit there is the Mallory is more durable and easier to get parts for.
I know a lot of guys who built up Rover V8's for MG's and it CAN be done but it seems to have much less return on the investment than just about any other engine ever made. You could easily drop $10K on one of these Rover V8's and still only have a half decent engine.
 

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Okay Great Divide, while my case won't apply to all here (it will apply to Steve with that very nice '72 Rangie) I have used a complete system approach.

First, I dumped the aging 3.5L in my carburetted '85 5 speed Rangie. I went with a 4.0L thanks to Terry Spencer, a regular on this board. From there I went with an RP4 cam from RPI along with the prerequisite bits and pieces.

From there I tried a Davis distributor. That was a waste of time. I just love dealing with a company that changes its story as it goes along. When it comes to Davis, run away, run away. The stuff just doesn't fit. So I installed a Mallory Unilite along with one of their Master Coils.

I use Magnecor 8.5's, NGK 6BPRES plugs. Oh, I forgot, I have a dual roller timing chain, a K&N air filter which sits nicely atop an Edelbrock 1404 four barrel carb mounted to an Edelbrock intake manifold.

All of this gets dumped through a set of exhaust manifolds from a '96 Disco and it proceeds down stainless straight pipes until the exhaust threw a Magnaflow muffler.

While I haven't had the opportunity to test the engine on a dyno, when I talked with RPI about my aims, they felt that with all of these improvements I should be seeing in the neighborhood of 220HP. Keep in mind that that is on a fairly stripped down Rangie not your bloated NAS version.

With a 5 speed, when you get on the accelerator it actually gets out of its own way. Still it's not as fast a the VW Cabrio my wife drives and I'm lucky to get 10 MPG with spirited driving. It gets worse when I work the truck in 4WD low. If i drive like a granny, paying judicious attention to the vacuum gauge I've installed on the dash, I see 13 MPG.

In the end, it's nice having the extra power but if you were to calculate the cost of the entire venture, I think it would fall into the category of the absurd for a twenty one year old Rover. But, hey, what is it they say about boys and their toys?
 

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Explorer4x4 said:
Summit Racing has headers for a 3.5 for $135. Wouldnt these work on a 4.2 also?
Nope..... and the flanges are too thin.... you get what you pay for!!!
 

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Mallory trumps Davis any day...

Honestly, I don't think those mods would do 220hp... I could very well be wrong but that strikes me as about 190-200 tops. When the weather gets warm again we are considering putting a 4.2 with the 3.9 EFI and ECU in the old Rangie... with a sprintex supercharger. :)
 

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4.2

i have a 4.2, i have not decidied to rebuild it because of the amount of negativity that seems to surround it. one of the tech at ab advised me to get rid of it. other seem to rave about it.

i don't want to get lots of power out of this engine in a horse power sense, i would like to optmize this engine and work on the torque curve. The first thing to go will be the ignition system, in my opinion the weakest link. i really don't think that this is the place to look for horse power, just realiablity and effiency.


there has to be room for improvment in flow, even if it's port matching, a cam and headers,( any one heard or used the stuff from d&d fab?) and a good exhaust. the most critical is to optimizing the right combo is going to be fuel delivery mapping.

extrude hone will add an increasein power by equalizing the flow in all the runners, or intake/exhaust port. i would do this as a last finishing touch.

what i was looking for where people who have done these things and there actual set ups( mostly efi). this would allow me to evaluate what needs to get done and where to spend extra on things during the rebuild that are cost effective and oportunistic.

i tried to get a mallory distributor for my truck last year. i had not researched the specifics, but the tech guy at summit racing said that there was not an aftermarket distributor the was for a rover 3.9. was he incorrect? i'm tired of ignition issues.


muddy oval- are you going to change your feul mapping for the supercharged engine, will you use stock connecting rods, and what comp. ratio will you have for the heads?

why do you think that improvments in performance will cause overheating? is this a known fault.

pro's and cons of the 4.2
are they weak in the bottom end, prone to overheating, bad oiling system?



any thoughts good and bad will be well recieved.
al :beer:
 

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the 4.2 isn't a bad engine- not sure why a "tech" would advise against it in particular. If given a choice, get a 4.6- there's a lot of them in junked P38's now.
I know people who have done port matching and all that to Rover engines for MGB conversions and the return on investment has been very poor. Even improving flow sometimes doesn't help because of the restrictive computer controls. Keeping with the earlier EFI systems and the standard distributor (yes, there is a Mallory- we sell tons of them $318) is the way to go. When we supercharge old school Range Rovers, we use a piggy-back computer module that manipulates the oem computer and doesn't trip the MIL. The supercharger kit is no longer made, but we have the prototype still and are thinking of bringing it back. Our old Rangie put down 0-60 in just a hair under 8 seconds. :) More boost would be possible by lowering compression, but the idea was to have a bolt-on. If building from scratch to be a forced induction engine, I build them with lower compression.
It depends a lot if you want to have something that's legal too-
 

· ryans ROVER
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i saw ur post about getting a glasspack...i jus put one on today and i am very pleased with it and the kickass sound it makes
 
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