The V8 Owners Forum -

What will give me the smoothest power curve, and the best fuel consumption?
I was thinking of maybe a Holley 390?
I assume that most 2/4-barrel carbs will out-do SU's on the power front, so I'm mainly interested in the best MPG.

I'm currently running twin HIF44 SU's, but these have only done 800 miles from new, on a manifold that has done the same mileage. What could I reasonlably expact to sell these for if I cleaned them up like new?

Or should I completely scrap the idea of carbs and go EFi? A decent hot-wire set up is a good way to go I've been told, but a full set up is pricey and hard to find!!

Cheers
Tom.

I don't know what spec your engine is but if its standard ish you already have the best carbs for fuel economy and you aren't stretching them performance wise either. A lot of people say their nice new 4 barrel carb gave them more power on their otherwise standard engine but have no figures to prove it. Chances are it didn't and all it did was make less power low down so the kick felt like more power or their su's were knackered. Personally I prefer the Webber 500 if you still want to change as once set up properly they are a great carb. Another option you could look at is a Webber 38 DGAS. It has been done a good few times in the past, gives really good torque and is economical. Course the DGAS isn't a bolt on kit and takes a bit of fabrication.

It will need to be a bolt-on job as I have no welding gear...
I'd really like to go hotwire if I can, but someone would need to be selling a kit at a good price, nothing on ebay at the moment...

I've even thought of modifying a carb manifold myself to take LPG injection - whadda people think to that?
I can use a proper Range Rover ECU and AFM, but just modify the manifold and fit injectors near the heads, just like an original efi system, but instead bypass my vaporiser unit, and inject the liquid LPG directly.

Does anyone know if I'll need special injectors for LPG or will petrol ones do? Also I don't know what pressure the gas supply is delivered to the vaporiser at, so I would need to make sure it wasn't too high to blow the injectors when they stop pumping.

Anyone know of a place to source good injectors? I know the LR standard ones are very expensive and I'll need 8! Any aftermarket ones available?

Sorry to ramble - maybe the DIY manifold idea needs its own thread?

I think you need to look into how LPG works as 99% of the systems aren't injected. You certainly couldn't use any rover ecu to inject it with.

For someone who needs a bolt on solution you seem to be doing a lot of DIY manifold to get LPG injection.

Ok just forget all that I just read your asking all sorts of the same questions in threads all over the place

From the various threads you have running may I sugest that first you establish if the fault you think you have is a leaking inlet manifold or just that it keeps being warmed up and stopped once a week or so (very likley with this engine) then rather than spend more money making more mods just buy some petrol and take it for a good run! If you want cheep performance at a sensible level the SU's and the set up you have is ideal, forget the LPG, sell what bits you have and tune up your SU's properly. LPG only pays for itself if you do enough miles in a year (more than about 25K) I ran it for 2 and a half years and did 80k miles in the process, with the extra servicing (you need to change plugs and plugleads frequently), reducesd reliability, its tendency to eat inlet ducting and all it was bearly worth it (and it spoiled the performance)
I'm sorry but I think what this vehicle needs more than anything is a good run and proper use. Keep it simple, remember an LPG injection system will cost about £2.5K a second hand injection set up, referbished and with a working ECU (aftermarket ofr modded standard about £1000-£1200 including injectors, a manifold and a four barrel £800 -£1000 buy you have set it up. That buys alot of petrol, sell the LPG set up for £600-£800 and all of a sudden you can aford the petrol to run the thing.
sorry bit of a bleet but why not run it?
Mike

I know I seem to be asking a lot of questions, but that's just who I am! I was wondering about supposed "best carbs" because I was thinking of changine, and that sort of started a thougt progression to EFI systems.
As for the LPG injection I know that's an expensive route (but have since discovered kits to do it on ebay) but I was more interested in the practicalitites rather than seriously thinking of attempting it myself.
The first thing I will be doing is getting rid of the water leak situation and get it tuned up - that way I can start thinking about where the rest of my wallet is going...

Kiwicar:

sorry bit of a bleet but why not run it?

Because it's miles away

I'm currently at uni and there's no way I either need, want, or could afford to park a car in Portsmouth, and the landy lives at home 75 miles away.

Over the summer break (commencing 10/06) It will be run nearly every day. (see post in "engines" area...)

Also you say that LPG only pays for itself after a good few miles - surely the amount of servicing is directly proportional to the amount of use and therfore costs the same to run? If you had to buy the conversion in the first place then it wouldn't be worth it for a 3k mile per year vehicle, but the conversion was left over from the other engine, I spent about £30 modifying it for this engine.

As for being unreliable - in my experiance far from it. I ran my last engine for 1.5 years on LPG and it never missed a beat, and had been running on LPG for 4 years previous to that no trouble either.
On the flip side, my carb was dicking me about all over the place so I drained the petrol tank and ran 100% gas for a year!
I'm deffo not going to get rid of the gas set-up, a bit more fine-tuning after the leak is fixed, and all will be ok I'm confident.

My mate's selling a complete Range Rover (running) with LPG and a freshened up engine for around £500 if you want a cheap solution.

Pete

Sorry to jump in, any T&T on that Rangie?

Hello Tom
can see why you dont wan't to take the landy with you, I went to Pompy a good few years ago either the salt will rot it or the locals will strip it.
Glad you had success with LPG, for me it ruined a perfectly good rangie, backfired and blew the inlet tract up as soon as you opened the throttle, burnt out the exhaust seats, wrecked the injection , needed the plugs changing every 6-7k miles (not cleaning, changing) with plug leads rotor arm and cap or it just ran like a dog, did 13-14 to the gallon of gas (18 to 20 on petrol) and introduced me to one of the most incompetant idiots who ever called himself a business man (the dork that "installed " the system). To get any range on the thing at 13 to the gallon I had to have two 80 litre tanks so had no load space and the weight where it was behind the rear axel wrecked the handling. as I said before I think you need to do alot of miles to make sence of it.
At 32 miles maximum on a trip you are not getting it hot enough to drive off any condensation from the block or any water absorbed into your oil when standing, the fact that it is steaming from the oil shows you are just starting the process. Get it out and give it a good run (100 miles at least) but if you have been doing these short runs for a while drop out the oil and change the filter first good old halfords 20/50 but change it often. Stick some decent petrol in it first as again if it has had a tank full and been left in it for more than a couple weeks the the volatile components evaporate off and you get left with rubbish petrol. understand toe desire to ask questions, and it is what makes the site fun for me but try and be a bit focused and run one thread at a time as it is easier for all of us to follow. also try reading some of Gav's (ihatesissycars) past threads, i think he has asked everything that can be asked about the rover V8 (but he will come up with a new idea next week which I look forward to!

You're right about the locals - when we walked to my girlfriends car the other morning, there was a foot print on the bonnet, 2 on the roof (and a dent!) and 1 on the rear glass. Why walk over a car?!

I need more time to spend tuning the LPG as it's still not nearly as good as petrol.
My good experiences of LPG weren't with a V8 either, they were with a 2.5 4-pot, but I've heard good things about LPG on a V8 too.

I've got no imcompetent fitter to complain to either - I did it myself!
I only changed my plugs and leads once - magnecor leads and NGK Iridium spark plugs (mucg harder electrodes don't wear away so quickly.

I'll make more effort to make my posts linear in future, I get annoyed reading a rambling post but also seem to manage to write some corkers myself!!

Ho Hum I'll change the oil when I'm home and run it for a while (say 50 miles?) Then check for mayo. If it's back then am I safe in assuming it's a coolant leak and not just long-term condensation in the block?
Then it's pressure test time etc...

Cheers all - I'll post up when I know what's going down...

try and get out all the Mayo you can before you run it as warter in the engine, even if it is in an emulsion isn't good for the engine.I heard nothing but good opinions on the Rover v8 and LPG and alot of people on here swear by it, however I believe the combustion chamber on the rover is the wrong shape and is too slow burn, this has the effect with the LPG that it brings out the need for alot of advance and the need for a damn good spark, both problematicle on the rover, the spark because of the relativly poor Rover standard set up, and the advance because if you advance it enough to get the mixture to burn compleetly before the exhaust valve opens it will backfire at the slightest provocation.
Back later
Mike

Ok I'll tip in some ATF and run it for a few miles, and whip off the rockers and clean before I replace it?

RE: the combustion chamber shape, is there any grinding I can do in the chamber on the head to improve this? e.g open up the neck around the spark plug thread, and around the valves?

Little to be done with the standard chamber unless you can weld in material to create a better squish area and this is not an easy proposition. I have ranted in a couple of threads on this topic so again try reading some of the old posts. The heads respond very well to a mild clean up and opening up of the valve throat (pocket port in amarican terms) but are very limited in flow for more than 200-220 bhp (you can get more but the heads make it expensive needing alot of mods and give a poor powerband) when it is a good SDI casting at £100-£150 plus £600-£700 of porting plus £150-£250 for new valves and springs and guides and the things still limmit performance on a 3.5 engine to about 7.5K you can see why the rover boys here are getting excited about the RPI Heads at £1100-1200 and they have a better chamber shape. (bear in mind the equivelent heads for a chevy imported to your door are about £750)
Mike

Not to hijack this thread but.... I've got a 3.5EFi RRC which was on LPG when I got it. Now, I did have a lot of problems to start with as the chap who owned it before be belonged to the "Bodge-it-and-Scarper" club!!!

However, it's now sorted. Adjust timing, correct NGK plugs, decent cap and rotor, and a set of Formula Power 10mm leads (as advertised in the discount section but I got them before that!!) and I've had no problems for a year (25k ish)

I'm just in the process of fitting an additional tank lengthways in the boot to increase range as the cill tanks only give me between 135 and 160 miles, depending on right foot, for a £20 fill. I'm perfectly happy with it, just want better range and a little more go would be great! I'm always tinkering, but that's just the nature of the beast, and I'm completely happy with it. I love being able to run the big comfy V8 for less than a modern saloon car!!