Outer Limits 4x4 Board

I know there are a few of you on here, so help me out
I am installing a straight gas set-up on my 4.2 maverick in the next few weeks, and I need opinions on what works well. I already have the tank, and the cradle for it is half built, I have a convertor, but it may be no good to me as it has twin outputs? Or can I plumb the two outputs into one carb??
I want to run a gas carb straight onto the intake manifold, do any of the manafucturers make a mounting plate/throttle body to suit, or do I have to make one up?? What is the best brand carb to buy? Performance, reliability, price, etc, etc... Gas research? Impco??

The "New generation" is the better of the two and is considerably more modern, however Impco's have been around for ages and are tried true and tested.... The consideration may be $$$ or availability new or s/hand.
Forget a mixer...... go gas injection, more power,more economy, simple to install, cost to purchase is higher tho. As for fitting...you got a drill and a tap n die set ???. One of the locals fitted one to his LWB patrol he gets greater economy than he ever could on petrol and more grunt !
As for a carby ???? just a throttle body would do, I have seen a diesel throttle body used for this b4 and it works well, also a local fitter and turner made up a throttle body from a 2 n 1/2" milkline shutoff valve!!! fitted it to a Holden V8 (bout 3 years ago) and its sweet too!!!

P/S.... forgot to ask what size tank and where are you locating it ?
I run twin LPG tanks, one is where the fuel tank was (80 lits)and the other is beside the transfercase(40lits)....120 lits total in LPG, also made up a fuel tank that sits at the very rear of the MQ and holds 38 lits(emergency reserve).

tank will be slung under the floor at the back, the cradle forms a skiplate with a 5mm base. It'll still be a bit exposed, but will have about 70mm more clearance than my petrol tank does now, and it only gets hit occasionaly, and only has a few leaks

moderator edit (smiley spelling)

i agree, the ultimate setup would be straight gas on a high compression motor running gas injection and electronic ignition.

But, you can achive good results with no carby, just a throttle plate/butterfly valve hooked straight upto a 300a mixer on the 4.2.

I think a impco 425 would be a bit large for a standard 4.2 but one running straight gas and higher comp + gas cam and you may get back the bottom end grunt you will loose with the 425 and then some

if you bump up the compression ratio a bit and put a gas cam in it you will see very sizeable performace gains over the same mods on a petrol car.

Impco is great stuff to use, easy to get, easy to fix( get you home) and very very reliable.

Electronic ignition is something you need to consider seriously as that in itself will give you more power and smoothness in a LPG engine. LPG engines are much more reliant on a good ignition system than your average petrol engine.

So if you want something tried and tru. rip of the carby and all polution shit, just stick on a butterfly , bang on a impco mixer that will do 5.0 litres and slap on a 300a , put in some good plugs and leads and electronic ignition and start playing from there.
a complete setup from an ex cab ( ford carby) will have everything you need bar the throttlebody, and i think the ford baseplate and butterfly will just about fit on the nissan manifold anyway!

Jes

The series '300A impco' is a good choice ( "model 1 & 20" ) and will suit the 4.2 lit motor no probs, (bout as common as 6cyl holden red motors)
If you plan to put a larger motor in at some time in the future you may need to update the mixer... IE a 350 chev would require a Impco series 300A, model 45 & 70 so it could breathe!
Swap meets are the best place to pick up cheap gas conversion stuff as are trading posts and some wreckers.

thanks guys, some good info there..

Oh yeah ...almost forgot...... the reconditioned LPG tanks ( re stamped date wise, new shutoff valves, & a lick of silver paint, etc) are just as good as a new one but around half the price. For some unknown reason they usually have a better variety of sizes too.

Wendle wrote:I already have the tank, and the cradle for it is half built

So will the convertor that I got with the tank, that has twin outputs, be usable with the butterfly setup, or do I turf it and build the system from scratch??

What make & model is the converter ?

V8Patrol wrote:What make & model is the converter ?

Can't remember, I'll take a photo of it tonight.

ok

ooga booga

mmmmmmm not seen one of those converters b4.... have emailed fatherinlaw ( LPG GOD !!) with the pic and thread link. Will let ya know what he says.
Morning father in law ( John)

what did john say?

he knows about it ......just hasn't caught up wid me yet....I'll ring him 2nite

cheers dude.

ahh the landi hartog, still got one in the shed. It will do upto 6 litres ( just)atleast. I had one installed on a mild 302 cleverland years ago, and then ran it on a mild 351. it had a weird ass mixer though, had to use washers to get the airflow right.


Jes

b4 I start I should explain one thing.......
There are 2 main types of mixers/converters....
1; complex mixers/converters
2;simplex mixers/converters

a complex converter works with simplex mixer only
a simplex converter works with complex mixer only

what you have is a "hartog" converter.... it needs a simplex mixer IE: with this converter all you need is a gas ring that sits between the carby and aircleaner. ( one with twin inlets to match the twin outlets on the converter)

that said now down to the guru/gods words of advise.....
1; if money is not a consideration..... go gas injection
2; if money is a bit of a concern....... go "New Generation Gas Research"
3; if moneys a major concern .......... go with a "Impco" / "Landi" setup
4; if money is non existant................. get a gas ring for the "Hartog"

1=$1200 and up ....
2=$500 is a start ....
3=$200 at the most ....
4=$75 !

John said the Hartog would work ok but..... he'd recemend that you pull it apart an look for corrosion as they are prone for it, fit a rebuild kit to it if you can find one as they are scarce as diamonds in rocking horse shyte. Problem with the hartogs is that they are a tad old in their design and mainly seen on forklifts these days. Part availibilty is non existant and if your running sole gas when it lets you down ....hook up a tow rope!

He said the "Impco 300A" was a good choice and most wreckers charge around the $150 mark for a complete kit minus tank, but if your looking for a bit better performance for a few extra bucks then look for a "Landi SM90E" kit ( bout the $200 mark from a wrecker minus tank).

Both the Impco and Landi kits will no doubt need an adaptor that fits onto your carby unless you find one off of the same motor/carby, the adaptors sell for around the $50 mark each.... some are dearer like ones for 4 barrels ( $95) and some are cheaper ($30) thats new prices not 2nd hand.

The other consideration is do you want a "snorkel" setup or "directly over the carby" setup, This will depend on the amount of room between the bonnet and the top of the carby, most holden V8's say in a HQ run a "snorkel" setup ( big elbow off of the carby, long tube to the mixer which sits upside down) they run this because there's no room under the bonnet. If room is not an issue then get the direct on top adaptor. I run one of these on the V8 patrol, works a treat !!

I can get some pics of the Impco setups if you need to see what I'm talking about ( both snorkel and directly over models) as there's one of each in the shed at the moment and the missus bought a digi camera

next question .............
kingy

this is a reasonably good site for Impco stuff

http://www.vags.net.au/productrange.html

this one is for "Landi" systems....
click the english flag for real language !!!!

http://www.landi-gas.it/

good site so take ya time here.... there's good pics and info.

A couple of questions:

Is gas injection legal and reliable? I was looking into it for my latest project and was told to hold off for a while...

Next is carby selection: Correct me if I am wrong but would you only use a gas ring if you had too on a duel fuel setup? Or is it dependant on the converter used? It would be easy to machine a ring into a throttle body for a neat and compact setup...

By far the best looking setup is the GRA carby, but everyone I know that is using one has spent ages fine tuning them (I have machined many metering rods!!). Even Gas Research Tech dept. have said that the impco has excellent fuel control and is easier to setup. I have been told that they are more sensitive to LPG quality as well although I don't understand how or why... Great for turbo and hotrods?

For reliability and ease of use that seems to leaves mounting the Impco. If you were for a gas only setup on a TB42S, would it be an advantage to remove the carby and replace it with a throttle body (from what car?) and attach the gas carby to that? Can you adapt the 300A to it neatly or would you use a 225 or a 425 which are easy to mount?

Also, assuming that you have electronic ignition - what timing curves are people using on a gas only 4.2?

pic of a "gas ring" to suit the hartog converter.
This fits between the standard aircleaner and carby but lifts the aircleaner up by about 40 mm.
(pic "borrowed" from Landi site)

snorkel setup
( pic on a V8 patrol I'm rebuilding, rust removal + respray)
converter is up against the firewall ( not bolted up as yet)

direct setup....
this is on my rig and is a 300A impco series 45 & 70 mixer. The motor is comming out this w/end and a new 350 chev & 5 spd is going back in.
Converter is on the firewall..... bolted up this time !!!

I'll get a shot of ChevyMQ's set up aswell..... his is a bit easier to see side on ....brb.

pic of a Impco setup ( inline) on a toyota troopy...
converter is on the drivers side inner guard....
aircleaner top and crossover tube removed for better view.
(motors phucked and is getting the chev treatment next month when the owner comes up wid the $$$$$$$$$$$$$$$$$$)

side view of a Impco direct setup on a 350 chev....
The adaptor I was talking about can be seen between the carby and aircleaner..... this is the adaptor for a Impco 300A mixer to a 4 barrel carby, in this case a 650CFM Vac sec Holley.

side view of a Impco direct setup on a 350 chev....
The adaptor I was talking about can be seen between the carby and aircleaner..... this is the adaptor for a Impco 300A mixer to a 4 barrel carby, in this case a 650CFM Vac sec Holley.
Its the same setup as on my rig ( cept I run a 4 bbl Rochester carby), diff is that my "mud guard" covers the mixer/aircleaner .

for those lat donot favour LPG see this http://www.autospeed.com/cms/A_0043/article.html

Excellent to see some good LPG tech info getting posted up

Cheers,
Jes

excelent site jessie....... well found