LPG Conversion questions - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

04-30-2002, 00:13

To begin I have the following engine at the moment.

- 289w
- Single plane alloy intake (weiand 7515) and a 1/2 in spacer which I may get around to trying
- 600 cfm edelbrock carb (1406)
- Some kind of dual high volume external oil filters
- MSD 6a ignition box
- MSD pro billet dist.
- 8 or 9mm braided wires
- K&N filter
- c4 auto
- 2.8 rear end
- dual exhaust manifolds (they look original)
- who knows what on the inside, doesnt sound like a hot cam tho.

I am looking at getting an LPG conversion, due to the fact that my milage sucks (11-12mpg in the city no matter how light footed, 15-16 on the freeway), and petrol is around 95 cents per L here versus 35 for LPG.

Questions:
- I was wondering what kind of modifications I would need, whether I could run LPG only (ie pull the petrol tank and replace it with a storage compartment) without damaging the motor.

- I heard of some additive which you put in via the vacuum tee to lubricate the valve seats or something?? that is if youre not using petrol at all. Anyone know what its called and how $?

- What kind of cost would I be looking at having it converted in Sydney, and does anyone have some places they recommend?
- Could I expect any power increase (due to having a single plane intake on an engine which really should have a dual considering the internals seem to be stock)

- Slightly off topic, but does anyone know where I can get a jetting kit for my carb in sydney? I havent had much luck :/

XR8chic · 04-30-2002, 00:36

For LPG conversions you can go to "The Gas Man" in Alexandria, or "Advance LPG" in Waterloo.

I have dealt with both companies and they are pretty good.

Not sure on the prices now - but it used to cost approx $1800 for a conversion for a falcon.

You can run lpg only, or run it dual fuel.
]
If I was going to run LPG again - I would go for dual fuel... as it is more convieniant... (ie... if you run out of LPG - you need a tow, if you run out of petrol, you walk to a servo and bring back a gerry can)

Jesmol · 04-30-2002, 01:47

The valve seat lubricant is if you run alloy heads, I have LPG on the ute with no lubricant because the head was designed with LPG / Unleaded in mind. Might be OK on a cast iron head, but a LP installor would be best (as long as he doesn't try and rip you off)

Might be worth looking at LP only install using gas research carbies, apparently they have great performance. the cons of gas only are the issue of running out, no different to running out of petrol though (except you cant get a 5 litre tin to hold LPG), but you usually get more notice of when you running out, eg I can run for at least 50k after the first notice that the tanks getting dry (a whistle from tank, and occasional surging, stalling)

ebxr8240 · 04-30-2002, 01:50

You don't say what body this great little mill is in.I'd guess a better carb or as you said jetting it would be better.

You'd be better off with a torquer inlet as in dual plane.Single is more for high revs 4500rpm pluss .Thats your problem..I.M.O.. With fuel consumption especially...

How much would you pay for some near new efi heads that will just go with lpg?

Jesmol: Alloy heads are usually designed for Unleaded or lpg.They have to have hardened valve seats in the first place.The reason Taxi's use Fords since they have had alloy heads for years.Since July 1980....X flow X.D...

Iron heads with Lpg or unleaded nead the same longterm...

xced · 04-30-2002, 02:52

from OCAU forums I take it ? :)

im not gonna type out eveything i typed there again !

bdave351 · 04-30-2002, 07:21

If you go gas on this reasonably mild motor (?) one of the impco / ohg 425/450 would be the good cheap way to go. Set up properly they are good for up to 300hp.
And LPG works better in this case with your existing single plane manifold due to the way gas flows/sits compared to petrol.
Apparently GRA are the go but a good system from them is decent dollars compared to about 1500 for the impco. And yeah you have to do something about the heads.

Dont forget to get your distributor redone also!!

smciner1 · 04-30-2002, 14:22

Why oh why have you got a big single plane intake manifold with an auto with no stall & such a tall diff and crappy standard exhaust manifolds???? That in itself is a problem. Sounds like it could be a reasonable combination when sorted, why spoil it with LPG??

xced · 04-30-2002, 15:58

with the heads, alloy heads already have hardened valve seats in them - so they are usually Aok on unleaded / LPG

iron heads usually dont have hardened valve seats insterted into the iron head, thats why you need the lubrication. I can also be used when running a super car on ulp (better than that LRP crap) as long as you dont have pinging

my car is a 250 x flow, imco 300A muxer, holley carb, cain inlet - on gas I have virtually the same power as on petrol tuned for economy (#63 jets) and on LPG it uses ~12.5 L / 100km... which is pretty cheap IMHO :)

station-rat · 04-30-2002, 17:28

On dual fuel installations the car is run on petrol to lubricate the valve seats and stems, as LPG is a dry fuel. If LPG only you would need to add a upper cylinder lubricant to prevent valve seat recession which will occur even on alloy heads with hardned seats.I use a "Morreys" upper cyl Kit that drips oil in to the manifold (about 1L per 10,000 km) on a EFll factory fitted system.
Station-rat

05-01-2002, 21:31

Quote:

Originally posted by smciner1
Why oh why have you got a big single plane intake manifold with an auto with no stall & such a tall diff and crappy standard exhaust manifolds???? That in itself is a problem. Sounds like it could be a reasonable combination when sorted, why spoil it with LPG??

I don't really know, it was put on by the previous owner. I would have done alot of the engine building differently if I had done it myself - especially the exhaust and manifold. Judging by the quality of the wiring and some other bits and pieces the PO was a bit slow in the head. :D

Why spoil it with LPG? Well since I already have a single plane manifold which is supposed to be good with LPG, I thought it would be a nice way to vastly reduce fuel costs.