Straight gas 4L conversion.

[Wes 214]

OMVL look cheap and nasty by comparison and less reliable i'd reckon.

The main difference between the two would be that the IMPCO uses a vacuum reference to the secondary diagphram on the converter while the OML uses a stepper motor for it's metering run off the crank sensor signal.

They look cheap and nasty, that's for sure but they perform much better than Impco on the E series motors. The impco is a simpler unit but you cannot compare the two. In 10 years the one I set up on my fathers one has never faulted. Gets him 450km to a small 66 litre tank. No way in hell an impco will do that. His previous impco one also never faulted but it was a cunt to start in the mornings without some love and understanding and returned 100km less economy for the same engine.

[GspecZL 979]

Ok I think im set on the Impco 425. I know I can set it up and that's enough for me. Classic case of KISS keep it simple stupid.

 

One question. Will it work with my OMVL converter. I have dual fuel on the ZL now and there is an OMVL converter all plumed in and ready to go. so can I or do I need to get an Impco converter.

[deankxf 20,292]

Ok I think im set on the Impco 425. I know I can set it up and that's enough for me. Classic case of KISS keep it simple stupid.

 

One question. Will it work with my OMVL converter. I have dual fuel on the ZL now and there is an OMVL converter all plumed in and ready to go. so can I or do I need to get an Impco converter.

OMVL use a simple mixer, so thats a no..

 could probably use the gas ring that is currently on it but they are usually down to 40mm inside (compared to 70mm efi throttle body)

 

for a 425, the usual choice these days is a Aussie B2 converter at about $200 plus fittings

[GspecZL 979]

Thanks Dean. Will buy both.

[deankxf 20,292]

Thanks Dean. Will buy both.

just check double check they will do whats needed but i had same on a mild 265 hemi and it was as good as GRA on that motor.

the 425 is good for about 400hp, and the B2 is often used on 351s so should be good,

i had a mate with an Impco 425 on a 253 holden V8 and it was awesome.. so they work fine on small motors too

[GspecZL 979]

I think it will be fine. Il get a holley base to. Simple.

[Gav 616]

They look cheap and nasty, that's for sure but they perform much better than Impco on the E series motors. The impco is a simpler unit but you cannot compare the two. In 10 years the one I set up on my fathers one has never faulted. Gets him 450km to a small 66 litre tank. No way in hell an impco will do that. His previous impco one also never faulted but it was a cunt to start in the mornings without some love and understanding and returned 100km less economy for the same engine.

 

Mmmmm...my expectations must be low....I get 450km to the same type of tank with a 225CA/B2 set-up on mixed city/country driving and thought that was great! Simple, reliable and starts okay first thing. Performance acceptable as well. I chose the set-up because it didn't appear to offer as much restriction as a ring type/complex convertor arrangement and thus better performance. Admittedly I came from a complex convertor/hood-type system on a carbed 4.1 that got 350km to the tank on a good day with performance that sucked - a lowish benchmark. So it depends on your points of reference I s'pose...

[GspecZL 979]

do you think all my lines will be good to use? Im hoping il only need the converter and the gas carby and that my original tank and lines will be ok.

 

Although i will eventually want a second tank to give me long range. I will remove the petrol tank for that and get a doughnut tank.

[dizzy616 183]

do you think all my lines will be good to use? Im hoping il only need the converter and the gas carby and that my original tank and lines will be ok.

 

Although i will eventually want a second tank to give me long range. I will remove the petrol tank for that and get a doughnut tank.

yeh man i was thinking a second donut tank too. they seem like a good idea

[deankxf 20,292]

gas lines and wiring should be fine. usually on efi they dont use 1/4" lines, but even still i have ran 1/4" with a 351 clevo and it was ok albeit not ideal. 

 

i havent seen a gas tank mounted where the petrol tank on a sedan goes yet. not even a donut tank

have seen 2 tanks in the boot of sedans though.. does take up a bit of room(could mount a space saver spare where the fuel tank went probably)

 

i have seen a section of floor cut out with a wagon half in half under boot/floor but its not legal as far as engineer?(might be certifiable perhaps, but they usually dont like cutting holes in bodywork)

 

on a ute is different, can get 2 under the back and one under the back window etc..

[GspecZL 979]

Ive seen a ZF with a modified lower quater panel to hide the tank. Was cool.

Well thats all good to know anyway. I want a the second tank for places where gas is a bit less common like when i was in tassie there where places i couldnt get it.

 

I dont really wanna loose anymore boot space though.

[deankxf 20,292]

ZF have a removable petrol tank though with a big hole in the floor able to fit 2 tanks in... ZL = plastic tank under the floor

[GspecZL 979]

yeah it just looked funny had a big bulge at the bottom.

Il see what can be done anyway. Im happy with the one for the short term.

[dizzy616 183]

i was thinking of putting a donut tank under the panel that lifts up on the ute where the petrol tank use to be. maybe 2 under the back see how it gos. i like the lift up panel to be accessible so i can put my spare tyre in there get the full space out of the tub

[dizzy616 183]

so now im thinking of getting a couple parts over some time but want to get the engine running ready for no computer. apart from ignition computer maybe. im thinking does the au straight gas inlet fit on the e series head. i got a eb lined up maybe. will that inlet need a computer or just hook up the converter to it and tune it right. and i was wondering too if like say oil pressure sensor from a xf and the temperature sensors be able to be bolted onto the engine? also im looking at trying to put the starter motor on the right side with a t5 what bell housing should i use?

[Thom 6,651]

Ea to Au this intake interchanges, BA they changed the port design

[dizzy616 183]

sick so can i just hook up my converter to the au port and go? maybe take the accelerator cable from a au

[Thom 6,651]

so now im thinking of getting a couple parts over some time but want to get the engine running ready for no computer. apart from ignition computer maybe. im thinking does the au straight gas inlet fit on the e series head. i got a eb lined up maybe. will that inlet need a computer or just hook up the converter to it and tune it right. and i was wondering too if like say oil pressure sensor from a xf and the temperature sensors be able to be bolted onto the engine? also im looking at trying to put the starter motor on the right side with a t5 what bell housing should i use?

 

Why do you want to put the starter back on the drivers side? Afaik all 4.0l's had the starer on the passenger side and you can get a hold of a 4.0 to t5 bellhousing pretty easy they're not uncommon, oil pressure sender will fit, pretty sure the temp sender will fit too, run straight gas with a rpm frequency switch to control the variable intake (about $40 from jaycar)

[dizzy616 183]

man i might need to hire you too help me get this thing working. im not up to date with this rpm frequency switch. lol. so no problems of changing starter motor position?

[dizzy616 183]

my ute is allready on gas. its got a 225 of some sort looks like a impco rip off. is that the thing that gets the pulse feeds off the leads or positive of the coil?

[Thom 6,651]

More room, also prevents the starter getting cooked by extractors

[gerg 10,871]

Limp home mode, it's rare that an Au even gets to that stage, general they have less overheating issues due to having more reliable head bolts (it's not uncommon for 4.0ls break a head bolt which causes coolant loss which then causes head gasket failure)

My EF did a head gasket this way. I have 2 theories as to why this happens:

1) engine cooks (for whatever reason), head warps, breaks a stud and loses tension in that area, head gasket blows.

2) head gasket weeps coolant next to a stud, corrodes on the threaded part and snaps at that point, gasket fails.

 

With you being the OHC guy, which one is more likely?

 

One thing is almost certain: if you blow a gasket on an E-series, you'll likely find a broken head bolt/stud next to the blown area, like I did. Also I found that when un-doing the bolts, they vary greatly in tension: some bloody tight, others nearly finger tight. I think these heads are prone to warpage. Crossies also.

[gerg 10,871]

my ute is allready on gas. its got a 225 of some sort looks like a impco rip off. is that the thing that gets the pulse feeds off the leads or positive of the coil?

It's not a Nolff's is it? I had one on my Corty, but a 300. Great carby, I'd actually rate them over an impco, better idle adjustment. 225 is painfully small though, especially for gas. You need double this for LPG for any kind of performance.

[dizzy616 183]

nah i haven't been able to find any brand names on it. taking a bit of a stab in the dark that its a 225 from my memory size about that

[Thom 6,651]

 

 

My EF did a head gasket this way. I have 2 theories as to why this happens:

 

1) engine cooks (for whatever reason), head warps, breaks a stud and loses tension in that area, head gasket blows.

 

2) head gasket weeps coolant next to a stud, corrodes on the threaded part and snaps at that point, gasket fails.

 

 

With you being the OHC guy, which one is more likely?

 

 

One thing is almost certain: if you blow a gasket on an E-series, you'll likely find a broken head bolt/stud next to the blown area, like I did. Also I found that when un-doing the bolts, they vary greatly in tension: some bloody tight, others nearly finger tight. I think these heads are prone to warpage. Crossies also.

I've found they usually have a telltale around the headbolt seats if they're slightly recessed the head has been way overheated and is usually warped to the shit house, au's run a different head bolt and I can't recommend anything better to use in any 4.0 (as well au head gasket)