NK 6G74 on LPG?

[gray]

Hi Guys,

Its finally time to upgrade the old NG. I have just spotted an NK in my price range that is fitted with LPG. I'm not sure what type of LPG, I'm about to drive out and have a look at the NK.

It has the DOHC version of the 3.5l which I was trying to avoid as they are a bit thirstier than the SOHC and apparently like the PULP. But my brother owns one and my god it has got some power.

Whats the general consensus on this engine running LPG? My old 6G72 was never meant for Gas but it spent most of its 400'000km's drinking it and without much grief at all. I did put hardened valves in seats in it after the head went and it has been great.

I really want one on LPG, it has saved me a fortune on the NG and this car will be my daily driver, family camper, and when required mud submarine.

If anyone has the DOHC running gas, I'd love to hear your thoughts on it.

Thanks in advance.
Graham.

[Roy.kay]

No

I have just come back from travelling around Aust for 2 years has been great but make sure coils and leads are new or will backfire
I have a new set for Dohc 3.5 if anyone needs regards roy

[schnitzel]

havent got one on gas but have a complete sprintgas mixer system sitting at home that i am going to sell one day.

[Bogger]

Gas ?????????? ........................ great for BBQ's

[gray]

Thanks guys.

I'm having the vehicle inspected as we speak so see what the guy says.

I actually haven't test drove it yet so I'll let you know what it 'feels' like.

Graham.

[Goody]

I know what you are looking at is a DOHC but Ive had my SOHC 3.5 on gas for 7 years and I agree with Roy, make sure you have the right plugs, leads and coils and always start on petrol, mine is a manual version so I have to remember that.
When you fill up and watch other drivers fill up, it makes you happy, they pay $120 and you pay $50ish, makes me smile anyway.
Been towing a 21 ft van, 4wding, and touring in my bus. Had some drama's of late, but any car would have done the same

[Pauly Faulkner]

As long as you either run hardened valve seats and/or valve saver injection they'll run forever on gas.

As was said, ignition system needs to be in tip top shape or you'll blow the the airbox clean off and it's happened to a lot of people.

A few people I've spoken to have said the advice from the specialist was "run on petrol till the engine warms up, don't just switch to gas straight after startup".

[Kubrick]

I havent had mine very long but it runs well on lpg. I had to take the heads off when I got it and the valves and valve seats were in perfect condition.

Its been my experience that most cars designed to run on unleaded do fine running lpg so long as it it is tuned well. It is running lean that burns valves and pinging that recesses valve seats.

However my air box has been damaged at some point so I am thinking about fitting a larger one with round type air filter from something like a bt-50 and I can set up a snorkel at the same time. I will also fit a proper backfire valve .

[gray]

Thanks for all the info guys. I bought it 2 days ago and so far I am very happy with it. It runs a little sluggish on petrol which makes me think it has spent most its time on gas, but runs great on the LPG. I'll put some injector cleaner through it and put some of the expensive juice in it for a while. Hopefully that clears it up.

I'll make sure I start it on petrol and wait till it warms up.

The pre purchase inspection came up good but I'm still giving it to my mechanic for the day next week so he can change all fluid and filters and give it a good looking over.

The original air box was damaged so I got them to replace it. Looks like at some stage there was a quite a back fire. I might fit a valve to just to be safe too.

Thanks.

[Skexis]

I've got one and I reckon it runs better on gas than petrol. Economy isn't too good though - get around 22l per 100 k on gas just running locally. Petrol (98 RON) gives me around 17l per 100k and these figures are with no towing and not being heavy on the throttle.

Don't bother with injector cleaner - just run a couple of tanks of 98 through it and it should be good.

[Kubrick]

if it runs poorly on petrol id check your fuel pressure. When fuel pumps dont get used much they tend to fail. The LPG changeover switches that start on petrol are great because they save your fuel pump and the engine starts a lot nicer.

Mine barley ran on petrol when i got it. Fuel pressure was extremely low. Pulled the pump out to inspect and found the feed hose from the pump someone had used a non fuel type hose and it was disintegrated. Replaced with high pressure fuel hose and it runs sweet now.

[Ian Sharpe]

Gas ?????????? ........................ great for BBQ's

yes but also great for cars, beats paying 1.60c per litre for petrol!

[gray]

Thanks Kubrick. Its a new fuel pump but I will check out the lines etc. I have a feeling that the injector may have been damaged from running on LPG. I've ran about 400km worth of petrol through it now and while I got some improvement early on, it has not got any better from there on.

At least the LPG runs great.

Graham.

[luvthatpaj]

How did you go with the petrol side of things Graham? My DOHC NK GLS is on LPG and when I first got it, it ran very smooth and started fine on LPG and ULP. Now after 3-4 weeks of owning it, it idles very rough and takes a few seconds to start. It does have a newly rebuilt engine, 10k old. When the motor was done, it also had new pump/filter, injectors serviced and new plugs and leads.

Cheers
Luke