Fuel type for Nissan Patrol MQ 4ltr 1984 petrol

Submitted: Friday, Jan 17, 2003 at 09:56
ThreadID: 2993 Views:3668 Replies:3 FollowUps:3
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Hello All,

I own a Nissan Patrol MQ 1984 4 ltr petrol and I am planning to take it on a three month trek from Melbourne through the centre and over to the Kimberleys and Kakadu. However, as the engine is a 1984 4ltr petrol I have been advised that I can not use unleaded petrol, only lead replacement petrol. This is a problem as many fuel outlets in the outback only supply diesel or unleaded. Finally my question. Does anybody know if one can put any brand unleaded fuel in such an engine with a lubricant additive, such as BP does with their unleaded fuel?

Thanks very much,
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Reply By: OziExplorer - Friday, Jan 17, 2003 at 11:30

Friday, Jan 17, 2003 at 11:30
This is starting to become an expensive exercise.

You have to add a product called Valvemaster to your petrol in the prescribed quantity. Valvemaster prevents valve seat recession and lubricates the valve stems and prevents seizing of the valves in the valve guides - No, there is no substitute or another product other than Valvemaster that is regarded as satisfactory for use. Valvemaster is advised to be used by all major oil companies, and was used by (from memory) Monash University in their test of leaded against un-leaded fuel.

Now, to get anywhere near the octane rating of the previous Super petrol, you really need to use Unleaded Premium, or better still Shell Optimax. This is going to be the same issue as lead replacement in rural areas, once you get out of the main regional centres, few have it and it is expensive. Usually, but of course you cannot rely on this, that service stations who do not have the lead replacement fuel will normally carry the Valvemaster.

What I would do if the vehicle was mine, is use the Valvemaster with standard unleaded petrol and get the engine tuned and possibly re-jetted so it does not ping on the unleaded fuel before you go. This would require somebody who has a decent automotive scope and an exhaust analyser. This is not the sort of thing you would want to get done and then leave straight away. Ask the person that does the re-tune to explain to you what is the ideal colour to see at the end of the exhaust pipe to ensure optimum running of the engine and to ensure it is not running to lean. If the colour is not correct, you will need to get this corrected.

Here is a PDF download from BP which is not specific to your problem, it actually mentions the use of the Valvemaster product.

If you are a member of a motoring organisation like the RACQ, RACV, NRMA etc. etc. I would phone their technical information centre and they may be able to point you in the right direction to somebody local that has the necessary experience and equipment to re-tune the engine correctly.
AnswerID: 11429

Follow Up By: Member - Andy - Friday, Jan 17, 2003 at 11:45

Friday, Jan 17, 2003 at 11:45
Thank you Ozi. That is fantastic information and exactly what I was looking for.

I had a feeling when I bought the vehicle that fuel was going to be a problem but for a 1985 Nissan it really is in great shape and it is what I can afford. I will have to go back to the maps and do the numbers.

FollowupID: 6360

Follow Up By: Oziexplorer - Friday, Jan 17, 2003 at 12:00

Friday, Jan 17, 2003 at 12:00
Andy overall they were a good solid vehicle and people loved them for towing. They are a rather thirsty vehicle and that was the problem with them. If you take it easy and cruise at around the 85 to 90km/h mark you can make a substantial saving in fuel. A cruise control from K Mart at about $169 approx can be quickly paid for on a long trip like that in fuel savings. They are exceptionally easy to fit, and are really a no brainer to do on a vehicle like your Nissan. Realisticly, I would say 3 hours to fit from start to finish and no special or fancy tools required. Everything is supplied in the kit. There are two models from memory available with little difference in price. One is an AP50 and the other is an AP60. The AP60 is the preferable unit.

Here is a previous message in the ExplorOz archives from Ray to say how easy they are to fit. Looks like SuperCheap has them as well.
FollowupID: 6363

Follow Up By: Member - Andrew- Friday, Jan 17, 2003 at 15:23

Friday, Jan 17, 2003 at 15:23
Thanks Ozi. I drive at 85 to 90 ks at the moment, I'm in no hurry to get anywhere quickly especially when I'm travelling. Its all a part of the enjoyment. Cruise control sounds like a good idea.

FollowupID: 6373

Reply By: Savvas - Friday, Jan 17, 2003 at 13:08

Friday, Jan 17, 2003 at 13:08
Andy ... I understand that some aviation fuels are ok to be used in a leaded petrol engine. For example, helicopter fuel. Someone recently posted here that they used it regularly in older Toyotas. If you don't have a choice and need to get out of a situation where there is no other type of petrol available, then it's an option.

AnswerID: 11435

Reply By: Member - Willem- Friday, Jan 17, 2003 at 19:49

Friday, Jan 17, 2003 at 19:49
I am not sure if there is a difference between a 1984 Nissan petrol engine or the one that I drive, the 1978 Nissan G60 4 litre petrol. I had the engine rebuilt at the beginning off 1999, 62,000kms ago and have run it on unleaded fuel at all times without additives. When rebuilding the engine we replaced all valves with standard ones. I cannot remember if the mechanic inserted special valve seating but the whole head was done in the stock standard way. So far the engine is running beautifully. How long would it take for unleaded fuel to damage the engine? It is possible ofcourse that my old trucks' engine can be run on all kinds of fuels without damage :-) Cheers, W
AnswerID: 11451

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