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from what i know, its the type of oil that racing cars use... not sure though... i don't think it can be purchased over the counter here in australia.

Uhhh no. Delvac is a diesel oil.

Mobil Delvac 1 5W-40

Diesel oils are, from my understanding, certified to higher standards due to the generally tougher operating conditions within diesel as opposed to petrol engines.

As such they are arguably a good or even the best option for using in petrol engines as they are designed for a tougher environment in the first place.

Not sure where you could get it from though sorry... perhaps a truck mechanic/supply store?

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Uhhh no. Delvac is a diesel oil.

Mobil Delvac 1 5W-40

Diesel oils are, from my understanding, certified to higher standards due to the generally tougher operating conditions within diesel as opposed to petrol engines.

As such they are arguably a good or even the best option for using in petrol engines as they are designed for a tougher environment in the first place.

Not sure where you could get it from though sorry... perhaps a truck mechanic/supply store?

Errr.. no . Don't go putting diesel oil in your skyline is my advice and also that of the oil manufacturers. It's really not a consipracy.

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Errr.. no . Don't go putting diesel oil in your skyline is my advice and also that of the oil manufacturers. It's really not a consipracy.

Missed the part where I said it *was* a conspiracy actually? :)

Im not saying you should use diesel oils in a skyline, nor in any other petrol engined car for that matter.

I am also not saying that diesel oils are better to use - just outlining what I understand to be the reasoning behind some peoples opinions who do. Like I said, they are 'arguably' a better choice.

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Missed the part where I said it *was* a conspiracy actually? :)

Im not saying you should use diesel oils in a skyline, nor in any other petrol engined car for that matter.

I am also not saying that diesel oils are better to use - just outlining what I understand to be the reasoning behind some peoples opinions who do. Like I said, they are 'arguably' a better choice.

Ahh... I see.

I just found new evidence that supports 'conspiracy' , you were right!

Also as some have argued for diesel oil to be used in petrol engines, I would like to add using premix two stroke oil into the 'arguably' a better choice bracket too as a replacement :laughing-smiley-014:

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Just do a quick search on the forums for Delvac, many guys here use the stuff.

Quoting cubes from another post

If you really want to clean her up throw some Mobil Delvac 1 in. Its a diesel full synth 5w40 and can be picked up for under $60 ($50 here in Adelaide)

Don't let diesel scare you, its perfectly fine in a petrol engine and meets the API SL specification for gasoline engines, mobil state so them selves.

http://www.mobil.com/USA-English/Lubes/PDS...vac_1_5W-40.asp

OR.. Even better, throw Motul 300v through it, nothing cleans like an ester based oil. smile.gif

Bob is the Oil Guy

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I'll generalise a bit:

Diesel oils contain very high amounts of detergents to remove carbon build up. That's why the oil goes black so quickly in a diesel, when the oil's doing its job correctly.

Use it in a petrol and you get the same result, bye bye carbon seal and hello blow-by.

USED to be popular with race engines in the olden days before modern synthetics etc came onto the scene, but that's hardly a recommendation for the every day car engine.

If you really want to ruin your petrol engine's carbon seal try some 2-stroke diesel oil. That's super high detergent to keep ports, pegged rings etc clear from carbon.

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Ill start by saying that in the US where Delvac 1 (fully synthetic 5w-40) is readily available, it is a very popular choice for enthusiasts, and it has always given good UOA results.

I use it in my Skyline and have not noticed any adverse effects compared to the petrol engine oil i was using before although I have not done any UOA so i cant say for sure, but for the price is is a great engine oil.

Now to quote Mobil themselves :

" Question:

Mobil 1 vs. Mobil Delvac 1® for a Gasoline Engine

I have read on the Internet that Mobil Delvac 1 oils may provide better performance in high-performance passenger-car engines than regular Mobil 1, since they meet CF-4 specs. What about using Delvac in gasoline engines, especially high-performance engines?

-- "Tribological", Richmond, VA

Answer:

Mobil 1 formulas will deliver everything you need for your gasoline engine. In fact, during development, tests are run in both gasoline and diesel engines to demonstrate the superior performance of Mobil 1. Mobil Delvac 1, which is designed for heavy-duty diesels, meets most diesel engine oil specifications, and also meets API SL certification. And because Delvac 1 operates in a different environment – diesel engines run longer, generate soot and run hotter, it contains different types and amounts of additives than Mobil 1. Even so, Delvac 1 still meets API SL certification for gasoline engines, and because of its high performance, we would expect it to do a good job of protecting your gasoline engine. If you use your gasoline vehicle in "heavy-duty" service, Delvac 1 will provide many benefits compared to conventional oils. When compared to Mobil 1 performance, those benefits may not be as obvious, and in fact, Mobil 1 would be expected to outperform Delvac 1 in many gasoline applications. "

http://www.mobiloil.com/USA-English/MotorO...ine_Engine.aspx

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I have used diesel oil in a petrol engine in the past to clean it out between oil changes, engine run at idle (V8 pushrod motors with lots of kms on them). With a motor thats run synthetic all it's life you would never require this.

Because of the soot you need a high amount of detergent in a diesel oil but, there is a sacrifice in the percentage of this vs the actual lubricant in the mixture. That sacrifice is lubrication protection. Not to mention the additional wash down reaction between the petrol and the higher levels of lubricant in the diesel oil. Diesel puts alot of soot everywhere including the bores, so the diesel oil to suit washes it off better. Those same detergents help a little to pull fuel into the oil as a down side. This happens with any oil and it's one of the reasons to change oil regularly. If you have an engine that has large cams / poor mixtures off idle etc this by itself effects oil change intervals, rich mixtures mean shorter intervals.

To put it another way; How much does your engine need cleaning Vs how much lubrication protection. Mobil 1 won't do a better job of performing in an RB if you bung in more detergents. My understanding is that Delvac will therfore need more frequent changes to remain effective in a petrol motor and I'm quite sure the level of lubrication protection is significantly down on it compared to fully synthetic oils designed for petrol engines.

At basically the same cost as a fully synthetic oil actually designed for high performance petrol engines I think getting some delvac into the motor is a nice big step backwards and terrible value for money.

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At basically the same cost as a fully synthetic oil actually designed for high performance petrol engines I think getting some delvac into the motor is a nice big step backwards and terrible value for money.

Delvac 1 which is what i have referred to is a fully synthetic oil. There is a cheaper version of Delvac which is not fully synthetic. Mobil 1 is approx $70/5L, Delvac 1 is $50-60/5L, so i dont think that makes is terrible value for money.

Im sure the points you have made are valid but you are generalising.

Delvac one has a HT/HS of 4.1, Mobil 1 has s HT/HS of 4.2, they are not significantly different in their level of protection.

Edit: When i say Mobil i mean the 5w-50.

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Delvac 1 which is what i have referred to is a fully synthetic oil. There is a cheaper version of Delvac which is not fully synthetic. Mobil 1 is approx $70/5L, Delvac 1 is $50-60/5L, so i dont think that makes is terrible value for money.

Im sure the points you have made are valid but you are generalising.

Delvac one has a HT/HS of 4.1, Mobil 1 has s HT/HS of 4.2, they are not significantly different in their level of protection.

Edit: When i say Mobil i mean the 5w-50.

I appreciate that the Delvac 1 is fully synthetic. The reason for the discrepancy in price is most likely the ratio of detergent to synthetic oil content.Diesel fuel isn't too shabby as a combustion chamber / bore lubricant compared to petrol which isn't.The additional difference on a motor that runs high sustained rpm (unlike a diesel) is bearing life (mains and big end).

I would suggest that spending $10 more to better protect an engine worth many thousands is always a good move. . The diesel oil is quite simply a very bad choice for a motor like the reving RB sixes in my opinion.All of the race engine builders I know (not that I know all that many) favour the petrol intended products bar none, this includes pushrod v8 guys.

Proceed with caution, it hasn't taken the world by storm and there is a good reason for it.

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I appreciate that the Delvac 1 is fully synthetic. The reason for the discrepancy in price is most likely the ratio of detergent to synthetic oil content.Diesel fuel isn't too shabby as a combustion chamber / bore lubricant compared to petrol which isn't.The additional difference on a motor that runs high sustained rpm (unlike a diesel) is bearing life (mains and big end).

I would suggest that spending $10 more to better protect an engine worth many thousands is always a good move. . The diesel oil is quite simply a very bad choice for a motor like the reving RB sixes in my opinion.All of the race engine builders I know (not that I know all that many) favour the petrol intended products bar none, this includes pushrod v8 guys.

Proceed with caution, it hasn't taken the world by storm and there is a good reason for it.

Well according to plenty of UOAs from plenty of people using Delvac 1 in their petrol engines there is only evidence that it protects the engine very well. There is no evidence of more wear on any part of the engine compared with other good quality full synth engine oils.

In some ways the Devlac 1 is regarded as a better formulation than M1 5w-50 due to less viscosity modifier(more base stock) and better additives.

I dont think the generalisation that you shouldn't run diesel oils in a petrol engine applies when talking about Delvac 1, and I don't see how the opinion of race engine builders applies when considering the lubrication requirements for a factory built road driven engine with long drain intervals.

Caution is not required, results show otherwise :)

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