Oil for Audi 12V on LPG

[Guybrush]

Dear oil guy,

I have a ’96 Audi 12V V6 2.6 150 bhp which I’ve had converted for LPG operation. In my ownership it has run 30.000 kms and I've been using generic "Biltema" 5W-40 fully synthetic (API SN/CF, ACEA A3/B4, VW 502.00). The car has a flat tappet engine and the cams are showing some wear at 200.000 kms.

I've read that "word" is min. 1200 ppm zinc for flat tappet engines. I read with concern that most oils today are formulated for newer cars - which have roller cams - and for stricter emission standards (not for engine wear.) There’s also the issue of oil nitration due to gas operation. My current oil had TBN 8,0 when poured in. I can do better. Some say to use a special oil, e.g. Penrite HPR Gas 10W-50. But that oil is exotic here, and very thick, made for Australia. I live in Norway.. 90 % of my cold starts happen in 0-15 ‘C range, and winters here can get -20 ‘C or less.

I can get Shell Helix Ultra 5W-40 for a good price. It meets VW 502, among many others (MB 229.5), but doesn’t list ZDDP or SAPS. A user on BITOG posted an UOA of 5000 kms on Shell Helix Ultra 5W-40, and it revealed only 800 ppm zinc!? I know it is an SN oil (zinc
I've read so much about oil these last days... any help would be appreciated!

 

[Rand]

Maybe a mixed fleet type oil.

Suitable for use in both gas and heavy duty diesel engines.
Not familiar with your brands

but in the US that would be Delvac 1, Delo, Rotella t6 (all 5w40)

and have 1200+ zinc afaik

They also make concentrated additives for racing purposes to raise the ZDDP level.

 

[19jacobob93]

Penrite is very popular here and most older cars and those with flat tappet cams run nothing but Penrite because of it's 'Full Ten' add pack with a huge dose of Zinc. The HPR10 10w50 that you mentioned is probably the most popular choice in these situations.
Being a 10w it SHOULD be okay down to -20c (10w30 is okay down to -25c).
I have used a 15w50 down to -12c (yes Australia gets cold too!) and it seemed fine so I'm guessing a 10w50 would be fine beyond -15c.
Diesel oils can be good for this and another option would be Liqui-Moly MoS2 additiv. Many people in cold climates use it with drastic impovements in cold starting! I use it because it just makes my engine smoother, quieter and more fuel efficient.
It is the perfect additive for flat tappet cams because it plates overlapping layers of moly that slide over each other and prevent metal to metal contact in engines. I have over 200,000kms on my engine and I have ZERO visible or noticable wear at all but my engine has roller rockers. MoS2 has worked wonders for me as well as many other people in your situation so if I was you I'd consider it as a fairly cheap alternative

 

[abycat]

I think you are over thinking it. I have non roller valvetrain and at 316xxxkm I also have minimal wear but it's never going to hurt my engine. I think you should just run the correct weight and buy whatever oil you want.

 

[SnowDrifter]

Redline oil is high in Zinc and Moly

 

[expat]

Originally Posted By: abycat
I think you are over thinking it. I have non roller valvetrain and at 316xxxkm I also have minimal wear but it's never going to hurt my engine. I think you should just run the correct weight and buy whatever oil you want.


I tend to agree.
I have an old Flat tappet engine in my Triumph, with an aggressive cam, and don't subscribe to the 'More is better' (with regard Zinc) idea.

 

[abycat]

Originally Posted By: expat
Originally Posted By: abycat
I think you are over thinking it. I have non roller valvetrain and at 316xxxkm I also have minimal wear but it's never going to hurt my engine. I think you should just run the correct weight and buy whatever oil you want.


I tend to agree.
I have an old Flat tappet engine in my Triumph, with an aggressive cam, and don't subscribe to the 'More is better' (with regard Zinc) idea.



I bet your triumph is pretty much the same engine. besides mine has fuel injection. Both of ours are ohv. Very mild cam and Springs. Not high revving. Well mine is definatly not. I hate the more is better cause the more of one thing means less of everything else.

 

[hotwheels]

Rand mentioned mixed fleet oils, and I tend to agree regarding their suitability in older VW engines. Rotella T6 5W-40 has over 1,200 ppm zinc, if I rememeber correctly, which should offer sufficient protection for your engine's cams and tappets.

hotwheels

 

[Garak]

I wouldn't worry about specific LPG type motor oils. In the taxi fleet, we never bothered with them. You certainly can - they'll have lower TBN and might be a little harder to find. When I had my gasoline Audi, I used all kinds of different stuff, including both oils that are in my signature now, with a 15w-40 being used most of the time. A 5w-40 or 0w-40 would be a fine year round choice.

 

[Revving2Redline]

Redline Oil is uber high for zinc and moly. Not cheap but cheaper than new motor.

 

[Shannow]

In Australia, late 90s, there was a call for "LPG" specific oils to be on the market.

The manufacturers took their mixed fleet Diesel (Delvac MX, Delo 500), and put them into 5L containers with "LPG" on the front.

Mixed fleet would do you fine.

 

[Garak]

I believe Chevron still offers LPG/CNG oils up here, with lower TBN. Petro-Canada might, but I'm not certain; in fact, they reference LPG/CNG on their ILSAC oil data sheets. I'm fairly certain that Imperial Oil and SOPUS do not offer such an animal any longer.

Mixed fleet was fine for the engine on gas and will be fine for the engine on LPG. The taxis used the early energy conserving PCMOs with no concern.

 

[Shannow]

Garak...makes sense...

Just dug the Feb 2000 Caltex lubes book out of my stash, and in 2000, VitalGas LPG lube was a 20W50

"low ash, multigrade engine oil for gas, dual fuel, or petrol type automotive engines. It is designed to minimise the problems of higher oxidation, nitration, corrosion and oil consumption caused by the higher combustion temperatures associated with gas fuels. Minimises valve seat recession and copper/lead bearing corrosion".

TBN was 8.9, Sulfated Ash 1.10...oh, and it's VI was 123.

Similar to their mid ash HDMOs (and obviously not 15W40).

Now I've got to find where the rest of the old docs are stashed.

 

[Guybrush]

Interesting.

My discoveries the last 24 hours has gone in the same direction as this thread...

Quote:
For a long time I wondered why there are "LPG engine oils." I recently I found a great site that explains that. Actually quite simple and logical. One should LOW SAPS use oils that are required for a number of years with the diesels with DPF. These are low-ash oils. Ash-rich oils, NO Low Saps, standard oils, no matter what price range, the intake valves can become encrusted, since a small amount by the shanks is drawn and blowing through the vent. Also the piston crown may become encrusted. LOW SAPS oils are far less inclined to do so. When enough petrol additives in it to wash the valves and keep the pistons / combustion chambers clean. Case of LPG, as we all know, nothing in it ... Anyway, everything positive and enlightening. My car get future only LOW SAPS. Regards, Heiko


The text above is google translated from Lpgforum.de, where they recommend VW 504/507 oils because they are LOW SAPS. I do not know if this is sound advice for flat tapped engines.

They recommend Fuchs Titan GT1 Pro C3 5W-30 (see data sheet). The oil is ACEA C3, ACEA A3/B4 which means HTHS >3.5 which is right for my Audi. (For reference: Audi 12V can have 5W-30 - Blauparts actually lists a 5W-30 oil for it with kinematic viscosity at 100 'C of 10.x.. - But I've read on BITOG that if going 5W-30 it should be a thick one, like the Fuchs in question which @ 100 'C is 11.7.)

But I assume it has pathetic zinc and phosphor due to VW 504/507 low saps formula. Fuchs doesn't say. But I was lucky enough to find a VOA (virgin oil analysis...for newcomers like me) of the oil!

Although Fuchs doesn't market this oil for LPG, it looks similar to AMSOIL Synthetic Vehicular Natural Gas 15W-40 (see data sheet ) in terms of being low ash, low TBN,..

These attributes were surprising to me, as some people recommend HDEOs like Mobil Delvac 1. These oils are pretty much in the opposite end of spectrum...? Compared to the aforementioned AMSOIL, Mobil Delvac 1 5W-40 (see data sheet ) is up 105% on TBN, and up 130% on ash content!!

HDEOs has bucket loads of zinc and phosphorus, but according to some, ZDDP is dead...? Do you call [censored] on this?

Would you personally use the Fuchs with Boron 80, Zinc 750, Phosphorus 650, HTHS >3.5 in a flat tapped engine?


Cheers

 

[Garak]

ZDDP is not dead. There may be work in other directions, but it's far from dead.

I think worrying that something like Delvac 1 might be in the wrong direction is a bit needless. An LPG engine gives you more options, not fewer, when it comes to oil choice. Yes, you have the freedom to run a lower SAPS oil, and in some ways, that's optimal. But, you don't have to. For a given TBN level, generally, one can go longer on LPG than gasoline, given the absence of fuel dilution. With respect to deposits, it's not going to be an issue. I've never had issues with deposits in combustion chambers and the like on LPG vehicles, and I've taken many of them apart over the years and had them go hundreds of thousands of kilometres. Some burned significant amounts of oil, and none of them would have been standouts on Noack or TEOST tests, or whatever one wishes to look at.

My view would be run what was originally recommended for the engine as a first choice, particularly with respect to viscosity. There's no need to hunt something special down just because it's LPG. In the taxis, "normal" ILSAC rated motor oil was used, the OCIs were automatically doubled, and that was it. There was no use of synthetics or special LPG/CNG oils (since the current generation of low SAPS oils wasn't even in sight yet) used by us.