Most suitable engine oil for 1,500 mile intervals?

[GreenGoddess]

Hi Guys,

 

I know similar questions have been asked countless times but I have seen various recommendations for oil ranging from 10/60 to 15/50 to 20/50.

My car had an engine rebuild 500 miles ago and is due an oil and filter change. I plan on changing the oil every year (approx every 1000 - 1500 miles).  

What would be your recommendations? I don't want to use really modern watery thin stuff that will seep through the gaskets. I want the engine to have the best possible protection without risking oil leaks.

I'm tempted to just go with what it says in the original handbook, but are there any more modern oils that would be a better choice?

My car is a 1984 Turbo (UK Spec).

Thank you.

[Barrykearley]

I use a millers nanotechnology race oil in mine - it’s lovely stuff and sticks to everything. 

[jep]

Valvoline Racing 20/50 is my preferred oil. I use it in all my older engines and is often the oil of choice for historic racing specialists.

It also worked well in a 1978 Porsche 928 I had. It raised the oil pressure in a worn engine but I think the previous owner had used a far too thin oil. 

You'll get many suggestions but unless you really want to do significant expert research, I'd stick with an oil the engine was designed for. At 1500 miles pa, provided it is a suitable thickness and quality, it really won't matter. 

Justin

 

[esprit22]

Castrol Edge 10/60 with a K&N filter is the best combination that I have found for my 86 Turbo

[Escape]

You are absolutely right to stay away from modern thin oils! Too many classic car owners get talked into using some expensive synthetic oil that does more harm than good.

As said, with your low mileage any decent 20/50 or 10/60 will be fine. I use 20/50 from a reputable local company (BelCo) in all my classics, changed at 3000 miles or 1 year.

[jep]

My 4.2 litre Jaguar engine (1973 straight six) was blueprint rebuilt in 2016. The specialist recommended Valvoline Racing 20/50 (which I was already using). 20,000+ miles later, the engine still does not use any oil. I drive it relatively hard but the key to older style engines in my view is to let them warm up for at least 10 to 15 minutes (by driving under 2500/3000 rpm, not letting it idle cold). And the 900 series Lotus engine should also not be revved at all until the oil pressure registers (about 5 seconds) - I think that is even in the handbook for my Excel. The Jaguar engine takes a few seconds for the oil pressure to register, it is more common on older designs but the Lotus 900 is particularly slow to register. Which is why you must fit a correct Lotus approved oil filter that retains some oil inside when the engine is not running, so it picks up pressure quicker on start-up. Brian Angus (chief engineer at Lotus for years) wrote about this in Club Lotus magazine earlier this year.

I once had a Lotus agent not fit a Lotus approved oil filter to a 900 series, so check this very carefully.

Justin

 

[ChrisJ]

You should use a semi-synthetic oil for running in, I used Castrol 151B20 MAGNATEC 10W-40 for 10000 miles after running in both my engines - this was on the advice of Gerald at GST. Change after 1500 miles and increase the revs 500 rpm per 500 miles travelled. Also, the correct lotus approved oil filter is a must as Justin says above.

Gerald explained it to me that if you jump into fully synthetic too soon all the parts of the engine don't get a chance to mesh together, and you get what he described as a slow engine. He insisted on keeping to semi-synthetic for 10k miles to ensure everything is fully bedded in. He rebuilt both engines, so I took his advice.

 

[GreenGoddess]

Thank you all so much. I'm aware that I need to use a Lotus approved oil filter but I didn't know about the 5 second start up rule, that's good to know!

I will go with a good 10/60 or 20/50 oil as that seems to be the consensus on here.

I don't know what I'd do without this forum 🙂

[Escape]

The 5 seconds is not a hard rule, it's more common sense. Our engines are equipped with an oil pressure gauge and while the absolute reading is not that important, it is good practice not to put much load or revs on the engine until the gauge registers pressure. It's the same with my Jag V12, especially as the pressure sender is on the other end of the engine as the oil pump (and it's a big engine). 

Contrary to Chris I was advised to use 20/50 semi-synthetic or even mineral on a freshly built engine. This was for a V8, by an ex-Lotus employee turned V8 builder (Lotus, Rover, TVR, ...). Again, as long as it's a quality oil and the running-in process is carried out with care I don't think it matters that much.

I do know what I would do without this forum: get bored at work and possibly fall asleep during remote meetings...😁
Now off to start up my V8 to relocate for the 4th meeting of the day...

[top-plumber]

10/60 Castrol edge. Factory filter. 
I don’t know how it can be judged what one oil is better than the next unless you are having oil analysis after every change or tearing down the engine on a regular basis. 
use a high quality oil that comes with factory recommendations or is an equivalent replacement. These 910 engines are high performance but pretty basic engineering. 

[drdoom]

Over a period of years I've tracked postings in an American based forum in which engine technical aspects are discussed. One chap who's clearly possessed of top credentials in the realm of oiling has lately responded to my queries on oil for the 900 series, as well as break-in procedures. Attached are clips of his remarks.

Cheers

[GreenGoddess]

1 hour ago, drdoom said:

Over a period of years I've tracked postings in an American based forum in which engine technical aspects are discussed. One chap who's clearly possessed of top credentials in the realm of oiling has lately responded to my queries on oil for the 900 series, as well as break-in procedures. Attached are clips of his remarks.

Cheers

Thank you for all that, I really appreciate it. That's a huge amount of information for my little brain to process.

My decision has been made. It will be 20W-50.