The Lotus Grand Tourers

I've just been advised to change my oils as follows.
Change to cheapest 20/50 and run for 100 miles.
Then change to good oil, filter etc

This surprised me and I wondered if anyone had a strong opinion for or against.

He said synthetic oils on low mileage coat things and the budget oil allows cleaning.
My Excel has 38K miles and does about 500 pa.

Considering there's quite a bit of oil left in each change (cooler, pipes, cam towers plus what hangs) I'd not want poor (cheap) oil in my engine. If you are doing 500/year and you still need to change it every two years it is 1000 miles, so why not just put a decent oil (something like Valvoline) in and the same oil type next time?
Worth asking oilman from Opie oils

As said above. I wouldn’t be adding cheap oil and running it for 20% of your total annual mileage (btw these cars are much better driven regularly).

Valvolene VR1 is a good oil to use.

Also if doing such low mileage then I’d be more concerned about petrol going off, especially if using E10, gumming up carbs etc and increasing chance of rusting tank.

Our engines retain quite a lot of oil when the sump is drained, 1.2 lts or 25%.

If your existing oil is a synthetic then do not use a non-synthentic to flush as you will be left with
25% non-synthetic.
The cam carriers hold back sludge, for a good change it is worth taking the cam covers off, particularly
if you have seeping saddle type covers. Also an opportunity to check valve clearances.
It is easy to drain the oil cooler and pipes, but refill the pipes before reconnecting to reduce start up time.
To go the whole hog, when did you last change the timing belt.
With the belt off you can prime the new oil circuit by spinning the auxiliary shaft (oil pump) before replacing
the belt.
Oil filter must have a non-return valve.
I use Castrol Edge synthetic, not the very thin motorbike grade.

Dave the cog.

We use Elf 10W 60. Wouldn't use anything else.

If the purpose is cleaning the engine you can add an engine flush before changing the oil. But at a normal oil change and driving there should be no oil sludge.

Curt

I think your guy is just wrong. Maybe he is thinking about the effect of running in new engines with synthetic - definitely a no-no. Modern synthetic oils are renowned for NOT leaving sludge etc.. in an engine - they have detergents to help prevent this. Your engine is probably cleaner inside than most that have been run on older style oils. How many miles does the current oil have on it? How old is it? What oil are you using? So long as you make a point of getting the oil properly hot when you do use the car it should be good for at least two years.

Pete

how much oil does it take?

Sparrow wrote: ↑

Thu May 13, 2021 21:30

how much oil does it take?

Dry 6l, refill 5l

Thank you very much.

Perhaps when I mentioned sludge it was exagerating, merely a brown colour which I did not expect as I had previously completely cleaned the engine during an engine rebuild. The car had only done 1500km over 3 years.
However it is easy on HC engines to lift the cam covers to remove oil.

Dave the cog.

Some replies to the above (for which thank you all)

It's several years since the oil was changed (too many I know) - to Mobil 1.

Annual mileage is about 500 mostly short journeys including a once a month run round the adjacent main roads and a bit of motorway. No trackdays, just Sunday runs

Tomorrow it will get a change to Gulf Competition 20W40 on the advice of Opie Oils. We will also diagnose a binding back brake. We will fix that.

Then it goes in for a cam belt and all the oils seals across the front of the engine.

I've had 10 years of pleasure with minimum trouble. The only nasty event was a burst power steering hose which was not a routine repair.

20W/40 is on the thin side when hot. Not a major issue per se, but you will lose more oil past the rings and down valve guides when hot compared to the 15W50 Mobile one.

I'm using 5W/50 Valvoline racing fully synth in mine.

Pete Boole wrote: ↑

Mon Apr 19, 2021 16:54

I think your guy is just wrong. Maybe he is thinking about the effect of running in new engines with synthetic - definitely a no-no. Modern synthetic oils are renowned for NOT leaving sludge etc.. in an engine - they have detergents to help prevent this. Your engine is probably cleaner inside than most that have been run on older style oils. How many miles does the current oil have on it? How old is it? What oil are you using? So long as you make a point of getting the oil properly hot when you do use the car it should be good for at least two years.

Pete

So That's interesting you mention good for two years, is that based on low mileage and quality oil. Ive always thought it and sometimes do an oil change every 2 years if I do less than 1000miles, this years the cars have been tucked away with covid restrictions so the oil is still golden

I know our engines are a bit old fashioned in their design but my Mercedes only has an oil change recommendation every 18,000 miles!! It's got a huge sump and I change the oil after about 6,000 miles, but I probably don't need to. My point is that modern synthetic oils are much more durable than old non-synthetic oil types and so long as they get to their proper working temperature to boil off any water/fuel contamination they will be fine for 2 years - more possibly.

Pete