motor oils

[mac]

Any suggestions on the best choices for motor oil for my series 1 with 20,000 kms on rebuilt motor?

[Huib]

I assume you have a non-tuned standard engine and the car is used normally (no racing - no high speed rallying)
There are two basic strategies.
1. Use an expensive synthetic oil and leave it in for a long time.
2. Use a decent mineral oil and change oil and filter frequently.

1 does not really work on engines of the sixties and seventies. Too much combustion products and unused petrol find their way to the sump.

I use strategy 2 with a 20W50 oil. On Fulvia's which are used frequently and also on long distances I change oil and filter every 5000km. If used ocassionally every 3500km or once a year. Some people suggest, the filter can be left in for 10.000km.

I use the Millers 20W50 mineral (they also have a semi synthetic). What puzzles me, is that the car uses no oil for the first 3000km after an oil + filter change and then suddenly starts to use oil at a rate of 1 liter per 1000km. I would be interested to know if anybody has a similar experience with the Millers 20W50 or any other oil. Does anybody have an idea what causes this behaviour?

[nistri]

I agree with Huib that frequent oil changes are essential for the Fulvia engine. However, changing oil without replacing the filter is not advisable because the powerful detergents of modern oils release sludge and dirt trapped in the old filter, making the new oil useless very quickly.

I don't know if a rapid increase in oil consumption in a new engine is attributable to the type of oil. In my last rebuilts it has not happened though I don't use Miller oil. If the engine uses a lot of oil, it would be good to investigate if there is a problem with the valve guides or the piston rings.

[Thomas]

Huib:
I was also interested in your response to this question, being confronted with the possibility of installing a standard engine with only 20.000 km from new (car was crashed in 1968 and kept as donor). Though I agree on the "average oil/frequent replacement" strategy (certainly changing oil filter for the mere 10 Euro), it is more out of fear to damage the engine with loosening of dirt which is triggered by the synthetic oil, which perhaps would not count on an engine so little used since it left the factory.
I have had the same experience of sudden combustion of oil (from 0 to say 0,5L/1000 km) though I cannot contribute it to oil-type or anything else with certainty.

[Randy Adams]

I always assumed the sudden combustion reflects the fact that oil dilution resulting from those fat Solexes has reached the critical mark.

[Huib]

Do you have the same experience then? That immediately after an oil change there is no consumption. In my case for 3000km and then suddenly the consumption goes up.

I changed to the Millers 20W50 a year ago. Before then I used low cost15W40 from the store around the corner. As far as I remember the engine used oil all the time.

There is no special reason BTW for me to use the Millers 20W50. They have an office here in town, gave a nice discount for the quantity I use and deliver it to my workshop for free.

[Huib]

The correct thing to do with an engine that has not run for nearly 40 years is to disassemble it. Inspect and measure everything and clean everything. Be thorough in cleaning oil channels including those in the crankshaft and camshafts. With a bit of luck you get away with only new piston rings and honing.

[Randy Adams]

Huib, I haven't owned a Fulvia in about seven or eight years but, yes, I had the same experience back when I did. I did not think anything of it then as I did not know about oil dilution but I did use the car as a daily driver, was not the type to wind the engine much above about 4,500 when driving around town and I did use the choke (starter) control in the morning. The spark plugs usually exhibited a dark reddish brown color instead of the lighter tan/brown color I was used to seeing on less heavily carbureted cars. I learned very quickly that Lodge plugs could not be used on my car with my style of driving because they would soot up.

I don't know if my Flaminias do the same thing as they are not driven nearly as much and I just change the oil every year regardless by which time each car probably has not done 1,000 miles.

Over the years, many people have told me that it is typical for Italian cars to run a bit rich. I am not qualified to comment on this but I can imagine that a bias toward a slightly rich mixture might be a safety measure against burning pistons and valves on high speed engines before the advent of computer-controlled fuel injection.

Maybe it's not oil dilution at all; maybe motor oil just passes by the rings more readily as it loses some of its viscosity control. But my theory is oil dilution.

I doubt that your chosen brand of oil is a problem. Frequent changes at short mileages are the key and you are already doing that.

[Mac]

Thanks. I have been using an expensive synthetic oil, thinking it would be best for engine long life. We dont have Millers oil here, so perhaps a shell or castrol 20W 50?.... although I thought as the car only does mainly short trips (on sunnny days) a 10W40 might be better for start up protection? Thanks again...looks like I should reconsider my approach

[Huib]

Shell or Castrol 20W50 would be fine I suppose.
If I buy oil at the discount supermarkets I always look to see if the Volkswagen and Mercedes approvals are listed on the can. The very cheapest one does not have the approvals. The others do. That is here in the supermarket.