Engine Oil

[BenMcCarthy]

Having spent rather a lot on an engine rebuild for the big-bore twin cam on my +2 130 I am naturally anxious to use the best engine oil from the outset. Its done 5 hours on a dyno with a running-in oil and I was planning on changing the Motaquip 20w 50 oil its now running at 1,000 miles.

I'm counting on using Miller's Classic Sport 20w 50 becauseI've read that being Semi-Synthetic that they reckon is just the thing for engines like this one. Does anybody have an opinion on whether this oil is the best one? I'm presuming the part synthetic formulation gives it better durability for the same SAE rating at low/high temperatures. But I know you can get Fully Synthetic 20w 50 such as used in some more modern race engines I believe.. Why should I/should I not use that?

1. Is Millers the best product to use?

2. I'm counting on changing oil every 3,000 miles. Is that necessary with a more durable oil such as this?

3. I also wondered what filter was the best to use? And

4. is there any truth in the belief that filters are better if kept on the engine for an extra oil change because the 'efficiency increases'? I don't understand the logic in that statement.

Any thoughts appreciated

Thanks


Ben

[rickf]

I don't have the nerve to try either of these, but I remember reading about thirty years ago about a US government study of the performance of various brands of oil. Re-refined oil came out the best. Also, there was no measureable difference in wear between engines with oil changed at 5,000 miles and at 10, 000 miles. Like I said, I wouldn't try it myself.

I understand oil filters tend to clog up and the oil bypasses them, so I'd say the opposite is true. Changing them more frequently than the oil would be of more benefit.
You can cut them open and see what's got caught in there. Kind of like an inquest.

Also, there's services where you can take a sample of your used oil and send it off to be analyzed. They look for bearing material, etc.

[steveww]

I use Castrol Magnatec 15W40 in my twinc. Why?

Good quality oil at a resonable price I can pick up easily from Halfords etc.

The oil pump on the twinc was not designed for thin oils e.g. Mobil 1 0W40 and has trouble getting the pressure up. I get 40psi hot not problems with the Magnatec.

I change the oil/filter every spring which is about 3,000 miles. Most service schedules usually say every 12,000miles or 12months with ever comes first. I get my filters from PM and they are a FRAM unit.

[bill308]

I this it advisable to use dino oil (not synthetic) during the break in process, say up to at leat 1500 miles. I'm of the opinion that the synthetics are just to slippery to allow all clearances to bed in properly. After break in, synthetic might be the way to go but be forwarned that synthetics tend to leak more than dino oil. This is of particular concern with British cars. Of course there are the benefits of rust prevention.

[poiuyt]

I've got about 1500 miles on a rebuild and will be changing the oil and filter this week. The only oil that my S4 will ever see is Mobil One full synthetic. 15W50 spring through fall; 10W30 if I use it in the winter. I have used nothing else in my VW GTI VR6 and it's going to reach 180,000 miles this month with everything original.

This is the only oil that goes in any of my cars, the two motorcycles, the lawn mower, etc.

Steve Becker
1969 Elan S4

[JACKJABBA]

You should go with what the manufacturer states as the correct oil to use. Using the same oil in all your engines can be the wrong way to go, especially on motorcycles because of the wet clutch and the different types of clutch plate. Modern engines are built out of different grade materials with much tighter working clearances. Just seen a report on running in motorcycle engines which was carried out by the Castrol Technology Centre.

According to Peter Brett , Synthetic oils interfere with running in. This is for the reasons that go beyond their low friction properties - there also seems to be a chemical process happening which hinders it. "Although you can treat an engine as fully run in after 500 miles, surface stabilisation continues for at least the first 5000 miles of an engines life", he says. "Synthetic oils actively prevent this from happening , possibly by holding friction surfaces apart". The consequences of using a synthetic too early is your engine will never run in properly. He suggests waiting until 10,000 miles before using it in most engines subjected to normal use. Until then , you are best to use an inexpensive but branded mineral oil.

[BenMcCarthy]

Thanks for your thoughts,

Current thought at my engine rebuilders is that the 20w 50 semi-synthetic is the best option straight from 1,000miles and synthetic is possibly risky.

Knowledgable chap at Mobil Technical states that Fully Synthetic oils can tend to let seals relax on older engines but that this is overstated when compared to the longevity benefits of running a fully synthetic. Especially on a newly rebuilt engine I presume that leaking seals should not be as great a concern. He states that the 15w 50 would be better flowing at lower temperatures and much superior at high revving and higher mileage use generally. Owners had used fully synthetics in even vintage engines that were reasonably tight and in good condition and certainly there would not be a problem with the type of unit in the Elan.

Thought at Miller's Oils was that the selection between a fully synthetic 15w 50 and semi-synthetic 20w 50 was very marginal. The plus for the semi-synthetic was that there would be lower oil consumption by the engine. He also stated that while both fully and semi-synthetic would be much improved over mineral oil on cold starts, contrary to Mobil's view the semi-synthetic would be better at cold starts because of better flow at low temperatures.

[BenMcCarthy]

Castrol, on the other hand, of all options available (including 15w 50 Magnatec) recommend Castrol Formula RS 10w/60 full synthetic for CLASSIC CARS especially high performance engines. Apparently its not 'too thin' to cause leaks to seals. I haven't heard any field test results though

[heinrichgoldmann]

For street TC-engines go to 2o/50 Valvoline Racing, - 100% mineral- it is from bedding in to long life all your engine need.
I tried in the last 10 years on 4-bolt-engines Castrol 15/40, Castrol 10/60 RS, Millers 20/50 fullsynth., they all go trough the rear oil seal and also new oil seals are like glass after about 500 km.
So you life with a "baby" all the time to use pampers under the bell-housing.
What you can do on 4-bolt engines use 10/40 BMW (from BP) mineral, it costs EUR 2.50/liter here on ebay and is good for running in, but change to longterm use to the 20/50 - these new 20/50 is made for all purposes, also for high rpm-engines.
It is expensive but your engine is quiet a lot expensive to rebuild . Now I?m using it on a new rebuild 5-bolt engine and it is fine.
Heinrich Goldmann
Germany

[types26/36]

Five bolt engine???:huh:
Brian

[rgh0]

Not sure if Heinrich meant it but the Datsun steel crank conversion is 5 bolt

Rohan

[poiuyt]

I use Mobil One full syntheyic in my S4 - generally 15W50 - in the New York City area. I do not expect to use the car much in the winter, except to get it out once and a while to keep everything lubed and working, but I'd recommend Mobil One Synthetic 10W30 in the cold weather.

I have no leaks and the car runs fine. In fact, I use Mobil One in every engine my wife and I have: the Lotus, two VW GTIs, a Fiat X1/9, two motorcycles , the lawn mower, etc.

Steve Becker