Narrow Case engine oil: synthetic or mineral?

[narrow_monza]

I have a feeling this topic has been discussed extensively but for some reason I don't get any hits when I search for "oil" on this forum.
Basically I am looking for oil recommendations for my 250 NC scrambler engine. I live in a moderate climate (Northern California) and I don't plan on racing the bike.
I did hear someone mention that synthetic oil tends to seep through paper gaskets but I might use Three Bond Liquid Gasket 1194 instead of paper gaskets.

Thanks

-Adrian

[amartina75]

when you are searching for information in old posts try using quotation marks if you search "engine oil" you will find this post
http://www.motoscrubs.com/forum/viewtopic.php?f=3&t=724

personally I use Valvoline VR-1 Racing Oil 40wt because my local autoparts stores carry it and it has the highest zinc content of the oils they carry, that is
easily available to me. it is also not too expensive, and can change it often. I think the most important thing to look for is a high zinc content oil, or you can buy the additive seperatly.
zinc is no longer put in automotive oils because it cloggs catalytic converters.

[JimF]

I too use Valvoline VR-1 Racing Oil (straight) 40 weight. Easily available.


So much has been written about oil and so much is yet to be written.


I can recall being told that owing to the clutch's utilization of the engine oil that I should stick with straight weight oil and not multi-viscosity and not synthetics.


It works for me, and I do change oil very often.


Jim

[narrow_monza]

Thanks for the feedback.
What about paper gaskets?
Can I get a better seal with a liquid gasket product such as Three Bond instead of using paper gaskets?

[Bevel bob]

Loosing gaskets will affect shimming in some areas and sealants are considered to be a no no by many Ducati experts. Used very sparingly they can be usefull in a couple of areas.

[LaceyDucati]

Hi Adrian

I recommend a Silkolene oil, Comp 4 20W-50 as described on our site.

http://www.laceyducati.co.uk/news/?page_id=73

Found these sites in the US for silkolene oil, http://www.motorcycle-superstore.com/25 ... =SLIsearch
http://www.silkolenestore.com/shop.asp?PgID=3&CatID=1

We have been recommending and using this oil for more than 10 years now, with no issues. I know however this may not be available everywhere and there are more than likely many other suitable oils. For a road engine most classic straight 40's or 20/50's should be fine (Ducati did recommend 20/50 in the 70's). I've seen engines which have been run on fancy expensive synthetics and castor based race oils and to be frank I've never seen any noticeable advantage. In fact sometimes I suspect the opposite!

I don't know if synthetics wick through gaskets more as I have never experienced it, certainly Caster based oils do. Many modern gasket materials are designed to swell on contact with oil, so experience with older old stock gaskets may not be relevant. I have not experienced any leaks using the gaskets I use with good faces and semi synthetic oil.

I wouldn't recommend using full Synthetic oil when running in, as I have had customers (not following recommendation) who have had ring/bore bedding in issues . I do however use Semi Synthetic oil in the race bikes for running in and haven't experienced any issues.

Ducati Bevel engines have very limited filtration so regular oil changes are ideal and many of the synthetic advantages are therefore lost. Modern oils are designed for modern engines with 4 valves with less cam lift and modern coatings on cams, followers, pistons etc, so the loss of the zinc and other friction modifiers in large levels is less of a problem. Having spoken some time ago at length to a now retired chemist at Silkolene, it appears there is a lot more to oil than grades and the mineral / synthetic argument. Also it would appear there is a lot of bull excrement in marketing and written on packaging.

I've read so much "hog wash" about oil in bevels over the years which frankly with even with my limited knowledge of oil doesn't add up.

Much is said about:

Bevel gears break down multi grade oil. - Personally I can't see any difference between bevel gears driving a cam and a gearbox in this respect. Bearing in mind nearly all motorcycles since the 60's have gearboxes running in the engine oil, I cannot see how this can be of any relevance.

Roller bearing cranks need specific oil. - Honda, Yamaha etc. have been using roller bearings in singles and some twins from the 50's through to now. So any motorcycle specific oil should be suitable. All 2 strokes run roller bearings with petrol oil mist!

Clutch slipping issues? - Again nearly all motorcycles from the 60's to modern day have wet clutches in the engine oil, so therefore again any motorcycle specific oils should not cause issues.

This is not to say that certain oils are not more suitable than others for bevel singles, more that any specific needs are more to do with deficiency in material, manufacture and design! Just wanted to mention this before we all started around the actual reasons for special requirements cropped up!

In my opinion it is only possible to judge an oil after many years of use and subsequent close examination of parts. This is fortunately possible quicker in racing, as the engines are more stressed and tend to be inspected periodically. I also think oil is blamed for many a component failure, maybe a different oil may have faired better but there is normally many other factors to consider.

My guides to avoiding possible poor oil choice:

I would not out of choice use general automotive oil as the needs of a modern car engine is quite different to that of a classic motorcycle. Although they may be suitable I would think it less likely.
Consider if the engine is old and "dirty" or fresh clean build, most modern oils have detergents. Which is fine for fresh build but maybe not for an old original engine.
Go by qualified recommendation and experience, check how long they have used it, how the bike has been used and how many miles they have covered (think thousands not hundreds!)
Ignore the latest trends and the guy in the pub!

Probably many will have other opinions

Best Wishes
Nigel