sunbeamtiger.co.uk

Need sone expert advise. I have been using semi-synthetic 10/40 in my Tiger and I have been told this could cause damage and should only use a 20/50 mineral based oil. Is this fact?

Semi synthetic is not good for running in on older engines, but if run in, should not of done any harm. I think you should switch to 20/50 tho.
Lucus or valvoline 20/50 are both very good, allso the lucas heavy duty
oil stabilizer added will put you nearer the original spec for the 260 engine.

I have an other problem of tappet rattle after high revs, or long period's of high speed's, so i have been looking into correct oil's.
Problem is a lot less with lucas oil + stabilizer, but still happens now and again, I have high rev lifter's fitted. So if any one has a cure for this problem please let me know. [solid lifter's means a new cam, so not an option]

Harry

In my opinion there should be a “sticky” about Tiger engine oils, since it such a complex subject with so many variables.

What is “dino” oil?
Brand new engine or an old engine?
Flushing oil?
Mineral or synthetic or semi-synthetic?
Right grade of oil
Right filter
ZDDP and flat tappet camshafts

An easy way to resolve most technical queries is to contact Millers Oils:
http://www.millersoils.co.uk/index.asp

Tel: 01484 475 060 (Technical Help)

Email: technical@millersoils.co.uk

Dino oil:
“Dino” oil is US slang for mineral oil (from the age of the dinosaurs). Not to be confused with “dyno” oil (special mineral running-in oil) on an engine dynamometer.

Brand new Tiger engine:
As Harry (H, Sunny 65) mentioned, with a brand new engine, ONLY a mineral running-in oil should be used, never a synthetic. Ask any professional engine builder.
Wear and tear is actually good for a new engine. Synthetic oil, with its superior lubricating properties, hinders the running-in process.

Old Tiger engine:
An old Tiger engine is probably perfectly happy with a good old classic 20w50 mineral oil. It is also much cheaper than synthetic oil. There is no reason why changing from mineral to semi-synthetic/full synthetic should cause problems, except if a flushing oil has been used on a high-mileage engine.
The flushing oil may remove oil residue and other debris which could possibly clog up filters, oil pumps and oilways. In addition, a certain amount of flushing oil will be left in the system.

NB Contrary to popular belief, synthetic oil mixes readily with mineral oil, so there is no need to flush the engine prior to changing from mineral oil to synthetic or semi-synthetic oil.


Mineral or synthetic or semi-synthetic?
A standard Tiger engine is probably fine with a 20w50 mineral oil. A highly modified 289/302/347 etc will probably benefit from a full synthetic oil.
A semi-synthetic oil is basically a mineral oil with a small percentage of synthetic oil, whereas a full synthetic oil is 100% synthetic. A full synthetic oil offers far superior protection compared to mineral oils and semi-synthetic oils. The semi-synthetic oil was introduced to be pitched at an intermediate price point.

I hope that the following example clearly illustrates one of the main differences (running temperature capability) between mineral and synthetic oils.

General Motors put two identical high bhp V8 engines in two different road cars. The only difference between the cars was that one had an oil cooler and the other one did not.
GM recommended mineral oil for the one with the oil cooler, but they recommended synthetic oil for the one without a cooler.

This is because mineral oil should normally run at not much more than 70C, whereas a full synthetic, such as Millers CFS 10w60 will run at 125C continuously, peaking at 150C.
The synthetic oil will still maintain the engine's correct oil pressure at elevated temperatures in contrast to a mineral oil, where a noticeable reduction in pressure can occur after a good "thrash".

The right grade:
Be advised by Millers etc.

The right filter:
Use a quality filter, such as the V8F from David Brown and change it when you change the oil:
http://www.v8filters.co.uk/index.html

ZDDP and flat tappet camshafts:
Manufacturers have removed zinc dialkyldithiophosphate (ZDDP) from oils to minute trace amounts in order to satisfy emissions regulations (this is because ZDDP attacks the catalytic converters).

Extract from Millers Oils leaflet:
“Classic car enthusiasts are reporting frequent cases involving serious wear on camshafts and cam-followers.
Part of this problem is caused by the reduction of ZDDP (the traditional anti-wear additive) in modern engine oils.

Millers Oils formulations include the optimum amount of ZDDP to provide the best possible protection for highly loaded engine components, significantly reducing wear in both high performance and older classic cars .”

Here are some useful links on ZDDP and the lubrication of older classic engines using flat tappet camshafts:

http://www.joegibbsracingoil.com/traini ... ldcar.html

http://www.gt40s.com/forum/gt40-tech-en ... shaft.html

http://www.compcams.com/WhatsNew/NewsDe ... 1204901963

Valvoline FAQs:
http://www.valvoline.com/faqs/motor-oil/racing-oil/

***Note that Valvoline, very confusingly, uses the name VR1 Racing Oil to describe three different products which are listed here:
http://www.opieoils.co.uk/vsearch.aspx? ... line%20vr1

Two of the Valvoline oils are different grade full synthetics and the third is a 20w50 mineral oil.

NB Engines with roller camshafts are NOT affected by the reduced ZDDP content because the camshaft contact pressures are much lower than with flat tappets.

Harry,
If you are using a mineral oil then I suspect that the oil is simply getting too hot and very thin after a high speed "thrash", hence the noisy lifters.

some useful advice here thanks. Sounds like the 10 / 40 semi synthetic should not be a problem it may be because I removed the oil cooler & fitted a small spin on fiter on the block. After a long fast run Sunday the car stalled at a rounabout & was push started but hasn't sound right since

I just started to look at oil after my fuel contamination and found this very informed guy on the following forum.

http://www.cobraclub.com/forum/newbies/10175-oil-4.html

http://www.cobraclub.com/forum/newbies/10175-oil-4.html

I would be looking at a 15W 50 fully synth with zddp additive, if there is such a thing. That is with a broken in engine. This guy doesnt talk about zddp but if you want to know what the different atoms of oil look like, this is good stuff.