In the old days, life was simple. If you wanted an engine oil for your Tiger, you just popped into your local Halfords or car accessory shop and picked up a gallon of Duckhams or Castrol GTX 20w50 multigrade mineral oil.
With the passage of time, things have become more complicated with the introduction of full and semi-synthetic oils. The really serious problem for all classic car owners in recent years is that of ZDDP (zinc dialkyldithiophosphate), a zinc/phosphorous based compound.
ZDDP is an anti-wear additive which was used in the majority of oil formulations.
Unfortunately the phosphorous content of ZDDP and its associated ash content, have a detrimental effect on sensitive exhaust emission systems.
Modern car manufacturers have therefore insisted that the zinc/phosphorous additive in engine oils should be replaced with other additives.
This has led to many new formulations developed to meet the OE specifications from Ford, BMW, VAG, Mercedes etc., which have reduced levels of ZDDP.
This is fine for the engine of the latest Golf GTi or BMW, but NOT a classic car like a Tiger.
Here is a more detailed explanation from Millers Oils:
http://www.millersoils.net/1_Millers_r_AUTO_ZDDP.htm
http://www.millersoils.net/
Tel: 01565 653658 (Robin Longdon)
There are various important considerations for Tiger owners, especially those with the old style flat tappet camshafts, even if moly lube has been plastered on the cam lobes at initial start up. Even roller cam engines need ZDDP but the contact pressures are so much higher with flat tappet camshafts and therefore the risk of wear/failure is considerably greater.
For a newly built Tiger engine it is essential that the running-in oil is a MINERAL oil containing high levels of ZDDP, NOT a semi or full synthetic oil.
Two suitable mineral running-in oils are Millers CRO 10w40:
http://www.millersoils.net/1_Millers_fr ... RSPORT.htm
or Joe Gibbs Driven 15w50 mineral Break In oil:
http://www.aaoil.co.uk/racing-Joe-Gibbs-XP4
Joe Gibbs products are available from Anglo American Oil:
www.aaoil.co.uk/
Tel: 01929 551557 (Anders Hildebrand)
Email: racing@aaoil.co.uk
There is a lot more information on the Joe Gibbs Driven site including this:
http://www.joegibbsracingoil.com/traini ... toils.html
A company called Fluids in Motorsport Ltd can supply virtually every fluid you are likely to need for your Tiger and also give you sound technical advice. Ian Jacobs, the MD, is a regular HSCC competitor.
http://www.fluidsinmotorsport.co.uk/
Tel: 07913 377802 (Ian Jacobs)
For a Tiger's everyday engine oil with a good level of ZDDP, it depends whether the engine is standard or modified.
For a standard engine the Millers Classic 20w50 mineral oil is fine. For a modified engine it is probably better to use a semi-synthetic race oil such as the Millers CSS 20w60.
Joe Gibbs Driven has a 15w50 mineral oil, HR1, suitable for both standard and modified engines:
http://www.aaoil.co.uk/racing-HR-1
If you require more specific technical information, please get in touch with one of the above contacts.