Rover V8 Engine Oils and Ignition Timing (SumoV8)

['Mendip Wurzel']

On the runout on Sunday SumoV8 and I were talking about engine oils and ignition timing on the Rover V8. I said I would respond with where I had got to on this subject. This may be a bit boring for some so you may not want to read any further:

RV8 ENGINE OIL
I my opinion Silkolene Comp4 20w-50  is one of the best oils for long term protection of the Rover V8 engine. This is a fully synthetic oil providing maximum protection. Rover V8 have a high volume low pressure oil pump which is why a thicker 20w-50 oil is required. Other more traditional 20w-50 mineral oils are fine like the Millers Classic and Halford Classic but at the end of the day they are mineral oils and technology has moved on over the last 20 year. You will notice Silkolene Comp4 is motorcycle oil designed for high revolution engines. This high revolution oil does not froth in the same way as standard oil therefore allowing the RV8 to rev higher. The standard RV8 cam lifters tend to froth from about 5500rpm resulting in partial value lift and a progressive loss of loss of power as the engine revs higher. ZDDP is another important factor in oil selection for older engines.
A lot of modern oils have less ZDDP due to the advent of the catalytic converter. Lack of ZDDP can have disastrous affect of cam wear with an old engine. Silkolene Comp4 is high in ZDDP with more that 1400ppm. Most Classic Mineral oils have around 1000ppm which is a good amount. Any more that 1400ppm is not going to achieve anything.

GEARBOX OIL
For the LD77 type gearbox most seem to be using Castrol SMX-S which is lighter then the historic factory recommended grade and gives smoother gear changes.

SIERRA REAR DIFFERENTIAL OIL
For the Sierra rear differential I use Castrol Driveline 'Syntrax Universal' 75w/90, GL5 Specification

RV8 IGNITION TIMING (3.5L)
Firstly with an Edelbrook carburettor disconnect the vacuum advance because the Edelbrook produces too much vacuum.
Most workshop manuals will tell you that ignition timing should be set at 6 deg BTC. For best performance with the vacuum advance disconnected set at between 14 & 16 deg BTC for the 3.5 litre with 36 deg of total advance. The mechanical advance gives you approx 22 deg of advance. The most important setting is the 36 deg of total advance and not the tick over advance. You need to check the TDC flywheel marks are correct, as they are often wrong. I check TDC using a dial Indicator pushed down through the spark plug hole. You need to mark the flywheel with a BTC mark and say 15 deg and 36 deg.
On a standard engine full advance is usually around 4500rpm. For maximum performance you need a full advance set at between 3000 and 3500 rpm, you can check this with a timing strobe. On the standard distributor to get a quicker advance you need to alter the spring weights in the mechanical advance. Moroso do a GM distributor spring kit which will works on the RV8. With a Mallory distributor the unit should be pre-set for maximum performance  and can also be adjusted

Hope this helps

[Sumov8]

Many thanks this will be of use when I complete an overhaul over the winter

['The Gaffer']

Very informative post

[Krazyken]

Bear in mind that we have a deal with Morris Lubricants where Supporting Members receive 10% off.