Pinking on 4 cylinder engine - Will fuel additive help

A

Adrian - NW1

New Member
I have had the carb stripped and reassembled on my 1971 2000 sc manual (series 2) and the engine tuned / timing adjusted by my local workshop, and although the car now starts, runs and idles much better, it pinks alot, even in 2nd and 3rd as soon as the car is under load. The chap that did the tuning has alot of years in the trade, works on all sorts of old cars etc, though he is not a Rover P6 specialist, and he recons that retarding (?) the timing would help, but performance would suffer. Altrnatively he suggests leaving the timing / tuning as it is but using a fuel additive, like Castrol Valvemaster. Can anyone confirm that my best course of action is to use the additive, as I do not want to compromise the engine performance by retarding the ignition timing if I can avoid it; performance is just adequate as it is, the car having covered 110,000 miles on the original engine, and without a rebuild or major work. Cost of the additive is not an issue for me as currently the car is my 'second' car, basically a hobby, and does not get used much.
 
Adrian,
Make sure you get Castrol Valvemaster PLUS as this is the one with the octane improver - I use it in my 1968 V8 (which was built to run on 5 star) and it's fine with the timing retarded as well.
The cheapest option is to retard the timing and, for normal driving, you probably wouldn't notice any drop in power.
If, like mine, your car originally ran on 5 star then the static timing would have to be retarded to run on the old four star anyway. If it was originally designed for four star then Valvemaster should compensate adequately. Does this make sense, reading it back it sounds complicated? Hope this helps.
Regards, John.
 
John. Thanks. This all makes sense, and ties up with what my local garage / workshop suggested - Castrol VM+. They are fairly convinced that if I run the car on anything but 4* fuel it will in time burn the valve seats, and common sense tells me that a car designed in the 1950s to run on 100 octane fuel will not do well on unleaded thirty+ years later. So, I am going to try the Castrol additive and see if it cures the pinking, leaving the dissy settings as they are for now.
 
One other point to bear in mind is the mileage of the car. If its high you might have a build up of carbon in the combustion chambers which will raise the compression ratio and thus contribute to pinking.
 
Eliseman - car's done 110,000 on original engine, no rebuild or overhaul apart from new engine side plate on both sides, so this would seem to figure.
 
A top end overhaul maybe beneficial. Not only would the build up of carbon deposits raise the compression but it could also cause pre ignition through the deposits becoming incandescant.

Have you removed a 4 cyl head before ? If not be careful to lock the crank using the pin located at the bottom right side of the flywheel housing. Also lock the cam using the key provided which is bolted to the front cam bearing cap. Dont forget to release the tension on the top cam chain tensioner.

You will have to make sure that the bearings and the responding caps, tappets etc are replaced from whence they came.

Lapping in the valves will involve re-shimming the tappets which can be a bit involved.

Good luck
 
I dont know if you are aware of these or not, but hardened (as in unleaded friendly) valves are available from the big P6 suppliers, and I was told when I bought mine that the last 2000 heads were hard enough to take them.

If you dont mind getting your hands dirty its not too pricey (under £100) and teh cars runs well on Optimax.

Matt
 
Thanks to everyone who responded to this query. I have now added Castrol VM+ to the last fill, but it's still pinking alot. However, this is without yet retarding the ignition, which is the next thing to try. Eventually I will get the head taken off and overhauled (don't have any facilities myself so it will have to go to someone who hopefully knows what they are doing).
 
Adrian,
I think that your 1971 2000SC manual should have a 9.0 : 1 compression ratio and was built to run on 4 star fuel this means that the static (or using strobe with vacuum advance conn. blocked) timing will be 4° b.t.d.c. Check your handbook or workshop manual first as I only have stuff on the V8 and am going on memory!
(Watch out for timing marks "wandering" due to play in distributor shaft)
If it still "pinks" then retard in small increments towards t.d.c. until pinking stops. A de-coke may well be in order!
Best of luck and regards, John.
 
Adrian,
Your 2000sc was designed to run on 4star (not 5star) the car should run very happily on super unleaded with the castrol additive. Super unleaded is 97-98 Ron, the same as 4star and if the timing has been set up correctly it should not pink. If you wish to run the car on regular 95RON unleaded, then you will need to retard the timing.
These cars don't need to be decoked, with modern petrol and if the engine is running fine normally, there is no need for a top end rebuild.
 
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