Additive for unleaded or not?

neilc

neilc

Member
I am sure this question has been asked many times, but as a newby to V8 drving, I am taking the liberty of asking the question again. Recieved opnion seems to be later V8s in the P6 don't require a lead replacement additive, but trawling through the archives opinoins seem to differ, so I am opening this old chestnut again (sorry!).

Thanks

Neil
 
Hello Neil,

You won't unfortunately receive a definitive answer, not even from Land Rover who was responsible for manufacturing all Rover V8 engines from 1972 onwards. So you will need to do what will allow you to sleep at night. It is your decision... :wink:

Ron.
 
Ron is correct, Neil, but for my 'twopenneth' I've done around 70,000 miles on original high compression engines in 2 P6Bs without additives & without problems. 8) You will have to retard the timing a bit, but this may have already been done.
 
I concur with those above. I do think it is a good idea to run at the correct timing position and sort out the octane rating of the fuel to suit with octane booster though. Presuming yours is a 10.5:1 engine then I use two bottles of Millers per tankfull. That's quite pricey but then I don't do that many miles.

As an engineer my own take on this is that the engine ought not to need lead replacement (steel valve seats cast into an aluminium head should already be of the required quality). Plus you get a reasonably long period of grace as the lead used in the past is absorbed into the valves and seats, so there is a "memory" of past lead use. However I've spoken to numbers of V8 "professionals" who insist that lead replacement is necessary! My compromise is therefore to use one bottle of straight octane booster and one bottle of combined octane booster and lead replacement per tank.

Make of that what you will!

Chris
 
yea i uses a oadditive on mine all the time get my from halfords about £13 i think as mine dont get use much it does last for a quite a long time
 
For what it is worth I don't use anything, just unleaded and adjusted timing. I read somewhere
that after a few years the seats become work hardened, so I just got a spare pair of heads and
drove it. The heads are still in the workshop, this was 20 yrs ago the first 15 as a daily driver
and since then only occasional use, now once revived will go back in to regular use.
 
Hi,

I use Millers VSP, I probably slightly under dose as each bottle is designed to treat 40L of fuel and I dump one in each time I refuel and typically I get a bit more than 40L in each time, more like 50 or 55L. It’s pretty low cost in the big scheme of things as my mileage is pretty low. As said above you’ll find any amount of advice out there both for and against its use so you’ll just have to make up your own mind.

Tim

(Edit) Sorry should have said my car is a 74 V8.
 
neilc said:
I am sure this question has been asked many times, but as a newby to V8 drving, I am taking the liberty of asking the question again. Recieved opnion seems to be later V8s in the P6 don't require a lead replacement additive, but trawling through the archives opinoins seem to differ, so I am opening this old chestnut again (sorry!).

Thanks

Neil
Click to expand...

Earlier (high compression) V8's need an octane booster, ideally, for them not to pink under pressure, however later lower compression 9:1's (which yours is) seem to run very happily on super unleaded.

My info from years ago was that any V8 engine after 1970 (there must be something on the earlier engines different) is unleaded compatible. I've not heard of anyone having valve problems on a V8 due to unleaded fuel (although 4-cylinders are a different ball game, particularily 2000TC's)

Cheers
Nick
 
I use Castrol Valvemaster plus in my 10.5:1 CR engine with the timing set at 6 degrees BTDC. I also put Shell V power in it too but I do a lot of miles in my car. I have had to fill up on unleaded a couple of times due to no V power being available and I didn't notice any difference. Not sure what effect prolonged running at the level with low octane unleaded would do but I'm not prepared to test that :)

Dave
 
Just a quick question from a non EU resident....

Do you have only unleaded fuel there, or is there a Lead Replacement Fuel available? I'm merely curious as to how things are in the rest of the world. In SA we have unleaded and LRP (lead replacement petrol) to choose from, hence my query.
 
LRP was available for a few years but is now more or less completely extinct. I seem to recall hearing it wasn't entirely satisfactory?

Chris
 
unstable load wrote,...
Do you have only unleaded fuel there, or is there a Lead Replacement Fuel available? I'm merely curious as to how things are in the rest of the world.
Click to expand...

Hello UL,

Here in Sydney, Australia, LRP has vanished, while on the unleaded front there is 98 octane, 95 octane and E10 which is an ethanol blended fuel which varies from 91 to 94 octane depending on the oil company responsible.

Ron.
 
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