octane boosters

R

rovermorris999

New Member
My 73 3500s has the 10.5:1 CR engine and is detuned to TDC instead of 6 degrees BTDC. It runs happily on unleaded or LRP. In the quest for maximum power (why else have a manual?) I'm thinking of using an octane booster to bring unleaded (or super unleaded) back up to 100 or 101 octane. I've found stuff called Tetraboost, which is the real McCoy, tetraethyl lead in solution, the same as used to be in leaded fuel. The question is...how much more power will be liberated going from TDC to 6 degrees BTDC? Is it worth the expense? I know the V8 doesn't require lead but I would like to have that nice grey deposit back in the exhaust after a long run!
 
Did you read my article in the April P6 NEWS?
If you live near one of the garages that sells REAL 4 STAR this will probably be your best option (as you crave power!) and your ignition could be returned to 6° (degrees) before t.d.c.
Where did you hear that the Rover V8 does not need lead?
The additive that you mention is not on the list of approved (i.e. tested) petrol additives and as such may, or may not, do the job that you want it too. Sorry to sound pessimistic, but you shouldn't take any chances with your (very) expensive engine. Adjust timing on a rolling road to check the amount of power increase.
Hope some of these points make sense and help your decision.
Regards, John.
 
To come to Rovermorriss's defence John, "Tetraboost" IS the lead compound they put "leaded petrol" (so it won't be on the substitute list), you can't buy it in the shops because its so poisonous, you can only get it mail order.
But I air a note of caution Rovermorriss, this stuff is VERY poisonous, do not get on hands, breath it in etc etc, Lead piosoning is acclumative over time as well.

I looked at the stuff and decided it was not really worth the risk and got a unleaded head conversion. I still run high compression but use Aldon or Silkoline octane booster if using so called premium unleaded.
As John said current REAL 4 star is 99 octane (nearly 5 star) apparently.

Get your car checked on a rolling road, with wear and tear the "real" timing will be different to the book, my car on Super Unleaded is running 7 degrees btd, work that out ?
 
I heard via the MG owners club (I think), that Land Rover (or whoever builds the V8) confirmed to them that all V8s since 1970ish could run unleaded.

Van
 
Indeed Veetee, early Range Rovers were sold in California where unleaded has been mandatory since the early 1970's. Apparently, the part numbers for the valve guides and seats are the same as for UK cars, so they can use unleaded. Unleaded was never recommended for UK cars purely for octane reasons.
Also I read an interview with an engineer who worked at Brimax, the company that made all of Rover's ally heads since the war. He said that all ally-headed Rovers would cope with unleaded as the seats and guides were of top quality. Likewise, all Roll-Royce cars can cope with it too.
I might try tetraboost, I'm mad already so a bit more lead won't hurt! You don't have to handle the stuff as it comes in dispensing bottle and a pair of gloves as used for diesel are enough protection. By the way, did you know that benzene, used heavily in unleaded, is very carcinogenic? Every time you get a whiff of fuel these days you get a nice dose of this nasty substance.
 
Tetraboost is OK - just don't overdo it and make sure you wear the gloves when you put it in.

OFFICIAL wisdom is that no V8 pre 1979 (ish) runs unleaded. That said I have heard the tale about the American market as well for engine post 1970 (ish) and also have seen documentation from the company that made the valve seats and valves that looks interesting. I would err on the side of caution and use something.......
 
Does anyone have the parts books for an early RR and a saloon of the same age? I don't think it's a tale. A mate of mine checked the numbers.
The reason it's not recommended IMHO is purely the low octane.
A lot of hogwash has been written about unleaded and LRP, usually by fuel catayst salesmen! LRP was meant to be all doom and gloom and yet I've run (hard too) 2 moggy 1000's on LRP for 1000's of miles with no probs.
 
As far as I'm concerned we had good information a few years ago from Brico, who made the heads, that ALL P6 Rovers are basically unleaded friendly. The only problem is pre-1970 cars with different valves springs I believe. Anything post 1970 should be fine and dandy on unleaded.

Try Shell Optimax for a tiger in the tank. Fantastic petrol. My cars love the stuff. My manual 2000SC has standard timing and doesn't like LRP, let alone on straight unleaded, but goes like a cruise missile with a tank of Optimax. They won't publish the octane rating but I'm well informed it's more than adequate...

Cheers
Nick
 
Just to throw a spanner in the works, i use to own a 1972 (k) reg 3500s, it now rests in the great scrap yard in the sky, only through pure rot may i add.
I use to run it on unleadded fuel, no additive, no nothing, just petrol, and never had a moments problem with it. Well only when coming back from the lake district, the rear suspension decided to part company with the car. That was the same year as pete became editor of p6 news. How long ago pete, it seems like an eternity.
Well i digress, there you go.
Paul. :p
 
Oh bum !!

I wish this conversation had happened last autumn, all that work and cost putting SD1 heads on ! Maybe I could have got away with it. I'll just console myself with the supposed extra umph and being able to buy my sparkplugs at Halfords.
Just for the record, I had read (somewhere) that Land Rover V8's were a different spec to domestic Rover p5/6 V8's of that time, Land Rovers being for export and all sorts of crudy petrol, and civilised Rovers living on a diet of refined 5 star.

On the subject of piosons, Benzene is terrifying stuff too, I once had to look after bottles of the stuff in a Lab, they had BIG warning stickers with words like DEATH on them. Lead Tetra.... is just as nasty and can be absorbed through the skin, I would'nt handle either without big long heavy duty rubber gloves, very good ventilation etc, etc, also keep in a secure place. Diluted in Petrol is bad enough, concentrated is worse !
 
I think the L-R engines were just a lower compression ratio to cope with the lower octane fuel. Think of all those old landies with the overhead inlet, side exhaust valve engines, let alone V8s, pottering round the old empire rfrom the '50's on. No decent fuel there in those days (or perhaps even now) and they worked fine.
As an aside, I have an old Ferguson tractor, with a low compression version of the Standard/Triumph engine found in the Vanguard and 2000 etc. It runs on petrol or tractor vapourising oil which is no longer available. But you can mix your own:
1 part diesel
1 part petrol
3 parts home heating oil
plus a dash of 2 stroke.
You have to start on petrol, but once warm it runs fine on this stuff. No lead in there, but the engine is only 5:1 CR
 
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